This is a video demo of the very rare ETI 4600 international synthesizer.
The ETI 4600 synthesiser was the brainchild of Trevor Marshall.
Trevor Marshall’s intention was to make available to pop groups a synthesizer that would cost less than the average of around $1,400 (Australian Dollars). The magazine Electronics Today International approached Trevor and featured the design in a number of articles.
Barry Wilkinson of ETI was responsible for the packaging and kitting coordination. It was adapted for Europe by Maplin Electronic Supplies of Rayleigh, Essex who produced full construction details, and were able to supply all the components for the project including PCBs, printed panels and case.
If you’ve used a ETI 4600 International Synthesizer, leave a comment with your thoughts.
Read more about the #TI 4600 at ETI4600Synthesiser.org.uk.
via scienceforce:
This is the ETI 4600 intarnational synthesizer, structure based on Matrix patch panel like EMS VCS-3, AKS.
There are two different ETI 4600 versions: one blackface and the other extremly rare Silver face!
Sounds like Space Odyssey 😉
I was raised in Rayleigh, Essex and used to frequent the first Maplin shop in Westcliff, in the days when all the staff knew about electronic components and were all very relaxed and helpful. They had a 4600 in the window, but could never be persuaded to switch it on for me to have a play with it. At the time, I just assumed that they knew I wasn't a serious customer, but now I strongly suspect it was just the front panel on an empty box!
Doug, the manager, used to be really helpful and friendly to kids as he recognized a future customer when he saw one. Of course, when he retired and sold up it all changed, and now I buy all my parts from Rapid.
I still have my 4600 silver faced beast.
It has the Fairlight digital scanning keyboard modification as well as the inductors in the EQ section replaced by gyrator circuits.
It is still a great machine with quite a unique sound.
Hi what’s the Fairlight digital scanning keyboard modification ?
Hello MirlitronOne
I remember it well. Doug Simmons was one of the directors of the company although he may well have carried out managerial duties as well. He didn't retire though. Maplin became extremely successful and was bought out by a finance company or rather a company with financial interests. Doug and his wife then went to Taiwan where he took over or formed (I'm not sure which) a company that supplied Maplin. I used to be the technical man there based in Hadleigh and I built the first 5600s for the company, taking it to Paris for an exhibition there on one occasion. Nowadays its seems to be all soft synths and a lot of the fun has gone. I don't think it was an empty box, more likely it wasn't working, there were a lot of problems with the 4600 at the time.
Hello MirlitronOne
I remember it well. Doug Simmons was one of the directors of the company although he may well have carried out managerial duties as well. He didn't retire though. Maplin became extremely successful and was bought out by a finance company or rather a company with financial interests. Doug and his wife then went to Taiwan where he took over or formed (I'm not sure which) a company that supplied Maplin. I used to be the technical man there based in Hadleigh and I built the first 5600s for the company, taking it to Paris for an exhibition there on one occasion. Nowadays its seems to be all soft synths and a lot of the fun has gone. I don't think it was an empty box, more likely it wasn't working, there were a lot of problems with the 4600 at the time.
Thanks for the reply and additional information! It was a great little shop and a shame that in some ways it became a victim of its own success. The staff were always friendly and helpful, and I'd know a lot less about electronics today if it hadn't been for their patience.
It was certainly a change from our local TV repair shop where I'd go in and be served by the technical assistant who looked and acted just like Lurch from the Addams Family. I'd ask for a 0.1 microfarad ceramic capacitor and twenty minutes later he'd reappear from the workshop at the back triumphantly clutching a burnt paper capacitor, rated for 750 volts and about twenty times bigger than the piece of veroboard I wanted to mount it on!
Do you also remember Bi-Pre-Pak in Southend / Westcliff?
Thanks for the reply and additional information! It was a great little shop and a shame that in some ways it became a victim of its own success. The staff were always friendly and helpful, and I'd know a lot less about electronics today if it hadn't been for their patience.
It was certainly a change from our local TV repair shop where I'd go in and be served by the technical assistant who looked and acted just like Lurch from the Addams Family. I'd ask for a 0.1 microfarad ceramic capacitor and twenty minutes later he'd reappear from the workshop at the back triumphantly clutching a burnt paper capacitor, rated for 750 volts and about twenty times bigger than the piece of veroboard I wanted to mount it on!
Do you also remember Bi-Pre-Pak in Southend / Westcliff?
Thanks for the reply and additional information! It was a great little shop and a shame that in some ways it became a victim of its own success. The staff were always friendly and helpful, and I'd know a lot less about electronics today if it hadn't been for their patience.
It was certainly a change from our local TV repair shop where I'd go in and be served by the technical assistant who looked and acted just like Lurch from the Addams Family. I'd ask for a 0.1 microfarad ceramic capacitor and twenty minutes later he'd reappear from the workshop at the back triumphantly clutching a burnt paper capacitor, rated for 750 volts and about twenty times bigger than the piece of veroboard I wanted to mount it on!
Do you also remember Bi-Pre-Pak in Southend / Westcliff?
Oh those were the days! I used to have a 5600s that almost worked (often went off tune and a few dud keys). I always had the intention of spending some time getting it back in A1 condition but as with all things in life I never got 'round tuit'. In the end it went to that great synth store in the sky by means of the local council tip. What an idiot I feel now having seen that one went on ebay for £3200!
It'd be great if Maplin went back to their old grass roots and supplied kits like this again instead of catering for PC, Disco/DJ etc. They'll be selling toasters and kettles next! – regards, Nige.
Hi Royce,
Do you still have the technical details of the Fairlight keyboard controller, I have 3600 that could use it.
Thanks for your attention.
