MATRIXSYNTH: Trevor Pinch's Vintage DIY Modular Synth


Monday, April 26, 2010

Trevor Pinch's Vintage DIY Modular Synth



via Inverse Room, via Muff's:
"You guys will dig this.
Some of you probably know Trevor Pinch from his book Analog Days [Amazon hardcover & paperback, preview on Google books], about the history of the Moog synthesizer. Trevor's a friend of mine--we both teach at Cornell U.--and he recently restored his moribund DIY modular that he built in the seventies. Last night he and our friend James Spitznagel (together they are Electric Golem) played a show here in Ithaca, with Trevor on his synth and Jim using a Mopho, Evolver, Orb, Nintendo DS and various iPhone apps.

Oh BTW sorry these are not better photos. I should have brought a DSLR for this but I had a digital rangefinder camera with me that is not so hot at high ISO. Full set is here (for now): http://inverseroom.creotia.com/golem/"

I contacted Trevor Pinch and he had the following to share:

"Hey Matrix:
I built that synth in London in 1973. I used it til 1975/6 in a collective band/scene in London and then in Manchester - we also had a VCS3 and various gizmos from EMS as one of our band knew Tristram Cary, one of the founders of EMS. By the way anyone interested in EMS should check out the half hour documentary Matt Bates made for Australian TV - 'What the Future Sounded Like'. I was a talking head for that movie. It's got tons of info in it and great clips of Hawkwind, music of early Floyd etc [below].

My synth was kinda in storage before being shipped to the States in 1990. It was smashed up badly in the move and I only started work on it again a few months ago when Park Doing here in Ithaca persuaded me to get it going to jam with Johnny Dowd, Richie Stearns, Brian Wilson, and others for a 'Requiem for Analog TV' show we did at Cornell. Since then I've played out with it a couple of times with Park's band, the Atomic Forces, and once with The Electric Golem with Jim Spitznagel.

The schematics come from the hobby magazine Wireless World August 1973. Tim Orr did the design (he was the same guy who designed the EMS Vocoder). I built it 1973. The Voltage Control filter is online [link]

VCO 1 has square, triangle, sine , and variable mark space (I think in the US they call it duty cycle - adjusting the width of the top of a square wave). It turns out the variable mark space is one of the most musically useful controls I know.

It has three frequency ranges from very low to way up there! There are two VCO inputs with 1 K pots to control the voltage in.

VCO 2 has square, triangle, sine, ramp, and pulse outputs. There are two VCO inputs with 1 K pots ditto.

VCO 3 is a six-step sequencer with an incredible frequency range, with each step selectable and tunable. This is the awesome guts of the beast. There are two VCO inputs with one K pots. You feed the sequencer output as an input into the VCO1 and VCO2 and away you go.

There are also the following modules:
2 voltage control amplifiers
2 exponential converters
A keyboard module for operating a resistor chain monophonic keyboard - I abandoned the keyboard as I could never get it in tune and it sounded better out of tune!
I voltage control filter - band pass or low pass output - band pass only is working
I mixer with three channels and two virtual earth mixers for summing and reversal with three channels each,
White noise source and blue and red noise (variable) outputs
Spring reverb.
Envelope shaper. Not yet working
Two preamps. Buggered.
2 very low frequency outputs. Not yet working.
Sample and hold - Never worked!
Joy stick control and circuits with two pots providing variable X and Y voltages.
The joystick is home built by using three pots (design based on the first one that David Cockerell made for VCS3) my killer control for live performance (think Brian Eno and the way he used the joystick on the VCS3 (Putney)). The joystick was beat up terribly in the move and was the hardest single thing to get working and nicely balanced. Read the story of how the pitch and mod wheel were designed for the minimoog in Analog Days! Having a controller that feels right when you play is for me half the battle.

There is an onboard power supply for 240 volts in and 15v plus and minus and 5 volts plus out. Useless in US! So got new power supply built.

The modules are mainly built on plug in breadboards made by a UK company called Electrokit. So when I blow out transistors - happens all the time - I can unplug for easy access. Also I like to leave it open so shaking the instrument shakes the modules and affects the sound and of course the reverb. Opening the black box is my aesthetic.

Housed in hand machined painted aluminium case (wise choice in hindsight as it is sturdy, light and didn't rust!)

Patch bay is banana plugs, wires and sockets (what we used to call banana plugs or Wonder plugs in the UK). US banana plugs are too big - anyone know where I can get the UK banana plugs from as I need more?

If anyone is interested in my early experiences in playing the synth, they are written up in a chapter in a book by Sherry Turkle, Evocative Objects - the reflection is online at a awesome exhibition, "Remix, Rewind and Replay" at Scottsdale Museum of Contemporary Art which I was on a panel for. http://www.rewindremixreplay.org/pdfs/pinch.pdf

By the way, that essay was written before I got the synth working again. In that essay I said the synth had no name. When I unearthed the old schematics to start soldering work I found I did give it a name, "Stray Capacitance". That's what the synth was like - full of capacitance.

The synth truly has a unique sound : the sonic energy is simply amazing. It can cut through like a chain saw on magic mushrooms - everything sort of feeds back on everything else in various unpredictable ways. Its like a live bucking beast to control. Park Doing says I shouldn't call it a synth and I agree. It's more a sometimes controllable sound and noise maker. John Robert Lennon (aka Inverse Room) on seeing and hearing it in action the other day - said how come it just doesn't explode. It's a miracle that it works at all! Its industrial sound is awesome in a punk band and when playing alongside someone with more varied and sweeter sounds (like Jim Spitznagel can produce) it can cut through and complement and attract attention. With the spring reverb it sends you into space. In the early days we also used to use huge tape loops as well.
That's it!

Trevor"

I'd like to give a huge thanks to Trevor Pinch for taking the time out to share this with us and of course Inverse Room for sending this our way.


YouTube via inverseroom — April 25, 2010 —

"Inverse Room interviews Trevor Pinch, author of "Analog Days" and other books about the history of technology, who demonstrates the DIY modular synth he built in the 1970's.

The thing I find really cool about this design is the step sequencer that can be run at high enough speeds to create, in effect, a new oscillator with primitive custom waveforms. And of course there's the total lack of sides to the case--gotta love that, too!"

4 comments:

  1. super cool post! really made my day
    love the fact that its filmed in his bedroom

    ReplyDelete
  2. thanks for sharing!
    For all EMS fan please visit the EMS forum:

    http://forum.thesynthi.de

    Regards
    leomodular

    ReplyDelete
  3. that's great. Thanks for sharing this with us.

    ReplyDelete
  4. FYI, that's actually his basement, where his kids usually hang out! We borrowed it from them for the video.

    ReplyDelete

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