this looks neat...is it doable? or worth it?
some crazy mofo up for a challenge?
http://www.korganalogue.net/korgother/X911/X911_service.pdf
ancient guitar synth things seem to be pretty cool in my humble experience....but too noob to glean much from this..
I think we should just do a forum synth project. I've got some bass synth stuff I've been working on here and there.
Maybe start off with a comparison of the building blocks, simplify them, etc? We have, now, 4 different NEW synth units popped up since the summer, 3 just in the last 2 or 3 months. I bet we could come up with some kind of DIY-friendly universal synth, given the tighter tolerance of parts available to us today.
BTW, this thing is gigantic! lol... not as much as the PhaseII, but still pretty big. I have seen one of these in the past at a shop, sitting with a couple other rack synth boxes. Wish I knew I'd be getting into this stuff, I would've picked up at least 20 pieces of rare gear for ultra cheap, lol. All the pieces I've passed up will never be the same as the '69 Hi-Flyer bass I stupidly gave to a girlfriend. I keep wishing I'd have a chance to get it back. Ugh. The things you do when you're a teenager.
Quote from: Earthscum on November 13, 2011, 01:14:47 PM
Ugh. The things you do when you're a teenager.
like...trading off a ludwig phase II for a half a bag of columbian? :icon_redface: :icon_redface:
Quote from: pinkjimiphoton on November 13, 2011, 02:39:02 PM
like...trading off a ludwig phase II for a half a bag of columbian? :icon_redface: :icon_redface:
Lol... yep. I haven't, myself, but I have known many others. Our band has a pair of SM57's through one of those transactions :D
One thing I noticed the Korg uses more CMOS than the other synth boxes. I keep looking at these things and wondering why more CMOS isn't used (then I remember the dates these things were made). I mean, figure if you have to use any more than 2 or 3 schmitt triggers, save a ton of resistor/cap/tranny and use a 14-pin chip. Heck, anything that outputs a pulse or gate signal can probably be simplified with a 40106. as an example. I don't know if I would go as far as to sub 4049's for OPA's, but a large amount of synth trigger and threshold and gate and ADSR, etc... could be simplified with CMOS. Heck, even used switched capacitor filters, now that I think about it.
ok...
so, in english that means the circuit could be simplified with modern components somewhat in a way that would be copascetic and pleasing to the ear in a way reminiscent of the original massive box before us?
that could be really neat! :thu:
x911 is pretty cool and tracks ok but i would suspect a DIY version would end up costing quite allot and would be bigger than the original
the pitch to cv section of the x911 however is similar to the korg ms03 which would be a more doable project and let users pair there own synths as they saw fit (it has both hz/v and oct/v)
It's a real shame the circuit diagram isn't clearer.
I'd really like to have a go at this (after the Ludwig Phase II of course)
Andy
The most critical part of the X911 is really the P/V. Once you have that, there are plenty of other analog modules you can tack on for more sonic flexibility than what the array of buttons on the X911 provides. I certainly wouldn't "kick it out of bed" if I came into possession of one, but for the work involved in a replication of one, there isn't really enough value-added to doing the whole shebang, AFAIC.
As an aside, There was a filter resonance mod in POLYPHONY which I added to a buddy's X911 back in 82 or 83 and it was a big step up in terms of flexibility of tones.
Hmmm, three comments....
1) I'll stick to my GR-50....
2) Andy, you're a crazy mofo (but we love ya anyway)....
3) Refer to point 1). With some net vigilance, you can even find a GR-1 for less than what this sucker will cost to build. Besides being infinitately more flexible.
Not really rare, or unique enough for me to consider building something analog this complex. I've seen a video or two, and listened to some clips, but nothing really there to blow up my skirt. I'm having the same trepidation over the FK-1, and the Synth Traveller, although the FK-1 might be a bit more easily intregrated with other effects. It's a tough call.
