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The EMS Synthi Mk 1 AKS

Submitted by on July 6, 2009 – 7:51 pm No Comment

My certifiable obsession for electronic music and electronic instruments in general, especially synthesizers, started in my elementary and middle school years, sometime in the 1980’s. Frequent trips to the library, an institution in which I am still indebted and have recently devoted my “career-life” to, enabled me the opportunity to browse many books on analog synthesizers and the like. Page after page and picture after picture of intriguing Buchla systems, lovely Serge modulars, and Moogs filled my mind with delight. However it was two units in particular that stuck out for me from those pages: the EMS Synthi AKS and its L-shaped forerunner, the VCS3.

Most synthesizers pictured in these books had some sort of discernible semblance as how you made a sound or “played music” with them. The typical, modular, if one could be permitted in using that term, for example, had a normal looking keyboard, knobs and patch points where one could understandably connect one module or sound source to another, etc. The EMS units however, appeared otherworldly, the VCS3 had no keyboard, but it had a joystick?!  And what were the grid and odd-looking pins for? In my mind, the bright, multicolored knobs on the EMS machines resembled sparkling gemstones. Adding to their bizarreness, the “A” was in a suitcase and the “3” was in an unusually shaped wooden box and their small sizes compared to the other manufacturers’ massive systems, set them apart as something very different.

But peering at these lovely analog devices from the pages of a book, regardless of the visual delights it offered, was not without its hint of melancholy. These systems were untouchable for most adults, let alone a mere KID. So, for now, I would have to settle with listening to these music machines on records, whether it be my parent’s Tomita and Beaver & Krauss records or my own British new wave collection. I also got to experience lovely unearthly tones and noises coming from my favorite programs of the time such as The Tomorrow People and Dr. Who. It was only later that I found out that a lot of those sounds were coming from EMS synthesizers! Anyhow, it was probably a culmination of listening to these sorts of things that I formed an idea of what a perfect synthesizer should sound like.

The Roland D-20

By now it was the early 90’s and I began to get serious about making my own electronic music.. I had outgrown my Casio SK-1, a toy in its time but still a great board! Unfortunately, for all of you in the know, the early 90’s were not a good time for someone looking to waltz into a musical instrument store and buy a keyboard and have it sound like what I had in my mind; i.e. an analog synthesizer (this case has thankfully changed over the years). I think I just thought at the time that a synthesizer was a synthesizer and even though all the keyboards in the store did not have knobs or patch points like the ones I had seen pictured in the library, I figured, I’d be able to make due. I wound up with a board that only had a few buttons and an LCD screen: a Roland D-20. Audio-wise, I remember it being complete crap, although it did teach me the principles of an on-board 8-track sequencer. Ultimately, though, it was a very disappointing cry from the sounds in which I came to distinguish solely belonging to the analog family of synths.

Since then, I have come to own a variety of synthesizers (i’ll have to make a list soon!), including some nice modular and semi-modular units, all of them having tonal differences and unique functions. I had finally found the sonic control I was looking for with these synths with knobs and discrete analog circuitry (as they say…). But as my quest for the perfect analog sound refined over the years, EMS gear began to haunt my aural nightmares. My mind kept wandering back to the beautiful images I had seen as a child in the library and the more audio examples I heard from these magical machines, the more my craving grew.

The Acquisition

It was then last year in 2007 around this same time that I had an opportunity to buy a Synthi A Mk 1 from someone in NY. I was so excited when it finally arrived, it looked lovelier than the pictures, this being the first one I had ever seen in-person. My first reaction to the sound was that the oscillators seemed alive.. a pure sine wave with no treatment sounds like it could etch images in glass. Finally, this was the synth I had been looking for since I heard it’s sounds, almost subconsciously, in my youth on BBC programs… thank you BBC Radiophonic Workshop. End of story?? not quite…

After a few days learning the machine, I discovered that it had serious faults. This is something I had almost expected from an electronic instrument dated from it’s serial number back to 1972, but surprised nonetheless as it was sold to me under the pretense that “everything works perfectly”. The ring modulator did not function, the envelope shaper was behaving very oddly, the channel one mute switch for the internal speakers did not work and therefore could not be switched off (this is more serious than it sounds as you can not effectively perform on the Synthi patched into an amplifier or monitoring system as you hear both audio sources and the annoying delay it creates), audio signals were bleeding through where they shouldn’t have been, etc., etc… Damage from shipping the short distance from Brooklyn to Central Jersey? Perhaps, but of course, still shattering. What do I do?

Robin Wood and his merry men from Cornwall, UK

I was overjoyed when Robin Wood, the current owner who has been with Electronic Music Studios nearly since it’s inception, answered my email pleas for help. It was soon settled. I would send the Synthi overseas for a complete overhaul and some modifications while there. It was disheartening to depart from the Synthi after so little time spent with it, but I knew that the unit was special and a fully functional one would be well worth every cent… an investment of sorts, but more importantly, a future fully functioning mystical music machine for alka. So…

As the weeks turned into months, my thoughts were consumed with all things EMS. I tried many things to pass the time, like make a scrapbook, read 3 EMS manuals, reviewed all the EMS posts on Matrixsynth, discovered the excellent Synthi blog and became friends with the creator: PIN. Soon, the idea filled my mind of how nice it would be to add a KS unit (Keyboard Sequencer.. the lovely blue metal touch plate thingy) to my Synthi. After all this reading up on all things Synthi, I learned that the Mk 1 units could not accept a KS as their power supplies were not significant enough. And besides, Robin could no longer obtain any KS units and said they were fast becoming “extremely scarce”.

