muff clipping switch question/explanation?

[jrhevron]

Hoping someone can explain how this works:

I'm a little short on time these days, so I got a pre-made muffin fuzz off of reverb from a builder I really like.

The muffin has a clipping switch that is wired as such: there are two led's soldered into the 2nd stage clipping slots on the board. For one LED, the leads were left long and two wires are soldered from there to the center lugs of a on/on/on dpdt switch with other clipping options on either side.

How does this work? When you select, one of other diode clippers, is it the led clipping from the board + the other diodes? Is it stacking the two? Would it be better to not have diodes on the board and just have the two options?

 

[Fama]

It is often done like you said, but as far as I understand functionally the way they did it works just as well.

If you have a lower and a higher forward voltage diode both going to ground in parallel, the lowest forward voltage diode starts conducting first, and at that point it doesn't really matter if the higher forward current diode is there or not - the signal is already being fed to ground from the lower forward voltage diode.

So in simpler words, if there's only a LED, it will clip when the signal strong, but if there's a LED and a silicon diode, the silicon diode will (generally) clip already with a weak signal - and it will also clip with a strong signal. So the LED can be there or it can be disconnected, it doesn't make a difference, but it will also not stack.

(if they are in series, then they will stack though, and I believe it basically raises the forward voltage)

 

[jrhevron]

It is often done like you said, but as far as I understand functionally the way they did it works just as well.

If you have a lower and a higher forward voltage diode both going to ground in parallel, the lowest forward voltage diode starts conducting first, and at that point it doesn't really matter if the higher forward current diode is there or not - the signal is already being fed to ground from the lower forward voltage diode.

So in simpler words, if there's only a LED, it will clip when the signal strong, but if there's a LED and a silicon diode, the silicon diode will (generally) clip already with a weak signal - and it will also clip with a strong signal. So the LED can be there or it can be disconnected, it doesn't make a difference, but it will also not stack.

(if they are in series, then they will stack though, and I believe it basically raises the forward voltage)

@Fama thank you for that explanation! I figured it was a fine way to do it, but wanted to check.

One more question.... because I'm unable to help myself, I still went in and modded the pedal

I switched out the 2nd stage clipping LEDs and when I did that, only one of the LEDs lit up when I ran tests with the lights off. I know that clipping LED's aren't going to be bright. Still, one would light up and the other would not. Is there any reason for that? Or is it more likely that I somehow lifted the trace etc when desoldering?