If somebody can clone the pitch to voltage section, and perhaps the onboard VCO, i'll build and test it. The X-911 is something i've been looking for for some time, but they're always way too expensive the few times i've seen them for sale.
(http://4.bp.blogspot.com/_FMBJEkaC8Lw/R8r76uLZyDI/AAAAAAAAP7o/gV5WI4ETIaM/s400/fd59_1.JPG)
Quote from: snufkin on November 15, 2011, 06:14:21 AM
(http://4.bp.blogspot.com/_FMBJEkaC8Lw/R8r76uLZyDI/AAAAAAAAP7o/gV5WI4ETIaM/s400/fd59_1.JPG)
This might help; http://manuals.fdiskc.com/flat/Korg%20MS-03%20Service%20Manual.pdf (http://manuals.fdiskc.com/flat/Korg%20MS-03%20Service%20Manual.pdf)
I got it from here; http://manuals.fdiskc.com/flat/ (http://manuals.fdiskc.com/flat/) . There's a crap load of synth manuals there :icon_mrgreen:
Not that the Korg P/V circuit wants for anything, but I have always been curious about the Gentle Electric P/V unit, that was out around the same time as the Korg ones. Have any of you ever seen the innards of one?
Hey Mark, don't rub the lamp unless you want the genie to appear :^) As I remember, the Korg X-911 (is that really 'nine-eleven' in the name, how fitting...;^)
did not work worth a sh!t in my opinion. (I'd like to hear from anyone who thinks it was acceptable...) As for the "Gentle Electric" why as a matter of fact I
had one that was totally dead (someone reversed the power supply voltage) and I repaired it, including reverse engineering the "fundamental extractor module" so I have been 'under the hood'. Its not suitable (imho) for guitar because of the lack of any pre-filtering of the signal, and it cannot accommodate the sharp harmonics that sometimes give multiple peaks of the same amplitude in the same polarity. You can expect octave hop galore with a guitar signal... That said the basic design
of the P/V is quite good (more later...)
H^)
Korg had several units with "external processing" capability. Examination of the MS-20 reveals a P-2-V circuit with adjustable passband (setting high and low corner frequencies) to improve rejection of the content outside the range of expected fundamentals.
FWIW, I etched up a board or two of the P-2-V circuit you had on Tom Gambles old EFM site, when he had all those analog modules, before he went VST. The board is only partially populated, so I haven't tried it out yet. As the obvious expert in it, would you recommend completing that population, or selecting another design? I have two of the Penfold mono guitar-2-synth interface boards awaiting installation and final wiring.
(P.S.: Still trying to reach Mike. Can't get him on the phone or by e-mail, but I have his mailing address)
more later... (sorry I had to do some WORK). I just looked over the Korg X-911 schematics and I don't think they are complete. I don't see
the VCO anywhere. It should have a three position range switch and I didn't see that on any schematic page. If I'm all wet, let me know where
you think it is...
One thing to consider. Do you want to have a guitar synth that is strictly monophonic or polyphonic ? Most P/V converters either need a hex pickup, or you need to
have impeccable guitar technique to minimize tracking errors. I did a DIY P/V converter for guitar some years back, its about as complex as the Gentle Electric
or the Korg (it shares some heritage with the 360 Systems "Slavedriver". It uses a hex pickup and tracks the lowest or latest of the low three strings of a guitar in such a way that you can play chords etc and get a reasonable tracking bass line. The Electronic Peasant expanded the design to a five string synth-banjo (you can Google that). There is no reason the system cannot be used with a six string guitar, I just didn't find the three upper strings useful to track so i made it more simple.
All the reasonable P/V converters for guitar are about equally complex BTW, don't hope for too much simplification with 'modern' parts. Modern parts are more for building FCP's (fvcking cell phones).
My best take on how to do guitar synthesis is to use (essentially) direct string to waveform conversion (like the Roland GR-50) and avoid P/V to VCO where possible. Normal guitar technique is that when you release or mute a string, the sound stops. Trying to keep a stable pitch with no input is really a tough task.
