Re: Bondi Effects - Sick As Overdrive
Posted: 24 Sep 2016, 13:11
It doesn't look like there are enough resistors alone to be the same as a Klon. But how about for starters just listing out their values? Some would have to match what the Klon has, right?
So next, you look for what are probably pairings with some of those resistors with uncommon cap values, like 10k/68n, 15k/82n, 5k1/68n, 1k/390n, 2k/27n, 422k/390p, 392k/390p, and so on.
Then next, simply try to determine if there is the following:
pin 1 or 7 of op amp -> 1uF (or similar large value cap) -> 1k -> clipping diodes to ground -> 1uF (or similar large value cap)
Lots of pedal builders don't seem to understand how changing the value of the 1k resistor will alter the clipping from either the op amp or the diodes, so they tend to leave it the same as whatever pedal they are borrowing from. This is probably especially true if a pedal like the Klon is being copied.
If you can determine that the clipping diodes are indeed shunted to ground, and that the forward voltages are on the low side, like with the Klon, it would stand to reason that the gain pot simply varies between the clipped or bypassed signal paths, like with the Klon. Otherwise, you would need something pretty clever to not have buzzy distortion with a big volume drop as the gain goes up. To at least avoid the latter, you would need clipping diodes with a (combined) forward voltage of well over 1000 mV - it would probably be easier to just use LEDs.
Someone said that it's most likely a Baxandall tone circuit? That's usually not as hard to determine, because you'll have pairs of identical resistors or capacitors, and there's probably a chance that they are in proximity to the bass and treble pots.
I think that doing at least some of the above will at least give a better idea of what the Sick As either is or isn't.
So next, you look for what are probably pairings with some of those resistors with uncommon cap values, like 10k/68n, 15k/82n, 5k1/68n, 1k/390n, 2k/27n, 422k/390p, 392k/390p, and so on.
Then next, simply try to determine if there is the following:
pin 1 or 7 of op amp -> 1uF (or similar large value cap) -> 1k -> clipping diodes to ground -> 1uF (or similar large value cap)
Lots of pedal builders don't seem to understand how changing the value of the 1k resistor will alter the clipping from either the op amp or the diodes, so they tend to leave it the same as whatever pedal they are borrowing from. This is probably especially true if a pedal like the Klon is being copied.
If you can determine that the clipping diodes are indeed shunted to ground, and that the forward voltages are on the low side, like with the Klon, it would stand to reason that the gain pot simply varies between the clipped or bypassed signal paths, like with the Klon. Otherwise, you would need something pretty clever to not have buzzy distortion with a big volume drop as the gain goes up. To at least avoid the latter, you would need clipping diodes with a (combined) forward voltage of well over 1000 mV - it would probably be easier to just use LEDs.
Someone said that it's most likely a Baxandall tone circuit? That's usually not as hard to determine, because you'll have pairs of identical resistors or capacitors, and there's probably a chance that they are in proximity to the bass and treble pots.
I think that doing at least some of the above will at least give a better idea of what the Sick As either is or isn't.
