Tone stack idea-will it work?

[daz]

i was thinking about ways to make the mids sweepable in the typical passive tone stack. I have a marshall style build with the typical .022/.022/500pf tone stack with a 33k slope. what i am thinking of trying is putting a sweep pot in and wiring it up so that i have a second mid cap, probably a .1uf wired up to the pot so that i can gradually add it in parallel with the .022uf. Using duncan's calculator i would be able to sweep the mids from about 400Hz to about 900Hz. Theres a world of tones within that area and i think this could prove invaluable in being able to fine tune an amp to taste because it's really the mids where a lot of the character of an amp is. Not sure if it will work, but i was wondering if anyone has done anything similar or knows of any past designs that utilized something similar.

I need to try this but can't till probably this weekend at soonest. So in the meanwhile i'd like to hear any thoughts.

[loudthud]

Try puting a 50K pot in series with the 33K. Then maybe a switch to change the .022 that goes to the mid pot to .01, .022, .047.

[daz]

I've done the variable slope thing but found i like 33k all the time. As for the mid cap, i wasn't so much wanting to make it switchable but continuously variable in trying to make it sweepable from .022 to .1 and anything in between. whether that will work or not i dunno, but thats what i was asking.

[cbarrow7625]

Daz, instead of trying to make the 0.1 come in parallel with the .02, you'll probably hve better luck and a wider range of tones by adding a second pot to independently ground out the .1 cap.

Connect one end of the .1 cap to the end of the 33k resistor and the other end to the wiper of a 50-100k audio taper pot with one leg grounded. That way you'll be able to dial out a little mid with the .1uF pot but still dial in a little grunt with the standard .022uF pot.

I've never tried it, but it just makes more sense to me than trying to just parallel another cap around the .022 with a pot in series. You wouldn't really have a lot of tonal control with that setup.

[daz]

Well, i suppose thats a different take and i'll try that too if what i proposed doesn't work. i imagine both will do something. Whether either will be useful i'll have to see, but i'll give that a try if my idea doesn't work. thanks.