Mark, I would not expect much of the PV-1 (EFM) circuit. It does not have the prefiltering you would need etc. I did front the circuit up with the preamp of the Shin-Ei octave box and it tracked pretty good, but it was slow (the PV-1 divides by 2 so you need on the order of 50ms to get a voltage). It could not hold the CV
after you end a note, that could be added.
Hey if folk want to do a guitar synth I'd be willing to assist, but you are in for a really big project !!!
H^)
Oh yeah one more (or two more) things... The MS-20 is the queen of 'tachometer' P/V circuits, but not useful for tracking a guitar at uhhh... guitar speeds.
A good starting point for a full-range guitar synth (no hex pickup) would be the E-H "Deluxe Octave Multiplexer" with a P/V converter instead of the phase
locked loop approach. In my opinion, the best way forward is to make a sawtooth wave directly from the guitar string and use that for synthesis. Its easy to
get fundamental, octave up, and octave down waves from that. OOPS, I should say "straighforward" not 'easy' (it is still very complex...)
H^) harry
Or indeed the EH Guitar Synth itself for which circuits are on Mark's site.
Since it is hard to find, and since I did not wish to send people on a wild goose chase, I took the liberty of pasting Harry's
initial comments from the document for the old PV-1 he alludes to, since they give a little more detail about functioning of
P2V units in general, and I wanted to save him the time of having to re-explain what he's already explained nicely.
I have omitted the content related to the actual design of the PV-1, given the shortcomings he notes.
A pitch to voltage converter takes a frequency input and converts it to a voltage output. There are several forms of this
circuit, both digital and analog. Most of these can be grouped into two basic classes. The Tachometer circuit, and the Ramp Sample/Hold.
The Tachometer circuit is the simplest. The frequency input is converted to pulses of a fixed width, and these pulses are
integrated, or averaged over time. There is a trade off between how fast you can get to a new level, and how much feed
throughof the input frequency you can accept. The less ripple you wantin the output, the slower the circuit responds to a
change ininput frequency. Tachometer circuits are best for frequencies that :
1) You want to average over a long time anyway
2) Frequencies that are continuous (do not start and stop...)
Note that things like motors etc... are the most common use for Tachometer circuits.
The best example of the Tachometer circuit as applied to Electronic Music is the Korg MS-20 external signal processor. It
features a filter at the input and output that are linked... so the user can set the tradeoff between ripple and acquisition time to
best fit the signal they are processing. The circuit also has an extended range Tachometer circuit... at very low frequencies
the pulse width is fixed. As frequency increases, these pulses get closer together. At even higher frequencies the pulses
overlap, and occasional gaps appear in between multiple pulses. This allows the circuit to perform at frequencies above
the normal range of the Tachometer circuit. There is still a very real delay in how fast the circuit can track a rapidly moving input
frequency.
The Ramp - Sample/Hold is another class of circuits used to solve the problem of slow signal acquisition. The input
frequency is divided in half, and then a linear ramp is generated for one cycle, and then sampled and held during the
following cycle, and the ramp is reset. This happens over and over again... so the output is always one cycle behind the
input. No matter how large the step in input frequency (within reason) the output will follow within two cycles of the
fundamental.
The advantage of the Ramp circuit is speed of acquisition, and lack of ripple. The drawback is that it is more complex, and
sensitive to noise in the input frequency. This approach was used in the 360 Systems "Slavedriver" Guitar to CV interface
(mid 1970's) with some success. The noise problems prevented the circuit from achieving satisfactory performance at that
time. Speed of response is still an issue.
Consider the lowest note of a Guitar = 80Hz, which has a period of 12mS. The Ramp circuit needs at least twice that time to
process the Pitch Voltage, or 24mS. This is a physical limit for converting the pitch. If you have a lot of noise in the signal
(harmonics etc.) it will take even longer.
The Pitch to Voltage converter must have an accurate reference to derive the pitch from. Harmonics will cause false
operation, so inputs from real instruments like guitar, voice, etc. usually need signal processing before the pitch conversion.
