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Hexaphonic piezo rewiring?

Posted: Sat May 30, 2020 1:23 am
by rsdio
I need to stop coming up with new ideas for modifications, and get to playing. That said...

Has anyone rewired the piezo bridge to separate the six strings into individual channels? That would surely require a 13-pin jack or other multi-channel wire, but it seems possible. Each piezo bridge piece starts with its own wire.

I'm curious whether anyone has tried modifying the piezo wiring, even just to split it into stereo.

I probably won't be starting any kind of project like this for a while, but I still have my thinking cap on...

Re: Hexaphonic piezo rewiring?

Posted: Sat May 30, 2020 1:34 am
by vjmanzo
I think the Graphtech Ghost System lends itself to this very easily. I’d have to check the manual to be sure, but I think the 13-pin output should carry the discrete string signals on six different pins.

Re: Hexaphonic piezo rewiring?

Posted: Sun May 31, 2020 4:15 pm
by rsdio
My Godin Freeway SA has the Ghost system, and I like it. You're right: Each string has its own channel on the 13-pin connector. As a bonus, there is a 7th audio channel that carries the magnetic pickup signals like a standard, passive guitar's mono output. You probably know that the 13-pin carries power, too, so that eliminates the battery.

I didn't realize that the Fly has a Graphtech Ghost system. I'd assumed that it was custom because of the fixed height that matches the fretboard curvature. Maybe it's just the piezo elements that are Graphtech?

p.s. I've designed a couple of outboard preamps that convert the 7 audio channels from a 13-pin connector to balanced audio - either on TRS or DB-25 - as well as providing power to the guitar. This works well when you want the raw audio instead of being tied to something like the Roland GR-50 Guitar Synthesizer.

Re: Hexaphonic piezo rewiring?

Posted: Sun May 31, 2020 7:28 pm
by vjmanzo
Hi @rsdio, yes, the later Flys used both the Graphtech piezo elements and the Ghost system; a summary of the Fly changes through the years is available here.

Somewhat related, I'm also interested in multiple timbres, so I've designed a multi-channel guitar jack that is the exact size of the Fly output jack:


Re: Hexaphonic piezo rewiring?

Posted: Sun May 31, 2020 8:51 pm
by rsdio
Wow!

Re: Hexaphonic piezo rewiring?

Posted: Sun May 31, 2020 8:56 pm
by rsdio
vjmanzo wrote: Sun May 31, 2020 7:28 pm yes, the later Flys used both the Graphtech piezo elements and the Ghost system; a summary of the Fly changes through the years is available here.
Ah, right:
the Graphtech signal noise is potentially compounded by using the original non-Graphtech Fly saddles with the original Fishman piezo elements.
I hope to separate the signals from the original Fishman piezo elements, without changing any of the mechanical aspects of the setup. I also might create some custom electronics rather than try to drop in a Ghost pcb as-is. But, it will be a while before I start that project.