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I recently built this amp and it seems too bright. I changed the cathode bias cap at v1b to 10uf but still sounds bright.. any thoughts about adding a bright cap at the master volume to shunt some highest to ground?

Dabreeze wrote: ↑

Sat 06/25/22 4:57 am

I recently built this amp and it seems too bright. I changed the cathode bias cap at v1b to 10uf but still sounds bright.. any thoughts about adding a bright cap at the master volume to shunt some highest to ground?

What speaker are you using?

Which schematic did you follow?

I wouldn't rush into taming the brightness too much. In a live setup you'll need the extra treble.
Things that you could try:
1. Speaker swap like Josh is insinuating in case you have an overly bright speaker in there. If it's a brand new speaker it might still have to be broken in to loose that brittle top end.
2. Add a 50p to 250p snubber cap across the PI plates
3. Put a 100p to 300p cap in parallel with the plate load resistor of V1A.

Those are simple things to try which are not invasive. Fiddle with the values to taste..

The other things to consider are the tone stack, which is why I asked which schematic was used. The treble cap and the mid pot value both impact the top end significantly.