How to perform Tone Wicker mod

[Guitarfreak]

I've got a Big Muff Pi and I've already installed the Tone Bypass mod and I'd like to perform the Wicker mod as well.  I've done enough research to find out that the mod supposedly bypasses three 470pf caps that roll off the top end on the pedal.  It says that you do this with a 3PDT switch, I haven't got a clue how to wire it.  If the mod is a bypass to the caps then do you remove the caps from the board and replace them with in/out wires on the 3PDT as well as solder the caps to the switch?

[dune2k]

The first three transistor stages all have caps to roll of treble in them.
You only have to break the connection on one side of the cap to lift them out of the circuit.

The rest should be easy to figure out.

[Guitarfreak]

So it would be something like this then?

[Ben N]

Yup.

[tubelectron]

Hi,

I have a Big Muff Pi plus Tone Wicker (the white one with green lettering and the 2 small switches) - I bought it in May 2009.
At that time, I did not found any info about the Tone Wicker.

I opened my pedal and, except that the PCB is realized with mounting surface components (so nearly impossible to modify IMHO), I saw nothing apparent about the switch of the Tone-Wicker.

But I will try to look further, now.

A+!

[dune2k]

Yup.

You got to turn the switch 90° left or right, then it's fine.

[Guitarfreak]

Yup.

You got to turn the switch 90° left or right, then it's fine.

Well that's relative to which contacts are linked to which other contacts though.  Are the contacts on the actual switch labeled, or am I taking a 50/50 shot when I wire it?

[JKowalski]

Yup.

You got to turn the switch 90° left or right, then it's fine.

Well that's relative to which contacts are linked to which other contacts though.  Are the contacts on the actual switch labeled, or am I taking a 50/50 shot when I wire it?

Check it with a multimeter. I don't think they are labeled. Usually the direction of the lug holes are the pole (you can stick a long wire through all the holes in the lugs and that will be your pole) but that may not always hold true.

If you don't have a multimeter... Hmmm.... How about hooking up an LED to it, like 9V->Resistor->LED->middle lug of switch and try grounding the other side of the LED (turning it on) by touching a grounded wire to all the contacts that could be the pole.

[stringsthings]

if you can find a 3PST switch, you may be able to save a bit of money ....

[Guitarfreak]

Awesome insight, I didn't know that about the switches, even if it may not always be true that's interesting.  The 3PST switches I am finding on Mouser are the same price as 3PDT's.  It's a neat idea though, I may actually prefer using 3PST because then I won't have any unused lugs.  Not that it matters too much, but my eyes are very OCD 

[Guitarfreak]

Sorry to bring back a dead thread, but I have the switch in front of me and I'm planning on doing the mod within the next few days.  The drawing I posted earlier, that is still valid right?  I don't need to have the other throw connect to the capacitor output completing the circuit right?  Because the capacitors are in the transistor stage's negative feedback loop so they don't technically need to be there to complete the circuit.  Do need, don't need, what do you think?

[DC9V]

The drawing I posted earlier, that is still valid right?  I don't need to have the other throw connect to the capacitor output completing the circuit right?  Because the capacitors are in the transistor stage's negative feedback loop so they don't technically need to be there to complete the circuit.  Do need, don't need, what do you think?

That's right, you only need a way to break the contact to one of the poles of each capacitor, so your drawing is correct, assuming that your switch is properly oriented...
...but if you're using a center-off 3PDT, you could use the other side of the switch to try another set of capacitors, and the center position would be the wicker mod.

High roll-off mod: Notice those small ceramic caps on 3 of the transistor stages? They are used to roll of excessive highs. Normally they are 470 pF (C2, 5 & 8 ) but larger values roll of more highs. You can also remove em for a great result.

[igerup]

You can use the other side of the 3PDT to switch in a set of different capacitors; either a different capacitance or a different type (film/paper-in-oil/NOS-Mallory/etc ) .It'll make for more tonal variations.