Fixing another Fostex R8

Today I am fixing another Fostex R8 from a customer. The problem was that the plastic capstan wheel was slipping on its axis, and the spooling motor wheels did the same. This is a common problem with these decks. The Fostex will not play and/or spool correctly then.

Fortunately, John from makes aluminium replacements. These fit tightly on the axis and can be fastened with a screw.

aluminium capstan wheel replacement
aluminium spool wheel replacements

I also replaced the belt. Now, the deck plays and spools perfectly.

A small problem

But unfortunately, one problem remains: the arm on which the right tension roller is mounted, has got a fair amount of play, maybe caused by a blow or something.
This is causing the right tension roller to guide the tape in a skewed position. It is not a show stopper, but it is certainly not ideal for the tape path.

Calibrating a Studer B67 for a Mastering Studio

Recently I got in contact with the owner of a Mastering Studio. He owns a Studer B67 and had a problem with it regarding calibration levels. He wants to use the B67 as a ‘bounce to tape’ device to get the tape compression-effect. And there was also the problem of randomly dropping levels when calibrating.

When I got the deck I could replicate the problem with the levels. I It seemed weird to me, but I suspected that the REC AMP cards, or maybe the Power Supply was faulty.

The deck had been fully recapped and serviced before. And I can say that the person who did that did an outstanding job! No complaints whatsoever.

I spend a lot of time diagnosing the problem, measuring every aspect of the deck, checking pots, solder joints, etc. etc. whatever I could think of.
I found one shorted tantalum cap in one of the REC AMP cards, but I wasn’t sure if that was causing the problem. The card was functioning normally. I replaced the tantalums for quality elec. caps.

After a lot of testing, the problem seemed to have gone away, as I could not replicate it anymore. It could very well be that the initial tape used to test the deck with, was not performing as it should. Anyway I tested the deck with my own BASF 911 tape and I found no problem anymore.

So I continued with the second item on the list: recording the middle speed of 19 cm/s with such a high fluxivity that tape compression could be achieved easily without over-driving the input chain too much.
At the end I put the slow speed ~@320nWb/m, the middle speed ~@510 nWb/m, and the fast speed also at ~@320nWb/m, as per the customer’s wishes.

These are the frequency sweeps: 9,5 cm/s

19 cm/s:

38 cm/s:

The Studer A810

Of course.
So I just got my Studer B67, from Germany, and I was still very much enjoying it, when the opportunity arose to buy a Studer A810. I know. When it rains, it pours.

The Studer A810 came from a company that services professional studios all over the world, and has been in their possession for a number of years and was still in use regularly. So it came with a bit of assurance that it would be OK. It had been recapped and kept in good working order.

The price however, was very steep. So that price, and the fact that I had júst gotten my B67, made me hesitate to buy it. I doubted a lot, and then some more, but I finally took the plunge and did it anyway. I did it also because in 2014 I bought my Studer A80 also at a (then) high price, but that price is now a joke. It’s nothing. It is worth so much more now. And I never ever regretted the purchase.

So then it was a matter of getting the deck. It is a bridged version, which means that the deck is in a console with an overhead VU-meter bridge attached. It is a complete package, but it is also a challenge to transport. Luckily the company that I bought it from, offered to bring the package to my home in their truck. They often have to do this I suppose in their line of work, which is servicing studio equipment.

Package for you!

So a few days before Christmas 2021 a big yellow truck pulled up on my driveway and 2 guys stepped out. I was very excited as they wheeled the A810 into my garage.

We had a nice talk about it and taperecorders in general. After they had gone I wheeled the deck into the living room, because, as it was a cold damp day, the deck needed to be acclimatized before turning it on.

The first power-up

So the next day, after having spent the night in our living room, and being all warm and cozy now, I dared to turn the A810 on for the first time. You only get this feeling once! After loading a tape I plugged in a pair of headphones, as I have no equipment to hook it up to in the living room. I have a nice tape that is recorded on my Studer B67 that sounds great. The deck and the tape did not disappoint!

I played around with it and I was pleasantly surprised at the smoothness of the tape handling. I got myself familiar with the keys on the keypad and their functions. I loaded some pancakes to try out, and that too was very enjoyable.

I was a bit disappointed because there are 2 headphone connections, one in the bridge and one in the deck. The one in the bridge turned out to be mono, and the volume of the connection in the deck was way too low to be able to listen to the music at a normal level. I could of course do that upstairs, but that would have to wait a bit until we managed to get the console upstairs.

Then, I was very curious to find out about the various cards in the machine. I opened the flap, or tray or however you want to call it, at the bottom of the frontpanel with a hex key and found this:

From left to right:
MPU Unit 1.820.780.82
Tape Deck Controller 1.810.750.81
Periphery Controller 1.810.753.00

channel 1:
HF Driver 1.820.713.00
Record Amplifier 1.820.712.81
Reproduce Amplifier 1.820.710.83
Line Amplifier 1.820.714.83

HF Driver 1.820.713.00
Record Amplifier 1.820.712.81
Reproduce Amplifier 1.820.710.83
Line Amplifier 1.820.714.83

Upstairs at Philip’s

After a couple of days, it was time to move the A810 upstairs. For that I removed the A810 from the console and transported the deck and the console separately because of the combined weight. Separate it was doable.
In my ‘studio’/’mancave’/’hobbyroom’/’repaircenter’ I could finally listen to my new Studer and appreciate the sound through my headphones at a normal level, using the MAckie 24.8 output, and over the loudspeakers (KEF) at room level. Again, it did not disappoint!


Time to do some test recordings. The recorder was calibrated on SM900 for 38 cm/s for Tape A setting. I used my FiiO K5 Pro Digital Interface to play 24/96 tracks from Yello, Steely Dan, Dire Straits, and also some other less audiophile artists.
Later I also did a test recording from my Pioneer CD player which has XLR outputs directly to my A810. I have installed the Pioneer in the 19-inch rack that is located in the console below the A810 recorder, so now it is easy to connect them for a recording.

Tinkering and maintenance

After a few weeks, after getting really comfortable with the deck I was able to reprogram some of the keys on the deck to a different function. The Studer A810 makes that possible, and now the button layout is more intuitive for me.
So I now have 2 memory slots for tape location.

A slight problem

After a few months the deck developed a problem. When it was idle, sometimes out of nowhere the clapms on the tension arms would engage and release immediately, and that clicking would occur a few times. Also, the PLL light indicating capstan speed would blink on occasion.

I contacted the seller, who has a repair business for professional studio tape gear, and he suggested to look at the connectors and the settings of the tension arms. I investigated and found nothing wrong at first sight, but I started to calibrate the left and right tension rollers nevertheless. I quickly discovered that I needed some special Studer gauges for the adjustment. These were, of course, nowhere to be found and/or very expensive to get hold of.

Fortunately, there was a close up photo of such a gauge on internet. I found the correct dimensions and adjusted the image and made my own version in a CAD-drawing program. You can print it out and use it to adjust the left and right tension arm according to the official service manual. Here it is:

You can find the file on my site, in the Studer section, Documents, A810.

After adjusting the tension arms and checking and securing the connectors on the hall sensors the problem did not occur again. Oh, and I had to adjust the position of one of the sensors for it to work correctly.

Calibrating Tape B

When I got the A810, only the Tape A / 38 cm / CCIR setting had been calibrated, to SM900 @ 410 nWb/m. But I have a lot of AGFA (BASF) PER528 tape that is very good and that I would like to use. So I took the manual and started calibrating for that tape.
The Studer A810 has 2 settings: Tape A and Tape B. It has 2 EQ curves: NAB and CCIR and it has 4 speeds (9,5 – 19 – 38 – 76 cm/s). That gives a total of 224=16 possible combinations, each of which can and has to be calibrated separately.
I say that now, but it is not entirely true. Some settings are the same for NAB and CCIR, like low speeds.

Now I won’t go into the details of the complete calibration, because that would far exceed the purpose of this blog, but it involves setting the parameters into the computer instead of twisting pots like in other conventional tape machines. I will probably do a video on that in the future, so follow my Youtube channel to be able to see that.

I also made a handy spreadsheet (or paper sheet), where you can manually enter all the data that you store into the memory during calibration, or, if you wish, read all memory data that is currently stored and fill it out on the sheet to have it handy for when that data might be lost. You can find that on my site as well, in the Studer section, Documents, A810.

While I was calibrating the Studer A810, I also made a short summary of the calibration steps from the Service Manual. This is much easier to handle than all those pages from the SM. Again, you can find that on my site as well, in the Studer section, Documents, A810.

Replacing eproms.

The Studer A810 is a computerized deck, that means that it has a microprocessor built in. In this model it is the Motorola 6803. A microprocessor always follows a program, which in this case is built into an EPROM chip.

It is called the firmware. This was common practise at the time (1983). When the unit is turned on, the display will show the version of the firmware. Newer firmware version were issued by Studer later in the production cycle of the A810 and they fixed small bugs and had little enhancements. The firmware version 01/88 is considered the best and latest, firmware versions that came after that were merely fixes for synchronizers (to sync the tapedeck to other decks or to SMPTE timecode).

So I wanted to upgrade my firmware from the version I had which was 13/83 (week 13 1983) to that 01/88 version. Newer EPROM chips could be obtained from sellers, to replace the chips on the MPU board (containing the microprocessor), but they were expensive and I really wanted to burn the chips myself. Also I wanted to be able to later offer this service to other deck owners. We got to help each other, right?!

