Welcome to the world's FIRST one stop Synth Technician stop!

      Pardon the plain pages. This is a COURTESY to friends who are still on dial-up, but click links on individual synth pages for pictures of the unit usually etc. This page is designed to get you to the information YOU want.
Shipping a synth? (A helpful guide focused on putting stress in the right places, and saving money on materials!)
Dead Beats and others to avoid dealings with. MOst of my online experience is great, but beware of these special cases.
     A synthesizer is a machine designed to give the user control over aspects of the sound while playing. Take a look at this page which gives a history of various landmark developments in synthesizer design. What synthesizers have which chips? Which ones fit into basic 'Attribute groups'? Click here to find out. Also here's a philosophical note on why I believe Analog synths have made a comeback. Here is a page showing a map of my studio, where you can click on synths for sound samples. And how about a POLL from the synth DIY group about which synths are best in various categories.
Click here for a few helpful links on modular synths, organs and combo organs which are otherwise not addressed on this site much, save a few mfg'd by companies that make other synth products.


Here is our FEATURED LINK! (Gustav Andersson's fantastic project)

Click here for some great DIY electronics links!
Click here for a list a Technicians who work on synthesizers.
And some general synth tips.

Select a Manufacturer

Access Akai Alesis ARP Casio Clavia Crumar Elka EML E-mu Ensoniq Fairlight Fatar/Studio Logic Fender Rhodes Hammond Jen Kawai Korg Kurzweil Moog Oberheim Octave Peavey PPG Roland Sequential Circuits Siel Teisco Waldorf Yamaha

KEY to synth pages: MRP was intended to be mfg. retail price. However some were taken from Keyfax omnibus which I found was probably listing dealer typical prices on some. So if anyone can supply actual info along the way please do! Also number manufactured is approximate obviously on most. Some from Omnibus, some from other articles like SOS stuff, and some from careful examination of many serial numbers to get a good statistical approximate. Please inform me of bad content on any of these pages! Thanks.


    Here is a link to help locating parts including major sources for electronic parts, some of my semiconductor, key, and misc inventory, and some accessory links that seem useful. NOTE that for keys, if you know the keyboard you are looking for simply pick the mfg. above, then your keyboard, then 'keys' under the parts section and it should take you there without searching.



Some good general links with helpful repair tips, circuit ideas, etc. :

Osama Hoshuyama's Synthesizer Circuits page with a very nice collection of circuits and notes!
A list of common parts/sources and some circuits and pics Jim Patchell's DIY page.
Rene's Synths 'R' Us with lots of cool circuit info. Hey someone else likes tube VCF's!
Ken Stone's awesome page of module designs.
Wilson's VCO design page.
Ian Fritz's Sound-house page.
VCF's from various classic applications.
Ring Mod circuit that looks cool/easy.
Tiny Synth an open source code/ diagram synth project
Papareil's Synth Labs with various cloned filters and some original modular designs.
Gyraf's site focuses on compressors, EQ's, mic Pre's and has lots of diagrams for hard to find stuff in that area as well.
Standardsfor MIDI, .wav etc. A good programming resource.



Synth related parts information

Curtis Electromusic in memory of the great chip designer Doug Curtis. Lots of useful information on these chips used in Oberheim, Sequential, Moog and many other top end synthesizer products.

For some tech info and what chips are used in what,SynthDIY chips page
And a list of which chips go in some common machines at the moogulatorium page.
Or for another list focusing only on SSM and CEM prefixed chips, Synthtech page
Obsolete device data for nixie tubes and semiconductors.



Books on Synthesizer design:

Musical Applications of Microprocessors- Hal Chamberlin
Musical Engineers Handbook- Electronotes
Formant synth building page



Synthesizer Technicians:

MITA or Music Instrument Technician Association for a wide variety of qualified service technicians.

Analog Synthesizer Service Greg is a top notch SCI and Korg expert and has reasonable rates. Bay area.
Music Technology - These guys are helpful and do a lot of different things including synth work. In Springfield, VA
Rogue Music - comes recommended from Synth groups
Paul Brooks Does synth repair in St. Louis, MO
Analogics for wood restorations by Wes Taggart
Davidson Electronics Were real helpful when I bought an ebay OB-8 they had awaiting payment. Long Island area.
Sound Doctorin' - In my unbiased opinion (..rotating bias pot on my opinion CCW)...a generally helpful guy. :-)


Generally helpful links/info for techs:

Reset proceedures for most digital synths.

General Tech Tips for synthesizer repair. (Cleaning key contacts, interconnects, sliders/potentiometers, battery changing/types of batteries, etc.)

