A Killswitch with no popping

[Bishop Vogue]

Hey all.  I recently built the Beavis Killswitch and, although it was good, the popping noise was a drag.  I experimented with pulldown resistors of different values and even a cap to ground, but no dice.  Then I had an idea, and, after a few minutes messing around came up with the design below.  Tested and works a charm.  Thought someone else might find it useful.



(The LED and LED should be isolated in an optocoupler.  Don't forget 2K2 resistor b/t LED & 9v)

[Joe]

Nice idea and drawing, thanks for sharing.

[DDD]

Great idea!
Thanks!

[Bishop Vogue]

Knew I was forgetting something... you'll also need a 2K2 resistor (or similar) between the LED and 9v.  Probably goes without saying...

(I added a note to the original post)

[Brisance]

Wouldnt it be better to use the LDR with a resistor in a voltage divider configuration to pull the signal down instead of just in series?

[Groovenut]

Wouldnt it be better to use the LDR with a resistor in a voltage divider configuration to pull the signal down instead of just in series?

You could put a 1M shunt resistor across the output jack but there really isn't any need for it. The LDR will use the input impedance of the following circuit as a shunt resistance and function pretty much the same way with one less part. IMO, YMMV et al...

[samhay]

OP - have you tried it with a buffered pedal before it?