It would be possible to update the E-H guitar synthesizer with more available components. Some people might miss the availability of a CV (P/V) output.
I think from my simulations that the E-H has about half of the tracking covered with the adaptive filter, and the rest with the PLL VCOs. Just trying to extract
the fundamental from the adaptive filter stage does not work well enough (imho) for reliable pitch tracking. There seems to be some room for improvement
here, but at the expense of MUCH more circuit complexity (I'm looking at a tracking filter loop modification that essentially makes the loop a track/hold when the input level falls below the compressor input range, the loop CV no longer remains stable and the filter starts to 'open', causing the dreaded 'octave hop' to start to appear. This might happen after most musicians have moved on to the next note... or maybe not.
The big question is, do people think that guitar synths have hex pickups, or not. For me, I insist that my guitars be playable polyphonically while still outputting a synth waveform (ie HEX pickup). That makes things a lot more complex.
H^) harry
QuoteThe big question is, do people think that guitar synths have hex pickups, or not. For me, I insist that my guitars be playable polyphonically while still outputting a synth waveform (ie HEX pickup). That makes things a lot more complex.
I'm just a layman, and I only speak for myself; Guitar synth = hex pup.
Anything else is just a digital, or analog, circuit "faking" it. A synth to me is something like my GR-50. I play my guitar, and I hear synthesized strings, horns, drums, etc. An EH microsynth, Korg X911, or anything else in that vein, is just a circuit mangling the guitars original signal to sound like certain synthy sounds. Hell, a fuzz through a Blue Box sounds synthy! But, alas, in my book, a guitar synth it does not make :icon_cry:.
Before anyone jumps all over me, I realize that I'm treading in both fields here, but it's just that there is just a big difference in how the signal is processed (from what I understand). The X911 will never do what a real guitar synth can do, but it doesn't make it good or bad. It's just different. In my case, owning a "real" guitar synth, just makes it impossible for me to justify buying, or building this particular box.
Maybe that's why I built so many fuzz boxes, because there's no Germanium in my Digitech GNX3, or Boss GT Pro :icon_mrgreen:. I love "real" wahs, because I've yet to find a digital processor that can give me "that" sound. I love analog as much as anyone, but everything has to have a purpose at some point, and some things are just better (subjectively) than others.
Sorry if I offended anyone, just my 2 bits.
I think it will depend on one's playing style in general. Some players ARE largely monophonic, whether playing in the conventional guitar-into-amp way, or playing through a synth. Others adopt a style where the harmonies or even dissonances between strings are an integral part of what they play. Still other players are sort of in between, picking a note at a time, but incorporating open strings and making use of the overlap between notes. And then there will be players who are generally polyphonic, but revert to mono when it comes to producing synthesized sounds.
I suspect the needs, with respect to conversion and prepping for synthesis will be different for each type of player.
I owned one of these and in my view it would not be worthwhile replicating for the following reasons;
1. The tracking is inaccurate and glitchy, and relies on the usual 'humbucker, neck position, tone rolled off, well damped single notes' style of playing that afflicts the Blue Box.
2. The synth voices are mainly pretty thin sounding and cheesy.
3. The total envelope duration is that of the plucked note, therefore limiting envelope and filter effects.
4. Modulation options are very limited.
5. The circuit is too complex for what it ultimately achieves.
There are many straightforward synth modules that could be pressed into service for guitar use based around 1v/oct and fully compatible. I've built many MFOS and Thomas Henry modules. The main thing is getting the triggering and P/V conversion (tricky). The rest is then pretty straightforward, as each module is no more complex than a stompbox. Still a lot of the same limitations above, but the payoff is proper fat synth sounds and way more possibilities to expand the system.
Suggest two audio oscillators (make one a Henry Thomas XR2206), a simple LFO (MFOS), a VCF (Parker-Steiner Synthacon very highly recommended) a VCA (Henry Thomas) and an EG will go a very long way and produce spectacular results way beyond the x911.
