SOLVED Muffin Fuzz - Works, but humming

[BipolarBear]

Hi all,

Just finished up the Green Russian Muffin Fuzz, pretty straightforward build, gut shot below:



When I plug it in and play, the bypass is pretty clean and the fuzz works, but I'm getting a pretty loud humming when the pedal's on, even with the power unplugged.

https://soundcloud.com/bi-polar-bear%2Ffuzz-troubleshoot-power-on

https://soundcloud.com/bi-polar-bear%2Ffuzz-troubleshoot-power-off

What do you guys think could be causing this? Before I boxed it up I went over it looking for bad solder joints, could it be some sort of grounding issue? The hum gets louder when I touch the strings. I made an audio probe to poke at it but just wanted to ask before I unbox it to see if I'm missing anything obvious.

Thoughts?

 

[Barry]

That 5817 and the adjacent transistor don't look like they're soldered too well, from this side of the board

 

[music6000]

Hi all,

Just finished up the Green Russian Muffin Fuzz, pretty straightforward build, gut shot below:

View attachment 6797

When I plug it in and play, the bypass is pretty clean and the fuzz works, but I'm getting a pretty loud humming when the pedal's on, even with the power unplugged.

https://soundcloud.com/bi-polar-bear%2Ffuzz-troubleshoot-power-on

https://soundcloud.com/bi-polar-bear%2Ffuzz-troubleshoot-power-off

What do you guys think could be causing this? Before I boxed it up I went over it looking for bad solder joints, could it be some sort of grounding issue? The hum gets louder when I touch the strings. I made an audio probe to poke at it but just wanted to ask before I unbox it to see if I'm missing anything obvious.

Thoughts?

Have you tried grounding the Jacks to the Enclosure?

 

[Chuck D. Bones]

Have you tried grounding the Jacks to the Enclosure?

That's definitely the problem. Those are insulated jacks, so the case is floating, not providing shielding. Here's the fix:

1. Remove the stomp switch and the tooth washer.
2. Solder a wire to the tooth washer. you may need use a bit of flux to get the solder to adhere. Wire should be about 1.5" to 2" long.
3. Install the tooth washer back onto the stomp switch.
4. solder the other end of the wire to the center pin on the stomp switch.
5. Reinstall the stomp switch.

Now the case is grounded. Hum should be gone.

 

[BipolarBear]

That's definitely the problem. Those are insulated jacks, so the case is floating, not providing shielding. Here's the fix:

1. Remove the stomp switch and the tooth washer.
2. Solder a wire to the tooth washer. you may need use a bit of flux to get the solder to adhere. Wire should be about 1.5" to 2" long.
3. Install the tooth washer back onto the stomp switch.
4. solder the other end of the wire to the center pin on the stomp switch.
5. Reinstall the stomp switch.

Now the case is grounded. Hum should be gone.

Did all this and it worked like a charm. Thanks Chuck!!!

Makes me wish I hadn't bought so many extra insulated jacks haha

 

[Chuck D. Bones]

You'll find a use for 'em. Check out the VFE pedals on Madbean, they all use insulating jacks on the switching boards.

 

[benny_profane]

You'll find a use for 'em. Check out the VFE pedals on Madbean, they all use insulating jacks on the switching boards.

The new switching board (v3) doesn’t have the board-mounted jacks anymore. It’s designed for any off-board jack you’d like. The current documentation might not mention it, but the earlier revs included the exact grounding strategy you mentioned. I think Peter at VFE grounded the board-mounted jacks via one of the jack ferrules.

 

[Chuck D. Bones]

That's where I learned it.
The V2 boards could be wired with the jacks either on-board or off-board. I like the board-mounted connectors, even though I had to remove one to reset the height on a transistor.