So I bought an EPROM programmer, an UV-light eraser and some empty EPROM chips. I obtained the files for the new 01/88 firmware from a well known American Studer professional and successfully managed to burn my own EPROMS.
I made a video of that which you can find here:

A Fostex R8 multitrack 8tr. dolby C 38cm/s deck

So I could purchase a Fostex R8 cheap. The unit was supposed to be in a fairly good working condition, maybe a few scratches on the front. The price was that good that I could not walk away from it. Besides, I always wanted a Fostex. Just because.


This deck is squeezing 8 audio tracks onto a standard 1/4 inch tape. To put that into perspective, normal home audio deck use 4 tracks (2 -> and 2 <-) and the professional world uses just 2 tracks onto that same width of tape. So the tracks are super small. To compensate for the loss of fidelity and the added tape hiss the speed at which the tape runs is fixed at 38 cm/s or 15 IPS (cassettedecks run at 4,75 cm/s). Also, the deck has Dolby C. Dolby C comes from the cassette world, it is an enhanced version of the omnipresent dolby B and it works quite well on this deck. But I’m getting ahead of myself.

The deck, being one of the very latest generation of tape deck being made, is heavily computerized. Not for the calibration electronics, like the Studer A810 and all Studer models beyond that, but in the controls. There are a LOT of possibilities and functions that I have not even tried tried yet.
When the deck is turned on, the display shows a scrolling text of ‘FOSTEX’.

First impressions

When I got the deck I first cleaned the outside. I like to work on a clean deck. This one was not dirty, but sometimes you can get a lot of dirt off decks you collect. After that, I cleaned the heads and the tape path in general. I noticed the very plasticy rollers and the flimsy arms. Also, the roller covers were coming of way too easy. Hmmm, not so good.

I put a tape on and the deck played. So far, so good. Rewind, fast forward, no problem. The capstan was noisy however. I played around with it and decided to try recording. I was NOT disappointed with the sound quality. I was surprised how well it sounded on playback. I tried several channels and it seemed ok. The dolby C noise reduction really took away tape hiss in quiet passages and in between tracks. Just like on cassette decks.

Capstan wheel

After a while I noticed that the tape speed was dropping a little. It was ok after a while, but just after hitting PLAY it was not good.
And after a little more testing, the tape was not moving at all anymore. Even pressing the pinchroller to the capstan did not work. I noticed the capstan was not spinning anymore. When in STOP, the capstan would slowly start spinning again. Only to come to a quick stop once I pressed PLAY. But I could hear the capstan motor spinning constantly. Weird.
I had already ordered a new capstan belt, as is almost always necessary when old rubber belts are involved, so once that had arrived I put it on. But, unfortunately, that was not a solution. I found out that the wheel attached to the capstan motor shaft was slipping. It is a simple plastic wheel that had come loose from the shaft, probably because it had worked itself loose after being clamped on in the past. But now the wheel was just stationary and the shaft of the motor was spinning because of too much room inside. (blowfly pun intended)

Tascamninja to the rescue

I tried to glue the wheel to the shaft a couple of times using instant glue and some stuff that had worked great in the bathroom glueing shelves, but after a short while the wheel came loose again. I had to bite the bullet and order a replacement wheel made out of metal from the website
I could not play any tape, or do some more tinkering while waiting for the arrival of the metal wheel, because the slippage was such that the capstan did not move at all anymore.
It arrived in about 2 weeks time, and as soon as I put it on, the tape speed was super reliable and super constant. Very happy with this solution!

recapping audio cards

I did do something in the meantime however. I recapped some of the audio boards. Although this deck is one of the last reel to reel decks to be made, it still has 40 year old capacitors in it, so the cards could use some fresh ones. But first, I had to get these cards out. Noone on the internet that I found managed to get them out, or, at least, did not mentioned it at all. Also the manual and the Service Manual had no mention of this removal. I was beginning to suspect that maybe they weren’t supposed to be removed.

But, eventually I managed to pry them out. They are just on connectors on a backplane, so definately supposed to be removed..

Knowing that I had to recap 8 boards, I made a document to use as a Quick Reference Guide with some handy info on the location of the caps and their value, the location of the pots for calibration, and the complete summary of the calibration procedure. I made it along the way as I worked on the deck.
The document is available at my site at: R8/
You can find the latest version there.

After recapping I started to go through the calibration procedure. It is very labour intensive, doing everything 8 times, but the 0-locate-and-auto-play function of the Fostex is a very handy feature. But then I found an even better feature: you can repeat a section of the calibration tape endlessly. To achieve that, do the following:
– press CLR
– type timecode of beginning, like 0000 and press STO and then the number of the position slot you wish, like 1
– press CLR
– type timecode of end of the fragment, like 29 and press STO and then the number of the position slot you wish, like 2
– press CLR
– type ‘1-2’ and STO. display shows 2-1.
– make sure you play the section and the deck will automatically repeat the section.
I type this from memory so I hope this is correct 🙂

Testing after calibrating

I tested the sound quality when I was done and it sounds very good!

This is a sample from playing the calibration tape. But recording a sweep to 18kHz resulted in an equally straight frequency responce! (I forgot to take screenshots)

I recorded a youtube video where you can listen to a sample. You can find it here:


DCC Quick Reference Guide to recording

Start new recording (completely overwriting a DCC tape)

To initialize a new or used tape.

-bulk erase your tape (if applicable)
-rewind to beginning of side A
-press APPEND
-the deck will now do its magic and write a LEAD-IN and put itself in REC PAUSE
-check levels on meters and adjust recording level (analog input only)
-press REC/MUTE to start the recording

-bulk erase your tape (if applicable)
-select side A
-press REWIND (|<<)
-the deck will now do its magic and write a LEAD-IN and put itself in REC PAUSE
-press SELECT/PAUSE for the correct source, and check for the correct levels on an analogue source (press TIME 3x)
-press RECORD to start the recording

-bulk erase your tape (if applicable)
-select side A
-press REWIND (|<<)
-the deck will now do its magic and write a LEAD-IN and put itself in REC PAUSE
-press REC SELECT/PAUSE for the correct source, and check for the correct levels on an analogue source (press TIME 3x)
-press RECORD to start the recording

Start New Side Marker(730/951), Next Mark(600) (with rewind), also called ‘Dual Album Format’ or ‘Start New Side’

This marker makes the tape switch from A to B and then REWIND to the beginning of side B.
Track numbering starts with track 1 again on side B (independent track numbering per side).

-press REC PAUSE
-press MARK WRITE (NEXT MARK is written and tape spools to beginning of side B (A to B) and writes LEAD-IN MARK)
-continue the recording by pressing REC/MUTE

Bonus – to make tape rewind to beginning of tape after the last music track finishes playing on side B:
-during recording, after last track on side B has finished, press REC PAUSE
-press MARK WRITE (B to A)
-Tape winds neatly to beginning of side A.

When in REC PAUSE mode or in STOP mode, press EDIT key and select START NEW SIDE and press RECORD to actually edit the tape. The START NEW SIDE marker is written on side A and the tape will spool to the beginning of side B (starts again with track1!) and write a LEAD-IN.

Reverse Marker (no rewind), also called ‘Single Album Format’ or ‘Continue B’

This marker makes the tape switch from A to B immediately but does NOT REWIND to the beginning of side B.
Side B is marked immediately with the next track number (continuous track numbering).

-press REC PAUSE
-press SIDE A/B (REVERSE MARK is written). Tape switches to side B and enters PAUSE mode
-continue the recording by pressing REC/MUTE.

-when in REC PAUSE mode or in STOP mode:
-press EDIT key and select CONTINUE B
-press RECORD to actually edit the tape.

Split, Connect or Renumber tracks (DCC730), START MARK, MARK ERASE or Renumber (DCC600)


  • When in PLAY or RECORD, press MARK WRITE to write a START MARK.
  • When in PLAY, press MARK ERASE right before the marker to be deleted.
  • To renumber, press RENUMBER.

When in STOP mode, press EDIT key en select SPLIT TRACK, CONNECT TRACKS or RENUMBER DCC. Press RECORD to actually edit the tape.

Make recording from CD to fit side A and side B

press EDIT, EDIT and select tape length with |<< and >>| keys (or type length with number keys) and press EDIT.
The display will show the number of tracks for side A and the time.

How to record from various sources on a Philips FW68

Philips FW68 DCC Mini HiFi System

When recording a DCC on this cute little Philips set, there are some questions and challenges.
There are three little preset buttons on the FW68 that let you do CD -> ACC, DCC -> ACC and CD -> DCC recording. But what if you want to do something else?

You can record from ACC -> DCC, and also from TUNER -> DCC or TUNER -> ACC, but you can not use one of those three little preset buttons for recording.

How to do this:
Suppose you want to record from ACC -> DCC.
-put the ACC and an empty DCC in the machine
-rewind the DCC
-press REC PAUSE on the DCC part
-RECORD is shown in the display, the DCC player starts writing the LEAD IN etc., just wait a while until that is finished
-press PLAY on the analog deck and PLAY on the DCC deck
-A recording will be made from ACC to DCC.

The same procedure for recording from TUNER or AUX to ACC or DCC:
-press REC PAUSE on the tapedeck
-press TUNER or AUX
-and press PLAY on the tapedeck.
This works with the analog and the digital cassette deck.

