Ok silly question and I think I got the answer but want to make sure. On gyrafs schematic he has the hi boost as 10ka but I think I read somewhere that the a and b are different I Europe than in the U.S. And 10ka actually is linear. In Europe. So just to make sure, the 10ka on his schematic as a hi boost actually is linear. Is this correct?
Pultec pots
- Thread starter Coldsnow
- Start date
Help Support GroupDIY Audio Forum:
yes, both 10 k pots are linear. there should be no difference between european and american parts. only one (100k) pot is logarithmic.Coldsnow said:
head to this topic for further assistance: http://www.groupdiy.com/index.php?topic=37837.0
best regards
weiss
I don't think it's wrong, but the PCB overlay has a wrong designation iirc.
HighBoost is 10K linear
LowBoost is 10K log
LowCut is 100K log
HighCut is 1K lin
High Q is 2K2 lin (or 2K5 if you're in the US)
Bypass gain is set by HighCut/HighBoost ratio (1:10, 20dB) - but as potentiometer tolerances are usually +/-20%, bypass unity gain may be slightly off. This easiest adjusted by adding a small trimmer to top end (clockwise) of either HighBoost or HighCut pot.
Jakob E.
HighBoost is 10K linear
LowBoost is 10K log
LowCut is 100K log
HighCut is 1K lin
High Q is 2K2 lin (or 2K5 if you're in the US)
Bypass gain is set by HighCut/HighBoost ratio (1:10, 20dB) - but as potentiometer tolerances are usually +/-20%, bypass unity gain may be slightly off. This easiest adjusted by adding a small trimmer to top end (clockwise) of either HighBoost or HighCut pot.
Jakob E.
MiamiBoy
Well-known member
So it doesn't matter if you use a 10K linear or logarithmic for LowBoost?
..yes, that difference always matters - it is about how action is distributed across pot working area. In the Pultec, LowBoost is 10K log..
MiamiBoy
Well-known member
Got it. My silkscreen/schematics says 10K LIN (rev.3).
Anyways, I've added a LOG 10K to my mouser cart
Last edited:
