January 4th, 2012, 12:46 PM
So I am finally finishing my Sunking Klone and for the hell of it i tried some red LED's as the clipping diodes while i was testing it out before boxing it. It had way more od than the diodes i was trying but there was also a lot of squelch and blattiness, so i figure led's are cheap i'll give other colour and sizes a try, which i will. But has anybody gone down this path before, got any suggestions, anything not to bother with?
January 4th, 2012, 10:10 PM
The forward voltage of LEDs are going to be higher than the Ge diodes that a Klon usually use - maybe you're hitting the rails on one of the op-amps?
January 5th, 2012, 09:34 AM
if i understand "hitting the rails on the op-amp" properly that would probably explain the fact it sounds pretty distorted and "blatty". in my limited understanding of what clipping diodes do i thought the higher the forward voltage the greater the raunch, but maybe i have that wrong?
i won't be trying with this one though i just boxed it and it isn't coming apart again without a good reason, there's no battery in it so unless it stops working i can't think of one, and even if i do i didn't leave myself any room to get diodes in and out.
January 5th, 2012, 12:24 PM
Hitting the rails just means that you are trying to amplify a signal past what your supply voltage allows. When that happens, the signal is clipped and you get distortiion. That distortion is pretty nasty though, and is not very musical, so we use something else.
Diodes, including LEDs, set a voltage limit based on their forward voltage, and they sound much closer to what we think of an overdriven tube amp. So when using op-amps, we put diodes in the feedback loop or after the op-amp to ground, and make sure that the diodes clip at a voltage lower than the op-amp will amplify to.
I just remembered though, that the Klon uses a charge pump to operate at 18v, instead of the normal 9v. You probably weren't hitting the rails using LEDs, maybe they just don't sound good in a Klon.