Mig Buff

Fakir Mustache · Post by **Fakir Mustache** » Sat Aug 08, 2015 1:53 pm

so I started making one:

one weird thing about it is that a whole bunch of the caps are shown on the pc board and schematic as polarised, well it does say use whatever type according to version

anyway I put in a couple more caps (non-polarised) than in the pic, but then the stuff on the left is not on the schematic I'm working with (Civil War, but it'll probably be more like Black for lack of 430pF caps).

I'll certainly put in that diode (D5) since I'm powering by adapter, and also the filter cap is a good idea I'm sure, but I'm kind of stuck as to what value to use (it says 100 uF, but the Sovtek green or black versions use a 20 or 22 uF). In any case it has to be polarised here.

I'm leaving the LED out, so I guess that resistor that goes with it is of no use, plus I don't want to mess with a funny switch (it shall be false bypass).

Also don't know about R23, that 1 meg resistor. I've seen it show up in some schematics of Sovtek muffs, but not on Kit Rae's page.

timhulio · Post by **timhulio** » Sat Aug 08, 2015 5:17 pm

The filter cap should be 100u. Although it doesn't really matter what value you use and it won't affect the way it sounds.

R23 in the first schematic is a pull-down resistor to prevent switch pops. You may or may not need this depending which bypass system you use.

Fakir Mustache · Post by **Fakir Mustache** » Sat Aug 08, 2015 5:42 pm

Ah, thanks, it won't be too complicated to solder that in if it makes pops.

You make a nice version of this pedal it seems.

So the only difference in between the versions is the 430/470/1000(in series) pF caps? Other than the different transistors and diodes of course.

timhulio · Post by **timhulio** » Sat Aug 08, 2015 10:51 pm

You cannot hear the difference between 430pf and 470pf caps in this circuit. A chap wanted me to make a muff which was switchable between these versions, but in the end we had to use massively different values here for any audible change.

Any difference between the sound of the versions is down to the choice of component types and parts tolerances.

Fakir Mustache · Post by **Fakir Mustache** » Sun Aug 23, 2015 3:40 pm

o.k., so I wired it up for testing, no bypass:

sounds really good, one of the best fuzzes I've ever played, blows away my Eno fuzz.

One thing though: there is a constant beep, like the fixed carrier frequency of a ring modulator, and this seems dependent on the volume knob: all the way down, quiet and no sound, turn up the volume and it gets louder.

Zack · Post by **Zack** » Sun Aug 23, 2015 8:17 pm

Fakir Mustache wrote:One thing though: there is a constant beep, like the fixed carrier frequency of a ring modulator, and this seems dependent on the volume knob: all the way down, quiet and no sound, turn up the volume and it gets louder.

Hrm, maybe it has something to do with not being in a case? The issue sort of reminds me of picking up radio frequencies, maybe isolating it will help. Try a different power supply perhaps?

Fakir Mustache · Post by **Fakir Mustache** » Mon Aug 24, 2015 9:10 am

Yeah, that was it, power supply. Thanks. Plugged in a 1spot and it doesn't beep.

It had nothing to do with radio signals, doesn't sound anything like that. Kind of sounded like when you plug a pedal in backwards (although I didn't), but not quite as loud.

paul_ · Post by **paul_** » Tue Aug 25, 2015 5:41 am

It's not grounded yet because it's not in a metal case/ground lugs of jacks aren't connected.