Make a CD fit on sides of a DCC for recording.
-prepare the CD and DCC (or ACC)
-press EDIT on the CD | C-60 appears
-press NEXT to select the correct tape lenght
-press EDIT to confirm
-press CD -> TAPE or CD -> DCC to start the recording.
Pressing PROG REVIEW to show time.

You’re welcome.

P.S.1: ACC stands for: Analog Compact Cassette, the old, well-known compact cassette in contrast to the Digital Compact Cassette.
P.S.2: The DCC side can playback DCC and ACC (though NOT recommended), but can only record DCC. The ACC deck can record and playback ACC’s only.

Another Studer Tapedeck Has Finally Arrived! The Studer B67 Mark II

So, I got myself another Studer. This is the Studer B67 Mark II. It is in very nice condition. The model was introduced by Willy in 1975, and it is the first model that came out after the famous A80 (that I also have, which was introduced in 1970) and it is more compactly build. It has been in production until 1989. There have been 18 version of this model produced throughout the years. It was very popular with the BBC who bought a lot of units.

It is quite a heavyweight with 35 kg. I really like to handle it with two persons 😂. I have the Mark II version with the VU meters built-in.

The B67 MK2 offers the following additional features:

  1. Easier access to the tape heads for better marking and cleaning
  2. Improved editing: The tape tension sensors are mechanically blocked in stop mode, at the same time the brake moment is automatically reduced.
  3. Tape lifter defeat in wind mode. Both push buttons “fast forward” and ”rewind” must be pressed simultaneously in order to activate the ”defeat“ function. After this initial activation, one push button (< or >) must be constantly pressed to maintain the defeat function. This is not possible from
    the remote control.
  4. Spacing of the spooling motors has been increased. This allows the use of 282mm (11.1 inch) spools or up to 1000m (3281 ft) of tape.
  5. Tape tension adjustments are accessible from top (front, next to audio adjustments).
  6. Drop out of record mode when pressing play.
  7. Dump editing mode (spooling motor off) is improved: counter stops automatically (jumper selectable); motor off can be activated in all modes.
  8. Reproduce amplifiers have an additional filter which rolls off frequencies above 20 kHz. This results in a better noise figure.
  9. The timer roller mass has been reduced and the roller is equipped with a ball bearing.
  10. The audio basis board has been completely modified. The positions of the stabilizer and of the pilot amplifier have been changed. Most wire harnesses are of plug-in type and the connectors are easily accessible on the right—hand side of the basis board.
    Connectors are provided for: VU meter panel (2 CH or mono), mono/stereo switch, safe/ready switch, monitor amplifier, pilot tone connection.
  11. The power cable to the mains switch is soldered onto the logic board. A coded connection is provided at the power supply.
  12. The recorder has been modified according to the IEC recommendations.

This is the 2 track halftrack with butterfly heads. 3 Speeds (9,5 – 19 – 38 cm/s).

I got it from Germany. It came very well crated.

It has been one and a half year in the making before the deal could be finalized, because of all kinds of circumstances, including COVID-19 related stuff. But, it is finally here and I am really happy with it. I got it from a guy who has his own studio, and the guy (as I will call him) had already recapped the deck and replaced all suspicious parts throughout the machine (power supply etc.) and replaced bad parts (pinch roller) and adjusted and replaced the brakes.

He also, as a service, has calibrated the B67 perfectly for my preferred tape – AGFA/BASF PER528.

Everything is nicely organized in insertable cards.

There are a lot of possibilities in this deck. The tape path and the tape handling are super smooth.

And it sounds wonderful! The guy I bought the Studer from supplied a tape that was recorded in his studio and that tape sounds very, very good.
I have put the Studer B67 in a trolley now to be able to play pancakes.

It is a very nice, and very welcome addition the the family!

Here’s the video:

Treating old DCC tapes for the first time

When you receive one or more DCC tapes of unknown origin, you have to assume that they have not been used for a very long time. This means that you will have to treat them in a certain way, even before putting them in a deck or playing them.

Why, you ask? Because the tape has been sitting still in its shell for a long time in the position that it is in now. It has become deformed at the place where it is guided along the heads. And even worse, there is a sticky residu that has formed on the back of the tape where there are two internal felt pads inside the cassette. I am not talking about the felt that is opposite the head. These felts are inside and can not be seen, unless you break open the case, and this can not be undone.
These two felt pads have started to ‘leak’ a sticky oily substance onto the backside of the tape in the place where they touch the tape. That sticky bit will prevent the player form playing beyond that point, because well, let’s say it slips and cannot continue. It will either stop or go to the other side continuously. Until you fix this, the tape will be unplayable.

So now you know why you will always have to resist the urge to play them right away to hear what is on them, and follow this procedure.

The steps.

  1. So you will have to carefully pull the tape out. Be careful not to crease or rumple the tape, because that will surely create a dropout on that spot. To be able to do that first you must get the protective aluminium slider out of the way. Open it manually and place the wood part of a cotton swab into the round hole that has just opened up. It will fit almost perfectly and it will hold the slider open.
  2. Then, carefully pull out a length of tape of about 30 cm or more, making sure that you get tape from both reels. I use a pair of bent tweezers for that. Lay the tape flat on a white clean soft surface, like a piece of paper, with the shiny side down. The shiny side is the side that the DCC head touches, where the magnetic information is. But the gunk is on the backside. Lay the tape so that you are now looking at the matte back coated side. You may need to use some tools to hold the tape in place, I use two erasers, they are heavy and soft enough to hold the tape down.
  3. Now, and this is hard, look for some sticky residu. It will be hard to see, I use a desktop light and/or a handheld flashlight to find them. These patterns may also repeat at a ~10cm interval, so look up and down the length of the tape that you have pulled out the casing.
    I tried to make a picture:
  4. Once you are able to see the problem area clearly, take a cotton swab and put some alcohol 96% on it and gently rub the backside of the tape. Do it gently as not to crease the tape. Rub very carefully but firmly up and down the length of the tape. Once you have done this a few times, you will get the hang of it. Make sure all the gunk is gone. Let the alcohol on the tape dry for a minute and check again and repeat if necessary.
  5. Once you are satisfied with the result, you should see an even back-coated surface with no spots on it, and you can carefully manually rewind the tape into the housing using a pencil or the end of the cotton swab or as I do with the tweezers. After the tape has been carefully stored back into it’s shell, only then you can remove the wooden stick and close the lid, not sooner.
  6. The tape has been cleaned, but the third felt pad (yes the one opposite the head) needs your attention now.
    I can not explain it better then Ralf did in this video:

Now you understand why it is vital to not wind DCC tape when you first handle them and not put them in a deck first, because the deck will spool the tape a bit and after that you will have a hard time finding the greasy spots.

The 2 felt pads will of course still continue to shed oil a little bit, so always rewind tape after use. You will never know when you are gonna use it again, could be years from now.

See also my older post:

Install acestream in openSUSE Tumbleweed

If you are like me and watch a lot of TV streams using acestream, you had the problem that there was no Linux client. So you had to use a window$ PC for that (with all the hassle that brings) but we don’t want that.

So I resorted to using wine for that. And that works beautifully. But the hope remained that it would be possible to run it native on Linux. I have found out how, and here are the instructions for tumbleweed:

install the acestream packages

First, we add a repository where the acestream software is to be found. Then we install the latest beta version of VLC, and then I will show you how to start it all.

# zypper ar -f acestream-repo
# zypper in acestream-engine acestream-launcher

install vlc

This next section is not necessary, you can skip that if you already have a working VLC.

The reason that I install the latest VLC -beta is because in the future I hope to stream to my chromecast. The latest VLC *should* do the trick, but here it is not working yet. Anyway, I installed and use the vlc 4.0 beta version.
You will have to get it from the packman repo, so if you haven’t already added it, do it now:

# zypper in vlc-beta

In order to satisfy the dependencies, you will have to agree with de-installing the regular -installed- VLC version.

how to start

And now for the real stuff. To start it all, as user do:

$ acestreamengine --client-console

and leave the terminal open. In a new terminal console do:

$ acestream-launcher -p vlc acestream://67665adae9b7535a10f7b7a22d43f15683e78bde

The VLC player will open and after a short while (hopefully) the stream will start playing in the vlc window. And of course you substitute the acestream-id in this example with the one that you found for your stream.

Happy viewing!

P.S.: the instructions in this article worked as of 26/8/2018

updated 30/8/2018 for typos.

A New Member of the Family: Otari MX-55 N-M

So, the inevitable has happened……….again.

I have bought myself another piece of studio equipment to live next to my Studer. I got myself an Otari MX-55N-M

This one I discovered in Belgium. Yes, down there. It came originally from a guy with a small studio who sold all his stuff, but I got it from someone who bought some records from that guy and got the Otari as a side catch.

Getting it from Belgium required a road trip. In about 2,5 hours we were there, it was actually not too far across the border. The place was a 2nd hand vinyl shop with a lot of records, but it had CD’s and DVD’s too. Oh, and comic-books, like Suske en Wiske.
The Otari was all dusty and just a little bit dirty, but not much. I brought a test tape that I had recorded with my Studer, as this is also a 2-track studio machine. I loaded the tape, plugged in my headphones and after fiddling with the knobs (how to put this thing in playback mode, and how to get signal from it) I got some sound from it and boy, did it sound good! Within a few minutes I knew that the sale was going to be made. I just had to do a quick check for any defects that I could find and if they would be a showstopper. I could not find any.

