Reduce bass on 6G16 Brown Vibroverb

[waldner]

I've been playing with this new 6G16 build for a couple of weeks now and it's a great sounding amp except that there is too much bass- especially with P90's or humbuckers.  Using the 2nd (low) input on either channel doesn't really help much.  I need to be all the way down on the bass control with single coils in the neck or middle position and would like to be further than all the way down with p90's or humbuckers.  I'm trying to reduce the low end so that the bass control was in a more useful range.  See attached schematic and layout. 


Is my best bet to reduce the value of Orange Drop caps connected to the bass control of each channel - .1uF and .047uF ? These seem to be coming from the plates of V1 and V2 and there is a 100k slope resistor in series.  Trying to understand how it works too.   Is there any other way that's better?  What about the 25uF cathode bypass caps? 


Thanks in advance knowledgeable people!!!

[jordan86]

Changing the value of the bass cap in the tonestack will alter the midrange as well. Probably a more aggressive approach than you want. You can make the 25uf bypass caps on the first two stages smaller, like 5uf or 10uf. Or you can adjust the .1 coupling caps between the PI and output stage to a smaller values. .047 or .022

[sluckey]

What about the 25uF cathode bypass caps?

Yes. Replace the 3 25µF bypass caps for V1 and V2 with 2µF or 5µF. Do these first. Then re-evaluate.

[waldner]

Cool.  Will try that first.  Thanks Steve.

[AmberB]

I would suggest replacing the .047 tone cap with a .02 cap, and the .1 tone cap with a .047 cap.  Or you could replace both caps with .02 caps...

[sluckey]

Another popular mod is replace the .1µF 6L6 grid couplers with .047µF.