8ball oscillating

[Alaboogie]

Anyone else have their 8ball oscillate on the down position of the dpdt switch? It oscillates when I turn the gain up pretty high, maybe the last 20-30%.

Should I switch out anything? (Resistors, diodes)

Other than that this build screams! Talk about adding volume to the original design! It's pretty awesome

[mgwhit]

Anyone else have their 8ball oscillate on the down position of the dpdt switch? It oscillates when I turn the gain up pretty high, maybe the last 20-30%.

Man: Doctor, Doctor!  It hurts when I do this.

Doctor: Don't do that!

But seriously, maybe try spanning R8 with a small value ceramic cap -- like that 47pF C2.

[Alaboogie]

So you're saying to put a 47pf cap on top of the resistor already in there? Or to replace the resistor with a 47pf cap...? Haha!

*update* so I actually did both. I swapped it out first with a 47pf cap, and then I put the resistor in along with the cap. Unfortunately neither worked

Let me know if pictures are needed, or voltages

[mgwhit]

Yeah, I meant put in a capacitor in parallel with the R8 resistor.  Oh well.  Maybe someone else will have some better ideas.

[drolo]

In an overdrive I have been tinkering with that is also based on the bluesbreaker, I had the exact same problem. When disconnecting the diodes in the feedback loop and connecting the diodes to groud (to Vb actually), it would squeal and motorboat ...

it seemed to have to do with the current going directly to Vb. What I did to solve my issue was to connect the diodes to the actual ground instead of Vb. Not sure you would be able to do that easily on the PCB though ...

[Tremster]

Very sorry to dig up this ancient thread but it addresses just the problem I'm having.
I haven't done much, pedal-wise, last year and today wanted to get started fixing some issues. One of which is just this. Searched the forum and found that other people have this problem, too: http://www.madbeanpedals.com/forum/index.php?topic=21647.msg213691#msg213691
On the LED setting (down position of the switch) when gain is maxed the pedal oscillates. Dial it back just a bit and all is fine.
Never bothered me much because I mainly use the silicon setting and with lower gain, but it would be cool to fix the issue. I love this pedal!
Has anyone been able to get rid of this? Does anyone have an idea (simpler than drolo's)?
Thank you!

[drolo]

try a larger value for R10, could be too much current sinking through the LED's, perhaps.

[Tremster]

Thanks, I'll give that a try.