So then came the problem of transport. My car has a loading space with a flat floor that is 70 cm high and 100 cm wide. But the machine is with a cart and wheels and a meter bridge, as you can see from the pictures. We measured the Otari and thought: well, I may fit just laying on it’s back. And it did. So I didn’t have to dismantle the meterbridge or take the machine from the cart. That was good.

After we got home I cleaned it up. From beneath the layer of dust came a beautiful and almost pristine looking deck that has no marks on it of prior use. I started to play with it and explore it’s possibilities.

  • the deck is tilt-able in various positions.
  • it has a selection switch for 2 standards: NAB and IEC.
  • it has another 3-way switch for selection of the reference fluxivity. I found that mine is calibrated to the following setting:
    • LOW – 250 nWb/m
    • MED – 320 nWb/m
    • HIGH – I don’t know, I haven’t got a calibration tape in that range. It will probably be around 510 nWb/m.
  • high and low speed is now set to 19 & 38, but can be adjusted to 9,5 and 19.
  • has a built-in oscillator with test tones of 0,1-1-10 kHz for bias calibration.
  • reel size is selectable for LEFT and RIGHT reel separately.
  • Slack tape can be picked up by pressing STOP.
  • in- and outputs are fully XLR and +4dBu.
  • the speed is adjustable from veeeerrryyy sllllooowww to very fast.
  • Startup is very quick, 1-2 cm at 38 cm/s and its up to speed.
  • Digital tape counter hms with goto and 3 memory positions.
  • Recording and playback levels are adjustable at Standard Reference Level (SRL) or user controlled with a knob.
  • Tapedump function, where the takeup reel is switched off so the tape is dumped.
  • Button for listening (cue-ing) while spooling.

This is what I found so far. It came with a remote control with 10 meter cable, 2 Otari NAB adapters (which are very well built), and 2 aluminium reels.

I noticed that the left tape roller is making more noise than I would have liked, but it works ok and someday I will replace it. The heads are ok.

I am very fond of the smooth tape transport and the overall robustness of the machine. This Otari really is meant for heavy duty studio use.

I have not measured anything except for the fluxivity levels yet, but I expect the results like wow/flutter, distortion, frequency response etc. etc. will be very good. This will make a nice younger brother to the Studer.

Oh and by the way………..

I am looking for the manual, service manual and schematics for this MX-55 N-M.
I have found manuals for other models of the MX-55 family, but not specifically for the N-M. 

I found some manuals online, but they only contained the first two chapters.

So, if anyone know of these manuals, either in printed or electronic form, I would be happy to get hold of one. Please leave a message in the comment section.

Philips EL6021 elektrodynamische microfoon

Recently I got a Philips EL6021 mic:

It has the following specs:

Since the cable that came with it was unbalanced and noisy, making the mic rather useless, I decided to rewire the cable to make it balanced so I could connect it to my Mackie 24.8 mixer.

Some reverse engineering led to this diagram:

The connector can be fitted in each of three positions, giving the microphone 3 different impedances. See the side of the connector on the mic for the details.
It is absolutely noiseless now and it has a surprisingly good audio quality!
If you have any questions or remarks, please do not hesitate to ask me.

PM2505 electr VAΩ meter Philips transistor list

This is the transistor list inside the PM2505:

BC548 2x
BF256A 3x
BC549C 2x
BC558 1x
BC559 1X

In case you need to replace them 🙂

I replaced almost all of them in an effort to fix my multimeter. It did not function anymore. When I turned on the meter, the needle would go straight into the far right corner and do nothing, whatever the dial or switches setting.

After replacing the transistors and 2 caps that are on the board, I assembled it and when I wanted to test it I found out that one of the small metal balls that operate the function switch Volt-Ampère-Ohm had come loose and was freely inside the case. This is not good of course.

So I secured it in the correct place, the function switch is working as it should and the meter is also functioning perfectly! Happyhappyhappy!

Latest acquisition: AGFA Bezugsband 9,5 DIN 45513

Just a quick post about my latest acquisition: an AGFA Bezugsband 9,5 DIN 45513.

Some pictures here:

I think it was made in 1967, which is a good construction year 🙂

I came with some documentation, which I will post here for reference and archival:

Funny the documentation mentions 250 pico Weber per millimeter track width, where nowadays we use NanoWeber per meter.

Also, much use is made of time constants like 3180 µs, which corresponds with 50 Hz.

The tape appears to be in very, very good condition.

DCC digital compact cassette tape length identification

Sometimes, for instance when there is a sticker on top of the text that says whether it is a DCC90, DCC75 or DCC60, you have to guess the tape length.

Not anymore. I have created this diagram that show you just how long the tape is by looking at the casing (backside):


It is really silly, some brands (hello BASF!) mention the length of the tape only once on the casing, and that is exactly where normally a title sticker would be placed. By looking at the diagram, you will no longer have to guess. The black circles in the drawing are holes in the casing.

DCC90 would mean 45 minutes on side A, and 45 minutes on side B, totalling 90 minutes. In practice, there will always be a few extra minutes of tape in the cassette. This goes for all the formats.

DCC75 is a bit strange, it was also not used in normal analog compact cassettes, but it would gave you 2 times 37 1/2 minutes. Not quite sure what the reasoning behind that was.

DCC60 is 2 times 30 minutes.

Have fun with it!

Walhalla Symfonie PvdM

In the early 1980’s Dutch public radio featured a program called ‘Walhalla Symfonie’. It was described as ‘an acoustical listening trip’ (translation).

The program duration was one hour, broadcasted late in the evening. Only 34 (+4) were ever made. It basically was music, sounds, quotes, experiences etc. all put together into a one hour composition. It had a strong influence of electronic music. And every one of them had a theme. The series also had a leader tune, created on a synthesizer.

I remember some of them from my childhood. It was an exciting experience to listen in the dark (sunday evening 23:00) with your headphones on to this broadcast on the radio. Recently I found all of them on the internet, downloaded them and I again enjoyed listening to them. They have a unique atmosphere to them.

This triggered me to make one myself. So here is my attempt to make a Walhalla Symfonie!
It is much shorter, around 20 minutes. And it has a different feel than the originals had, mine is less experimental, less far out there, more mainstream. But I think that it is agreeable to listen to as a listening experience. So, if you have 20 minutes to spare, take a listen and let me know what you think! (quality headphones and a relaxed listening environment are strongly advised)

fixing DCC audio cassette tape

A box of DCC tapes

I have lying around a box with +/- 50 used DCC tapes that I purchased a while ago. DCC is the Digital Compact Cassette, invented by Philips. I have gone through them all, I listened to some of the tracks on each tape and sorted which ones I wanted to keep because of what was recorded on it. But most of them could be recorded over.


In my youth I had the privilege to experience the evolution of the compact cassette (CC), also a Philips invention btw. It had just made its way from dictafoon-like devices to the hifi/consumer audio market. And I witnessed its rise to a high end audio device (Nakamichi et al.). I have lots of CC tapes, probably my entire youth is recorded on those.

Then, in 1992, DCC came. But by that time, I had lost interest in recording music, or audio as a whole for that matter. So I never really noticed at that time. Also the Sony Mini-disc and DAT recorders went completely past me.

But when I rediscovered my audio hobby around 2010, I got very interested in these three now obsolete recording techniques. And fortunately you can get these devices rather cheap these days.

My Philips DCC600

I have all three devices now.

DCC surprised me in a very positive way. I got the same, familiar feeling playing cassettes that I had back then and that I had gotten used to. Also the deck that I got feels very solid and tape handling is direct. The DCC cassettes themselves feel very, very well thought about. Even the casing and the jewel box is outstanding well designed, even more so the prerecorded tapes.
On top of that, you get CD like audio quality. I say CD like, but I dare you to hear a difference. I was very, very impressed with the whole concept. In hindsight I wish I had used it back then.


I noticed when I went through the lot of old tapes however, that some of the DCC tapes were making a squeaking sound when they were played. And some of those would not play at all. The deck, just kept clicking, the drive mechanism reversing a few times, before finally giving up. So I thought that these were bad tapes, or maybe they had some shedding or sticky tape or whatever and that they could not be relied upon. I was resolved to throw them away.
It was clear that it was the tapes that were the problem and not the deck, because most of the tapes would play perfectly and the problem ones would not.
I did some research into cleaning the head of the deck, but found out that this was not a trivial task, and that the fragile head could easily get damaged. The general conclusion was that you don’t clean it, unless it is absolutely necessary because all tapes play bad and it is clearly visibly dirty. So I didn’t.


I researched some more and came across a post on a Dutch forum dedicated to Philips equipment. You can find the post here:

although I think you need to register first. And it is in dutch 🙂


It is described there that there are actually 2 problems: the squeaking and stuck tape. The squeaking problem is related to two pieces of felt that are inside the DCC cassette, not visible from the outside. There is also a third piece of felt, this is the familiar one that presses the tape on the head. The 2 problematic felts are located near the left and right rollers located inside the cassette:

These felt pads leave behind a greasy spot on the backside of the tape when the tape is not used for a long time. The deck has trouble running the tape past these spots and finally gives up. This spot is somewhat greasy, but also a bit sticky. This can be observed by pulling the tape somewhat from the cassette and checking the backside. It is not necessary to open the tape casing for this.

