small jack on active electronics question.

[Beate Ritzert]

Thanks Mark. So how is this avoided, besides turning the gain on the amp down or off when plugging or unplugging?.

You can use a *large* resistor from the ring of the connector to ground. This will greatly reduce the switching noise. But even with a silent plug it is better to turn down the volume pot of the instrument - otherwise You will still hear some switching noise. That resistor will of course eat some of the capacity of the battery.

A full explanation, albeit in German, is on the following page: http://www.guitar-letter.de/Knowledge/D ... tronik.htm

BTW, switching jack connectors are hard to find. despite of that - is the price of these connectors relevant regarding the price a custom made guitar necessarily has to have?

[David King]

The mono 1/4" jack with a normally open isolated switch is the one to use.
You can see all the Switchcraft options here:
http://www.switchcraft.com/Documents/Ja ... matics.pdf

See part # J-13 on this page: http://amprepairparts.com/jacks.htm

Switchcraft's part number is J1-1-A but that's not particularly helpful.

[Peter Wilcox]

Thanks for the information, Beate and David. I can see that a resistor from ring to ground will keep the ring at essentially ground potential for small currents, significantly reducing any current surge as the plug is inserted. The downside of course, as you mention, is the constant battery drain, shortening its life. The switching jack seems the way to go, connecting the plug tip to the signal before the battery is connected.

I still can't get my head around the potentials in the circuit before it is switched on - specifically the potential on the ring (negative battery terminal) referenced to the amplifier ground, which is where the current surge comes from. Oh well.