Cosmetics and Refinishing Tips


What we don't cover:
     Some synths are built more for home use and then tend to be fairly similar, cheaply built, and hard to find good information on so I haven't bothered including most. Ebay and different places have lots of them for sale all the time but I just can't get interested in them.
     There are many great sites showing synthesizers that are of a 'modular' design. These have often many boxes with individual components of a synthesizer in individual boxes that may be mounted in a rack or the like. For basic information, pictures, etc. on any unit you don't find try Vintage Synth Explorer. You might also join the "Analogue Heaven" mailing list or "Synth DIY" for even more technical info on such beasts. There are some venders who currently still make these. Go to the directory at modularsynth.com.
     Many devices with an "Organ" classification are part synth also and some have a great sound and a lot of historical significance. In particular I'm a fan like many of Hammond and Yamaha Electone series organs. And of course we can't say enough about Combo Organs now can we?!
     ALSO, the Soviets built many cool synths. I won't attempt at this time to say anything there because of the difficulty/impossibility attaining parts, etc. For more info, go here!
















Memory implementation in analog synths. -by Bob Weigel


     In units with panel controls, Variable resistors give a span of voltages as they are turned, and this voltage is attached to the input of an analog multiplexer. (this is a chip that has often 8, 10, or 16 lines; one of which at a time can be addressed to attach to a common line. So obviously the 8 channel mux has 3 address lines since there are 8 possibile combinations of address line highs and lows.)
     Ok so the CPU walks through the address possibilities AND further "selects" are used often to decide which chip is going to be accessed out of an array of them if we need more than 8 knobs to be read for instance. So anyway it walks through all the knobs and as it does it also calls forth the data previously stored in association with that knob from RAM. For machines which allow knob editing of previously stored data, there is a 'patch buffer' which is volatile memory often that stores a temporary copy of the data being worked on. Anyway, this data is latched for a DAC to convert it to an analog voltage. This voltage is fed to the pin of a comparator and the other leg of the comparator reads the knob's voltage that is currently being read. The output is always high or low on the comparator and so say they really are the same data..ie...nothing has changed in the voltage being fed from the knob's potentiometer. The CPU begins stepping the RAM data up until the comparator flops the other way! In the case where the data was supposed to be the same...this should be within ....whatever the resolution uncertainty is decided to be for the conversion process. And the software that runs the cpu is written such that if the comparator flops the other way within x number of increments, the data is considered the same and no change is made. The old data is refetched and written back, lest we walk around and create a perceived movement that wasn't actually there I suppose.
     And if a knob is actually moved (or you get a dirty/broken pot and it thinks it has moved...) then the cpu recognizes that the resolution limit has been exceeded and it assumes movement has occurred and allows the new data to remain stored in the patch buffer until a write command is issued in which case it will overwrite the old SRAM data.
     MEANWHILE..how does this information actually get to the analog circuitry? Usually the DAC output. Thus when you move the knob it takes the comparator acting as an ADC in conjunction with the CPU in order to bump the data up, and modify the DAC output to correlate with what the knobs are saying. This information simultaneously drives the comparator input AND is fed to another series of 4051 common inputs. As a chip is selected and the appropriate address is fed, the appropriate chip opens it's 'gate' and allows the analog voltage to flow onto a small sample and hold cell's capacitor. Then when the gate closes as the next function is being dealt with, the JFET or MOSFET input op amp buffers that voltage so that the capacitor is not quickly drained. And it's that output voltage of the op amp which actually drives the analog circuitry that is performing the analog synthesis function.
















Why is Analog making a comeback?