Thanks for that. Very helpful.
Thanks Mick. That kind of confirms my memory of trying (and not buying) the unit. The smaller Korg P/V unit that is pictured in this thread
has the same tracking problems. (as does the Gentle Electric unit, when applied to guitar !).
I still don't see any VCO in the Korg X-911 schematics. Anyone want to help me out here ??? afaik there IS NO VCO on any of the schematics.
Maybe it was a separate Korg module or something like that ???
Mark is right on about the playing style vs synth technology. I need my guitar to be a guitar with a synth ~added~ so it must repond to whatever
technique I wish to play with, without a glitch. OK maybe a teeny tiny glitch would be OK. But no Octave hopping !!!
H^) harry
Yeah, I can't see anything that is obviously a VCO either. There is the mystery module - the KLM-228 - which shows up in the schematic, but it doesn't seem to be situated at a point in the circuit diagram where you'd expect to see a VCO. The service manual makes reference to some trimpots for setting up the VCO, so maybe that provides some clues.
Ohhh I know (raises hand)
The KLM228 is just another board that ~is~ shown on the schematics, that circuit is at the bottom of another page. Its just a preamp
section, no magic there... Someone said that the sustain is limited to the string vibration time, that could be due to the envelope follower... or they could be synthesizing sawtooth waves from the recovered square wave. To do that you need a fundamental square wave and a pitch CV. Frankly I don't see that in the schematics... Its a real puzzle, as the mechanical print shows only the two PCBs. There is a header that has the three sawtooth waves and a ground, this
might be an input, or an output...
H^)
Mystery solved... the Korg X-911 table of contents shows TWO pages pf KLM229 schematic... only one is in the scan. Anyone
got the missing page ???
H^) harry
Quote from: digi2t on November 16, 2011, 12:48:25 PM
QuoteThe big question is, do people think that guitar synths have hex pickups, or not. For me, I insist that my guitars be playable polyphonically while still outputting a synth waveform (ie HEX pickup). That makes things a lot more complex.
I'm just a layman, and I only speak for myself; Guitar synth = hex pup.
Anything else is just a digital, or analog, circuit "faking" it. A synth to me is something like my GR-50. I play my guitar, and I hear synthesized strings, horns, drums, etc. An EH microsynth, Korg X911, or anything else in that vein, is just a circuit mangling the guitars original signal to sound like certain synthy sounds. Hell, a fuzz through a Blue Box sounds synthy! But, alas, in my book, a guitar synth it does not make :icon_cry:.
Before anyone jumps all over me, I realize that I'm treading in both fields here, but it's just that there is just a big difference in how the signal is processed (from what I understand). The X911 will never do what a real guitar synth can do, but it doesn't make it good or bad. It's just different. In my case, owning a "real" guitar synth, just makes it impossible for me to justify buying, or building this particular box.
Maybe that's why I built so many fuzz boxes, because there's no Germanium in my Digitech GNX3, or Boss GT Pro :icon_mrgreen:. I love "real" wahs, because I've yet to find a digital processor that can give me "that" sound. I love analog as much as anyone, but everything has to have a purpose at some point, and some things are just better (subjectively) than others.
Sorry if I offended anyone, just my 2 bits.
Personally, I don't care to have realistic imitations of strings and horns. I understand the allure of a "real" guitar synth, but I imagine this is just a difference in opinion as to just what a real synth is. To me, my favorite keyboards are analog monosynths and early polysynths that don't do imitations of horns and other such things, they just sound like synths. So personally I would love to have such a thing for a guitar even if it is a bit quirky, which I believe is the point of a project like this. I own a few vintage keyboards, but I don't care to drag them out to shows in addition to my pedalboard not to mention that my job in the band is as a guitar player and singer.
I guess my point is, I would love to have a project where I can get some fat monosynth sounds out of a guitar.
