Thinking of throwing together some pre-made harnesses to sell.

Soldering is no problem, on/off switch equally easy.

But I plan to include a volume pot, so piezo, pot, jack + wiring.

I know 500kohm pots tend to be used in multi-pup guitars, and 250kohm in single pup builds, but that tends to be for traditional variations on mag pups.

Any idea what the ideal resistance would be using a standard 27mm piezo disc?

Just thinking along the lines of not everyone is comfortable with soldering but can handle the woodwork would be happy to throw down a couple of quid for a ready wired harness that just needs fitting.

So any advice for pot resistance with a single piezo, I know there is an electronics and wiring group, but this is barely technical enough to be asked there.

Replies

Carl Robson October 10, 2010 at 3:26pm

Was planning just volume as getting a tone pot to do anything with a Piezo element seems to be tricky.

James Deeds said:
are you adding just the vol pot or will you be doing vol and tone?
James Deeds October 10, 2010 at 1:45pm

are you adding just the vol pot or will you be doing vol and tone?
Carl Robson September 23, 2010 at 11:44am

Hah, seems like a popular idea at the moment.
Naz Nomad September 23, 2010 at 11:30am

You should try selling some wood/bone ones ... oh wait, that's ''punishment by death'' in some places. :-))))

Carl Robson said:
Yup, guess it is.
Hopefully I can put a few glass slides out and about too since I bought the diamond cutoff wheels too.

Naz Nomad said:
I'm in the process of doing this too ... survival of the neatest, eh? LOL
Carl Robson September 23, 2010 at 11:24am

Yup, guess it is.
Hopefully I can put a few glass slides out and about too since I bought the diamond cutoff wheels too.

Naz Nomad said:
I'm in the process of doing this too ... survival of the neatest, eh? LOL
Naz Nomad September 23, 2010 at 11:20am

I'm in the process of doing this too ... survival of the neatest, eh? LOL
Carl Robson September 23, 2010 at 10:21am

Interesting. On my second build, I just used one 27mm and it sounds ok, but on my first build I used a 27mm and I think something like a 40mm in series. I was worried it would ruin the sound but it works OK.

My amp is just a little Nevada G10 which isn't really that good, but it was a couple of quid secondhand and just something to make a bit of noise through.

Kevin Lawton said:
Yeah, you need to match the Pot to the impedance of the piezo as closely as you can. 2 megohms - is going to be as close as I can guess without measuring the piezo myself. It might come as a 'standard value' 2.2 meg. That'll do fine.
The problem occurs if you are planning on running a piezo into an ordinary guitar amplifier without some kind of pre-amp to buffer it.
The input impedance of the guitar amp will be much lower than the impedance of the piezo and ruin the tone you hear.
A small pre-amp to buffer against this problem is the 'correct' way to go. A pair of matching piezos wired together in series (and in phase of course) can help alleviate the problem greatly.
Kevin Lawton September 23, 2010 at 10:17am

Yeah, you need to match the Pot to the impedance of the piezo as closely as you can. 2 megohms - is going to be as close as I can guess without measuring the piezo myself. It might come as a 'standard value' 2.2 meg. That'll do fine.
The problem occurs if you are planning on running a piezo into an ordinary guitar amplifier without some kind of pre-amp to buffer it.
The input impedance of the guitar amp will be much lower than the impedance of the piezo and ruin the tone you hear.
A small pre-amp to buffer against this problem is the 'correct' way to go. A pair of matching piezos wired together in series (and in phase of course) can help alleviate the problem greatly.

The Brits are coming

Replies