MATRIXSYNTH: Practical Electronics P.E. Sound Synthesiser


Thursday, April 03, 2014

Practical Electronics P.E. Sound Synthesiser

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Here's something you don't see every day. A completed Practical Electronics P.E. Sound Synthesiser. There is only one previous post with an image of the Practical Electronics magazine cover here. See the Practical Electronics channel for more.

"1973 Practical Electronics P.E. Sound Synthesiser

This is a modular analogue synthesiser and controller keyboard (actually a second modular synth in its own right) that was built from a design published in 1973 in the UK magazine Practical Electronics. This is the only one I have ever seen and is possibly the only surviving example.

The design was by G.D Shaw who later designed the Minisonic synthesiser. I think it is fair to say that the design was greatly influenced by the EMS Synthi in both functionality and controls (and sound I have heard). It was also the first magazine DIY synth published in the UK at least.

The Synthesiser is in two parts - a rack unit with the main sound modules (oscillators, amplifiers, tone filters, sample & hold, ring modulator, spring reverb, meter etc) and a separate controller keyboard with extra functionality (oscillator, VCF etc)

This example (the main rack unit) was built exactly to the published specification as far as I can tell and was completed to a very high standard (I would describe it as 'laboratory grade' construction). It features hand wired circuit boards (as per the published design and layouts) that plug in to a 'backplane' so it is a truly modular synth. All patching is done by 2mm plugs on the front panel, original patch cables are included.

The rack unit has a good range of modules included. Here is a complete list -

Stabilised Power Supply
2 x Input Amplifiers
2 x V.C. Modulators (Ramp & Pulse Generators)
2 x V.C. Oscillators (Triangle & Square Waves)
2 x Output Amplifiers
Reverberation Amplifier & Spring Line
Ring Modulator
2-Band Tone Filter
Envelope Shaper (Incl. Trapezoid)
Noise Generator
Sample & Hold
Differential Amplifier
Inverter
Analogue Meter

Quite a good specification!

The keyboard controller design was modified somewhat by the original builder to incorporate extra features (VCF, Joystick controller and extra oscillator I think) but crucially this part of the project was never completed, though all the parts are there, including completed PCB's, control panel, keybed, wooden casing and design notes etc.

The Synthesiser comes with full original documentation, including a full set of original magazines, all instructions supplied with the original kit parts, also many handwritten notes by the original builder detailing his modifications. Also included is a box full of many original spare components, patch cables, interface cable (for the keyboard I think) and other parts.

I bought this several years ago from the original constructor, I was told then that the main rack was fully functioning but had not been used for a long time, and that the keyboard was unfinished. Preliminary tests at the time showed that it powered up and some of the modules worked, but it would need some attention (I suspect the backplane plugs and sockets all need a good clean). I put it on my list of projects to do, but unfortunately I have never been able to get around to it. I have therefore reluctantly decided to pass it on to someone who can, as it is unlikely that I will ever have the time now. So, be prepared, this instrument will require a bit of time and effort to restore it to full operation. At the very least, I would recommend a complete inspection and overhaul of the main unit by a professional synth tech.

I imagine that this unit will appeal mainly to collectors, or those interested in the DIY synths of the 70's and 80's (as I am) I believe it has the potential to compete with an instrument like the EMS VCS3, which it was clearly inspired by.

Note that there is now very little information out there about this design. I have never seen another complete unit anywhere online or on youtube for example, apart from the original designers website (which is now sadly gone) and a couple of brief mentions on Matrixsynth from others who had built them (but no mention if the units still exist)

I think there is a fair chance that this may be the only surviving example, in which case you are looking at a truly unique piece of synthesiser history. I would be very interested to hear from anyone who has one though.

This is a big, heavy item and will require careful packing and shipping arrangements. I will ship worldwide, exact cost to be determined at the time and depending on location, but I expect it could cost up to £250 to ship to some locations (but probably a lot less, I will only charge at cost) I have put an extended dispatch time on this listing just so I have plenty of time to pack and arrange things properly, but I will try to send it at the earliest opportunity. Local pickup is also possible by arrangement.

Please Check out my other items! and Thanks for looking."



1 comment:

  1. https://www.americanradiohistory.com/Practical_Electronics.htm
    just go down the page until you reach 1973 and start with february of that year and go to february of 1974.

    ReplyDelete

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