Roland MC-8 Micro-Composer

Vintage Roland MC-8 Sequencer Archive

Ralph Dyck Reunited With Another Long-Lost Synth Creation

Encouraged by the recovery of his Carson Graham synth, Ralph went in search of another synth he made around the same time for the UBC. Bob Pritchard of the UBC Music Dept. confirmed that the synth was still sitting offline in his office, and after a quick consultation with the school’s administration, it was decided to gift the synth back to its original creator! Ralph has been working on the synth for a few months now. Here’s a bit of Q&A about it, along with some pics and sound examples.

Q: Can you tell us a bit about the history of this synth, why it was built, and how you arrived at its design?

Ralph: Well, I don’t know where to begin because I don’t remember very much at all, I have a clear memory of the Carson Graham but not anything detailed about the UBC.

I had been using the UBC Electronic Music lab for about 2 years at that point and had already built my own synthesizer. Cortland Hultberg was the professor there and he and I conspired to make a copy of my synth. He had a way with budgets and would funnel funds to us (Wayne Carr and myself) to add on to the Lab, this time he must have found a bunch of money. I remember that I wasn’t using the Lab at all because I had my own stuff now! He must have had some students that helped in the installation of the synth, my 1st one was completed months before and I learned from my mistakes and made the UBC modules better, they still are! The front panels are 8″ by 4″ aluminum sheets for which I cut slots for slide pots by hand using a nibbling tool. I developed a ferocious grip. The UBC ones, I just noticed recently were done by machine! Obviously I did the Letraset lettering as I had done before, by hand. Here are 2 photos, my VCO from the 1st synth and my VCO from the UBC.

We kept everything as close to my original synth as possible except for the box containing it, I had one made for my own synth but UBC’s lab was circular with an opening so one was surrounded by equipment and the Moog and Buchla had their own cases where as mine (RDE) was mounted in a very nice pre-made oak veneered cabinet, there were gaps at the ends of each module row because of it being made for something else. It’s still in the same cabinet, there was also a satellite cabinet to the left that apparently contained VCFs (which I had made later) and a sub-mixer and additional matrix patch panel. The synth cabinet still has 3 holes for cables to attach to the satellite cabinet. The installation must have been done by students with me being there part time because I was very busy playing with the Paul Horn Quintet and we were traveling a lot. Actually, if any of the UBC students who helped in installing this synth read this blog then they should get in touch with me, please leave a comment here.

Q: Can you give a detailed rundown of the various components and signal flow of the synth?

Ralph: The UBC synth was meant to be an exact copy of my first synth which had…

  • 4 VCOs (only 3 now) with Sine, Triangle, Sawtooth, Square, Pulse and Mix plus additional switches to select polarity of waveforms. Sure sounds like a Function Generator to me! (except it’s 1 volt/octave).
  • The 2 ranges of the VCO are 20Hz to 20Khz and 0.02Hz to 20Hz. The Sawtooth is selectable as Positive or Negative going. The Pulse Width goes from 1% to 99% and is voltage controlled, 10% per volt.
  • 4 VCAs selectable as Exponential or Linear. 6db per volt.
  • 4 ADSRs. The first complex circuit I ever designed all by myself, they still work! Controls for Attack, Decay, Sustain and Release and Output level.
  • A Sample & Hold with oscillator. There is an input level control as well as an oscillator frequency adjust which has the same specs as my VCO regarding frequency.
  • I thought there was a Ring Modulator but it has been removed!

What is missing is the satellite cabinet containing the VCFs, Mixer and 2nd matrix panel. Apparently most of that will never to be seen again along with the power supply.

The synth is really a standard one in that usually for a simple patch one might go VCO to VCO for vibrato modulation, the modulated VCO to a VCA controlled by an ADSR.  The VCO pitch might come from a keyboard CV and the ADSR gate from the keyboard Gate out. No filter though, seeing that I’m fixing this up for my son to use I’m going to have to reverse engineer my old VCFs and build copies of them, oh joy! My son Jeff van Dyck is really into digital synthesis but grew up on Modular systems so this will add a different color to the scheme of things.

Q: Can you give a summary of the current state of the synth, ie what works, what doesn’t, and what needs to be replaced?

Ralph: Actually, it’s really amazing! Everything works perfectly! As I said before, VCFs are very necessary and a Sub-Mixer as well. The matrix patch panel is 25 vertical by 20 horizontal so I can’t hook up everything to it. Some patch panel 1/4″ jacks would be easiest by far and durable as well (and cheap!). Jeff and I have to think about exactly what to do. There’s really plenty of room on the existing frame to add extra items. The VCFs will have to be on a perf board wired by hand and controlled with rotary pots, same with the sub-mixer. For power supplies I’m going to use two industrial switching supplies, 60 watts @15 volts and 4 amps. I’ll wire them up for +/- 15 volt operation.

I left the synth sitting on my work table for at least a month and a half while I tried to think what was best to do. Because the matrix patch panel will not accommodate all the inputs and outputs available I had decided to mount 2 panels containing 20-24 1/4 inch jacks for a patch bay and matrix extension. However, I changed my mind entirely and I had the bright idea of going super simple! I would just use the 25 rows of 20 columns to connect the most necessary ins and outs. I decided to make the vertical rows as inputs and the horizontal columns as outputs because there are many more inputs needed than outputs. Here’s what I came up with:

Inputs / Vertical Rows

  1. VC 1 –  VCO 1
  2. VC 2 –  VCO 1
  3. PW   –  VCO 1
  4. VC 1 –  VCO 2
  5. VC 2 –  VCO 2
  6. PW   –  VCO 2
  7. VC 1 –  VCO 3
  8. VC 2 –  VCO 3
  9. PW   –  VCO 3
  10. VC 1 –  VCF
  11. VC 2 –  VCF
  12. AUD –  VCF
  13. VC    –  VCA 1
  14. AUD –  VCA 1
  15. VC    –  VCA 2
  16. AUD –  VCA 2
  17. VC    –  VCA 3
  18. AUD –  VCA 3
  19. GATE – ADSR 1
  20. GATE – ADSR 2
  21. GATE – ADSR 3
  22. GATE – ADSR 4
  23. SIG   –  S & H
  24. VCO –  S & H
  25. Audio Input

Outputs / Horizontal Columns

  1. MIX – VCO 1
  2. MIX – VCO 2
  3. MIX – VCO 3
  4. ADSR 1
  5. ADSR 2
  6. ADSR 3
  7. ADSR 4
  8. VCF
  9. VCA 1
  10. VCA 2
  11. VCA 3
  12. S&H VOLTAGE
  13. S&H GATE
  14. External Keyboard Pitch CV
  15. External Keyboard Velocity CV
  16. External Keyboard Gate

This works out very well and allowed me to do all of the wiring including the power supplies in less than a week whereas it would have taken months to drill new panels with many more cables.

Here are some photos as work progressed, once I was into it, it was vary easy and fast, like I had done this before! Forty years just flew by……

I tried making some sounds to test and all was okay except there was no musical value in any of the recordings I was making of the synth, I was much more interested in the quality of sound:

However, I satisfied all of my concerns when I improvised this little ditty, no keyboard for control, all I had was the Sample and Hold controlling the modules and vice versa.

 

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July 25, 2012 - Posted by | Interviews & Articles, Technical

1 Comment »

  1. Congratulations professor! What a treat it must be for you to awaken this beauty. Best wishes from an old friend.
    Amin

    Comment by Amin Bhatia | July 27, 2012 | Reply


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