     When the DX7 came to town, it appeared to be all over. Yamaha getting a slightly later start into the Analog game became determined to lead the pack in this new direction and utterly abandoned their attempts to market analog designs. Roland was a major player and robust enough to where they didn't have to have to lead the industry all the time. They had established a name early on with the SH series synths which heartily competed sonically with the American machines. And that momentum kept people looking at what they would do next for many years to come. And so about the time the DX came out so did the Juno-106 which took a simple to program great sounding series and added the MIDI interface and many people just had to take their music into that realm with Roland, so they sold 70,000 units or so even in the face of a landslide towards the Yamaha products. While these products had digital oscillator sections, they still involved analog vcf/vca modules and vca chips adding a lot of expense and setup hassle to the productions. Where the new Yamaha machines were pretty much assembled and shipped.
      Even as Roland began coming out with professional digital products including the S series samplers in 1986 and the D50 in 1987, they were still doing well in analog product sales with the JX series and alpha Junos. The market hadn't dried up completely yet but Roland dominated what was left of it pretty much. But all of these even had digital oscillator control.
     Korg had followed on the heels and developed a pattern which would make them dominant in the market eventually. They let someone else do the ground breaking, and then they set forth to make it better and cheaper. The PolySix had been a huge success and instead of trying to do something bigger and better, they saw where things were going and released a synth that would probably use up some of the parts they had left over, (the Poly61 with DCO's but analog EG's and OTA based filters) and again sold quite a few though not a raving success. But it was their venture into the MIDI world and it gave them a chance to evaluate where they wanted to take things next.
     Then the Poly800 came out with a price tag and sound quality that turned it into a good success. The DSS-1 probably didn't make them much money but it did look big and bad and kept them in the spotlight with another great sounding synth and a sampler until the M1 was ready. Korg never made another synthesizer with major analog components after the DSM-1, and the DS8 which came out about the same time was again an attempt to build something similar/cheaper to what others had been doing in the digital market. The M1 was the ultimate example though, taking the best of the Kurzweil K250 in the eyes of the typical working musician and hobbyist. Leaving behind the seldom used by the typical user sampling interface, keeping the great sampled sounds in ROM, and creating an easy to use sequencer interface in a light weight yet decent feeling package (DX7 keyboard movement). Result: One of the best sellers of all time.
      Meanwhile Sequential's direction was to continue making synths with analog vco's until the Prophet VS which was a consuming project that forged the way for a new approach to synthesis, but cost them I'm sure as they only sold 3000 of them. Their Prophet 2000 sampler was somewhat popular, but Ensoniq had come out of nowhere and snagged the pole position in the econo-sampling market with the Mirage. So SCI wound up with some better products perhaps but the pricing/popularity point ARP had already gone by the way due to bad management and Moog had the SL-8 on the table but when they saw the DX7 knew there was no way they could compete. They had poured their efforts into a direction that would result in small volume sales.
     Crumar had been popular overseas and developed the first DCO synth, but they continued into the mid 80's reaping the dwindling harvest of analog hybrid sales and never really produced a significant digital intrument and eventually called it quits in '87. Siel and Elka both continued on the similar path with compromised partly analog instruments that followed trends in that area, and continued also to try to scavenge what was left of that market. Siel had began by making synths that used divider network chips with one analog VCO behind it and a full analog synth on the other side (DK600), which maintained the warmth but got rid of the expensive dedicated analog oscillators. And they began to harvest the market that was seeking a different analog sound at budget prices. Then after some variations they made some with far fewer analog components (DK70, DK80) and then some cheap digital products. They had gained enough attention to where apparently Roland thought it best for business to buy them out and shut down the factory.
     In general though those who didn't begin to design innovative digital products by 1985 ceased to do business shortly thereafter. Except for Korg, because Korg made it their business to shadow the technology and they found a great following with people who were willing to wait a couple years maybe but get something that would do the job for cheaper. So by 1987 there wasn't really an analog product that was getting any significant amount of sales and hence no advertising was devoted to these products. In the public eye that can make something very unhip, so analog synths began to be sold for very cheap prices as people tried to get money for the latest digital.
     So goes the consumer market. Anyway the first digitals all had something in common. They emulated physical processes or, actually sampled physical sounds then performed physical processes on them largely. For instance the DX7 was an "FM" synth. A natural process emulated digitally. The K150 and K5 allowed construction of harmonic arrays as we see vibrations stimulating overtones in nature. Etc. Basically doing it digitally lost some quality but the hearer could still catch the essence of a real process and they could tweak it in a way that would have been extraordinarily expensive to set up...had it not been for digital processing! However..there was a down side. With so many options and so many WRONG (in terms of the way things really interact in nature) ways you could set things up for a sound, it is easy to get lost making utterly silly sounds with these units. This inspired me to write the K5 'macro' software which allowed you to construct presets that were useful and call them up as needed so as to be able to construct a 'skeleton patch' which one could then go in and tweak to perfection. Rather than getting distracted and totally losing the idea you had as you explore all the absurd possibilities. (Though that's still fun sometimes and you do stumble onto something interesting occasionally that way...)
     Down along the path software people began to put processes more and more distanced from nature at the fingertips of the synth programmer. While it might SEEM on the surface that having a synth that can do arbitrarily bizarre things is good, many really learned quite another lesson. Perhaps a lesson analogous to what old Solomon spoke of in Ecclesiastes. He tried everything. But it kind of left him..empty! A 'chasing after the wind' and that sort of thing.
     Human beings need meaning. Connectedness. Their souls long to be in touch with something firm. Not necessarily predictable to them. But something that rather..grows with them. A great musician is like this with his/her audience. Awesome live shows aren't just a pre-planned thing that starts at time "A" and shuts off with "thank you and goodnight" at point "B". Rather awesome live shows are where the musicians are in touch with the audience and they convey something together. Something that causes each person to grow together somehow.
     Even my beloved K5m...I find sounds that are way bizarre and unreachable by other synths, but they leave me flat and cold because the processes are completely distanced from nature. They are rather arbitrary and in that way they don't connect. A sound that connects is one that has surprising qualities that lend themself to the song they are being used in (or often, inspire I find. Sometimes in creating a sound a song will emerge just from playing the sound the first time) and work together with it somehow to make the concepts all the more real to the listener.
     A friend of mine, Paul Rose, let me listen to an old 80's group called 'Negativelyland'. The first cut is a farsical message to radio station managers, explaining how they've developed this new technology which will produce a 'hit song' that is ready for release in the current market. Then they play the 'designer song' which amounts to a bunch of crazy samples of cartoon noises and annoying music hewn together with a guy finally yelling "just a minute" over and over and "I can't hear a thing" as they flow into the 'is there any escape, from noise" theme. Very funny piece.
     But also quite relevant in terms of the direction things had taken in 1987 when that was released. Many great digital instruments have been made; most of them affording us the ability to carry nice sounding piano's around without a moving crew and the like. However...sometimes too much creative headroom...into the space of being arbitrary ....can actually be a distraction to productive creativity! I know many musicians who just spend too much time fiddling and not enough actually creating music that anyone wants to listen too. There are so many sounds available for download. But where does a person stop and actually learn to play an instrument well?
     In the wake of all this, many people began to remember...something real. Analog circuitry. Subtle deep intricasies that lend themselves to making...MUSIC! Well music that lends itself to communication. Hearing natural processes unfold, rather than hearing a software engineer's idea of what sounds like it could be a natural process if like wormholes were real and the whole studio got caught in one. :-) Real..bonafide..natural processes. Like any other musical instrument that was created prior to the idea that we could write software that would be able to let us design our own instruments in an arbitrary fashion. And up many of the prices started to go again. There are still some little known gems out there that can be found at a super bargain price. But don't expect to find a Matrix 12, CS-80, Synthex, Chroma, Minimoog, Prophet 5/10 or Jupiter 8 for a few hundred dollars anywhere anytime soon again. :-)
     It's interesting to think about..creation. And how the best things come when we explore it and work within it's boundaries instead of just arbitrarily saying "hmm wonder what would happen if I totally twisted that aspect of nature?" There's nothing like the real thing. Never was, never will be. -Bob
















