Subtle but annoying sound with Ego Driver (sound sample)

[Marshall Arts]

Hi there,

I built an Ego Driver, which is great, except for one thing: It has a subtle sound that comes and goes in addition to the wanted sound (sorry for not being able to describe it any better). It is a bit like a rattling string. You can hear it best with the second chord in the demo (it comes back at the end of the chord). Hear it?

Some further information: It is not a rattling string :-). There is no other effect in the chain. The ego driver is powered from an 18 Volts supply (from a madbean fat pants). I swapped the op-amp for a TL072 (as I had that lying around), I can confirm that the problem is NOT the op-amp. 

Any ideas?

[Marshall Arts]

Update: I did some check yesterday and connected it to 9V rather than the 18V it usually gets from a Fat Pants. Same thing, so it is NOT the voltage eiter. I noticed, that 2 box capacitors are a bit molten (I obviously touched them with the soldering iron). Could that be the source?! For debugging, should I try to follow the path with an audio probe?

[Marshall Arts]

Another Update: I built an audio probe today and checked along the audio path in the pedal. Funny thing: Just before the volume pot (between the volume pot and R11), everything is ok - obviously too loud, though. So, I thought, it has to be the volume pot (when full on, the annoying sound is also gone, of course). I wired one with the same specs in parallel (dont want to pull out the existing one, it's terrible work :-)), opend the existing one and pulled back volume with the new one - unfortunately, same effect. So, probably not the pot...

Does this make reason to anybody out there? How can rolling back the volume lead to hiss in tone?

[jball85]

I was jamming with my ego driver today on the clean channel of my amp. My pedal makes the same noise yours does dude. I think it's just the nature of the pedal when used by itself, rather than say boosting the gain channel of an amp. Mine is a version 4, perhaps the other versions don't possess this "tick". That's just a thought though... I'd be interested to hear if anyone else's Ego Driver has that hiss as well. Although, in all honesty it doesn't really stand out, and is not as bothersome in a band mix.

[Marshall Arts]

I will Build another one to Double check

[Marshall Arts]

So, I built another one, as promised. It sounds a bit different, but the sound is still there. I also built a Zendrive Clone, which has this sound on fading notes, though less recognizable. I meanwhile found this thread, which explains the issue as a typical symptom of diode clippers

[jubal81]

So, I built another one, as promised. It sounds a bit different, but the sound is still there. I also built a Zendrive Clone, which has this sound on fading notes, though less recognizable. I meanwhile found this thread, which explains the issue as a typical symptom of diode clippers: http://www.diystompboxes.com/smfforum/index.php?topic=97173.msg846692;topicseen]http://www.diystompboxes.com/smfforum/index.php?topic=97173.msg846692;topicseen]http://www.diystompboxes.com/smfforum/index.php?topic=97173.msg846692;topicseen. Hope that helps...

Great thread find.


This sounds like you're describing diode noise to me, too. It's one of the main reasons I prefer JFET drives.

[Marshall Arts]

Thanks... Any recommendations for a jfet Drive?

[jubal81]

Thanks... Any recommendations for a jfet Drive?

Lots of great ones. Kind of guessing what you're looking for, I'd recommend the Black 65, Formula No. 5, SVT or Monarch.