Fostex G-16S bias adjustment

[niva]

Hi there!


I am in the process of calibrating my G-16S.

I religiously folowed the Service Manual and adjusted the playback levels with my MRL tape at 0 VU (-10dB) (quite a "flat" reponse for a 1/2" 16 track!). So I guess the payback/sel sync head is OK.

Now I am in the bias setting...

The Service Manual doesn't say much about it:

1. Rotate Sync crosstalk at the center

2. Put all 24/16 tracks in record

3. Turn the BIAS ADJUST muti-turn pot until it reaches the peak,

4 . And then turn the BIAS LEVEL so that the level drops at 100mv.

I figure this method works well with a brand new or freshly relapped head.

Now, I followed this method (with no signal recorded and no tape on the machine) and I still have some significant differences between 1K and 10K, both played at -10dBV.

The manual claims that there should be a +/- 1.5dB difference, but I get 1.8dB (ok), 2.3 dB (not so good) and even 3.3dB (Ouch!) more gain with 10K compared to 1K (with NR OFF)!


So I guess that I should:

1. Record a 10K signal on a tape on each track and then.
2. Find the peak with the BIAS ADJUST pot (CLOCKWISE?) with Playback after record method.
3. Drop -3.5dB or -4.5dB as recommended on the web from the peak level with the BIAS LEVEL pot (COUNTER-CLOCKWISE?).

I'll set the bias for +6 tapes, although I'll be using +9 tapes as well. But I don't want to reset the bias all the time, so my reference tape will be +6.

For that, I guess I should use the PAR technique (playback after record) to see how the changes did affected the signal.


Am I right?

Thanks a lot for your guiding lights!

Guillaume, Qu?bec, Canada

[niva]

Hello!

I am still messing around with bias setting on my G-16s.


Can anyone help me out?


Thanks!

Guillaume