Wiring help for 9v Pre-Amp

**robin** · 21-04-2016, 01:04 PM

To all the wiring gurus out there (Weirdy, I’m looking at you) I could do with some advice please.

I am still researching my next build but (if I go ahead) it will include a pre-amp that I already have laying around that has volume, eq, etc as part of a unit that is meant for external mounting on an acoustic guitar. My plan is to locate this pre-amp INSIDE the body of the guitar thus making access to the volume knob rather problematic.

I was wondering if I could set the volume on the pre-amp to max and then insert another pot on the wiring that goes from the pre-amp unit to the output jack thus giving me an external volume knob. Would this second pot interfere/degrade the signal and if not would I need a special pot for this or would one of the run of the mill 250/500k pots do the job. Once the guitar is complete I could experiment with pots to see which gives me the sound I am after.

As I am a complete numpty when it comes to wiring any help would be appreciated.

Cheers
rob

**wokkaboy** · 21-04-2016, 01:14 PM

good stuff Westie07, is this an acoustic guitar or bass ?

better wait for the guru to respond. I'd guess a standard A type pot should be fine for the volume and shouldn't affect the signal.

**WeirdBits** · 21-04-2016, 03:02 PM

Do you have any details for the pre-amp, make/model, images etc? I take it you want to keep the pre-amp intact, not disassembled/modified etc?

**robin** · 21-04-2016, 04:05 PM

Hey there Warren. Acoustic? I wish.

It will be another solid body pine scratchie. I have not made any decisions as yet just thowing up a lot of ideas for now.

Researching the build is part of the fun. I need to boot The Black Dog out, so I will probably take some time with this one.

Hopefully I will make a decision soon and get started.

**wokkaboy** · 21-04-2016, 04:10 PM

Hey Westie, I didn't read your 1st post correctly, I see the unit is off an acoustic !!

sounds good bro

wiring guru chimed in needs more info

who the hell is Warren ? bwhahahah

**robin** · 21-04-2016, 04:32 PM

Thanks Scott for your help.

Its a Fishman, but I have no idea of model or specs. I know it was originally for a piezo pickup.

As long as it's not too technical, pulling it apart is no problem. I have already taken the back off as I will have to remotely locate the battery box as it is too big to fit in a regular size solid body electric. I'll post some pics tomorrow.

Thanks again for any help.

**robin** · 21-04-2016, 04:41 PM

D'oh. Double post

**WeirdBits** · 21-04-2016, 05:12 PM

You're planning on embedding this in the guitar to use with a piezo pickup, right, rather than trying to use it to amplify a standard magnetic pup? If it is the latter then it probably won't work well due to the low impedance of magnetic pups vs the high impedance of piezos.