23 January 2010

Oakley VCO Module

Yesterday I finished another Oakley module. Here is the PCB that I had done already. Right in the middle you can see the SSM2210P Matched Transistor pair with the big Tempco resistor mounted on top of it. I used some heat sink pasta again to make the contact between the two more optimal. Further more you can see that this PCB has 7 trimmers in total. 3 multiturn for tuning purpouses and 4 single turn trimmers for waveshaping the Triangle and Sine wave. It is a nice versatile VCO and it is supposed to track over a large octave span.

And here is the finished module from the back. As you can see it also has extra PCB's like the Discontinuity to hold the jacks and extra potmeters. As before I hard wired the connection between these PCB in stead of using connectors. You can build them really quick this way since you don't really have to think what goes where. Just wire pin 1 to pin 1 and so on. And it also looks very neat because of the short wires that you can easily bundle with some tie-wraps. OK so far for the building. Now it is time for some testing and tuning.

For testing and tuning I hooked it up to the Oakley MidiDAC midi2CV converter I build before. A good chance to see how this combination works. First thing I did was adjust the wave shapers to get a nice Sine and Triangle output. Then I started the tuning procedure. It was quite alike the YuSynth VCO module I tuned before. I did it quite roughly this time because I didn't have much time yesterday. But I got it tracking over 5 Octaves quite quickly. After that I tested the other modulation inputs with an LFO and everything seemed to work fine. I will be building some more YuSynth and also some MOTM VCO's soon. It would be fun to compare them to each other. I will do that when I have them done and post something about it on this blog. After testing I played some melodies on the VCO on a midi keyboard. I ran the output through a delay and it sounded quite nice. Can't want to hook it up to a sequencer soon, but I still have lots of work to do before I can get to that. I'll keep you posted.

2 comments:

Jim said...

Hi, I'm just starting a modular synth and I'm really curious about the various VCOs out there. If you get a chance to post your Oakley/MOTM/Yusynth comparison (?) I'd love to hear some samples. (Maybe your MOTMs are still waiting on hardware?)

Synth.nl said...

Yeah I could do that, but not any time soon. I'm in the middle of a couple of productions right now. And the MOTM's are not finished yet. I do have all the hardware in the mean time, but same problem. No time to finish them at the moment. Michel, Synth.nl