In order to do that, you must pull back the sliding cover and pull the tape out very, very gently with a small tool and make sure that you do not damage or crinkle the tape. You can see the gunk if you look very carefully. Let light shine on the surface. Make sure that the tape is at the problem spot when you stopped the deck and pulled the tape out, from BOTH reels.
It was impossible to make a good photo of this, so you will have to look for this yourself.


In order to clean the tape, make sure you gently use some non residu cleaner, like IPA or alcohol or videospray cleaner 90 or whatever fits you, and gently rub the problem spot using a cotton swab. Hold the tape down while you swab, careful not to damage or wrinkle the tape. That happens so easily! Remember it’s the backside of the tape.

After that, let the tape dry for a moment, simply wind the tape back inside the housing and play the tape. Voila! It’s working again!


For the squeaking problem: I fixed this by cleaning the felt located opposite the head as well. It won’t get completely clean, but just try to clean it as much as possible. I did it with a cotton swab with IPA. Just rub it a lot and also twist the cotton swab over the surface of the felt. Let the felt dry, this will take some minutes, and wind the take back inside.

After that, the squeaking was gone.

more tips

  • Always rewind the tape completely before you unload and store it for a longer period. The (clear) leader tape, that’s what the felt presses against when the tape is rewound, doesn’t seem to have as much problem with the grease.
  • Also don’t demagnetize the head! Never! It will ruin it forever. The head does not require demagnetization.
  • Never ever use a cleaning cassette. The head is way too fragile and it will ruin it forever.
  • If you absolutely have to clean the head, use alcohol or IPA . Preferably with natural chamois leather, but a cotton swab will work as well.
    Update: since I wrote this article, I *have* cleaned the heads of my DCC decks. Several times. No problem. Just use a cotton swab with IPA and be very gentle. I have taken out the mechanism however. See also my video:
  • Avoid playing normal (analog) compact cassettes in a DCC player. Normal cassettes are not as clean as DCC cassettes because they have no tapeprotection and will make the head and the drive mechanism dirty. But most of all the tape formulas used in the analogue tapes are not as good as in the DCC and will shed oxide on the head. Better safe than sorry!
  • See an other post of mine where I explain the tape length identification marks on the DCC cassette.

All info and the picture of the open DCC cassette are from the forum mentioned.

See also my new post here:

Leopard 2

Training in Amersfoort

I had my training in Amersfoort. To begin we had a lot of theoretical lessons. These pictures were taken during our first encounter up close with a Leopard 2:

First encounter with the beast, parked right there in the classroomAfter weeks of training, we went riding with it:

learning to guide the tank backwards from the command hatch.And finally, after weeks and weeks, we went on exercise with it:

This was out first night exercise with the tank.Me on top of the leopard 2.
This was during our first exercise as a platoon with the platoon leader putting on his cap.


After that period in the Netherlands, which lasted 6 months, I was stationed in Germany in Bergen-Hohne. Here are some pictures from there:

detail of the front of the wheel mechanism

This picture was taken from a tank of which the back had had a collision with a turrent.Here we are busy putting a new track on the leopard 2. Needless to say the track is very very heavy.A Eskadron 41 Tankbataljon

Field exercises

We also went into the field. A lot. Sometimes for a few days. Here are some pictures:

Waking up after a night in the field.

‘wasbord’. This terrain is formed this way with the bumps due to the tanks driving there. It gets worse over time. It is very uncomfortable to drive.Leopard 2 hidden behind a bump in the terrain.

All Terrain Vehicle. The leopard 2 has no problem with any terrain.

Full speed ahead, eeeh reverse I mean. This is a manoeuvre to withdraw, driving backwards full speed.

lolo. The leopard on a low-loader.

Parked in a ditch, this tank wasn’t coming out by itself. It had to be towed out.

What leo 2?

My driver managed to drive the tracks off of our tank, making a turn in very loose sand. It took us a while to get the track back on the cog.

Me in action. Reading the map doing a relocation during the excise. Unfortunately the picture is not very good, but the tank was moving around a lot.

My crew and my tank just after we rolled the tank from the train that had brought us to the exercise field on the other side Germany. This picture was taken in the morning, as the trainride was a night train. I am standing just behind my driver. I am the one with my back to the photographer.

Fill ‘er up! This takes long. Very long. 1100 liter.

Me giving the tank a thorough cleaning afterwards.

Shooting practice

In Bergen-Hohne is Europe’s largest and best shooting range for tanks. Of course we went there. Here are some action pics:

This actually is a small version of a Dutch shooting range where you can practice tactics, like target distribution between tanks etc.

Same small shooting range but then the view as seen from the tanks.On the big firing range. Drivers resting between sessions.

Grenades are stored right behind the shooting tanks.Me (right) and another tank commander talking to the platoon commander (middle).Alpha tank in action, ready for firing.

real world field exercise

At the very end of the tour, we did a NATO real world exercise, where you drive through the real world and drive the public road through villages and take shelter at some farmer’s place etc.


Here we’re waiting to get out of the gate at the barracks.

Through the village.

Some of these roads are very narrow.

There were also other military vehicles involved. In fact it was a complete exercise, where multiple countries collaborated.

Taking a stand in a field.

A moment of rest, parking in a small town by the side of the road.

Getting supplies like fuel (jerrycans) in the late evening.

Loader in action. He is in charge of the flashlight.

Queuing to return to the base. The exercise lasted about 3 days.

Dolby 363 rack with model 350 cards


Since I was very young I was intrigued by recording studios and the equipment therein. Can you tell?? (cue Studer A80 blog entry). A few years ago I had the opportunity to visit the famous Wisseloord studios here in Holland and needless to say that that was a thrilling experience. I am intrigued by the recording process, and mainly the tape part. But recording techniques in general have my interest. Like how to record a solo acoustic guitar, or how to record a symphonic orchestra. And as pure as possible. In order to do that, in the old days, you need a tape recorder, and there lies the base of my fascination.

tape hiss

Tape has a very nasty flaw: it introduces tape hiss into the signal. Tape hiss is clearly noticeable when you play around with consumer decks, giving a nasty hiss in quiet sections when you replay your recordings. This wasn’t so much of a problem when recording from LP or FM radio, which has a background noise that would make the tape hiss less noticeable. It became a bigger problem since CDs came around and the source of the recordings were becoming quieter or even dead silent.

If you wanted to minimize the tape hiss, you had to resort to quieter, and more expensive tape. You had to use the more high-end decks, and have them calibrated properly to that tape. Thorough maintenance became even more important.

studio – multitrack

If you thought that you had a problem with tape hiss at home, imagine the problem professional recording studios had with it. They have to conform to the very highest of standards because they are at the very beginning of the audio path, a path that would result eventually with you playing the record or CD at home. So they want to introduce as little noise (in general) to the signal as possible. Adding to the problem was the fact that multi-track recorders had 16, 24 or 32 tracks that all brought their hiss to the final 2 channel stereo end-mix.
Without proper noise reduction, even in the most expensive studio with the high end tapemachines and studiotape running at high speed the end result would suffer quite substantially from tape hiss.

noise gate

To circumvent this problem, studios often reverted to using devices like noise gates. When the audio level of a track would drop below a certain level, the noise gate would kick in and mute the channel on playback. This was of course done so that the downmix to 2 tracks would be more silent in the quiet parts. There is an interesting article on the use of Kepexes used by Alan Parsons on Dark Side of the Moon by Pink Floyd:

I remember extensive use of Kepex noise gates. I think part of the sound is these Kepex gates. They had a certain sound rather similar to tape compression. We were not just using them to reduce tape noise, they had a sound as well.

Read the article here:

Dolby A

But, toward the end of the 60’s a new technology came around. Invented by Ray Dolby, Dolby (“A”, as it was later renamed) promised a reduction in tape noise level of around 10-15 dB. It was targeted at the professional market, and it was also used in the recording of optical sound on films for motion pictures, improving the audio quality significant.
In music studios it was an instant hit. Much of the music of the 70’s would not sound so great on CD’s as we know it now if Dolby A would not have been around.
The card that enables Dolby A for the 363 is the Cat 450 card.

Dolby SR

Without going too much into the history of Dolby, (you can look that up on Wikipedia for yourself) suffice to say that in 1986 Dolby introduced its best performing professional noise reduction system to date: Dolby SR.
Dolby SR stands for Spectral Recording, and it utilizes different techniques to achieve an increase in dynamic range of 25 dB. Professional tests conducted using a studio environment (link) concluded that a recording made with Dolby SR was indistinguishable from a digital recording.
So, my fascination with professional tape recording equipment would not be complete without some noise reduction and/or compression units. I purchased a Dolby Model 363 rack with 2 Cat 350 modules.
There is also a combined Dolby A/SR card, that is the Cat 300 card.

The test

My intention was to test these out with my Studer A80. But, as I was preparing some test material, I found out that my A80 was actually too silent and my source material too noisy to test this properly. I had a vocal track that was almost super silent as far as noise is concerned.
So I took out my most ‘noisy’ deck, which I think is my Teac A3440, and recorded some vocal track on it. With, and without Dolby SR.
To be fair, this was a quick and dirty test, and in no way this was an exhaustive test. I tried to find a noisy tape as well. I found that using the SR unit I was able to push the A3440 to a level where it was rivaling a CD as far as noise and dynamic level was concerned. You have to hear it to believe it.

