Baxandall Tone stack...

[Bob M.]

Hi,

I've built a small in-house amp for myself and I'm quite happy with how it sounds (2x 12AX7A preamp, 2x power tubes, in parallel, 1x 10" speaker). But I'm unhappy with the current tone stack so now I'm doing Rev2 because I want to implement a 2-knob (treble and bass) Baxandall tone stack in this amp. I'm confused by all the various cap, resistor and pot values and tapers that I've seen with all the various Bax circuits that I've viewed schematically. Has anyone 'broken the code' with Baxandall values that sound and work good in a small all-tube guitar amp. If so, I'd greatly appreciate it if you would pass on your results. Values seem to vary quite alot from Ampeg to Orange to Hiwatt to Carvin and other amps I've viewed using a Bax tone stack.

Thanks in adv,

Bob M.

[Jazz P Bass]

See if this Tone Stack Calculator helps fill in the blanks.
Link: TSC

[Dave H]

The Baxendall tone control is an active (negative feedback) circuit. If you use the active circuit the pots should be linear taper so that the response is flat with the pots centered. If you use a passive circuit (James?) the pots should be log taper (10%?)

[J M Fahey]

I *suspect* (like Dave H hints at) that you name "Baxandall" what's actually a "James" type one.
If so, start by using the classic Ampeg tone stack, can't be too wrong with it

[dmartn149]

I used this layout on my converted Knight PA (6sc7 pre and 2 6L6)
Adam's Amplifiers: Tone Stacks
With component values pretty much as shown. Works and sounds pretty good. It's presented as a "Baxandall" but it's really a "James". I think the difference is in where it is in the circuit. I'm sure someone will correct me if that's not correct.