Cheers
Paul
I was one of the early adopters in Sydney, I built an ETI 4600 from a kit. It used the Fairlight 6bit digital keyboard variant.
At the time, I had a Signetics 2650 microprocessor which I programmed to interface with the keyboard. I wrote a very simple sequencer in 2650 assembly language. Lots of fun.
They were the days. I wish I still had that synth but unfortunately it was dropped from a height onto concrete and was destroyed.
My god,what a tragic end to a lovely keyboard,I think I would have been in mourning,[black armband included]!
http://www.ebay.ca/itm/Rare-original-vintage-ETI-4600-analogue-synthesiser-YouTube-demo-videos-/300763436491?pt=UK_Musical_Instruments_Pro_Audio_Synthesisers_CV&hash=item4606e5d5cb#ht_5165wt_1186
Sorry about the awkward posting of ebay item,just thought it was amazing!
I was a member of the Electronic Music Group at Imperial College (London) 1977 – 1983. The main focus of the society was to get a ETI 4600 and build it – which we did. We then seriously modified the keyboard circuitry to encode/decode the 4 x 12 keyboard signaling into pure 8 bit binary for storage into a 128 word RAM module that we cobbled together. This used a simple TTL cyclic clocking circuit settable from 1 to 128 steps to address the RAM – triggered by the keyboard to record the key presses and played back using a variable rate pulse clock to drive the cyclic addresser – to convert the ETI 4600 into a full blown sequencer (inspired after going to a Tangerine Dream gig at the Hamersmith Odean and seeing the racks of sequencers they used – complete with trace lights). I used to use the sequencer to record bass lines such as Floyd’s Money and practice playing in unison on a borrowed Rickenbacker.
Unfortunately the ETI 4600 was dropped down a flight of stairs (c) 1982 when being moved up to the student theatre – it never really recovered and I had no time left to repair it as I moved away to Leeds after graduating. I do still have the schematics of the sequencer circuit with its diode matrix keyboard encoder/decoder etc.
I am a professional electronics engineer with considerable experience of the ETI – Maplin 4600 synthesiser. Back in 1974 a friend, with little electronics experience, endeavoured to build this ‘beast of a synthesiser’ and he soon ran into difficulties. I was called in to assist with the project resulting in my becoming very well acquainted with it. We eventually resolved all the problems and got it going well.
In those days I worked for Plessey at the prestigious Alan Clark Research Centre in the Northamptonshire countryside developing all manner of new technologies some 10 to 20 years ahead of their time. So the very first ETI 4600 VCO I managed to get going was fired up in Plessey’s ‘Bipolar Process 3’ electronics lab.
Now, getting on for half a century later these rare, but very underrated synth’s are still around in various conditions. Being almost retired, I decided to revisit this project in my own electronics lab and re create some of the modules. This is not straightforward because many of the components and especially key microchips are now obsolete. So I decided to redesign areas of the original circuitry to enable me to use modern devices.
So far I have redesigned elements of the VCO’s and have a core circuit up and running without the need for the now obsolete 4416AE chip. The various waveform shaping circuits still have to be built but should present no problems. I have also redesigned elements of the White/Pink Noise Generator and Controller module and have a fully functional completed module. I will probably tackle the VCA modules next. I can see there will be clear problems with both patch board and the keyboard but I also believe modern solutions can be found.
Perhaps surprisingly I am not a musician and can’t even play a keyboard, so the keyboard may not be a vital component for my trip down memory lane. To be honest I’m not sure how far I will take this project. At one end it may end up as an elaborate and rather curious sound effects generator and at the other end I may go on to re build the entire thing with 21st century modifications. Much may depend on the extent to which I can convince my wife of the virtues of such an expensive and time consuming project. Interestingly, I have even considered adding totally new modules to the original to give even greater versatility to this outstanding design. There are many possibilities and to an analogue electronics engineer some fascinating new concepts exist.
Whatever the future may hold for this project, it is awesome to hear elements of this vintage synth springing back to life almost half a century later. I wonder when the last ‘new build’ of one of these modules was heard for the very first time.
Just an update on the above. My work in replicating the 4600 is going well. I’m actually building it on strip board. I now have 3 VCA’s up and running (2 VCA’s + 1 modified version for the envelope shaper). I have a VCF built and working and now need to build the second module. My first of 4 VCO’s is almost complete. I shall probably tackle the mixers and transient generators next.
I just discovered (by accident) a demo of an ETI 4600 Synth on YouTube, which led me to do a little further browsing. I have a particular interest because – back in the ’70’s – I worked with Trevor Marshall (the synth’s designer) in his Public Address business in Adelaide, South Australia.
Because I played in a band, I became the Alpha tester of the synth … using the very first prototype, then a more-developed version after Trevor took note of my comments on the ‘playability’ of the instrument.
The earliest versions were used (for only two songs) in concerts by our Christian folk-rock band (“Kindekrist”). One of the songs – ‘Fratricides’ – was recorded on our first album “Commonplace Forms” – making that the first recorded use of the synth, around 1971.
It’s amazing to see how far and wide those first explorations have gone.
I took the recent Covid Lockdown to restore a 4600 and 3600 from years ago.
I started with the 3600 and now have a working machine. It does have an issue, I can’t source the VCO range rotary switch (2 gang 11 way ). One of them doesn’t turn properly often bridging two connectors. Does anyone know where I can find a replacement?
Any thoughts on renovating such a switch would be appreciated.
I can get a dual gang 6 way but that reduces the range.
Most defects were noisy pots and dry joints in wiring.
The keyboard has sticky keys too and suggestions on how to smooth those would be appreciated.
Next stop, 4600 power supply rebuild.