Tandberg TD 20 A

I have recently acquired a Tandberg TD 20 A. This model was on my list of decks that I always wanted to own. It is a very good sounding deck, and received wonderful reviews in it’s days. It was compared once to a Philips N4520 and a Teac X-2000R in a magazine article and it came out 1st in some of the sections. I can not find the article at the moment, if I find it I will post the link here.

It is a deck from Tandberg, a Norwegian company. Not many decks came from Scandinavia, apart from B&O and some others. This deck is also available in 2 tracks, maybe I will come across one someday, I hope.

This deck came as ‘mechanical defect, does not run but signal in/output is good.’ So it will be a challenge to get it working. It also came with 2 very special Tandberg NAB adapters.
First it will need a good cleaning. Especially the front aluminum is yellow-ish.


First I took the deck out of its casing. Then I took of the knobs and the front plates. The knobs were cleaned, and fortunately on the front plate the lettering does not come off! The black upper plate looks nicer now too.

1st checks

It powers on: good. It winds: good.
But it does not play. It appears the pinch roller, or better the arm on which the pinch roller is located, is stuck. This looks like a bad case of stuck grease. 

After disassembling some parts, including removing a split-pen, I was able to remove the arm. I removed the rubber roller and put it into a detergent solution for a night to revive it. I cleaned the axle from old grease and lubricated it. Now it moves again effortlessly. I checked, cleaned and regreased all moving parts. Also the gears on the 4th motor, that manages the tape handling, were stuck. Cleaned and lubricated that as well.

Then another issue presented itself: the left reel dish was scraping against the brake. I readjusted that table so that it is in the correct position again.

Cleaned the tape path and the heads, made sure the tape guides were smooth in their movement.

provisional play test

Then I put a tape on: it was working! This deck has a very smooth tape handling when starting and stopping. It is a delight to see this in action. Also the music on the tape was playing, so playback circuit was working too. This keeps getting better and better.

provisional record test

I noticed something odd: the erase head is not in the position that it should be: it is slanted and it’s position is too low on the tape path. Apparently the construction on which it is mounted was dented once. This is an issue for later. Now I will just use my bulk eraser to erase a tape and record on that.

I put on some Agfa pe36 (which is not a very high end tape, but als not budget – a kind of ‘well, ok’ -tape) and the difference between source and tape was almost non-existent!. This is a very good deck as-is even without the maintenance, adjustment and calibration that I will perform on it.

NAB adapters

The matching NAB adapters have 2 peculiarities:

  • they haven’t got a clamp en turn mechanism like the ones from Teac and Philips etc. Nevertheless it works well: the outer ring covers the NAB hole in the reel, and the trident from the deck grabs the whole tight to the reeltable. Looking at it this way you could say that the other manufacturers have come up with a far too complicated construction 😀
  • using the large 26cm reels with these adapters, the reels are too deep relative to the tape path and the tape scratches the rim of the reels. This is mentioned in the manual: a disc is to be used to lift the reels a few mm. When I use the other brand’s adapters, there is no problem.

The tape guide arms can be adjusted to bring the tape lower to the reels, but I will not do that as I suspect trouble with 7 inch reels.

erase head problems

There is a strange thing going on with the erase head. This is the very first time that I experience a skewed erase head. And it is not only skweded but it is also too low.It looks like it has been pushed down. The construction is weird: the head is mounted on top of a kind of tincan strip which is Ω omega shaped. And that is dented. And while pushing it up again, one side broke.

What I did was load some blank tape, and by that I mean see-through tape, and line up the erase head. I put some nuts and ring under the plate until it was level with the tape. After adjusting the other mounting screws of the head my erase head was level again and at the right height etc. I tested it with erasing and it seems to work just fine. And I could always use the deck for playback only. Or first bulk erase the tape before recording with this deck when it won’t work after all.:)


After all the mechanical adjustments were made, the unit was cleaned, lubricated, demagged, etc etc I ran some tests to determine how well the deck was performing.

Wow & Flutter, 19 cm/s 9,5 cm/s:
flutter:             0,1         0.15
wow:               0.03       0.08
unweighted:    0.1         0.06
weighted:        0.05       0.15

DIN measured. The values still match the specs quite well!

Distortion: 1kHz 1,2V input:
0.14 % with DUT on ‘source’
0.5 % with DUT on ‘play’ but still on ‘source’
0.75% with DUT on ‘tape’

Tape is Maxell UDXL 19 cm/s. Around 0dB on VU meters.

frequency sweep

Then I proceeded to measure the frequency response. Although the deck sound very good, what I saw on the screen I wasn’t very happy with:

Yellow line is the source sweep, from 20-20kHz and measured through the deck in ‘source’ mode, and the green line is what comes back from that same sweep in ‘tape’ mode.

calibration tapes

I was sure that could be improved upon, but I wasn’t sure what was going on. It could be that recording was the problem, or playback, or both. So I mounted not one, but two (!) calibration tapes to examine the playback frequency curve. The result was this:

The red line is a BASF Bezugsband and the white line is a brand new MRL tape. Apart from the difference in levels, which is solely for the purpose of the graph, the frequency run is fairly identical. There is fall off in the higher frequencies on both tapes. So there is a problem with playback at the least.

REMARK: the BASF tape is IEC, the MRL is a NAB tape.

head alignment

I continued to go through the complete Service Manual of the deck. Starting with heads alignment, that already gave some better high frequency response because you not only align the playback but also the rec head.

After that I followed the rest of the service manual and calibrated the levels, the bias and the freq. curve. After I was done, the result was spectacular:

This is a recorded signal played back. The sweep is almost straight. At least as straight as I will (can) get it. The image comes from a new program that I found called BAUDLINE. It runs on linux and is very fast. I use the ‘peak smoothing’ feature to create a sort of peak-hold.

listening tests

After that was done, all the work I planned to do on it and that was necessary on it was done. The subsequent listening tests were a revelation: the deck sounds so good that even my trusty old Philips N4520 was left a bit behind. May need to rework that one as well sometime 🙂


at the moment the frequency curve when playing the BASF Bezugsband is like this:

Note that the curve is straight within +/- 0,5 dB !!

(the part around 250 Hz is not testtones – it is the announcement of the tones on the tape)

Measuring (baselining) with my new National Distortion Meter

I like measuring. So I bought a National Distortion Meter. It is the VP-7701a.

This device is capable of measuring the distortion of an sine audio signal. And can be useful to calibrate vintage audio equipment.


To be able to make any meaningful measurements, I need to do some baselining, meaning that I want to measure the distortion when the device is not measuring anything at all. If that makes any sense to you. It does to me anyway 😀
When the base distortion levels are extremely low, I can measure devices and discard the base distortion. But when the base distortion levels are significant, then I would have to subtract these levels from the measurement each time I do a measurement. Which I do not want, because it is a hassle.

So in order to do that I need a pure sine wave for input. The device does not provide that, at least not one that is available to the user. The device measures the distortion by subtracting its own sine waveform from the one that is being measured, and the result should be zero. But only if the supplied waveform is 100% equal to the internal sine waveform. My search for a matching waveform therefor brought me to 3 sources:

  • a pure sinewave provided by my soundcard from the computer, created in audacity
  • a test CD made for this purpose which I bought 20 odd years ago
  • a test CD that I created myself with pure sine waves created by audacity and burned to a CD

This is the test CD that I once (’90-s) bought:

It has all kinds of tests on it: frequency sweep, fase checks etc and also sine wave tones across the audio spectrum.


This is the result of my base line tests:

The results show that both my soundcard and the commercial testCD are useless for my measurements. The CD that I made myself is a lot better. It performed marginally better on my Technics SL-P777than on my Philips DVD 963SA player (SACD). The result is such that I think that the base distortion is low enough to not take it into account when I start to measure real equipment. So I will be using this CD as my source for sine waves.

One side note: my CD is recorded at 0dB level, so the player outputs 2,5V which is rather high. I may have to make a second CD where the levels are lower, like -10 or -20 dB.

My personal checklist for upgrading from openSUSE Leap 42.1 to 42.2 using online update (zypper dup)

** update — also tested ok on 42.2 -> 42.3 **

This is my personal checklist for upgrading from openSUSE Leap 42.1 to 42.2 using online update (zypper dup). This may or may not include all the steps necessary for YOUR system.

You may not need all the steps. So be careful. Read it carefully, and make sure that you understand each step. Use it as an aid. Use it at your own risk.
Remember, always update 1 versionnumber at a time, so go from 42.1 -> 42.2 -> 42.3 and do not go from 42.1 to 42.3 !!

