Big muff tone bypass mod

neiltheseal

Active member
Hi everyone

I built the Muffin fuzz to violet ram's head specs. As there is lots of space in the pedal I'm thinking of making some mods. The first one I'm thinking of is the tone wicker/tone bypass mod.

However I'm having trouble getting my head around this. I've seen this schematic but not sure how to go about doing this. Here is the Muffin fuzz schematic. Could i connect the collector of Q3 to one end of a SPDT switch (on/off) and the other end to C12?

Am I on the right track here?

I also would be interested in any other mods that are good. Considering a switch to swap between germanium diodes and silicon. It woudl be good to hear some suggestions.
 
Yup, that's what EHX uses for the bypass, a 150k.


Since you're going to put the diodes on a switch, I'd recommend putting at least one of the clipping sections on a on-off-on so you can do Supa Tone Bender-ish settings.


I can never remember which clipping section has the full diode lift on a TB... it's the first one.

Try this, see if you like it:

1st clipping section Ge-asymmetrical/None/Sili​
2nd clipping section Ge/LEDs/Sili​

That way you've got stock (silicon), ToneBender with clipping options, and full Ge with a hint of even-order harmonics.

If you socket some vero or perfboard and wire the switches to that, then you can experiment extensively with different diodes until you settle on what you like best. For instance maybe Schottky is a better fit than Ge (similar forward voltage, but not temperature sensitive as Ge); or Schottky with a MOSFET transistor's diode (2N7000, BS170, IRF510, IRF520); Green vs Red LEDs; doubled-up silicon vs asymetrical trios of silicon...
 
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Tone wicker is different from tone bypass. The tone bypass removes the tonestack stage from the circuit, while the tone wicker can be achieved by using a 3pdt to remove the 470pF caps from each of the first three transistor stages (c10,11,12 in the first schematic you shared; c2,6,9 in the muffin fuzz)
 
Yup, that's what EHX uses for the bypass, a 150k.


Since you're going to put the diodes on a switch, I'd recommend putting at least one of the clipping sections on a on-off-on so you can do Supa Tone Bender-ish settings.


I can never remember which clipping section has the full diode lift on a TB... it's the first one.

Try this, see if you like it:

1st clipping section Ge-asymmetrical/None/Sili​
2nd clipping section Ge/LEDs/Sili​

That way you've got stock (silicon), ToneBender with clipping options, and full Ge with a hint of even-order harmonics.

If you socket some vero or perfboard and wire the switches to that, then you can experiment extensively with different diodes until you settle on what you like best. For instance maybe Schottky is a better fit than Ge (similar forward voltage, but not temperature sensitive as Ge); or Schottky with a MOSFET transistor's diode (2N7000, BS170, IRF510, IRF520); Green vs Red LEDs; doubled-up silicon vs asymetrical trios of silicon...
Thanks. I like the sound of this.
 
Well I tried this as I described above (connecting the collector of Q3 to a wire and another wire to C12. I put a 100nf cap on each wire and a 150k Resistor in between them both).

It worked, but not as I had expected. It certainly had an effect on the tone, but the tone know still worked, I had assumed this woudl bypass the tone.

I guess the collector of q3 is still connectd to the tone circuit and I will need a way to completely isolate that.
 
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Wait a moment... your mod doesn't sound right, to me. Like that I think you have the new signal «100nF - 150k - 100nF» in parallel with the original Tone, so I expect the Tone still do something.

Look at the schematic with the Tone Bypass Mod, that is a real bypass of the tone, you need a DPDT switch to interrupt the signal at the begin and at the endof the tone, and make the signal pass through the «100nF - 150k - 100nF».
Try it.

(That is if you want to follow the original schematic, but maybe you can omit the second 100nF, and use just «100nF - 150k»).
 
Wait a moment... your mod doesn't sound right, to me. Like that I think you have the new signal «100nF - 150k - 100nF» in parallel with the original Tone, so I expect the Tone still do something.