Harry was over at my place for a synth/DIY "summit" about, hmmmm, I think it was 8 years ago now, and brought his guitar synth with him. I tried it, and I also tried out the late Peter Snow's (3 years since his passing from brain cancer) Casio MIDI-equipped guitar (MG-510) with a Yamaha FB-01 module. I ended up buying the guitar (which I had long covetted) from his widow this past year. The MIDI/module-based system was certainly capable of a broader variety of sounds, but I have to say that Harry's system just struck me as being more responsive. Maybe it was the difference between the rather lightweight and slender Ibanez he was using and the heavier and stiffer super-Strat style Casio, but Harry's was just livelier and had a greater sense of immediacy.
The MG-510 is slightly hampered by both the P-2-V conversion time and the time required to turn that into data and generate notes from the synth modules. I imagine if I made a MIDI-to-CV interface that would add even more time (though clearly not as much as the original P2V).
If he's reading this, Harry can correct me if I'm wrong, but I believe his unit was in between a processor, and a true synth like the x911. That is, it did not synthesize or generate notes via VCOs. Rather, it used a divided G-Vox pickup, separately fuzzed each string output to generate a harmonically rich and instantaneous signal, and used envelope detection and more standard analog synth shaping techniques to produce the sonic variations, via transient generators, filters, VCAs, etc. By NOT using P2V (again, I may be incorrect in my recollection), it was faster. And of course, by not obliging the unit to "know" what note was being played, there were no pitch tracking issues. It was an absolute delight to play, and a real benchmark setup AFAIC.
Quote from: Mark Hammer on November 17, 2011, 10:16:58 AM
Harry was over at my place for a synth/DIY "summit" about, hmmmm, I think it was 8 years ago now, and brought his guitar synth with him. I tried it, and I also tried out the late Peter Snow's (3 years since his passing from brain cancer) Casio MIDI-equipped guitar (MG-510) with a Yamaha FB-01 module. I ended up buying the guitar (which I had long covetted) from his widow this past year. The MIDI/module-based system was certainly capable of a broader variety of sounds, but I have to say that Harry's system just struck me as being more responsive. Maybe it was the difference between the rather lightweight and slender Ibanez he was using and the heavier and stiffer super-Strat style Casio, but Harry's was just livelier and had a greater sense of immediacy.
The MG-510 is slightly hampered by both the P-2-V conversion time and the time required to turn that into data and generate notes from the synth modules. I imagine if I made a MIDI-to-CV interface that would add even more time (though clearly not as much as the original P2V).
If he's reading this, Harry can correct me if I'm wrong, but I believe his unit was in between a processor, and a true synth like the x911. That is, it did not synthesize or generate notes via VCOs. Rather, it used a divided G-Vox pickup, separately fuzzed each string output to generate a harmonically rich and instantaneous signal, and used envelope detection and more standard analog synth shaping techniques to produce the sonic variations, via transient generators, filters, VCAs, etc. By NOT using P2V (again, I may be incorrect in my recollection), it was faster. And of course, by not obliging the unit to "know" what note was being played, there were no pitch tracking issues. It was an absolute delight to play, and a real benchmark setup AFAIC.
Harry's synth sounds pretty danged interesting, I don't necessarily need to trigger vcos, just something that sounds synth-like, polyphony is obviously a plus but not a necessity for me. I have a Casio MG-510 that I've recently re-capped and it still didn't fix the dead D string (corroded caps is a big problem with these things) so I break it out every so often and tinker with it but I have yet to use it live until I get it running reliably, I have messed around with using a Juno 106 as a sound module with it, but the guitar feels so different than the Jags, Mustangs, and SG-I I use that I doubt I'll ever make it a mainstay instrument, though I have seen JJ Cale playing one quite a bit.
edit: Sorry, I just realized, I have a PG-380, not an MG-510
My guitar processor "Muffy" can be seen at
http://www.wiseguysynth.com/larry/guitar.htm
It is essentially a hex fuzz outputting quasi-sawtooth, square, pulse, and rectified pulse (gives a sort of octave up effect). It has six envelope followers
controlling six 12dB VCFs with resonance. It has six VCA's which can act as either gates of be controlled by the envelope, or bypassed. Obviously it cannot
sustain more than the string itself does. There is an attack-delay circuit for each envelope follower. There are no 'unobtanium' chips used.
