Standby Switch

This is a very simple mod that absolutely anyone can perform.  Basically, this is a switch that cuts the guitar's signal.  The idea was to be able to simply "turn off" a guitar while the performer was on stage between numbers.  This meant that hollowbodies like the one pictured above would not yield embarrassing feedback if left unattended.  This switch had the additional advantage of preventing that obnoxious "pop" when the cable is plugged in (or unplugged).

They used to be very common on some models of Gretsch guitars.  Often, they can be identified by the presence of an extra switch somewhere near the edge of the guitar, just next to the Bigsby tremolo (the controls on Gretsch models have always been unconventional. But that's a story for another time).

Standby switches are sometimes referred to as a "silent switch."  An almost identical mod is a "kill switch" which I cover on this page.

A final advantage of this mod is that, if it is wired such that it cuts your guitar's connection to the ground, you can leave the instrument plugged in without draining any batteries you have installed (e.g., for on-board pre-amps, active pickups, or other devices).

How it's wired
This is modification is so simple to accomplish that I won't even bother to draw a diagram here.  Just about any switch will work since this all that is required is a SPST switch (see the components page if you don't know this terminology).  As such, any switch of any size or complexity can be used.  This is an ideal application for a push-pull pot if you want to hide it or you can use a toggle like that found on Gretsch guitars like the one pictured above.  However, rather than sticking with conventional guitar components, you can find interesting looking toggle switches at Radio Shack or your local hardware store (e.g., light switches).  I'll leave the aesthetics up to you.

As was mentioned above, this is a useful addition for guitars that use batteries as it is an easy way to prevent them from draining.  If you do this mod, make certain you cut the ground wire (i.e., the one that runs to the outside ring of the output jack).  Even though a guitar is an AC circuit, the ground is still on one side (don't ask!).  Of course, if you don't anticipate using active electronics, it doesn't matter which side of the circuit you break.

Ideally, the best place to insert the switch into the circuit is just before the output jack.  Certainly, some other places will work just as well, but this is the safest approach so you don't end up cutting, say, your neck pickup but leaving the bridge pickup connected.  That wouldn't get you anywhere.

An alternate approach
If you are just looking for something to shut off your guitar when you set it down (i.e., to keep it from draining the batteries), you can install a mercury switch.  These types of switches open or close (depending on their physical orientation) by conducting through a "bleb" of mercury encased in glass.  When the mercury falls across the contacts, the circuit is opened.

If you add one of these to your guitar, you can position it such that it will break the connection to the ground when you stand it upright when you are not playing.  However, in practice this can be a bit difficult to add because you can easily end up moving such that the mercury ends up cutting your signal just as you strike your killer pose in the middle of a solo.  Moral: don't be a poser!

Note that it is somewhat difficult to find mercury switches these days for a variety of reasons.  Specifically, hello!, it's mercury.  Since this is a toxic heavy metal (like that produced by many late-'80s hair bands), it isn't the safest thing in the world to have it just about anywhere.  Home thermostats used to more routinely use mercury switches (although bi-metallic strips are also common), but they're almost all digitally controlled these days.

Another problem is that these switches are notorious elements in home-made bombs.  Guy finds a package on his doorstep.  He picks it up and tilts it to see who it's from... BANG!  I wouldn't recommend looking for a switch and finding yourself added to an FBI "watch list."

What's in a name?
Like I said above, electronically there is no difference between a kill switch and a standby switch.  They both cut the signal.  However, the terms grew out of the fact that a standby switch is more like the "standby" switch on some tube amps.  In other words, it's something to cut the signal while the rest of your gear is turned on, warmed-up and waiting.  On the other hand, the kill switch is a momentary interruption of the signal for more immediate musical purposes.  Don't worry about the semantics; only the music matters in the end.  Think about how you'll use a mod, then implement what you want as you need it.

Copyright Alexplorer.