SOLVED Bellum Fuzz MKII - Low output

[MarX Halvick]

Hi everyone,
I built a fuzz war clone and it worked well, 1 time. Once I disconnected and reconnected it at my rehearsal room, I got very low output.

I tried to diagnose it with an audio probe and I can hear a drastic volume drop in C8 and C11, which are capacitors before TONE and transistor 4 (which has low input). Both capacitors have high volume input, low output (so I guess something is drawing a lot on the other side but I can't find what it is).

The other 3 transistors have pretty good input/output, amplifiying the signal a bit.

Link to schematic : https://docs.pedalpcb.com/project/BellumMKII-PedalPCB.pdf
Picture attached.

Is it normal that these capacitors (2n2 and 680p) drop the volume that much ?

Thanks everyone for helping a beginner in pedal troubleshooting !

 

[zgrav]

more details please. does it work in bypass without volume loss? does the LED come on when you switch the effect in? (seems likely those are all OK, but worth asking for your troubleshooting). Have you tried unplugging and replugging the power jack in to see if you might not have a good connection since it worked before? Providing an in-focus picture of the solder side of the pcb would also help other folks help you.

 

[MarX Halvick]

Thanks zgrav for the requests.

- Works great in bypass, without volume loss
- The LED does switch on when activated
- Tried to bypass the 9v input, tried it with a battery and a DC adapter = same result
- Soldier side pic :

 

[zgrav]

Does the volume level change when you are changing the settings on the tone control?

 

[MarX Halvick]

Hi. To test what you asked, I plugged it back on my amp and it worked... I will put it back with the screws and everything to see if it still works.

For now, the tone does not affect the volume.

 

[BuddytheReow]

The tone control does suck out a lot of volume. Do you notice a volume increase between c12 and c13? Trying to make sure the recovery stage works.

 

[MarX Halvick]

I did put everything back in the enclosure and it works, I was not able to recreate the issue. I will mark it as solved for now. Thanks everyone who (Tried to) help !
Sorry if you google that thread in the future