For the full (very good) documentation, see:


  1. Check your repos.
    1. Remove all repos that you no longer need, like I have the ‘kde updated apps’ repo.
    2. It is most preferable to leave only base (oss & non-oss), update(oss & non-oss) & packman repos.
    3. # zypper verify
      to remove cache files from the repos you deleted. Saves lots of disk space beforehand.
  2. If necessary, but this may be not for you, enable packet locks on packages that you need. For instance, I still need createrepo and KDirStat and I don’t want the upgrade to delete these packages. This step may not be for you.
    1. # zypper al createrepo
    2. # zypper al kdirstat
  3. update your system to the latest patch level just before the upgrade.
    1. # zypper up
  4. IMPORTANT!! Make sure that you have enough free diskspace, >4GB is recommended. (probably in /var/cache but i’m not sure) <– yes, confirmed

To change the repos:

  1. go to the repo directory
    1. # cd /etc/zypp/repos.d/
  2. change all references from 42.1 to 42.2 (or whatever version number you need)
    1. # sed -i ‘s/42.1/42.2/g’ *.repo
  3. check if the repo files are correct now
    1. # grep base * | cut -d”:” -f2-
      and check the output
  4. check to make sure that these new repos all exist and are accessible
    1. # zypper ref -f

To start the update:

  1. please read step 4.3 below first.
  2. I like to start the update not in an X session, so either:
    1. init 3 :to switch to runlevel 3, or
    2. CTRL-ALT-F1 to start a root session on tty1. This has the benefit that a graphical console is still available during the update. (press CTRL-ALT-F7 to switch)
      but his is not a necessary step. You can skip this if you want.
  3. I like to download the files in advance, so I don’t end up with a broken system when something goes wrong during the process. Please check for >4GB free disk space beforehand.
    1. # zypper dup – -download-in-advance
      Otherwise just leave the download-in-advance option out.
  4. Really, really check the output good before giving it a go.
    1. Check especially the section on ‘downgraded packages’ and ‘removed packages’ . Check if there aren’t any packages that you know you want to keep.
    2. To check the downgraded packages, I have a little tip: type ‘v’ at the promt where zypper is asking for ‘yes or no’, and the list will be repeated but now with version numbers!
    3. This step may be difficult to do on tty1, so you might want to do a test run of this command in the graphical console first, where you have a large scroll-back buffer. So check and then simply answer no at the end will do. Then repeat the command in the tty1, where you will answer yes of course.
  5. Once you answered ‘y’, the download will start. For me, it was ~4000 packages, ~2.1GB download. How long this will take depends on your internet connection.
  6. After the download, the installation of the packages will start. How long this will take depends on the speed of your processor and disk system.
  7. then you can reboot
    # reboot

After the upgrade to 42.2, my server performed its functions (database, webserver, nfs, smb etc.) perfectly. However I had a slight issue with the KDE-desktop. The taskbar would not come up and the desktop was inaccesible.
To solve that, I had to issue the following command:
# zypper in -t pattern “kde_plasma”

That command installed some packages that were probably missing. After that, I could use the desktop as normal again.

Have a lot of fun!

Cleaning contacts in audio equipment

file_342_9To clean contacts in audio equipment, I do the following:

  1. clean the contact with Kontakt 60
    this will dissolve the corrosion and is slightly acidic. Follow up with 2 & 3.
  2. clean the contact with Kontakt WL or IPA
    this will rinse the contact clean and evaporate completely
  3. protect the contact with Kontakt 61
    this will put a protective layer on the contacts to prevent corrosion and wear so that you won’t have to do this again next year 🙂

For potentiometers don’t use 60, this will erode the internals. Use Kontakt 390 or Kontakt Tuner(600). Tuner works very well.

Kontakt 390 is an old Philips recipe and should be an all-in-one solution. I have not used it yet.

Don’t use contactspray!

Good luck!

AEG Magnetophon AW-2

A very good acquaintance gave me some recorders recently. Among them was this beauty: The AEG Magnetophon AW-2.


As you can see, this recorder is from 1951 and is more than 65 years old! This particular device that I have was used in cinemas for sound reproduction. It sits in a suitcase for easy carrying around. It is quite heavy though. It uses platters and pancakes.


aufname und wiedergabe switch


on/off-volume and play/rewind switch

It is in a very reasonable condition. So far nothing seems to be broken beyond repair. My goal is to try to restore it so that it plays tapes again. I have not turned it on yet, it first needs a lot of TLC.
It appears that when used with ‘modern’ tape, this unit will nowadays produce stunning results that would exceed what would have been achieved back then.

For instance, there are three very heavy duty belts in this one motor machine. And with belt I mean like belt from a car engine. They are not in a condition to be used again, so these will have to be replaced. Also some of the electronic components, like capacitors and rectifiers are way beyond their normal operating life so they will have to go too. And then everything else that I will run into. Hopefully the tubes, there are a few, still work.

I have started to open the device up and clean it.


Immense belt


fltr: erase, r/w head capstan and pinchroller

the heads:


somewhere in this shell is the head


erase head before cleaning


oil’s well!

There are of course a lot of electrical components as well that need to be replaced. The first and foremost candidates are the capacitors, as there are certain types that don’t last for so long.

The device contains some paper-oil capacitors, like this one:


This will certainly have to be replaced before I can switch it on. I am told that ones like this will probably be ok:

The device is really beautifully made. When I ventured inside I fell in love with it more and more. But there are a few ‘minor’ issues to be resolved, like: where is this supposed to be connected?

I was told that this rectifier could go up in (probably very nasty) smoke:

So I will need to figure out how to replace it.

Fortunately I have got the electrical diagram:

Philips N4522 (twice) and another N4520: new arrivals!

I recently went on a road trip and came back with:

  • a Philips N4522 2-track. This machine is in very good condition and has recently been serviced in Germany.
  • another N4522 2-track, but this one is going to need some TLC. There are some issues with it, although none of them are serious problems. But I just like to fix it as much as possible.
  • another N4520 4 track. I already have one, but this new arrival is not recording well. This has probably something to do with the levels, but I have not looked into it yet.

So now a have a total of 4 Philips N452X machines and that looks like this:

The two on the left with the white VU meters are the 2 track stereos, and the two on the right are the 4 track stereo machines.

Wow! What speed flutter!

Why speed measurement

For some reason I got interested in the speed of my tape decks. Why, you ask? I really don’t know. I was fiddling around with my vintage Philips multimeter, which is capable of measuring the frequency of a tone, when I thought it would be cool to use that meter to measure the 1kHz tone which is a the beginning of my (generic) calibration tapes. If the tape runs too fast, the measured frequency would be over 1000Hz, and if the speed was too low, it would be under 1000Hz. Suddenly I was fascinated by the fact whether my decks were running at the exact speed or not, or if not, how much deviation it had.

Now, you have to understand that I do a lot (well, actually not that much) calibrations of decks, but I never ever calibrated the speed. I never bothered before. I never had a problem with speed before. I never had the need to adjust the speed of a deck. So whatever I measured now, it would be the ‘default’ speed, untouched.

So I loaded the test tape onto all of my decks, connected the multimeter, and did my measurements.

The results were sometimes surprising, sometimes more or less expected.

Merk/Type speed %
Akai GX77 980 98
Revox PR99 994,5 99,45
Teac X7R 995 99,5
Philips N7300 998 99,8
Teac X2000R 998 99,8
Philips N4520 1000 100
Tascam 34B 1000 100
Studer A80 1000 100
Teac A3440 1002 100,2
Teac X7 1011 101,1

And a graph says more than words, so:

What can we conclude from this?

  • The Akai GX-77 really runs too slow

  • almost all decks run within +/- 0,5% of the correct speed, which is within the DIN norm

  • only 3 decks run a EXACT the correct speed: the Philips N4520, the Tascam 34B, and the Studer A80.

    • the Philips N4520 is know for its quartz/PLL like control, so this is no surprise

    • the Tascam 34B is a professional deck, but this result still surprised me

    • the Studer A80…..well…….need I say more?

enter the wow and flutter

So that has been a very interesting experience. But then I started thinking about variations of the speed, also known as ‘wow’ and ‘flutter’.

Wow is the slow variation in speed, with a period below 6 Hz.
Flutter is the fast change in speed, with a frequency above 6 Hz.

One can experience wow then playing a record where the hole is not centered, and the speed goes up and down all the time.

Flutter is more difficult to hear because it is so fast. It can be measured however. Flutter is created by faulty mechanics: a capstan here, a roller there, dirt, bearings, the overall construction etc. It would appear that less flutter makes for a more tight and clean sound.

There is always wow and flutter. No mechanical system is without them. It is just a matter of reducing it as much as possible.

causes of W&F

what are the causes of W&F? There can be many. The capstan or axis involved might not be perfectly round. The bearing idem. The system may not be perfectly lubricated. There may be dirt on tape guides, causing jerky tape motion (on a microscopic scale). Tape may not be slit evenly. Etc. etc. etc. There really are too many to mention here.

Remember: There is always wow and flutter. No mechanical system is without it. Realize that.

measuring wow and flutter

Now there I had a problem. To measure W&F you need a special device called a ‘wow and flutter meter’. Of course, you can rely on Philips that they had such a product back in the days. They did. It is this one:

But unfortunately I don’t own one. It is on my wanted list though. They are relatively rare, and sometimes expensive. If you have one, or one like this, and you would like to sell it to me, please let me know.

software to the recue

What to do now? Fortunately I found an interesting program on the web that is supposed to measure W&F. It’s called WFGUI. Here is a screenshot of the program in action:

That looks impressive, right? It can measure DIN 45507, wow < 6Hz, and flutter >6Hz. According to the documentation provided with the program it has been tested against some real life hardware W&F meters and the results were very very comparable. Good!

Now I had a different challenge with this program, as it runs on windows, and I only have Linux. But, I soon found out that it runs perfectly fine in Wine! Yeah!

