Tape bias for 499 and GP9

[jsel84]

Latly I've beening running my Studer A-80 Mk2 at 15 ips to help on tape cost.
In away I like it a bit better.
My question is in two parts first what is a good bias for these two different tapes 499 and GP9. At 30 ips I would bias at -2db or -1.5..
I was told -3db was standard for 15ips? .
Any comments or advise on this?
In doing so at -3db at 15 ips 10K is too hot and I can't bring 10K to a balance with the trim pot.
Years ago when I first got the machine Studer told me to replace the two caps on the record EQ boards from 1nf to 2nf. That work out fine for 30ips.
I could try 3 or 4nf but before doing so just wanted get some feed back on this. I called John French (JRF) on this but he's on vacation lucky him.
Any advise on this
Thanks
jim

[@?,*???&?]

All Studer decks have a record gap of .25 mils. Quantegy recommends a 4.0 overbias setting at 15 ips. At 30 ips, they recommend a 1.75 overbias adjustment.

[jsel84]

Thanks thats just about where I had to bais to get 10k even.

[@?,*???&?]

Cool!

Off you go then to make the sound of rock!

[jsel84]

Any idea's on the mod for the eq card. the mod I have on the card is 2200pf. I could try eaither a 1fn first then a 2nf accross the cap that is already there to raise it to 3 or 4nf.
regards
jim