Pearl input voltage difference

[Zappa]

One question about the Pearl Phono project : what the hell is the difference of source voltages for the input FETs (Q8 - 11) means??? Are these voltages randomly choosed around a nominal value to simulate differences in Vgs or what??? Not very clearly explained in the original article...

Thanks!

p.s. aaaarg! I'm unable to post the .jpg of the Pearl input section I have on my HD!?!

 

[DavidMM]

I believe these are the voltages that were actually measured at the source. If you matched all the FETS, then these voltages should all be basically equal. I am not sure how closely they need to be matched.

Dave