Mute switch basics

Suppose I had a circuit like NYDave's "simple tube preamp/lineamp", currently found a few threads lower on this page. How would I go about implementing a mute feature in there? I'm thinking something along the lines of a mute that you could trigger with a pedal on stage, for sending to a tuner, or generally anything that doesn't involve some kind of sh!tty switch between the guitar and the amp. Could you just add a small active switch somewhere before the last tube stage that would send the plate straight to ground? Or would that cause pandemonium?

> send the plate straight to ground? Or would that cause pandemonium?

A 150V transient? Yeah, you'd probably be unhappy.

> doesn't involve some kind of sh!tty switch

For sound quality, the crapiest mechanical switch gives better audio than most solid-state switches.

> trigger with a pedal on stage

Perhaps the most direct approach for remote switching, if you don't want long lines or stomp-switches, is a relay.

low noise FET? 2n5457? that's what a lot of consoles use for muting..

FETs are fine for low signal levels or for use in virtual ground points where there is little signal voltage across the FET. But for an application like this, I'd use a relay.

Get a DPDT relay and wire it up just like a bypass switch in a guitar pedal. Or use a relay with more poles to add extras like an indicator light, etc.

Or maybe a vactrol type circuit. Check out this page for more info:
http://www.silonex.com/audiohm/softswitch.html

Awesome. Thanks very much. That opto-switch looks very interesting. Also I mean send the GRID straight to ground, not the plate. Would that be hum city?

oh, I thought he was using it for line level/guitar level stuff..??

Yes, line level- a mute switch for a pre-amp. Would that not work?