SWTC2 questions please

[FingerBlisters]

With regards to AMZ's SWTC2 the copy says: "...the volume always remains the same but the amount of treble is controlled from flat to boosted as the pot is adjusted. There never is a low frequency rolloff with this circuit."

Seems plain enough but I've read different things about the treble boost aspect and it got me wondering: if that tone control was added at the end of say an overdrive circuit where you're using a low-pass fitler throughout of around 4khz, will the SWTC2 'start' at 4khz and boost up to (for example) 5khz? Adjust those figures as need be, they're only used for example

According to the site copy that's basically what should happen but after reading things on this forum I'm dubious it's that simple from a passive tone control because you're effectively trying to add what isn't there earlier in the circuit.

So I guess my question boils down to: does the SWTC2 boost treble that was cut off earlier in the circuit?

Q2: If it does not do that, then what do you think would be a nice low pass for a distortion pedal? I typically roll off trebles at around 3khz on gainier units to minimise noise/hiss/bad juju but will have to extend that to around 5k or even 6k if the SWTC2 isn't the right option.

For context, I'm looking at installing a 'presence' control of sorts in a pedal that has a Marshall tone stack already, but just wanted some extra high end control.

[GibsonGM]

All that passive tone controls like that can do is drop everything, then allow you to 'bring back' a little bit...so it's an 'apparent boost'.    It cannot boost what isn't there, no.    Whether there will be much '4k and up' content in your scenario is variable - distortion in active devices does add higher harmonic content, so there may be more there than we'd think even after a 4k low pass! 

Some can probably give you a specific good roll off for a certain circuit; I don't think there's any particular 'magic number' that would work universally.  Mine seem to be different from unit to unit and have to be tweaked, varying quite a bit.

[FingerBlisters]

All that passive tone controls like that can do is drop everything, then allow you to 'bring back' a little bit...so it's an 'apparent boost'.    It cannot boost what isn't there, no.    Whether there will be much '4k and up' content in your scenario is variable - distortion in active devices does add higher harmonic content, so there may be more there than we'd think even after a 4k low pass! 

Some can probably give you a specific good roll off for a certain circuit; I don't think there's any particular 'magic number' that would work universally.  Mine seem to be different from unit to unit and have to be tweaked, varying quite a bit.

I'll see what happens with low passes set around the ~4khz mark, and I'll socket the cap in the SWTC circuit and see where we go. Cheers for the reply

[FingerBlisters]

Hey just for anyone reading now or in the future, I couldn't get this to work as written/described regardless of pot value or cap value.

So what I ended up doing was keeping the SWTC2 in there, but also using a 10n cap over the volume pot (lugs 3 to 1, or input to GND in my case). This was the missing piece of the puzzle. For reference I'm using a 50k presence pot with a 220n cap.