Piezo Bridge Passive Volume

[marksound]

I'm working on a solidbody acoustic/electric thing. I'm using an outboard preamp/DI, and I want to add a simple passive onboard volume control.

I've searched for days, but I've come up with nothing. What size pot? Do I need to add a resistor or capacitor? Help?

[lovekraft]

I'm not aware of a universally effectrive solution - for instance, the old Fishman Powerbridge spec recommended a 5 megohm pot wired like a standard volume pot, but they've changed that to a 250K pot with a simple RC highpass filter on the pickup and a treble bleed cap on the pot, and the LR Baggs X-Bridge uses a 5 megohm pot with a treble bleed cap. Check the documentation for the transducer you're using - it should tell you what works best with that particular pickup. Alternatively, you could insert an active buffer after the piezo and use whatever volume pot best suits your DI box.

[marksound]

Well, the transducer is an under saddle thing that came in a blister pack. Period. No documentation.

I have had it just soldered to the jack and run straight to the preamp. That worked ok, but I'd like some control at the guitar. It's not imperative, just handy.

I'll let you know what I come up with. Thanks.

[thedoctor]

Since everything else is going to be Evinrude , ie: outboard, I think the simple shorting pot as LK suggests is good except the value should be closer to 1 or 1.5 meg. If the top of the pot's range doesn't do anything, go to a lower value.