Mudbunny to Cornish G2

[GVC66]

I would be really interested in this "version",  but I have only found a partial schematic on the internets and I am not very good at reconciling schemes unless they line up (ie C6 = C6)

[juansolo]

Can't do all the buffering and I have a feeling it doesn't have a muff tonestack.

[GVC66]

I can do the buffering off board.  I was under the impression from the schematic I saw and guitarpcb.com that the g2 is a modified muff.  Any suggestions on taming the muff to get a more of a dirty overdrive sound?

[GVC66]

Here is the schematic I found.  Look right below the creamy dreamer...http://www.bigmuffpage.com/Big_Muff_Pi_versions_schematics_part3.html

[Guitarmageddon]

There is already a Madbean project for the G2 called the "Darkside," but I don't see any reason why you couldn't plug the G2 values into a Mudbunny. You'll need to be a little creative with the tonestack.
The emitter resistors set the gain for Q2 & 3. You'll notice the Q2 one is relatively high (680ohm) which reduces the gain at that stage substantially.
Use BC550s, ge diodes, the right coupling caps, modify that tone control and you'll be in the ballpark.

[Guitarmageddon]

Here's how to compare the schems, you can see the the circuits follow the same route. I've got an arrow showing R2 on the kit rae schem, you just need to plug the right values in for the rest. Grab a pencil and list the part values against the Mudbunny part numbers. I've done the first few for you.
I've also done the tonestack, as you'll need to modify it. Omit the crossed parts and add the extra 100k resistor to ground somehow. One neat way to do it would be to put the 100k in the R18 position and jumper pins 1 &3 of the mid pot. Alternativly you could tack it on to lug 3 of the tone pot and run it to any ground connection. I'll often do this sort of thing on the back of the board to keep it looking neat.

[neve1272]

are the way the clipping diodes drawn on the Schematic still able to work on the mudbunny board this is where i got stuck?

[Guitarmageddon]

Yes, they're electrically identical. MBs schem is just better drawn.

[neve1272]

cool wish i could see that as easily. thanks for such quick response 

[Guitarmageddon]

No worries, do us a favour and post the parts list here when you're finished.
This is a cool little diagram from the Kit Rae site too.

[neve1272]

r1 1m         c1 47n
r2 39k         c2  1n
r3 100k       c3 47n
r4 470k       c4 47n
r5 680r       c5  1n
r6 15k          c6 220n
r7 1k           c7 4.7uf*
r8 8.2k         c8 1n
r9 100k        c9 220n
r10 470k      c10 TS
r11 680r       c11 TS
r12 15k        c12 220n
r13 8.2k       c13 220n
r14 100k      c14  PS
r15 470k      c15  PS
r16 100r 
r17 15k
r18 TS
r19 TS
r20 390k
r21 100k
r22 8.2k
r23 2.2k (note 22uf electo and 680r parallel to ground)

TS= tone stack  PS = power supply
i still seem like the diodes are differnt this is the darkside? is it the shareing the nodes

[Guitarmageddon]

Well, maybe someone else will confirm this then, but I maintain that the diodes are electrically the same , just drawn differently. They are Ge in the G2 though.

Good catch, I overlooked those extra resistors at the output. The 39k can just go across lugs 1 &3 of the output pot, the extra cap and resistor on Q4 will have to be flown.

[selfdestroyer]

I like where this is going.. might have another build for the ever growing Juansolo muff excel doc.

[Clayford]

Here is the schematic I found.  Look right below the creamy dreamer...http://www.bigmuffpage.com/Big_Muff_Pi_versions_schematics_part3.html

Bwahahahaha... Juan can't get away from that site this month.

[juansolo]

lol, indeed!