Solving switch pop - two switches, one optocoupler?

[mdcmdcmdc]

Hi folks,

I'm trying to chase down some bypass popping in a pedal I built recently, and not having much luck with pulldown resistors and the like.

It's definitely the LEDs causing the pop (the pop disappears with the LEDs disconnected), and I've had good luck with voodoo labs-style optocoupler switching solving that problem in the past:



The circuit in questions is pretty simple; a depletion MOSFET OD sandwiched between two switchable gain stages:



Some of the extra pulldown resistors/caps I added to try and fix the popping aren't shown in the schem, there might be some other mistakes in there too (apologies!).

So, that's a lot of preamble to ask the question - is there a way to fire BOTH of the boost-related switches (SW1A and SW1B in the schem) off of a single optocoupler? I have a handful of 4N26 on hand, but I'd prefer to not have to use three of them.

If I can save myself $1.50 and some space in the enclosure it would be great.

Thanks!

[ElectricDruid]

So, that's a lot of preamble to ask the question - is there a way to fire BOTH of the boost-related switches (SW1A and SW1B in the schem) off of a single optocoupler?

Unless I'm not understanding something, the answer is "No". The Voodoo lab switching uses the optocoupler to send the signal to the effect, so if you want to switch signal to two separate effects you need two optocouplers (treating the separate stages as individual effects for a moment).

What you *can* do is switch both optocouplers on from one switch, in the same way that the diagram you posted switches on an LED and a optocoupler - LEDs are the same whether they're stuck in an optocoupler or not.

[mdcmdcmdc]

That's what I figured, but I thought it couldn't hurt to ask if there was a tricky way to make it work. Thanks for confirming!