After a few emails Robin announced that upon the very rare chance I could obtain a KS, he theoretically could provide a retrofit power supply for the KS enabling it to work with a Mark 1 Synthi… but good luck finding one. Well, this only piqued my interest further and I decided to try my hand contacting Ludwig Rehberg over at EMS Germany. This proved to be quite difficult.. he had responded very cryptically to my emails and seemed to not have gotten my very long distance calls and messages. PIN from the Synthi blog, living in Germany, said he communicated with Ludwig fairly often, and that he did indeed have refurbished old stock KS units available, which drove my ambition more! Finally after a few months I got a hold of a KS from 1978, in wonderful shape. It was not without the help of PIN that I was finally able to purchase one from Ludwig, and I owe a debt of gratitude to PIN for helping me.

Mk 1 AKS Frankensynthi

Once in the fine hands of Robin, the amazing feat of retrofitting a power supply to the KS was performed and the birth of perhaps the worlds first Mk 1 AKS occurred. The Mk 1 and Mk 2 Synthi differ in their power supply, as mentioned, but also in the Mk 1 pin matrix, which enables simultaneous patching of both waveforms available per oscillator, unlike the Mk 2 matrix. Another bonus attributed to the Mk 2 units that I wanted to incorporate into my Mk 1 was the envelope triggering of external audio through the input channels, something Robin was, again, able to flawlessly achieve, along with a host of other updates and modifications that I will list below with pics. He was also able to perform an essential KS mod (at least to my recording style): an external sync input for the sequencer.

All in all, it was a lengthy wait, in which everyday involved extreme anxiousness, but I remained patient as I valued Robin’s personal attention and expertise regarding these delicate machines. My Synthi is now finally back with me and it is even more unbelievable than I imagined the perfect synth should sound, and looks even more beautiful than the bejeweled gemstone version I saw pictured all those years ago in the library.

Repairs and Mods Performed (from Robin’s invoice)

1. Power supply unstable. Replaced 2 x presets + beefed-up
connections to new ceramic resistor.
2. Ring Mod not working. Replaced faulty BC258B transistor
3. Replaced both speaker mute switches + fitted signal triggering
modification to Output Ch2.
4. Output Ch1 unstable/hum. Replaced preset.
5. Osc 3 freq range fault. Replaced faulty BC169.
6. All pots checked. Lubricated stiff pots & cleaned crackly ones.
Replaced non-responders: Pan Ch1 & Ch2, Output Filter Ch1 & Ch2
Output Ch1, Osc shape(x3), Osc2 sqr, Filter Frequency,
Filter Response.
7. Replaced Osc1 & Osc2 verniers, plus internal frequency pots, and
calibrate dials.
8. Replaced 1 broken pin + supplied 4 spares.
9. Replace suspect AC mains on/off switch.
10. Ream pin park to fit pins. Fit foam retainer under.
11. Correct defects to Osc2 & Osc3 ramp waveforms.
12. Supply moulded replacement AC power cable (with ground pin)
13. Fitted wiring and switched joystick range pot for sequencer
input. Supply/fit short joystick + extension tube. Make
holes in case lid for KS screws.
14. Misc: Renew fixings to reverb, AC transformer, speaker baffle,
chassis to case, replace 4 x presets during alignment(2 osc tracking,
env sig null, ring mod B fund).

15. Fit modifications:

Oscillator stabilisation
Fit metal-can dual transistors
VC shape x 2
Hi/lo frequencer range
Osc sync (with pot) to Osc2
Switchable 18/24 filter mode
Switchable unslew to filter frequency
Patchable Inverter
KS step-time, ext.clocking & transposition
KS external power supply & cabling to Synthi

* Robin also discovered while he was working on my Synthi that the Mk 1 version set on the US Voltage setting is much less forgiving of voltage shifts. He informed me that these units will operate best when they are fed a clean voltage of about 110 V, instead of most US household outlets that output usually over 120 V.

Picture images (click for larger):

EMS Synthi top view
Top View

EMS Synthi suitcase

EMS Synthi side view
Side View

EMS Synthi connected

EMS Synthi Mk 1 KS mod power connection
Connection for the External KS Power Mod

EMS Synthi Mk 1 KS mod power outlet
The KS External Power Mod

EMS Synthi knobs close up border=
The Infamous Knobs

EMS Synthi Mk 1 AKS in Alka\'s Angels\' Den Studios
Home in Alka’s Angels’ Den Studios

EMS SYnthi’s turn up on eBay from time to time.  Check for them with our synth auction finder.

SynthGear Tags

  • ems synthi aks
  • vcs3 mkII
  • vcs3 power supply

This post was submitted by bryan michael.

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