Dippy idea, Patentable, or Already exists?

The mute is a mechanical function of the jack physically lifting contacts to break connection when pushed into place. I'm not an expert on every single amp out there but don't see it as something you could really switch externally.

Edit: you COULD however, have a send and return box with a switch placed between the two cables for the same effect. The lack of standardised distances between FX loop jacks means it wouldn't be one size fits all though.

 

^^ Pretty sure this is right.

There are 1/4" to 1/8" adapters that are basically just male 1/4" connectors with female 1/8" ports that could perform this function without any extra cable bits to worry about, but it being "switchable" would be tricky, if possible at all.

Heck, a properly-trimmed carrot might actually be applicable here.

 

yes , some of my amplifiers have a mute button.

not hoping to discourage you , but the fact that your idea can be done does not mean that it is usable. I mean , I could roll down the volume of my bass , or I could buy the mute , and then flick the sound off.

 

No they don't. What happens is the power amp source is switched from the preamp output to the f/x return. If there is no signal on the f/x return then there is obviously no output. But the amp is not muted. Any pops, crackles, hiss or other noise that appears at the f/x return will be amplified. If the amp is cranked then your speakers might be at risk.
Not a good idea, IMHO.

 

SteveCS is absolutely right.

What you really want to use is called a shorting plug. If you have separate send and receive jacks, then a shorting plug is just a ¼" phone plug with a short piece of wire inside connecting the tip and sleeve. Plug it into the return jack to ground the return input and prevent potential problems. (Don't plug it into the send jack.)

On the other hand, if the send and receive are combined on one jack, called an insert, then you would use a ¼ TRS plug with one signal conductor grounded (usually the tip) and the other (usually the ring) floating.