Joe Davissons Easy Drive...weird volume control issue.

[rockgardenlove]

So the Easy Drive sounds great, only problem is when I turn the the guitar volume up all the way on my guitar, it goes all fizzly like its biased wrong.  I know its not the guitars, or the pickup output, I tried it on a H/H SG, and a H/S/S Strat, neither worked with the volume all the way up.  I didn't use a 2n5089, I used a 2n5088, but that was too noisey, so I switched to a 2n3904.  The issue happened with both trannies.  Any thoughts?  I'm also using LED's for the clipping diodes, if that matters. 



There's the schematic for reference.  Any help would be appreciated.

Thanks

[rockgardenlove]

Bump

[Joecool85]

Have you double checked your resistor values?  Sounds like the Vcc one isn't right, make sure it is 68k.

[rockgardenlove]

I used a 100k pot, and I've used a straight 68 k too just to test it.  Doesn't matter at what setting the 100k pot is either, the volume works perfectly, the issue is that if the guitar volume is all the way up it goes fizzly.  Gain+volume knobs on the effect make no difference.

[MrChameleon]

I built this a few months ago, stock-standard (no knobs version) and I really like it.

I have not experienced the "fizzly" sounds with either humbuckers or single-coils.

The distortion is extreme (to my ears) however, with the pickup volume right up. I back the volume off a bit, and the touch-sensitivity is great.

I have tried it with a 2N5088 - less distortion, but too much noise.

Perhaps you should try the 2N5089 and 1N914s?

The leds will make it louder and cleaner, I think, but correct me if I'm wrong (often am).

[rockgardenlove]

Thanks for the suggestions...I guess I'll just have to try the stock parts eh?  Silly me...

[jmusser]

I never had any trouble with fizz either. It seems like about any NPN will work in there, and sound decent, so that wouldn't be it. I ended up using a OC144 germanium in there, and it sounded awesome through my tube amp. This is one of my all time favorite sounding circuits.

[Joecool85]

LEDs will make it louder and meaner, more of a metal distortion.  At least thats what they do in a bazz fuss.

[rockgardenlove]

Hmm, yeah it sounds great, just if I turn the guitar volume up all the way, it does this thing...sounds like its not biased right.

[rockgardenlove]

I ordered the stock parts, I guess we'll see how that goes...

Can anyone tell me why this might be happening in a technical sense though? 

[rockgardenlove]

So I know its not an issue with the LED...

Also strangely enough, if I put my rangemaster infront of it in the chain it works fine

Arghh!  What could be happening!?

[Joecool85]

Sounds like it is something with your input cap maybe...

[rockgardenlove]

Thanks, I think I may have found the problem...I believe there was sone voltage sneeking across into the amp input somehow.  I ran over all the veroboard seperating lines with a penknife, and I think it works now...but I'll post again if I have more issues. Thanks!