Truth_David Posted June 10, 2012 Report Share Posted June 10, 2012 Hi all. I have a project in mind to combine the wart end of the GK-2A with either a set of Graphtec Ghost hexaphonic saddles or RMC powerbridge saddles. Is this possible, given the fact that the Roland bridge is made up of mag p/ups, whereas the Grahptec and RMC bridges are both piezo systems? The GK-2A wart has a preamp, so I would expect that to be able to cope with either the output of mag or piezo pickups - is that correct? Does anyone have a wiring diagram for the Roland GK-2 that shows which cables feed which p/up? They are colour coded, and the final one seems to be an Earth connection, but it would be helpful to know in advance which strings equate to which colour on the wiring. Quote Link to comment Share on other sites More sharing options...
elmo7sharp9 Posted June 13, 2012 Report Share Posted June 13, 2012 (edited) The gk2a does not allow direct access to the pickups at the 13-pin socket. See http://img141.images...k2schem1da0.jpg for details. You'd need to hack the SMD-scale PCB to access the nodes where the mini humbuckers of the hex pickup connect. Even then, the mini humbuckers are (comparatively) low impedance devices and piezo saddles are the opposite. You'd probably need to add a FET preamp for each separate saddle (and there's NO SPARE SPACE in the GK2A casing). Edited June 13, 2012 by elmo7sharp9 Quote Link to comment Share on other sites More sharing options...
Truth_David Posted June 14, 2012 Author Report Share Posted June 14, 2012 Thanks Elmo.......my GK2A has a mini plug coming from the pickup with 7 terminals, one of which is ground, that is what got me thinking about this possibility. There is absolutely no way I would have even considering hacking into the PCB otherwise as you suggest would be necessary. It seems though that there is an argument for building the GK-2A into a small removable enclosure, if it's worth the effort to add the FETs or whatever. It's just that I happen to have both the Ghost saddles and a set of RMC Powerbridge saddles for a Strat going spare, and this particular GK-2A also has a wiring fault which needs checking anyway, as having an intermittent fault makes it useless to me. Both the GK-2A and GK-3 seem to have the same weakness in the support that grabs the cable coming out of the wart - the screw tends to get chewed up, then the cable works itself loose and becomes vulnerable to damage. The other thing is that the RMC saddles could be easily adapted to fit the bridge of my acoustic electric guitar, whereas the GK-3 pickup is too high for that instrument, as it has a very low action for an acoustic guitar. I already tried this instrument with the VG-99 and fitted with electric strings, and was really impressed with how well it works, apart from with patches with altered tunings, but the action was uncomfortably high for single string work.... Quote Link to comment Share on other sites More sharing options...
elmo7sharp9 Posted June 16, 2012 Report Share Posted June 16, 2012 If you can source a 13-pin DIN socket, you might be better off starting from scratch, rather than cannabilising a gk2a (especially one with "issues"). I reinforced my gk2a with epoxy at the weak spot you mentioned (the tiny retaining screw had chewed the thread in the casing), and it has lasted over 15 years. I built a "13-pin to 1/4" sockets" breakout box topan the strings in stereo (which was boring, because of the sterile sound)sum the pickups through a mixer to be able to vary the string balance in the drive signal to a sustainer (with, sadly, results roughly equal to using a conventional pickup).recreate the hex fuzz of earlier Roland guitar synths (which I STILL haven't got around to doing). I rarely use my Roland GR-50 guitar synth, as its Linear Arithmetic synth engine sounds "dated" to me and nowadays, freeware VST plugins do a faster job of note-following (not surprising, considering the comparative processor power) Quote Link to comment Share on other sites More sharing options...
