Types of output jacks

[Jerry Overstreet]

I'm going to be changing out some broken cheap hard plastic enclosed mono send and return jacks for the fx loop circuit of an amplifier.

Sources show a standard type and a shunt type.

So, for my curious electronically challenged self, just what is a shunt type jack and why or where would I need to use one?

Is this different than a make before break [and reverse] or something else?

...and what type jack would be best for the fx loop? Thx

[David Ball]

On the FX loops I've seen, the shunt type jack connects the "FX in" to "FX out" when nothing is plugged into the loop--lets everything work as if the jacks weren't there at all.

Plugging something into the shunt jack opens the circuit back up and lets the loop work. If that makes any sense...

Dave

[Jerry Overstreet]

So, would that be like where you would use a TRS insert cable?

[Jack Stoner]

So, would that be like where you would use a TRS insert cable?

No, its a standard "mono" jack, just has an extra set of "normal through" contacts. When nothing plugged the signal passes through the in jack. When a plug is inserted it opens the normal through contact and the input on the plug is used.

Peavey uses this type of jack on the return jack of effects loops and the Power amp in jack.

[Jerry Overstreet]

I think I'm beginning to understand. So that's what happens with bad jacks in the Peavey amps making it necessary to plug a cable between those S&R jacks?

I guess I'll have to wait until I pull the chassis out to see what I have. I was wanting to order the parts in advance to avoid having the thing tore apart, oh well

Thanks for the education David and Jack.

Anyhow, I see the jack is still intact, it's just the molded plastic threaded part that extends through the case that's broken. I have all the pieces so I'll just try to super glue them back on. Not in the mood to try and replace those PC mount jacks.

I can see this is just happening to all the jacks that have plastic threads.

[Bill Fisher]

Jerry, take a look at Switchcraft 12A jack, and you will get the idea. It is called a shorting jack.

Bill Fisher

[Bill A. Moore]

I think 13A is their transfer jack number.
I use one on my amp builds in the aux speaker output. With nothing plugged in, the 8 ohm lead is connected to the speaker. When a plug is inserted, it switches to the 4 ohm connection.

[Jerry Overstreet]

I appreciate all the info. I'm always glad to learn something. All useful input welcome.