You can select between the 2 most used frequencies in calibration: 3000 and 3150 Hz. (It also shows the measured frequency for your convenience.) Then there are 3 values to take notice of:

  1. RMS (%): this shows the root mean square value in % of the current measurement
  2. Peak: this shows the current peak in % using a nice needle display
  3. maximum value of RMS and Peak in % during the last 10 seconds
  4. and it also produces a nice waveform of the current fluctuation measurement (this is NOT the input or output sinewave)

Now, this is where it gets interesting. The program has different settings so it can measure different values. It can measure:

  1. DIN (Deutsche Industrie Norm), or more specifically DIN 45507
  2. wow: measure variations between 0,3 Hz and 6 Hz
  3. flutter: measure between 6 Hz and 200 Hz

Now I will not go into too much detail here, but take it from me that the DIN norm is a sort of average between the 2nd and 3rd setting, i.e. it takes a little bit of both. If you want to know more, you can read the documentation that comes with the program, that has some nice graphs that show it all. That will explain everything. For my measurements I used all three settings (DIN, wow and flutter), and I measured all 3 values (RMS, Peak and Max RMS)

calibration tape

The problem I had is that measuring these kinds of W&F is traditionally done with a tone of either 3000 or 3150 Hz. And, more specifically, you need a special (and expensive) speed calibration tape with that tone on it recorded in a very precise manner.
Guess what, I do not own such a tape. They are quite rare actually, although you can still buy them at I presume. My regular Bezugsband (German for calibration tape) has a 1kHz tone at the beginning, but that is used foor reference level measurements.

making my own test tape (huh?)

So I thought about it a bit and I knew I was never going to buy that special speed calibration tape (>€130). What if I took my trusted tone generator and used that to record and immediately playback a 3kHz tone? Of course that would be an imperfect recording, because it would contain W&F, but wasn’t that just what I wanted to measure? And if you play back that recording on the same deck, doesn’t that give a good indication of the performance of that deck? The more I thought about it, the more sound (pun intended!) the idea seemed to be.
Doing that would mean that I could not refer to a know calibrated source anymore. But I’m not interested in those figures. I can now compare the performance of my decks between themselves, see who stands out, either way.

Some people may argue that one can not make his or her own test tape. Of course that is true. But that is not the purpose. I want to measure the W&F of a deck. I was going to use the deck itself to record a tone and play it back at the same time.
Some may argue that that is not a good way to measure W&F. I disagree. I will explain.

When you record the test tone on the DUT (device under test), it wil will be recorded with wow and flutter. That is clear. So it will be an imperfect recording. So what. That is what I want to measure, so that seems ok to me. Let’s assume that the recorded tone will contain at the maximum an amount of W&F of n. If you would examine the tape in a laboratory you would find max n W&F. The DUT obviously has a W&F value of n. So at some points in time the value would be 0 (zero), at some points in time the value would be n (the max value) and most of the times some value in between. This will vary constantly, and it will vary very quickly.
Now I play back this tape on that same deck that has that W&F reading of max n. So again, some of the time that tape will play back with no W&F, and some of the time it will play back with the maximum value of n, and most of the time some value in between. The resulting W&F will be 2*n at the most, to be exact that would occur when a piece of the tape that was recorded at that moment with n W&F value will be played back at a moment that the deck plays back with a W&F value of n.


So again I dragged all my decks to the test bench and hooked them up one by one. Now reading the values from the program proved to be quite a challenge, because the readings vary a lot and change very quickly. So i took a sort of ‘observed average’ , as I would call it.

I did the measurement all at 19 cm/s, because that is the common speed all my decks have. I have noted where I used an other speed, like 38 cm/s.

 So what are the first results?

  • the kind of tape used for the test has a great influence on the end result. At first, I used an older tape and got very different (much much worse) result that when I later used a brand new tape of the same type. This was kind of shocking!
  • tape speed has a great influence on the stability as well. All deck produce much better results on 38 cm/s than on 19 cm/s. A few quick test at 9,5 cm/s were even worse.
  • I did not find any difference when using the beginning, the middle or the end of the tape, but I have not tested that on every deck. I suppose if a deck has too much or too little tension, the position on the tape would matter

After a lot of testing I had a spreadsheet full of values that were very difficult to interpret. So I made a graph out of all the numbers and this is the end result:

This may seem overwhelming and confusing at first, but it really isn’t. Let me clarify for you.

  • On the X-axis (lower) you see the three different measuring methods for each deck: DIN, wow and flutter.
  • Each deck has an corresponding line in the graph for these 3 values.
  • Lower values (lower lines) are better.
  • Legend is on the right, showing which line corresponds to which deck. It is a bit crowded but bear with me.

Here are the conclusions:

  • the most upper line, meaning the worst deck, is the Teac A-3440 at both speeds. This is one of my oldest decks.
  • for fun I included one turntable, my Technics SL1900. That is the blue dotted line. I found that I had a test record with a 3kHz tone on it, so I could actually do the measurement. I was surprised to see that the values produced were in the same range as the tape decks. However, unlike all decks, the wow is the worse value of the three.
  • the best deck is the Studer A80 @ 38 cm/s. Of course, Studer was famous for their mechanics and always paid special attention to the tape path. Studer used the best available bearings and even had special lubricant that had to be used.
  • a very positive measurement is the Philips N7300, the light blue line in the lower part.
  • in general, the newer decks (Philips N7300, AKAI GX-77 and Teac X-2000R) are in the better part of the graph. Maybe it is because when they were manufactured, the W&F was better under control, or it is simply because they are fewer used.
  • the ReVox PR99 (also a Studer brand), the dark blue line, is giving the A80 a run for his money.
  • the results for the dual capstan decks that I have (Teac X7, X7-R, and X2000-R) are not as I expected. Yes, they are good, but they are beaten by single capstan decks. The whole idea of the dual-capstan system is that that would eliminate (well, minimize) W&F values. I think the system fails to deliver. And on top of that, it introduces a lot of unwanted negative side effects, that are most notable after all these years when the decks age.
    The result of playing in the reverse direction were mostly comparable to the forward direction, so no real diffrerence here.

There you have it. I hope you liked my article. If you have any comments, please leave them below.

-edit  31 may 2016-

I have recently purchased a ‘real’ wow and flutter meter, the B+K Precision wow and flutter meter 1035. 
I have used this meter to check some results from the softwareprogram above, and the results fortunately match. Great!

A80@19 RMS Peak max RMS
DIN 0,0225 0,04 0,0294
wow 0,013 0,019 0,0166
flutter 0,0406 0,029 0,0484
a80@38 RMS Peak max RMS
DIN 0,0093 0,019 0,0136
wow 0,007 0,01 0,009
flutter 0,0368 0,059 0,0398

Re-capping a vintage quadraphonic amplifier: JVC MCA-V7E (quadrophonic)

JVC MCA V7E closeup

For some reason I wanted to do a recap job of my vintage quadraphonic amplifier, the JVC MCA-V7E that you see above. This unit is actually in very good shape, so the reason for me to do this is also unclear to me, really! But sometimes my ways are inscrutable.


A recap job means that you replace all the old, worn out electrolytic capacitors that are >40years old with new ones, preferably audio-grade types. Electrolytic capacitors are known to dry out when they get older. And then they lose their characteristics. Worst case is that they short out, or that they start acting as a coil or as a resistor. These are all things that you do not want in your amplifier. Or in any other device, for that matter. Also, the original caps were never the same quality as the ones that you can buy today just because manufacturing, tolerance and materials have become so much better in 40 years. So in theory this should enhance the performance of the unit.

Also, it is not a question if an electolytic caps will fail, but when. So after the recap your equipment will be good for at least another 40 years, but probably a whole lot longer.

Panasonic FC series

If you are gonna do it, you want to do it good. Then you go for the audio-grade caps.

These black caps are available at sometimes crazy prices of several euros a piece, but there is a very good capacitor at a very reasonable price. So all audio enthousiasts like me that do not have a money tree in the backyard use these FC series caps, as you will probably need a good bunch of them. In this case I used around 50-60 of them, but I have not counted them exactly.  I ordered them from  they have the complete range of values at good prices. The only problem is the minimum order amount of 50 euros.

The works

This is what the unit looked like before I started:


Basically all the grey capacitors that you see here had to be replaced. This consists of the Power Supply board, the tone/preamp board, the mainamp board, and the phono board which is located on the underside

I started with the PSU (power supply). These contained some big ones.


PSU after


PSU before

Note the difference in size. The new ones are a lot smaller. They have the same value nevertheless. After I had done the power supply, and the amplifier still worked (!!) 🙂 I tackled the phono board.


phono before

And then the preamp.


premp done


preamp before

And then the main amp:






all done

After all the works was done, it was time to turn the power on. Exiting! Nothing exploded and no component was getting very hot, so I connected an input signal on the four inputs and turned up the volume. Channel 3 was not working. Hmmm. I remembered a problem I had when removing the large capacitor from the third channel, when the copper strip had come loose from the board. On closer examination I saw that it indeed was not making contact properly anymore, so that was easily fixed. Now the 3rd channel worked ok!
The sound from the ‘new’ amplifier is very crisp, someone called it ‘clean’. I think that is an apt description. I turned the JVC up quite a bit, and experienced no problems. So I am very happy with that.

Testing & measuring

Next up is a bit of testing and especially measuring. Because I wanted to test some new type of transistors, I have installed them in the channel 2 pre-amp. I want to see how they stack up against the original ones. I am especially interested in distortion and overall performance. If they don’t perform well, I will re-install the old ones. Maybe the amp needs to be biased as well, but I’m not sure yet.
I also turned up the calibration on the meters quite a bit, so now the needles are showing signal even at normal volume levels, that was not so before. Previously they just lingered around in the left corner doing mostly nothing.

I have provided here a simple drawing of the electrolytics on both amplifier boards for your convenience, if you should decide to do the recapping as well. Good luck!