Green Russian big muff clone not quite working

[snow123]

So I built a green Russian big muff and only the input boost stage is working, like the pedal is only working as a clean boost and kinda a low end boost, with a tad extra fuzz. And I did some probing and can't find the issue, I might be blind and it could just be a missing component tho lol.

The bypass is working perfectly as well.


























and heres the layout im using:

[Kevin Mitchell]

Post the voltages of each of the pins of the semiconductors. Make sure your multimeter's black probe is on the circuit's ground and use the red to measure each pin.

Fill this out;
Q1:
E -
B -
C -

Q2:
E -
B -
C -

Q3:
E -
B -
C -

Q4:
E -
B -
C -

Your soldering is getting better! Maybe next time get the iron a little more hot and use solder with more flux so it flows easier and acts less sticky.

[snow123]

Post the voltages of each of the pins of the semiconductors. Make sure your multimeter's black probe is on the circuit's ground and use the red to measure each pin.

Fill this out;
Q1:
E -
B -
C -

Q2:
E -
B -
C -

Q3:
E -
B -
C -

Q4:
E -
B -
C -

Your soldering is getting better! Maybe next time get the iron a little more hot and use solder with more flux so it flows easier and acts less sticky.

Q1:
E - .1
B - .7
C - 4.3

Q2:
E - .1
B - .7
C - 4.3

Q3:
E - .1
B - .7
C - 4.2

Q4:
E - .9
B - switched between 1.3 & 1.9
C - 4.1

[Kevin Mitchell]

Voltages are about right. Though Q4 is questionable.
These suspicious sections may have something to do with it.


I had to rotate and mirror your image to compare to the layout. Doing this is good practice with any vero or strip board project. Now it's just rotated 180.

[snow123]

Voltages are about right. Though Q4 is questionable.
These suspicious sections may have something to do with it.


I had to rotate and mirror your image to compare to the layout. Doing this is good practice with any vero or strip board project. Now it's just rotated 180.

i fixed that and plugged it in, and now i get a more of a mid boost in addition to the volume and bass boost.

[snow123]

and i should note that im using a 3n3 mylar instead of a 3n9 mylar.

[Kevin Mitchell]

i fixed that and plugged it in and got nothing, not even a clean signal now.

No refund lol
I'm sure it has nothing to do with that monstrosity of a rat's nest 
You really shouldn't solder wires like that, even in a pinch. Asking for trouble.

Clean it up and see what happens.

and i should note that im using a 3n3 mylar instead of a 3n9 mylar.

That wouldn't make much of a difference for this build. Once it's operating correctly you can add a capacitor in parallel with the 3.3nF to get closer to the stock value. A 470pF or 680pF would be appropriate (3.3nF + .68nF = 3.98nF). But again, isn't much of a deal.

[snow123]

i realized i had the in/out jacks reversed when i wrote that i didnt get a clean sig at all, i just edited the comment to say what actually happens lol.

[snow123]

i fixed that and plugged it in and got nothing, not even a clean signal now.

No refund lol
I'm sure it has nothing to do with that monstrosity of a rat's nest 
You really shouldn't solder wires like that, even in a pinch. Asking for trouble.

Clean it up and see what happens.

and i should note that im using a 3n3 mylar instead of a 3n9 mylar.

That wouldn't make much of a difference for this build. Once it's operating correctly you can add a capacitor in parallel with the 3.3nF to get closer to the stock value. A 470pF or 680pF would be appropriate (3.3nF + .68nF = 3.98nF). But again, isn't much of a deal.

i am gonna clean up the wiring tho

[snow123]

i cleaned up the wiring and its still not working

[Kevin Mitchell]

An improvement nonetheless, I'm sure.

I'm looking at the photo I sent back in my previous post. You've very likely got more shorts between other tracks. I can clearly see them - though very small. Why wouldn't you?
It's on you to find them. Your meter has a continuity function that'll beep when there's a short. Use it!!

Electrosmash is a great site for understanding circuits. Check out this schematic;


So right now your problem is lack of distortion, right?
It wouldn't be the input booster.
It wouldn't be the tone stage
It wouldn't be the output booster.

Now you 

[snow123]

An improvement nonetheless, I'm sure.

I'm looking at the photo I sent back in my previous post. You've very likely got more shorts between other tracks. I can clearly see them - though very small. Why wouldn't you?
It's on you to find them. Your meter has a continuity function that'll beep when there's a short. Use it!!

Electrosmash is a great site for understanding circuits. Check out this schematic;


So right now your problem is lack of distortion, right?
It wouldn't be the input booster.
It wouldn't be the tone stage
It wouldn't be the output booster.

Now you 

ok, ive replaced some caps and stuff and now i just have a little more fuzz, it basically sounds kinda like the "you really got me" guitar tone but with a super low gain big muff i guess.

[Kevin Mitchell]

Now that you've swapped parts for no reason what about the shorts?
Sounds like you may have fixed one of the two clipping stages.

[ElectricDruid]

You could try audio probing it too. The Muff circuit breaks up neatly into the separate sections, with each one separated from the next with a DC-blocking cap, except for the tone control. So test:

C5 - Buffer output
C13 - Fuzz stage 1 output
Q2 collector - Fuzz stage 2 output
C3 - Tone stage output

If all those are working, the state of the output tells you if the output booster is working.

This should narrow the search down a bit.

[snow123]

You could try audio probing it too. The Muff circuit breaks up neatly into the separate sections, with each one separated from the next with a DC-blocking cap, except for the tone control. So test:

C5 - Buffer output
C13 - Fuzz stage 1 output
Q2 collector - Fuzz stage 2 output
C3 - Tone stage output

If all those are working, the state of the output tells you if the output booster is working.

This should narrow the search down a bit.

theres very low volume on the output of the clipping stage

[jimladladlooklike]

Audio probes are great for debugging I find. You've identified the problem area, so check all component values and connections around there. Something will reveal itself to you eventually, dont give up.

[jimladladlooklike]

Also, a problem that I had with a build I was recently debugging was that the copper traces of the board were breaking at points where off-board wires were connected due to me I having to get underneath the board multiple times to check stuff. Make sure to check this on your build as you continue to debug

[snow123]

well the collector of q3 is fine but when i probe the base (which is the output of the clipping stage) i get a much quieter signal.

[antonis]

well the collector of q3 is fine but when i probe the base (which is the output of the clipping stage) i get a much quieter signal.

Output of Q3 clipping stage IS Q3 Collector..!!

[ElectricDruid]

well the collector of q3 is fine but when i probe the base (which is the output of the clipping stage) i get a much quieter signal.

Ok, so if Q3 collector is ok, it looks like the first fuzz stage is good. What about Q2 collector? Does the second stage work too?