Bellum Fuzz MKII weak fuzz/ no sustain

[calmccrimmon]

Hey guys,

I've made a Bellum Fuzz MKII but it doesn't sound right. Theres a slow gating effect that removes all the sustain and makes the fuzz sound very weak and compressed even with the fuzz knob maxed. Its got 4 2n5088s with hfe's of 260-270. The diodes are D9Bs (i think) with forward voltages of about 0.3. I noticed that theres far more sustain with these out but it still gates and sounds awful. Lastly, I'm not very familiar with the big muff style of circuit and what each component does. I assume theres a wrong resistor somewhere possibly effecting the biasing or something like that but i've visually checked the components and everything seems right. Does anyone know what could be wrong or can point me in the right direction for voltages to check, resistors to replace etc?

 

[Dan0h]

Can you post a photo of the bottom of the board? Just from the top it looks like several of your solders need to be re-flowed.

 

[fig]

You may want to check this..

I hope it's an easy fix!

 

[zgrav]

see if you have good connections for all of your transistors. if they wobble in the socket you might want to put a thin coat of solder on the legs to get a better grip in the sockets.

 

[calmccrimmon]

Can you post a photo of the bottom of the board? Just from the top it looks like several of your solders need to be re-flowed.

 

[calmccrimmon]

You may want to check this..

I hope it's an easy fix!

I have pulled that resistor all the way through but it didn't fix the issue

 

[calmccrimmon]

see if you have good connections for all of your transistors. if they wobble in the socket you might want to put a thin coat of solder on the legs to get a better grip in the sockets.

Thanks for this suggestion. I just checked and the sockets are firm and the transistor legs are all continuous with their next contacts in the circuit

 

[Bricksnbeatles]

The 100r and 470k in the top left as well as the 10k on the bottom right appear to have globs of solder melted onto them. The 100r especially looks to have had its casing partially melted. I’d pull those three and measure their resistance, and likely just replace them regardless of if they meet spec or not, just to be safe.