hex pickup experiment...

Started by ubertar-fgn, September 26, 2012, 06:48:04 AM

Previous topic - Next topic

0 Members and 1 Guest are viewing this topic.

ubertar-fgn

There are so many sub-forums on this board, I'm not sure where to put this.

I'm Paul Rubenstein, the maker of ubertar hexaphonic guitar pickups.

Someone gave me a roland gk-1 a while back, just the pickup itself, not the preamp section with the battery and switches and all that. I was doing some experiments with a new, improved version of my now-defunct type 1 (low Z) pickups, and decided to see if the gk-1 coils would work well with the turbo transformers I used for type 1. It turns out to work very well. It actually makes the gk-1 into a very nice sounding, passive pickup.

What I don't know, though --and this is where you guys come in-- is whether the gk pickups actually give you the passive signal when the preamp section is turned off, or if the circuitry prevents that. So if someone here (Vance?) who has both a gk pickup and an ubertar turbo breakout box, can you plug the gk into the turbo box, with no power to the gk, and tell me the result? This would open up the possibility of a passive breakout box for gk pickups with really nice tone.

Also, I see no reason the same thing wouldn't work for the PowerGig stuff you guys have been using.

Cheers,
Paul

Elantric-fgn

#1
In Roland Gear,  the Hex PU signal is never directly "heard" - nor accessible.

We typically employ a third party "break out box" to access those signals.

Here is a typical modern Roland 13 pin preamp


The 6 signals from the hex pickup are buffered by internal op amps inside the GK-2A / GK-3, and sent to the 13 pin cable.


The only exception to this strategy are the Piezo preamps by Graph-Tech Ghost or RMC  - these will sum all six piezo signals to a summing node and often internal EQ  - and this is available as a separate "mono Piezo Output"

Also due to having over 7,500 members, we have a lot more daily traffic and discussions in these matters over at VGuitarForums:
www.vguitarforums.com
   
. . . the future ain't what it used to be . . .

ubertar-fgn

Thanks for the reply. I've made a fair number of hex breakout boxes for GK-users, and I'm aware that the hex signal is not directly accessible through Roland gear. I'm aware that, when powered, the signals are buffered, and sent to the cable. What I'm asking is whether the unbuffered signal, when the battery is removed (or switched off, if such a switch exists-- I don't own a GK, or I wouldn't be asking this) makes it to the cable.
If so, then my turbo breakout boxes provide a passive solution for hex output, with far superior tone quality. If not, then the only way to get this signal is to cut the cable from the pickup to the preamp, which not many people would be willing to do.

Thanks for the invitation to the V guitar forum... I may take you up on that.


Elantric-fgn

QuoteWhat I'm asking is whether the unbuffered signal, when the battery is removed (or switched off, if such a switch exists-- I don't own a GK, or I wouldn't be asking this) makes it to the cable.

The GK-3 is not battery powered, but powered via + / - 7VDC supplied from the GK13 Host processor 9VG-99, GR-55, etc)

Like most  op amp circuits - no power = no sound
Reference schematic again
. . . the future ain't what it used to be . . .

ubertar-fgn

The breakout boxes I make for GK pups are battery powered, because they're not getting power from the Roland processor when they're plugged into the breakout box. It's the RMC stuff that has onboard battery power, if I recall correctly now, so that may be where I got confused.

At any rate, I'd still be curious for someone who has both a turbo box and a gk to try it out, just for the hell of it. Sometimes things that shouldn't work in theory do in practice. No harm in trying, anyway. Also the PowerGig pups should work well with the turbo box, making those pups a lot more useful than they are without it.