The Synth Poll!

(Note: The number in parenthesis before a synth indicates the number who voted for it)

1) Best Analog synth (barring all thoughts of not having roadies to haul it, techs to keep it running, etc.)
    (2)Yamaha CS-80, Jupiter-8, Fenix, ARP 2600, Alesis Andromeda A6

2) Best Monophonic analog ("" "" )
    (3)MiniMoog, MiniMoog Voyager, EMS VCS3, Sequential Pro-One

3) Best practical poly analog
    Sequential Prophet 5 ( Rev. 3.3 w/ MIDI ), Roland Jupiter-8, Roland Jupiter-6, (3)Alesis Andromeda A6

4) Best practical mono or duo analog
    Sequential Pro One, (2)MiniMoog voyager, Roland SH-101, MultiMoog

5) Best full polyphonic
    (3)Korg PS-3200/3300

6) Best practical full polyphonic
    Korg PE-2000 Polyphonic Ensemble Orchestra, Korg PS-3200, Korg Lambda

7) Best paraphonic
    Roland 505, Crumar Trilogy (hey..it's semi-paraphonic with 6 shared filter/eg's) or Korg Delta

8) Best preset mono
    (2)Korg Sigma, Roland SH-1000

9) Best bang/buck monophonic
    Moog Prodigy, Sequential Pro-One, Moog Voyager, Waldorf Pulse, Yamaha CS-20M

10) Best bang/buck polyphonic
    Sequential Prophet VS, Sequential Prophet 600, (2)Alesis Andromeda A6, Akai AX80

11) Best bang/buck full polyphonic
    ARP/Solina String Ensemble (Technically partially paraphonic with one filter but poly decay eg.), Korg Lambda

12) Best bang/buck paraphonic
    is there any? (ha...ha. Only answer others gave) I'd say the Korg Delta! Or possibly Poly 800.

13) Best classic modular synthesizer
    Roland System 700

14) Best currently available modular synthesizer
    Serge Modular

15) Best bang/buck modular synthesizer
    Synthesizers.com

Honorary Mentions: Some people didn't apparently understand some of the questions. So I thought it good to mention that the Rhodes chroma did get nominated as best 'full polyphony' though it's max 16 voice poly, and also Alesis Andromeda in that category. Roland VP330 got a vote for best paraphonic. It's a vocoder and may have some paraphonic aspects. I'm not sure. That question was more aimed at the ARP omni and that type of synth which has paraphonic sharing of the filter but is full poly in terms of notes via divide down osc. Also Moog Voyager got an entry for best preset mono. However it's a programmable oriented mono not a preset oriented. This term usually refers to things like Sigma which have more preset aspects than parameters. Though it's close on sigma :-).



THanks to Steven Parsick, Mike Kent, 'jk', Guido, Alex Prescott, and...me.