How to lessen bass response in tube amp?

[bhuether]

This is unrelated to my last thread but pertains to the same amp - a Koch Powertone II. This amp puts out a LOT of bass even with the bass control turned all the way down. Its bass response makes playing with neck position humbucker difficult because the overpowering bass causes a somewhat rubbery sound.

I have a schematic if anyone is interested.

thanks,

brian

[black_labb]

a schematic would help. im unfamilar with the amp, so i cant help without it.

if its a combo it could be partially due to the speaker/speakerenclosure

[bhuether]

Here is the schematic:

www.guitar-dreams.com/misc/KochPowertoneII.pdf

I don't think it is a speaker cab issue because my other tube amps don't sound nearly as bassy.

thanks,

brian

[pdf64]

Any channel in particular too bassy, or all of them?
Does the damping switch help (try ultra low compared to high)?

[bhuether]

It is mainly the two gain channels where I notice the bass. The dampen settings do help somewhat. But they seem to alter the total frequency response versus affecting just the bass.

brian

[R.G.]

Cut one or more of C5, 8, 10, 14 and 17 in half. If that's not enough, cut them in half again a time or two. At some point, you'll start getting less bass.

[Guitarist]

and/or C1 and C6 could be 5 uF (vs. 4x that amount). Every clean channel I do now gets this treatment, thanks Howard.

[HTH]

I can't help thinking that the 470pF caps to ground (C9 and C16) may be dulling the amp's tone - sniping these out will increase treble and have the effect of less bass. You could of course just half the value of these caps and see if thats enough.

also, +1 on suggestions above - that 22uF cap on the cathode of the first stage won't be helping, try these too...

* C1 from 22uF to 1uF (less bass/tighter bass)
* C8, C10, C17 from 47nF to 22nF (less bass)
* try a 470pF cap accross R28 for more bite in the hi-mids
* C41, C42, C43, C44 from 47nF to 22nF (less bass)