Not sure how much this reply from Ciaran regarding the Sunn 200s would apply to the Bassman? I'm guessing that changing the 68K resistor would possibly have the same effect as acting as a pre-gain? but there is already a 47uF cap between the second FET's source and ground, so would increasing/decreasing that cap affect the gain?
Many thanks in advance
If you want to add gain you could try putting a cap between the second FETs source and ground...just like the first stages 250uF...maybe on a switch? Theres room on the layout for that.
Reducing the 68k at input will allow more guitar signal it hit the first gate. Maybe replace that with a pot and call it pre-gain?
Yes, changing the resistor to a pot would act exactly as described. Increasing the cap value will increase the gain. decreasing will lower the gain. But there comes a point where it just starts sounding terrible so I would definitely socket it and try a few values.
Thanks Ciaran, much appreciated been building for less than a year (Mostly successfully so far)and still haven't really got a clue what I'm doing, but thanks to the generosity of all those like yourself who are so willing to help and share their superior knowledge with the rest of us, I've managed to learn far more than I thought I could when I started......so now I know next to nowt, rather than absolutely nowt, and some day I might even now summat, until then simple questions and little steps
I built Bassman Preamp with ROG Condor Cab Sim and they worked very well together. The Cab Sim have excessive trebles to my ears and i will mod this. When i finish, i come back here to post a demo. Sorry my poor english.
I just finished the Sunn200s, everything seems fine, no bridges, no cold solders, but when I plug I just heard the guitar like really really quiet, in the background, at very low volume. The tone and the volume control seems to work fine tho.
Is just the signal that's comin' out too low.
What could be the problem? Thanks in advance, and sorry for my english...
Just finished this, and it sounds pretty good, however I find the high frequencies a bit hizzy and I tend to roll the treble all off. Is there a way to reduce the hizz? Also, why isn't there any diodes included in the layout?