Pots on Tone stack

[hebaton]

I am looking to add a channel on an existing amp and would like to use "James" tone stack. It appears they usually call for Linear pots but, for practical reasons I would like to know what to expect if I used Audio taper instead ?

Would it behave in a very different way ?

[Stevem]

Before we even talk about pots, what amp is this and how are you planing to add the extra channel and mix it in?

[hebaton]

It used to be a traynor YBA-3. THe front end was redone following Fender AB769 Twinn reverb ( as much as possible ) there is a complete dual triode avilable

[thetragichero]

have a play around here: https://www.guitarscience.net/tsc/james ... T_pot=LogB

[sluckey]

I am looking a add a channel on an existaing amp and would like to use "James" tone stack. It appears they usually call for Linear pots but, For practical reasons I would like to know what to expect if I used Audio taper instead ?

Would it behave ina very different way ?

Ampeg used log pots in their James tonestacks... https://el34world.com/charts/Schematics ... g_g12_.pdf

I used log (audio taper) pots in my James tonestack. Works very well... http://sluckeyamps.com/phoenix/phoenix.pdf

[hebaton]

Thank you, that's exactly what I needed. Solves my questionning.

[hebaton]

I am looking a add a channel on an existaing amp and would like to use "James" tone stack. It appears they usually call for Linear pots but, For practical reasons I would like to know what to expect if I used Audio taper instead ?

Would it behave ina very different way ?

Ampeg used log pots in their James tonestacks... https://el34world.com/charts/Schematics ... g_g12_.pdf

I used log (audio taper) pots in my James tonestack. Works very well... http://sluckeyamps.com/phoenix/phoenix.pdf

HI, thank you for the schematic. I am trying to do pretty much the same but for parctical reasons, I only have one position for both tone pots. SO I need to use a double concentric pot.
I cannot find a 1meg/1meg but I do see 500k/500K Audiotaper available. WOuld that behave much differently ?

I tryed runnig tha in the Tonestack emulator app but did not seem to see any effect from the change...
Your opinion please ?

Thanks again !

Claude

[sluckey]

Your opinion please ?

Try it and see. You ain't gonna blow up anything.

[hebaton]

you're right !

[hebaton]

I am looking a add a channel on an existaing amp and would like to use "James" tone stack. It appears they usually call for Linear pots but, For practical reasons I would like to know what to expect if I used Audio taper instead ?

Would it behave ina very different way ?

Ampeg used log pots in their James tonestacks... https://el34world.com/charts/Schematics ... g_g12_.pdf

I used log (audio taper) pots in my James tonestack. Works very well... http://sluckeyamps.com/phoenix/phoenix.pdf

HI again. I completed ( in fact had it done by a competent tech ) the amp and got two great sounding, very very clean channels. I aam wondering if you could suggest ways to make the "Ampeg" side, dirty up, preferably rather quickly ?

[sluckey]

I've always considered Ampegs (the blue diamond series) to be warm, clean sounding amps. Never even considered making them sound dirty. My old Ampegs responded well to pedals. Maybe just stick a dirt pedal in front and see what you think.

[hebaton]

Defenitely something to try. And, by the way, the combination of the two channels sound absolutely glorious !

[thetragichero]

didn't the owner/founder/whoever of ampeg outright state that distortion has no place in his amps?

[hebaton]

One more thing. Can anyone think of / suggest a way to compensate the loss in gain from the "james" tone stack so that there would be less difference in volume between the two channels ?

[pdf64]

It shouldn’t be too hard to reduce the gain in the other channels a tad, so as to even them up. eg lift a cathode bypass. Or (unless you’re turning the volume up full) use a volume control with a linear taper on the james channel; that will result in a higher gain level at moderate settings.