BACK OFF...passive control.

[anotherjim]

Bloody good puzzle.
As long as there was a pull down + working DC blocking cap on whatever it's feeding, it shouldn't click/ pop/crackle - well, no more than your guitars pickup selector does - 'cause all switches bounce.
Colour me 

If you consider that blocking cap in the next thing, with your circuit bypassed, then the in side of that cap charges to ground either via the guitar, or it's own pull down. When you bring in your extra pot, that also shows the input cap ground, in addition to the previous mentioned sources. Only in the brief changeover of the 3PDT will the next input be dependant on it's own pull down, and even if that's missing, it won't have time for the caps input side to drift far from ground - unless there is a DC fault because the in cap is leaky.

Check for some DC volts on across your out jack.

[deadastronaut]

its a puzzle indeed ...for such a simple passive bugger...

no DC on in /out..at all...

tried it with just the spitfire after , same thing....test recording ...click click click....

only noticable with gain...hmmm.........

[anotherjim]

Unlikely I know, but could it be a bad 3PDT?

[deadastronaut]

yeah ive considered that too.....hmmmm

i'll pop it out and change it...it has to be that.

i tried it in my lil roland cube too...same thing....very weird..

[Ben Lyman]

I'm curious to know what might happen if the pot were wired as a variable resistor rather than a voltage divider?

[deadastronaut]

^as VR there is no vol off


i just breadboarded it exactly as diagram,

nightmare with 8 croc leads on a 3pdt..(even used a black 3pdt instead of blue..)

test recorded... still clicks ..with distortion..

cant believe this simple lil bugger is kicking my ass

shame as its great to play with...hmmmm...

i really want this passive, rather than 9v power/ buffer etc...

bummer..

[ashcat_lt]

It's pretty common over at GN2 where some dude comes through complaining that he has added a kill switch (because Tom Morelo) and the darn thing clicks every time he flips it, but only when he's pounding it into some pile of distortion (because Tom Morelo)... 

I'm afraid there's just not anything you can do except teach yourself to flip the switch on the zero crossings. 

[deadastronaut]

yeah i get ya...@#$% tom morello cherry @#$%er...i just want/need an instant clean up box

yep, tested, tested....tested...

click..click...click...

no joy, bummer...grrrrrrr.....

[ashcat_lt]

yeah i get ya...@#$% tom morello cherry @#$%er...i just want/need an instant clean up box

yep, tested, tested....tested...

click..click...click...

no joy, bummer...grrrrrrr.....

Yeah, I'm sorry, but you are causing an instantaneous change in level -  a stair step - whenever you flip that switch unless it is actually (accidentally) happening right when the signal is at 0 crossing.  And that's even if your switch wasn't physically bouncing.  It almost has to click.  The fact that you don't hear it when it's clean means that it's a really low level to begin with, and it's only the gain-and-smash of whatever is distorting it after that makes it audible. 

The only chance of fixing that is if you can slow down the switching so that it acts as a ramp up or down rather than a stair step.  You could do that by putting a cap across the switch, but if you slow it down enough not to click, you'll also be filtering out all of the high frequencies from your actual signal, and I think that would be worse. 

If you really want the best chance to avoid clicking, you need to go active.  Transistor switching similar to the flip-flop bypass schemes in commercial pedals can be tweaked to switch more slowly.  Not sure if you want to go that far.

[Groovenut]

Rob

Have you tried putting a small value resistance in series with the input and output? Like before and after the switch so they are in circuit full time. My logic is that possible limiting the signal current will help the situation. My guess would be start with 100R and work up, see if it improves.

I think you are experiencing what a majority of all mechanical switches do when put upstream of high gain circuits. The high impedance of the circuit being fed allows the switching transient to couple to the input.


My 2 cents

[thehallofshields]

Hmm... This is okay, but I prefer a 7-Band EQ to achieve this 'Backing Off' 

[Rixen]

I have read that switch contacts can generate a small voltage when they hit each other, if true perhaps it is a piezo electric effect from an oxide layer on the contacts ?

[deadastronaut]

cheers lawrence, i,ll give that a whirl later ....

if not i,ll HAVE to resort to active....boo hoo....

[stallik]

Tried it a different way. No popping unless I held the switch (must have been my electric personality)
I only had a momentary footswitch so that may have a bearing on things but running into my spitfire, I ended up with a kind of variable clean/dirty/clean killswitch. Cool! May just box this one up


EDIT: Just added a treble bleed cap. Keeps this much clearer at lower volume. I used 1nf but adjust to taste Please ignore this bit. That's not where I put it. It shouldn't work but does - investigating

[deadastronaut]

clean, dirty variable, kill.....yep exactly what im after...

it works really cool for instant gain gontrol.....soft , full....lovely to play...

adds nice dynamics....

i think your  momentary might be negating the click though....

a pedal guy with no switches?....are you mad ha ha...

[stallik]

Lightvol?

Bring it on!

[stallik]

OK, I've now tried it with a 3PDT switch and it's still pop free.
Have to leave it now - meant to be mowing the lawn while my wife does the shopping

[Gus]

An untested idea

Wire the input to "top" of the volume control
"bottom" to ground
Connect a >=10meg resistor between the wiper and "top"
Connect the wiper to the output
Short the >=10meg for full volume
You always have a connection do not know if the 10meg step will be heard

Not ideal

Will mess with the taper and loading, however it should reduce the pop. 
Maybe if you use the control where it does not have the wiper near ground it might work well enough.
Could use a resistor between the "bottom" and ground as a limit

[ashcat_lt]

Tried it a different way. No popping unless I held the switch (must have been my electric personality)
I only had a momentary footswitch so that may have a bearing on things but running into my spitfire, I ended up with a kind of variable clean/dirty/clean killswitch. Cool! May just box this one up


EDIT: Just added a treble bleed cap. Keeps this much clearer at lower volume. i used 1nf but adjust to taste

That's not a volume pot, it's a variable resistance to ground.  It will work more or less like a tone control if connected directly to passive pickups, and probably some kind of HPF connected to the capacitive output of a pedal.  Any broadband reduction will be the resistive part of the source over this pot.  With relatively low-Z pedal outputs, you should have to turn it way down to get much attenuation.

If by treble bleed you mean that cap between the jacks, it ain't actually doing anything because its shorted by the blue wire.

If it works for you, though..

[stallik]

Yup, that's exactly what it is, hence my comment about a different way. You're right about the pot, I've got a 2M2 (linear is all I had) and I do have to turn it down, + everything happens in a small part of the sweep. Nevertheless, once set, it works without popping. It doesn't work as a tone control as there's no cap but a tone control is where I got the idea.
Regarding the bleed cap. Again, thinking about it,I agree. It should do nothing yet it does in my setup. Got to figure that one out. Will put a switch on it as it may just be a placebo effect