SOLVED Sabbath Distortion fizz only

R

RICHB555

Active member
Having an issue with Sabbath Distortion and would appreciate helpful suggestions. LED lights; signal ok in bypass. Only getting a fizz (shhhhh sound like). All parts as indicated on BOM. The fizz has less volume when gain knob turned down, but volume knob has no effect on loudness of fizz.

Changed out the 3PDT but fizz not resolved. Continuity checks of switch, jacks and ribbon cable all show continuity.
 

Attachments

  • IMG_5251.jpeg
    IMG_5251.jpeg
    538.8 KB · Views: 8
Sort by date Sort by votes
It's a long shot, but the fact that the Gain control affects the sound but the Volume doesn't is very unusual.

This one has an unusual control layout (what the heck was I thinking?), lets make sure you're not turning the wrong knob. :ROFLMAO:


1754488130547.png
 
Upvote 0 Downvote
Thanks Robert. Yep I’m turning the gain knob on the top row right and the loudness of the fizz is variable with the turn of the pot, but the volume pot on the bottom row left has no effect on the loudness of the fizz as previously noted.

I thought of one more thing because I noted earlier all parts as spec’ed but I used a BC184L sourced from Small Bear and a BC184 is spec'ed. Would the BC184L be a problem?
 
Last edited:
Upvote 0 Downvote
Did you try and put a signal (guitar) through the effect? If yes and you heard guitar sound, does the volume affect the loudness of the guitar?

My logic:
This circuit emulates a combination of a Rangemaster treble boost into a Laney Supergroup amp, to which the real deal is hissy and fizzy. I had a Catalinbread Galileo, which is all but a few part, the same pedal and it had a lot of inherent noise, because it was gainy in the front end (Rangemaster).

If the master volume isn't reducing the sound of any sound, the pot may not be making ground, either by being internally broken near lug #1, the solder joint or the ground trace near the solder joint (these can break from overheating).
 
Upvote 0 Downvote
andrewsrea said:
Did you try and put a signal (guitar) through the effect? If yes and you heard guitar sound, does the volume affect the loudness of the guitar?

My logic:
This circuit emulates a combination of a Rangemaster treble boost into a Laney Supergroup amp, to which the real deal is hissy and fizzy. I had a Catalinbread Galileo, which is all but a few part, the same pedal and it had a lot of inherent noise, because it was gainy in the front end (Rangemaster).

If the master volume isn't reducing the sound of any sound, the pot may not be making ground, either by being internally broken near lug #1, the solder joint or the ground trace near the solder joint (these can break from overheating).
Click to expand...
Thanks for your post - appreciate it! When running a guitar signal through the pedal direct to an amp, the circuit is only producing a fizz sound that sounds like “shhhh” similar to when between radio stations on a radio dial. There is no guitar signal at all except when the pedal is in bypass. To clarify, my issue is not noise that accompanies a guitar signal. There is no guitar signal at all, only fizz that is variable in loudness when turning the gain pot. The volume pot has no effect on the loudness of the fizz.

As shown in the photo, the solder joints to the lugs on the volume pot and other control lugs are solid.
 
Upvote 0 Downvote
RICHB555 said:
Thanks for your post - appreciate it! When running a guitar signal through the pedal direct to an amp, the circuit is only producing a fizz sound that sounds like “shhhh” similar to when between radio stations on a radio dial. There is no guitar signal at all except when the pedal is in bypass. To clarify, my issue is not noise that accompanies a guitar signal. There is no guitar signal at all, only fizz that is variable in loudness when turning the gain pot. The volume pot has no effect on the loudness of the fizz.

As shown in the photo, the solder joints to the lugs on the volume pot and other control lugs are solid.
Click to expand...

Cool. I'd still recommend testing the ohms readings between pin 2 and 1, then 3 and 1. The reason I say that is, with the volume pot being the very last component before the output jack, it should mute any noise or signal when turned completely off.

Sounds like you got solid advice on the FETs. Hope you get it fixed soon and are enjoying it!
 
Upvote 0 Downvote
If you have another medium gain BJT NPN lying around, like a 2N2222 (same pinout as BC184) you could try that instead. Maybe put it in a socket.

Edit: Here're some voltage readings from mine if you're interested: link
 
Upvote 0 Downvote
You must log in or register to reply here.
Back
Top