If I were doing it again, I'd make a voltage controlled ADS generator (you really can't have 'release' but what I've designed is a unit that shares the decay and release times. Careful setting of a trigger level could give access to all sorts of percussive sounds.
The actual P/V converter I added is about as complex as one of these boards, and that just gets you three strings monophonic. The best way to really get guitar synth imho would be a board per string, with P/V conversion, direct waveform synthesis from the guitar string, and an envelope follower / ADS generator, VCF and VCA. I can generate octave down square/sawtooth, fundamental square and sawtooth, (ready for this one ?) fifth up sawtooth, and octave up sawtooth from the guitar string directly. I'd include a VCO with saw, triangle, and pulse waves that can be hard sync'd to the guitar waveform (this eliminates any pitch tracking delays, instead you get a waveform distortion which is not very noticible... or you can have the VCO and guitar wave ~not~ sync'd, that allows the direct guitar wave to cover up the inevitable delay in P/V tracking. My P/V converter gets an output within one cycle of the fundamental so its maybe 2X faster than most commercial units... but it is complex. I also have a circuit that eliminates the droop when you lift your finger from a string. This makes the note go flat as a rule, as your finger does not damp the string in time to prevent converting that now slightly longer string length. P/V conversion is kind of nasty about these things...
Downside, connecting six boards to a voltage controlled front panel and putting it in a box is not cheap. The overall complexity would probably be about the same as an all-analog polysynth, without the neat SSM or CEM chips to do the functions. Probably it would be like an olf Oberheim 8 voice polystnth (made from SEM modules) in complexity. NOT for the faint of heart, eh ??? You could buy a Roland V-guitar for the price. Or any vintage guitar synth, but at least this one would work...
Maybe I'll get the camera out a photo what I have now...
H^) harry
Honestly I've been thinking the best way for me to go is to just get a hex pickup and hex to midi converter, then take my parts Juno-106 (the keyboard is trashed) and chop it into a sound module leaving me a good number of keys in case I break my good Juno. Of course, I've been planning to do this ever since I got my Casio... one of these days I can spend more time on my guitar and less time fixing my converted corn crib house.
Quote from: wavley on November 17, 2011, 10:39:32 AM
edit: Sorry, I just realized, I have a PG-380, not an MG-510
I get them confused too. The PG-380 has the voices on-board, where the MG-510 is simply a MIDI controller. I would imagine they're pretty much the same guitar in terms of playability, though, and I can't imagine the difference in their electronics has much of an impact on their respective weight.
I have a busted 106 too! :icon_biggrin:
I found the missing page from the X911 service manual:
http://img.photobucket.com/albums/v368/zero_thehero/schematics/X911-09.jpg
nice find! thanks mate! :icon_mrgreen:
The X911 tracks a lil better than everyone here seems to remember however as stated it has serious limitations
I have one and also a penfold pitch to voltage converter board partially populated for over 3 years ;D
If you guys were going to create a forum based guitar synth project while P2V units are cool I think that a hexaphonic processor would be more interesting
you could spec it for a pickup from here http://www.ubertar.com/hexaphonic/
then a processing stage and envelope detector in to --> a fuzz/waveshaper --> in to a VCF and a VCA in to a mixer
If each were designed with tim escobedo style economy the parts count could be fairly low even though it would have to be done 6 times !
basically a super fast responsive analogue hex fuzz and filter would offer something that cheap pich to midi (Sonuss) and hex to midi (axon/roland) systems don't
so it would be very playable and worth building even though it would be a pricier than usual project
a good bench mark for processing would be the gr300 as it is held up as the fastest and most playable guitar synth in the west
http://www.joness.com/gr300/patent.htm
the obvious downside of this proposal is that everyone who participates would need a cheap guitar to mod with a hex pu
On my list of projects to get around to is indeed an analogue hex fuzz with VCA and VCF. Something similar to a GR100, but compatible with current 13-pin synths.
