A question about trim pot values
Posted: Wed Jan 30, 2019 10:59 amI finally did some recording with the J99s and flipped out at howw good they sound. Looking at the frequency curve (sine sweep) there is about a +1db boost starting at around 6k and ending around 35k (from memory). Very smooth and present without sounding hyped.
Anyway, the gains match almost exactly (within 1/20th of a dB) at all settings when the trim pots are down, but with both up one preamp has about 1.5 dB more gain. In fact, while one has about a 6dB variance in the trim (as expected) the other has almost 8dB.
Is this something that is to be expected due to variables in the pots? ...or is it likely I botched a resistor somewere? Until I do some more recording I won't know if it effects soujnd otherwise...but I don't think so.
1.5+ dB extra gain seems awfully out of spec for just pot variances though. I did test each resistor as I stuffed the board, and other than the 2 phantom resistors being .3% instead of the commonly suggested .1% they were al well within tolerance range.
Peculiar. I think it must come down to the trim pot though, since the gains are almost exactly matched with the pot turned all the way down. I am using 990c's.
Shane
P.S. For those of you looking for clean gain, and lots of it the J99 is the best I have ever heard. Maybe it's becasue it's the newest one I have, but it even sounds better than the A12 and N72 in a lot of ways (although I still love them all!)
Anyway, the gains match almost exactly (within 1/20th of a dB) at all settings when the trim pots are down, but with both up one preamp has about 1.5 dB more gain. In fact, while one has about a 6dB variance in the trim (as expected) the other has almost 8dB.
Is this something that is to be expected due to variables in the pots? ...or is it likely I botched a resistor somewere? Until I do some more recording I won't know if it effects soujnd otherwise...but I don't think so.
1.5+ dB extra gain seems awfully out of spec for just pot variances though. I did test each resistor as I stuffed the board, and other than the 2 phantom resistors being .3% instead of the commonly suggested .1% they were al well within tolerance range.
Peculiar. I think it must come down to the trim pot though, since the gains are almost exactly matched with the pot turned all the way down. I am using 990c's.
Shane
P.S. For those of you looking for clean gain, and lots of it the J99 is the best I have ever heard. Maybe it's becasue it's the newest one I have, but it even sounds better than the A12 and N72 in a lot of ways (although I still love them all!)