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hardwiring a pcb mount mono switched jack socket help

bournemouth musician

Aug 29, 2015
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hi all, looking forward to being part of the group
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i have a lot of experience repairing guitars, wiring mods etc but have a conundrum ! i am building a Cajon and have taken the guts out of a little Nevada G10 ss amp to put in it, which will be linked to a condenser mic inside so that its self amplified.

The G10 has a mono jack input, volume, treble, bass and headphone out. So i have mounted the pdb inside the cajon and drilled so all the controls are usable from the outside except the input jack as this will be internally wired.

I have removed the plastic surround on thew input socket just leaving the 4 poles sticking out of the pcb.

To test and get the right connections before soldering up the mic lead to it, i have used a guitar lead connected to a guitar to make sure i solder to the right poles etc - my problem is i cannot work out how to do this as every configuration i try either is silent or you can hear the guitar but with a huge amount of earth buzz.

I have checked the back of the circuit board and seen that one pole goes into the circuit and all the others appear to go to ground I had just presumed it would be tip wire from the guitar lead going to circuit and ground to one of the others - but not the case clearly.

As i say i have tried all configs of connecting the poles, putting a jumper on from pole to poles etc but no joy . I have scoured the net for any info on how to do this but came up with nothing - any help or ideas would be totally appreciated. many thanks

PS - The mic i am using inside the cajon is an audio technica condenser mic that is powered by a single AA battery and has a balanced output. The actual mic has been stripped down so that only the capsule and battery bay will be inside the cajon.


Craig ps this is the type of mono jack i have stripped to the poles.
 

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shrtrnd

Jan 15, 2010
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Can you post pictures of your installation. It's a little difficult to visualize what you actually have.
My thought is that your input jack may not be a mono jack, but a stereo one?
That would explain the symptoms as I understand them.
 

bournemouth musician

Aug 29, 2015
2
Joined
Aug 29, 2015
Messages
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Hi shrtnd, thanks for the reply bud, will pop some pics up tomorrow when i am back home, its def a mono input jack though, as not only has it only 4 poles but in a cheap little 10 watt ss guitar amp. Cheers Craig
 

shrtrnd

Jan 15, 2010
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Joined
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A lot of those jacks have electrical contacts, AND a couple of pins that are meant to secure the jack housing to a printed circuit board for physical support only.
You need to make sure you're not connecting a sgnal to any physical mount pins that are not intended for signal use.
It's an easy way to accidentally introduce noise (or a short-circuit) into your signal circuit.
 
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