Look at the schematic with the Tone Bypass Mod, that is a real bypass of the tone, you need a DPDT switch to interrupt the signal at the begin and at the endof the tone, and make the signal pass through the «100nF - 150k - 100nF».
Try it.

(That is if you want to follow the original schematic, but maybe you can omit the second 100nF, and use just «100nF - 150k»).
Thanks. I didn't have a switch so thought I'd try without it. Obviously the wrong idea.

Once I get a switch i'll try it again. BY the way, what type of dpdt do you think I should use?
 
A simple DPDT On/On toggle switch is ok.

Another thing: if you are working on the PedalPCB you should interrupt some trace on it, after the Q3, the side between Q3 collector and C10, R17; and interrupt the trace between Tone 2 and the negative side of C12, because will be the switch to connect that two interruptions in one of the switch mode, the one with the Tone will work. The other mode will connect Q3 collector to the 100nF - 150k - 100nF to the negative side of C12.

It's not so easy work on the PCB like that, but it's not impossible.
 
A simple DPDT On/On toggle switch is ok.

Another thing: if you are working on the PedalPCB you should interrupt some trace on it, after the Q3, the side between Q3 collector and C10, R17; and interrupt the trace between Tone 2 and the negative side of C12, because will be the switch to connect that two interruptions in one of the switch mode, the one with the Tone will work. The other mode will connect Q3 collector to the 100nF - 150k - 100nF to the negative side of C12.

It's not so easy work on the PCB like that, but it's not impossible.
Exactly. ID'ing a component node by sight is not always intuitive.
 
Hi everyone

I built the Muffin fuzz to violet ram's head specs. As there is lots of space in the pedal I'm thinking of making some mods. The first one I'm thinking of is the tone wicker/tone bypass mod.

However I'm having trouble getting my head around this. I've seen this schematic but not sure how to go about doing this. Here is the Muffin fuzz schematic. Could i connect the collector of Q3 to one end of a SPDT switch (on/off) and the other end to C12?

Am I on the right track here?

I also would be interested in any other mods that are good. Considering a switch to swap between germanium diodes and silicon. It woudl be good to Ask AI APK - is a good application trusted by users, it supports you to solve problems in all different topics and fields Modsome suggestions.
From what you've described, it seems like you have the right idea. Connecting the collector of Q3 to one end of a SPDT switch (on/off) and the other end to C12 should effectively bypass the tone control circuit when the switch is in the "off" position, allowing for a brighter, more open tone.

However, it's important to note that modding a pedal can be a complex process, especially if you're not experienced with electronics. If you're not confident in your ability to make these modifications, it may be best to seek out the help of a professional or experienced pedal builder.

As for other mods, swapping between germanium and silicon diodes is a common modification for Muff-style fuzz pedals. You could consider adding a switch to toggle between the two types of diodes, allowing you to experiment with different tonal options. Another popular mod is to replace the stock tone control with a different type of EQ circuit, such as a mid scoop or a presence control.
 
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Tone wicker is different from tone bypass. The tone bypass removes the tonestack stage from the circuit, while the tone wicker can be achieved by using a 3pdt to remove the 470pF caps from each of the first three transistor stages (c10,11,12 in the first schematic you shared; c2,6,9 in the muffin fuzz)
Thank you!

Your description is the first I've ever come across that explains what the hell the "wicker" is.

Was wondering what the hell it it is, for AGES.
 
From what you've described, it seems like you have the right idea. Connecting the collector of Q3 to one end of a SPDT switch (on/off) and the other end to C12 should effectively bypass the tone control circuit when the switch is in the "off" position, allowing for a brighter, more open tone.

However, it's important to note that modding a pedal can be a complex process, especially if you're not experienced with electronics. If you're not confident in your ability to make these modifications, it may be best to seek out the help of a professional or experienced pedal builder.

As for other mods, swapping between germanium and silicon diodes is a common modification for Muff-style fuzz pedals. You could consider adding a switch to toggle between the two types of diodes, allowing you to experiment with different tonal options. Another popular mod is to replace the stock tone control with a different type of EQ circuit, such as a mid scoop or a presence control.
Thanks, this is great to hear.

