POP!!

[aettin]

Hi there--

If I have a pedal hooked up to a battery, and I connect the output jack from the amp to the pedal (jack-in already connected), I hear a pop. Not unexpected, but I'm trying to understand why this happens, and if there's a way around it. I have a rather unusual setup that requires this kind of switching (breaking the chain at pedal out), and was looking for some guidance please..

Since the 9V goes through the circuit at the same time as the audio signal connects, is that what causes the pop? Would something like a pulldown resistor ameliorate the problem? There is no pop when power comes through first and then I engage the pedal.. it's just when both occur at the same time. I realize this is not standard operating procedure, but is there a way to modify the circuit to decrease the pop when connecting a pedal-out jack on an engaged pedal with power?

Many thanks!

[R.G.]

Popping is always a symptom of suddenly changing the input to an amp.

I can't tell for sure from your description, but if you're asking about pulldown resistors, it's likely that you don't have one. Pulldown resistors hold the unconnected end of a DC-breaking (... and signal-coupling) capacitor to a 0-V DC level so that whatever comes after it doesn't get a sudden step in DC voltage from the capacitor being asked to change voltages suddenly when it's connected.

If you could show us even a simple schematic of your setup, we could tell.

Failing that, yes, put in a pulldown resistor of 1M to 4.7M from the output of the pedal to signal ground.

If that doesn't help, post again.