A better treble bleed circuit

[col]

Hi JohnH

I do not mean to perform surgery on the second pot to change the wafer. It would be dual-ganged pot, one 500K, and the other 2meg (or possibly 1meg). I've been working on an idea which requires the use of dual-ganged 500k/2meg pots and wondered if your circuit could be incorporated to make use of the 2meg pot.

Alternatively, might a resistor in parallel (680K) between the zero end of the 2meg pot and its wiper provide a workable sweep? Though, I am not sure if I have enough switch poles available to achieve this and the other switching the circuit would require.

If this is not achievable, I'll publish my circuit (without your treble bleed) soon.

[JohnH]

Ok, well given a few days I can check that out using GuitarFreak. As a starting point, would the 500k and 2M wafers both be log taper?

[col]

May 6, 2024 16:23:40 GMT -5 JohnH said:

Ok, well given a few days I can check that out using GuitarFreak. As a starting point, would the 500k and 2M wafers both be log taper?

The guitar pot can be either (but probably log). But the bleed pot will be linear.

Thank you, JohnH.

[col]

Urgh. I had missed that you used a log pot in your bleed circuit, JohnH. I do not wish to see you go to a lot of trouble. If you like, in a day or two, I can post my design (with a variant incorporating your bleed circuit) and you can then assess if it is worth investigating component values to hopefully make it work properly.

[JohnH]

ok thanks, sounds like a plan!

[stateofepicicity]

I had been using an 820pF||150k bleed for a while, finding it really good for rolling back, but it nagged me still that my tones didn't have the same kind of butt rolled back that they would with the volume at full.  I tried again, experimenting by ear, and found that 1.5nF||47k sounded just right for my tones these days, rolling the volume pots anywhere from 3 to 10.  I'm thinking it's not necessarily that a very close frequency shape across volumes at the input of an amp sounds consistent after being shaped by the pre- and poweramps.  I'm sure this is highly dependent on your tones and gear, but I think the values recommended in this thread are the best place to start for any bleed.