Help with modding a Big Muff

[Jwar]

Hey guys! So recently I was asked to mod a Big Muff circuit and after looking over the details a hundred times, I've got to say I'm just not a circuit pro. So I need help in the form of either someone doing the mods for me (will pay for them) or help with explanations.

So the mods are the following

9-volt plug on top
Creamy Dreamer mod (resistor on a knob and emittor on a switch)
The Supa Tonebender mod (on a second footswitch
Mids knob

For the 9 V, I would imagine you could simply cut the wires on the battery adapter and solder in a 9v plug. Is that right?


Here's a link to where the mods are found

http://rkerkhof.ruhosting.nl/Taas/Mods/Big%20Muff.htm

I mean some of them seem straight forward but again, I'm just not a circuit person. I don't work with them enough except for simple things.

Any help is appreciated!

[Nocentelli]

The mods you've listed are straight forward enough if you can follow the schematic, identify the actual parts on the board and de-solder and re-solder to the board without lifting pads or risking stopping it working.

For the DC socket, you just need to identify which positive contact is switched out when the DC jack is inserted - This one goes to the battery: You also need to wire the battery negative to input socket ring, and the input socket sleeve/ground to PCB "power ground": http://www.beavisaudio.com/techpages/StompboxWiring/

Creamy dreamer just requires a single SPST switch that grounds the emitters of Q1,2 and 3: According to kitrae, there's not much evidence that the original Sustain Punch pedals actually had the "resistor mod": http://www.bigmuffpage.com/images/schem ... ematic.jpg

However, reducing the interstage resistors gives a nice boost into overblown fuzz territory: You could use a dualgang 10k pot, or two 10k pots to replace the 8k2 resistors between the sustain control and Q2, and between Q2+3 - You just have the identify them, desolder them from the board, and replace their connection with wires to the pots.

Supa tonebender mod is just any switch (SPDT footswitches are common) that breaks/makes the connection between one end of the diode pair and Q2: Again, identify that spot on the board, desolder one end of the diode pair (keeping them connected), connect this end to one lug of the switch, and connect the other lug back to where the diodes ends used to be. Or you could remove the diodes from the board, and wire them direct to the switch.

Mids controls can be done in different ways - A 100k pot in series with a 100n cap, with both soldered in parallel with the tone cap that is connected to tone pot lug 3 will give a mid boost; The AMZ presence control allows mid cut/flat/boost, but you would need to remove both tonestack caps and replace them with different values to tailor the degree of cut/boost available - http://www.muzique.com/lab/tone3.htm

BTW I've built maybe half a dozen muffs and variants over the years, using all of the mods above at one time or another and I have to say, it is probably easier to actually build a pedal from scratch to those specs than to modify an existing pedal. Something to consider if you fancy a go at a vero build, for example.

[greeny23]

Yeh it's all real straight forward. Muff boards are super easy too cause they're all big and you have a bunch of room.

Is there anything specific you need help with?

[eatyourguitar]

PM'd