Monthly Archives: December 2022

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: