Tape reference level
Operating Level Flux@1000Hz Flux@700Hz 0dB 180 nWb/m 185 nWb/m +1dB 200 nWb/m +2dB 224 nWb/m +3dB 250 nWb/m 260 nWb/m +4dB 280 nWb/m G320 nWb/m +5dB 315 nWb/m +6dB 355 nWb/m 370 nWb/m +7dB 400 nWb/m +8dB 450 nWb/m G510 nWb/m +9dB 500 nWb/m Magnetic Flux level flux Φ LΦ 520 nWb/m +6.36 dB 370 nWb/m +3.41 dB 320 nWb/m +2.14 dB 250 nWb/m 0 dB 220 nWb/m −1.11 dB 200 nWb/m −1.94 dB 185 nWb/m −2.62 dB 150 nWb/m −4.44 dB
1/4 track machines will respond different that 1/2 track machines.
The 1/2 track decks can use 370 nWb/M (+6dB) but the A2300 will not work well with that level. It needs to be no higher than 250 but more correct 200 if you want full bandwidth. Like a lot of guys are oing they get blinded except for one spec and that is flux density. This may enhance S/N ratio but also distortion goes up and bandwidth goes down.
So you are better off with a 200nWb/M tape for the A2300 at 7.5 IPS and can also be used on the quad Otari. The 25-2 is not going to like the levels above 250 nWb/M as it is designed and the A7300-2T is better off at 250 as well. If you want to run 370 nWb/M the Tascam 52, 62 and ATR units are more suited and have jumpers for those levels. Higher is not always better!
The track width of machines has a lot to do with how much flux you can throw at it. The 1/4 track decks like to have 200nWb/M and on a rare occasion maybe 250 but nothing higher. the 1/2 track machines is where you have many options and depending on the speed you might be able to throw a lot of signal at it. You know the other thing in upping the flux density- the tape has a fixed saturation point let just say +15. If you go and set up a deck for +6(370) instead or +3 (250) then what you risk is a saturation happening sooner as you then do not have +15 headroom but +9.