However, I think there is a market for an all analogue, P2V synth. Personally, i'd like a last note priority P2V, dual oscillators + sub osc, with hex fuzz and analogue VCA/VCF. If it was based on the GR300, it should be fast as well as accurate, but i'd take fast over accurate.
i agree, the 13 pin deal would be probably the easiest. i've got a couple of those, but the necessary skill to build something like that at this point elludes me completely.
i bought one of them cheap "guitar controllers" for xbox, so i could scavenge the hex pickup out of it if the time ever comes...power rock? power gig?
i figure after i harvest the hex pup, i can mount a humbucker in there and just use it as a lap steel.
One seriously limiting factor with the Korg is that it isn't what you expect a mono synth to be. The normal controls you would expect from a synth for true subtractive synthesis are missing and it relies heavily on an envelope follower to add some interest to a rather dreary set of presets. You quickly lose interest in the fake flute and brass sounds and limited palette. Even the most basic single oscillator mono synth (such as the MS-10 or Jen SX1000) has more dimension.
Given Korg's history with synths, it's disappointing that they didn't build something more flexible. It has more in common with the Micro Preset than (say) the MS-20.
I still think that there's a lot of mileage to be had out of fundamental extraction, even if it is a little glitchy. I've got 14 modules in my modular synth and they were all pretty straightforward to build. It would be really nice to use a guitar to control it - the note would need to be sampled and held to release the full drama of a slow filter sweep on a PWM waveform - a guitar's natural note length is way too short. S&H is simple once a sucessful F to V is achieved. Perhaps going down the PIC route may yield something reasonable?
A simple 'starter' synth can be built around the SN76477 - see the SN-Synth project and sound clip.
Quote from: Mark Hammer on November 17, 2011, 11:42:49 AM
Quote from: wavley on November 17, 2011, 10:39:32 AM
edit: Sorry, I just realized, I have a PG-380, not an MG-510
I get them confused too. The PG-380 has the voices on-board, where the MG-510 is simply a MIDI controller. I would imagine they're pretty much the same guitar in terms of playability, though, and I can't imagine the difference in their electronics has much of an impact on their respective weight.
I have a busted 106 too! :icon_biggrin:
One of these days I'm going to get around to looking for some ROM cards for my PG, I kinda like the sounds it makes but I would really like to see what else it can do.
If your Juno has the busted DCO problem, they make clones now.
If you want an advanced hex fuzz project, check out my "Muffy" @ wiseguysynth.com. Its got a separate Fuzz/VCF/VCA/ and a really good
envelope follower. I don't have nay more raw boards but if someone wanted to do a run, I could share the artwork. Its not simple ~or~ cheap
but more in line with any decent analog polysynth. http://www.wiseguysynth.com/larry/guitar.htm
I also designed a remote control that can mount on a guitar with all the panel controls duplicated. Fits in a small hammond box and connects with a VGA cable
to the main unit.
That looks awesome! Shame you don't have any boards left, it's something I would have been interested in.
I am however even more interested in the version you have that includes a monophonic bass synth, any more details/samples?
Greetings,
Yes, I do realize this thread died almost 8 years ago! Has anyone of the previous contributors continued on with a similar project? Is anyone interested in getting the discussion re-started? I've been working with a few other collaborators on a true hexaphonic (divided pickup, Roland 13 pin standard), analog, modular guitar synth.
As anyone who has tried to do down this road has found, there are issues plenty and complications many to confront! If you happen upon this update and have any interest, post back and we'll see if we can get the discussion going again.
Hope everyone is having good luck with whatever projects that you're working on!
Best, Jim