I am fairly confident in my ability to mod pedals, just not good on the theory. I soldered a wire to the collector if q3 and another to c12. Just need a switch to test it out.

I like the diode switch option idea. I put the diodes in sockets to try different things out and I have made a 12 diode rotary switch to my Dod 250 clone.

With the tone control, do you mean change a capacitor in the tone section?
 
Thanks for the suggestions everyone. I ended up adding adding a switch to toggle between SI diodes and no diodes for the first set of diodes and a switch on the second to switch between stock and germanium. Now I just need to drill some holes.

I'm still a litte puzzled about the tone bypass mod. I tried again connecting the collector of Q3 to one end of a SPDT switch (on/off) and the other end to C12. I quite like the way it sounded so might do it anyway, however I don't think it fully bypassed the tone section as the tone knob still worked and affected the tone.

Shouldn't a mod like this completely remove the tone knob? I guess as Elijah-Bailey above said, I would need to remove the trace on the PCB as the tone section is still connected. I might have to try some other tone modification.
 
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I'm still a litte puzzled about the tone bypass mod. I tried again connecting the collector of Q3 to one end of a SPDT switch (on/off) and the other end to C12. I quite like the way it sounded so might do it anyway, however I don't think it fully bypassed the tone section as the tone knob still worked and affected the tone.

Shouldn't a mod like this completely remove the tone knob? I guess as Elijah-Bailey above said, I would need to remove the trace on the PCB as the tone section is still connected. I might have to try some other tone modification.
NO, you don't have to cut traces on the PCB.

YES, a tone-bypass mod should totally remove the tone knob. Some other Muff-PCBs that are available have provision for the tone-bypass mod whereas the Muffin PCB does not.

SO!

Here's what I would do for tone-bypass on a PedalPCB Muffin board:

I would NOT CUT any traces on the Muffin Board.
I would REFRAIN from populating the Muffin PCB with any of the tone controls, ie
C10, C11, R17, R18, TONE-POT

I would solder my tone-bypass switch DPDT on-on lug 2 to one of the nodes that is directly off Q3's collector, namely whichever side of C10 or R17 makes a beep on my DMM.

Lug 1 of the switch then goes to a 150k resistor soldered across to lug 4:

1 4
2 5
3 6

Lug 3 of the switch would then go either to a standalone TONE-pot wired up with the C10, C11, R17 and R18 such as on this Beavis Audio Muff Tone Diagram:

1683479066180.png

OR

If you're not comfortable with P2P wiring as per the Beavis diagram, then you could mount the components and pot to a small piece of perf-board (column on the left below, ignore the one with transistor recovery-stage) ala ELS:

BMP%2BTone%2BStack.png

OR

You could buy PedalPCB's "PEDALBLOCK TONE CONTROL" PCB and use that instead of P2P or Perf:

ToneControl-1-247x296.jpg



Once the TONE-pot is sorted...

The output of the tonestack goes to lug 6 of the DPDT.

DPDT lug 5 goes to Muffin-PCB's TONE PAD 2 .

Done. No traces were hurt in the making of this bypass. You'll have to decide which TONE method above (P2P/Perf/PCB) works best for you and where to put it in the enclosure. Might have to scoot the Muffin PCB down in the enclosure and place the offboard TONE above to form an inverted control-triangle, compared to stock.

To maintain the stock control-layout of the Muffin PCB I would opt for a lugged TONE pot with the components soldered around it rather than on the pot's back (as the PCB will be right underneath the pot) — but only IF there's enough clearance — and cover it in Goo or Tape to keep anything from shorting out on the nibs of the PCB;
If there's not enough room for P2P, then just have wires to/from the TONE-pot to a scrap of perf with C10, C11, R17 and R18 and double-sided sticky tape the perf to the enclosure wall.


Subjectively speaking, the better option is to build your Muffin board "stock" and select one of the other Muff-based PCBs that more easily accommodates the mods you wish to employ, such as the Muffin Factory — you weren't ever planning on only building ONE Muff, were you?
 
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