AB input without switch - possible?

[TheRisk]

Hey guys - new to the forum. 

So I have a pedal board that has a line 6 wireless that goes into my first pedal.  Annoying thing is every time I want to plug in with a cable I have to obviously unplug the wireless from the first pedal.

Is there a way I can build an AB box that bypasses A when B is plugged in without needing a SPST or DPDT switch?

[nocentelli]

Even quite cheap stereo jack sockets often have switched contacts, i.e. two sets of tip and ring contacts: one set connects with the jack, the other set is connected to these contacts only when there is no jack plugged in. Use an ordinary input socket from to receive the signal from the wireless, connect the tip and sleeve to a switching jack with ground to ground and wireless tip to the switched tip contact. Now wire the "normal" tip contact to an output jack: Use this switched jack as your auxiliary cord input, and it should cut out the wireless. Sorry I don't know the jargon, not tried it in practice, but I'm pretty sure it should work, I'm sure others will chip in if I'm hopelessly wrong.

[Jdansti]

Welcome!

Here are some different jack configurations. Sorry, I'm having trouble uploading to photobucket right now, but here's the link. "B" is the one that nocentelli is referring to. When the plug is in the jack, the sleeve and ring are connected. These two terminals form your switch.

https://www.dropbox.com/s/71i9jd5etqu8gpq/Photo%20Jul%2015%2C%206%2059%2013%20PM.png

[nocentelli]

I'm having trouble uploading to photobucket right now, but here's the link. "B" is the one that nocentelli is referring to. When the plug is in the jack, the sleeve and ring are connected. These two terminals form your switch.

https://www.dropbox.com/s/71i9jd5etqu8gpq/Photo%20Jul%2015%2C%206%2059%2013%20PM.png

I think diagram D was the one i was referring to, I think i didn't explain it terribly well. You can see the two tip and two ring contacts, with each pair connected by the arrow since there is no plug inserted. When the cable is plugged in, the contact is broken (i think):

[GGBB]

I have a couple of jacks that are like "D" above, but mono.  So only the tip has a shunt.  They are a little easier to hook up because they don't have so many solder lugs crammed onto them.  In case you like word descriptions more than diagrams:  you use the special jack for the guitar input and a normal jack for the wireless input.  The wireless input jack tip would connect to the guitar input jack shunt, and the guitar input jack tip would go to the A/B output jack tip.  When the guitar is not plugged in, the wireless input passes through the shunt-tip connection to the output jack.  When the guitar is plugged in, the shunt is disconnected, "unplugging" the wireless, and the guitar will go directly to the output.  All the sleeves/grounds would be connected normally.

[TheRisk]

Thanks guys - I guess I'm still feeling stuck...

So the tip on the wireless goes to the ring on the guitar input... Tip on the guitar input to the tip on the output... How does the ring of the wireless hookup to the tip on the output?

[GGBB]

Thanks guys - I guess I'm still feeling stuck...

So the tip on the wireless goes to the ring on the guitar input... Tip on the guitar input to the tip on the output... How does the ring of the wireless hookup to the tip on the output?

The shunt is not the same thing as the ring.  It is an extra piece that contacts the tip connector until a jack is inserted which pushes the tip away from the shunt and disconnects it.  Here's a pic:



Notice the three lugs for a mono jack - judging from this picture the shunt is the lug sticking upward, the tip is the lug in the background, and ground/sleeve is the one at the front of the picture.  Stereo versions will have the ring connector and a second shunt added for a total of five lugs.

[TheRisk]

Finally got it done - bought a jack with a shunt and it works beautifully!  Thanks a million guys!!!