Truth_David Posted June 17, 2012 Author Report Share Posted June 17, 2012 I still have the RMC unit, but one of the lugs came off the 13pin DIN pcb, and although I took numerous photos and did sketches of the wiring, considerable time has passed since and I really haven't a clue where to start rewiring everything. I downloaded a circuit schematic from RMC a long time ago, but I am pretty clueless with wiring diagrams. If anyone here might be able to help I would be appreciative. Thank you. I was thinking that it might be an idea to mount the RMC unit into an enclosure mounted on the guitar, rather than having to hack it to take the 13 pin socket and battery box etc. Quote Link to comment Share on other sites More sharing options...
ansil Posted June 25, 2012 Report Share Posted June 25, 2012 why not just build your own roland unit to hook up the unit too. there is a great selection on diy hex pickups on google thats where i found how to build mine Quote Link to comment Share on other sites More sharing options...
ansil Posted June 26, 2012 Report Share Posted June 26, 2012 in the rmc unit that was in my brian moore the 13 pin provided power, up and down for patches which never worked with roland stuff at least not mine. and buffered pickups ie magnetic and buffered individual piezo output. i don't know about you but the buffered guitar part sounded like crap i always ran the guitar as a midi synth and used the guitar output for guitar. but a hex buffer for the hex pickup could be done with a hex inverter since it was a non gain device. or 3 dual opamps or a quad and a dual. i still have the rmc stuff from brian moore if you like a copy Quote Link to comment Share on other sites More sharing options...
Truth_David Posted June 26, 2012 Author Report Share Posted June 26, 2012 in the rmc unit that was in my brian moore the 13 pin provided power, up and down for patches which never worked with roland stuff at least not mine. and buffered pickups ie magnetic and buffered individual piezo output. i don't know about you but the buffered guitar part sounded like crap i always ran the guitar as a midi synth and used the guitar output for guitar. but a hex buffer for the hex pickup could be done with a hex inverter since it was a non gain device. or 3 dual opamps or a quad and a dual. i still have the rmc stuff from brian moore if you like a copy Thank you Ansil, yes I would like a copy of the RMC schematics for the Brian Moore please . Do you have a Dropbox account? Quote Link to comment Share on other sites More sharing options...
Truth_David Posted June 26, 2012 Author Report Share Posted June 26, 2012 why not just build your own roland unit to hook up the unit too. there is a great selection on diy hex pickups on google thats where i found how to build mine I have neither the time nor the technical expertise.....I already spent a huge amount of time following the Sustainer thread, and never actually ended up with a working sustainer.....playing is my priority, unfortunately I am not like Allan Holdsworth who is not only an amazing virtuoso musician but also a very capable electronics engineer who frequently invents whatever he needs in the studio. I think these abilities are only for the very gifted amongst us... Quote Link to comment Share on other sites More sharing options...
Truth_David Posted June 26, 2012 Author Report Share Posted June 26, 2012 I was following a forum thread about Variax transplanting, and eventually a company began producing these in an external rackmount enclosure, and I believe they also combined the Roland 13 pin connections, so I find that idea appealing, but they were very expensive. I know that the Roland VG type gear sounds better with their magnetic hex type p/ups, and in fact I much prefer these over the RMC and other piezo systems. But unfortunately the actual design of the Roland p/ups leaves much to be desired aesthetically - I think they look really ugly, apart from the white or transparent variety that come with their custom instruments. But those are also very expensive for what they are, and difficult to come by. Pete from the Sustainer thread also had a really aesthetically pleasing design for a hex p/up, but he never got around to marketing it. In any case, it is not only the p/up but the enclosure that needs a radical rethink in terms of aesthetics. I also think it is about time someone implemented more midi control facilities into the device. Even the first relatively primitive guitar synths had more capability for controllers than the GK type p/up systems. And of course all that is light years away from what the Synthaxe was able to achieve. But being so costly to build and maintain they went under, and no-one has since had the vision to design an instrument with similar features, but with the benefit of today's technological advances. It was a behemoth, but my God what an instrument in the right hands!!! Simply awesome...... Quote Link to comment Share on other sites More sharing options...
ansil Posted June 26, 2012 Report Share Posted June 26, 2012 i dont' have a drop box account sorry just email me ansilgregory at yahoo dot com .......... i will have to dig it out of my email. its not really that complicated to build. it actually could be done inline instead of using that big azz box they use six buffers into a 13 pin din could be built on a pencil and then epoxied. the piezo tracks better i just never liked buffered pickups either go active all the way with filtering and gain stages and such or go home is what i say lol. you can also do a non buffered version with led photo fets tracking the strings Quote Link to comment Share on other sites More sharing options...
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