Anyone Familiar With The Rmc Circuitry?

[Truth_David]

A few years back, my Strat was fitted with an RMC piezzo/MIDI circuit, with hexaphonic piezzo pickups built into the bridge saddles. I have lost the original circuit diagrams, and would like to duplicate them, in order to be able to understand the circuitry in question.

At one time I was seriously considering transplanting the entire system to another guitar (or perhaps more importantly to a better vibrato bridge), but the wiring is so fine connecting the piezzo system, that I could not find anyone prepared to undertake the job here in Spain, especially without a correct wiring diagram. The guy who put it all together for me is back in the UK, and has no Internet or e-mail facility, although I suppose fax might be an option, but in any case we lost touch some time ago, so it will not be as easy as one might imagine.

As far as I understand it, the system is active, with a piezzo hexaphonic pickup system combined with MIDI and a pair of push button switches which only work with the MIDI circuitry. Then there is an extra blend control between the piezzo pickup mix and the normal strat 5 way switch circuitry for the 3 s/c pickup system. Then there is an additional active tone control, a volume control only for MIDI and another master volume with a built in push pull pot that seems to switch between piezzo and normal pickup mode, over-riding the blend control. The whole system is powered by a 9v battery fitted in a cavity just behind the tremolo recess under the bridge. It appears to also have the option of a stereo output, presumably in order to have separate outputs for the piezzo p/u and the normal s/c pickups, and there is a MIDI connector of the Roland GK type fitted for that type of connection. When thus connected the system draws power from the MIDI controller rather than the battery. Otherwise, as long as there is a cable connected to the mono/stereo input, the battery remains inline, which is a real pain in the butt, as when the battery dies, the guitar no longer produces any sound whatsoever.

BTW, another question: I have noticed that my guitar is starting to produce a kind of warbling effect, even noticable acoustically, such as that produced when the pickups are too close to the strings, and drag them toward the pickup magnets, thus causing them to go out of tune. But unfortunately, the manner in which the pickups have been set into the pickguard (standard Strat type), does not allow dropping the pickups further down in the normal way, just by loosening off the screws, as the guy who fitted the RMC system seems to have put a layer of foam under them. And so loosening off the screws has little or no effect. I really wanted to confirm that the proximity of the pickups to the strings was a likely cause before pulling the whole thing apart and attempting to remove the foam or whatever it is, so I can lower the pickups.

The pole pieces are staggered BTW, as with a standard old Strat, and I really don't see them being all that high in relation to the strings. But that said, physically pushing each of them down while attempting to pick the string simultaneously does seem to reduce the warbling effect. It actually alters the tone too, like a subtle wah effect, but so much so that I keep thinking I have Chorus on, when in fact there is none, so it is becoming really annoying!

Because the vibration can also be felt directly via the bridge, I actually thought that was the cause originally, but then I remembered the pickup/string proximity issue, and decided that was a more probable cause.

I would be grateful for any information, diagrams, explanations, advice, whatever....thanks!

Happy New Year.

David

[Mattia]

Ever consider contacting rmc directly? Google RMC pickups, it's easy enough to find...

[Truth_David]

Ever consider contacting rmc directly? Google RMC pickups, it's easy enough to find...

Hi Mattia,

Yes, I did that, and in fact today I received the circuit diagrams for the system. Richard is a really nice guy. But perhaps more importantly, he mentioned that Godin and Parker are involved in projects combining the RMC technology with their own. And apparently my idea of combining the RMC circuitry with the 'Sustainer' being developed in our forums is a valid one, as they are not incompatible with one another. But I am excited because I know that our home made prototypes already far surpass the technology available commercially. And with the think tank that we have at our disposal, it will not be long before someone comes up with a device that can be used on any instrument without damaging it in any way. Which is the upside of the e-bow technology.

You might want to check out the work zfrittz6 is doing on the forum.

Thanks again,

Regards,

David