Building Shika fuzz on Double Muff board

[zeropluszero]

Looking to build Shika fuzz on double muff board - Would just like to clarify a few things.
As the tone pot is reversed on the Shika, are the following mods correct?

R17 - 3.3nf
R18 - 10nf
C10 - 33K
C11 - 33K

And as the pot values are 50K for the Shika - 1, would it make a huge difference if they were 100K and 2, if so, I understand I can solder 50K across pins 1 & 3 to bring them to 50K, but are these the top or bottom in the dual gang pots - I'm planning to use the A side for the Shika (I think the traces look like to the bottom row, but to confirm)

 

[Feral Feline]

Your DoubleMuffin's C10 should be 39k, according to the Shika schematic I have.
Same for DM's C11 — my Shika schematic has 39k listed.


✔ R17 — 3.3nf
✔ R18 — 10nf
C10 — 39K
C11 — 39K

1, would it make a huge difference if they were 100K?

1) I don't think so, but I haven't breadboarded the Shika yet.

2, if so, I understand I can solder 50K across pins 1 & 3 to bring them to 50K

Resistor across 1&3 will change the taper. You could pull apart a 50k dualgang and a 100k dualgang, but a resistor across is far easier and how much the taper changes, I don't know if it matters enough to warrant disassembling two dual-gangs to reassemble and risk them being faulty afterwards.

[#3] but are these the top or bottom in the dual gang pots?

For your convenience, I've colour-coded the PCB for any "GOTCHA!"s, which are mostly down the middle:

 

[zeropluszero]

Thanks, yeh the 33K was just a typo.
I'll give the resistor across 1&3 a go - I think it should be fine.

 

[zeropluszero]

For anyone who reads this, I did the mods
R17 - 3.3nf
R18 - 10nf
C10 - 39K
C11 - 39K
And the tone pot still rotates the opposite to the green russian I built on the other side.

 

[Feral Feline]

Thanks for the follow up.

I thought you wanted it to be reversed like on the Shika.

...
And the tone pot still rotates the opposite to the green russian I built on the other side.

That sentence now leads me to believe otherwise.

Just to clarify, you want the Shika-side's tone knob to behave like the Shika (reverse) — or while retaining the values of the Shika, have it behave like a normal Muff?


SHIKA ROTATION: What if... you ...
Swap the caps?
R17 = 10n
R18 = 3n3
Will it then behave as you wish?


MUFF STANDARD-ROTATION: If you want Shika values but regular good ol' spinning bass left and treble right...

R17 39k
R18 39k
C10 3n3
C11 10n


The mod of swapping caps-for-resistors and vice-versa resistors-for-caps was to achieve having the Shika's side rotate opposite to the Russian side — to compensate for the standard rotation of the pot;
the original Hizumitas and PedalPCB's Shika both achieve the opposite rotation by flipping the pot's outer lugs, not by swapping where the HPF & LPF are located.

So... as in the schematic snippet above — Regular rotation lug-numbering top down:
3
2
1


SHIKA:
1
2
3

If you look at the Shika schematic, it has the same exact orientation of the HPF & LPF resistors and capacitors as any Muff, just the TONE-pot's outer pins are swapped.


I don't know if I'm being clear or muddying the waters further here, hopefully the former.

 

[zeropluszero]

What I have at the moment is
Green Russian B has scoop to the left anticlockwise and rasp to the right.
The shika side is the opposite, and I'd like them to be the same.

 

[anevilspar7an]

Easy mod, lop off pins 1 and 3 of the Shika part of the potentiometer and use either wire or diode cutoffs to wire pin 3 across to thru-hole 1 and pin 1 to thru-hole 3.

 

[zeropluszero]

is it weird that id prefer to move the caps and resistors?

 

[Feral Feline]

What I have at the moment is
Green Russian B has scoop to the left anticlockwise and rasp to the right.
The shika side is the opposite, and I'd like them to be the same.

The same, but ... which way?

Both like how the Shika side is, or both how the Green Russian is?

Easy mod, lop off pins 1 and 3 of the Shika part of the potentiometer and use either wire or diode cutoffs to wire pin 3 across to thru-hole 1 and pin 1 to thru-hole 3.

There is no need to do anything so drastic. I'll refer to my previous post, #5.


The Shika got its reverse rotation by the POT being "flipped".



If you want normal/conventional rotation for both the Shika and Green Russian...
DO NOT SWAP LEGS
DO NOT SWAP COMPONENTS
POPULATE AS PER EACH SCHEMATIC:



Whatever the refdes is, the above is taken from the PedalPCB docs, w/o refdes above because you need to work out the correct corresponding places-spaces to populate as above regardless of refdes.

THE ONLY MOD would be to put the 100k resistor across the SHIKA gang of the dual-gang 100k TONE-pot, which will give you the Shika's 50k value: 100k in parallel with 100k = 50k as per the 1728's online calc.

NOTA BENE, doing so will still alter the taper-response slightly, as noted in RG KEEN's THE SECRET LIFE OF POTS.

 

[zeropluszero]

I have the Green Russian in 'B' and this is set exactly as per muffin schematic.
I've done the 100K resistor over the A side of the volume, tone & sustain pots (works great actually, no volume difference when switching)

So if I have this right, because the pot is "correct" on the double muff PCB, and was only "incorrect" on the shika pcb, to correct what I have, I just need to put the

"A"
(a)R17 - 3.3nf -> 39K
(a)R18 - 10nf -> 39K
(a)C10 - 39K -> 3.3nf
(a)C11 - 39K -> 10nf

I guess I totally overcomplicated it in hindsight.

 

[Feral Feline]

I have the Green Russian in 'B' and this is set exactly as per muffin schematic.
I've done the 100K resistor over the A side of the volume, tone & sustain pots (works great actually, no volume difference when switching)

So if I have this right, because the pot is "correct" on the double muff PCB, and was only "incorrect" on the shika pcb, to correct what I have, I just need to put the

"A"
(a)R17 - 3.3nf -> 39K
(a)R18 - 10nf -> 39K
(a)C10 - 39K -> 3.3nf
(a)C11 - 39K -> 10nf

I guess I totally overcomplicated it in hindsight.

Yes, just put everything in its rightful place — resistors go where resistors should go, and same for caps:

(a) R17 = 39K
(a) R18 = 39K
(a) C10 = 3.3nf
(a) C11 = 10nf

 

[zeropluszero]

Fixed those up, all done.