tirsdag 9. juni 2009

Please reread the schematics...

...and you (I) will discover that the capacitors connected across the input power lines are intended for decoupling. Now go fix the PCB.

mandag 8. juni 2009

SMD based VCOs

The project focus has shifted slightly at the moment. I'm now thinking about building a polyphonic synth as well as a modular. To achieve this, I've started redrawing the modules from yusynth.net to use SMD components. Yesterday I finished the VCO, and the result is a 70 x 32 mm PCB, exactly 1/3 of the size of the yusynth one.

As I have little experience designing audio circuits, I have no idea of how noisy the new design is. To test the new PCBs, I've etched a bunch of yusynth PCBs to use as a reference. These will then be used to build a mono modular :-)

So far I've etched:
3 x VCO
2 x LFO
3 x Envelope generators
3 x VCA
1 x Moog filter
1 x ARP filter
1 x Steiner filter
1 x Diode filter
1 x Ring modulator
1 x Noise/Sample & hold
1 x Audio mixer
1 x power supply (Ken Stone)
1 x Auto bend

I'm aiming for a 6 voice, 3 VCO polysynth, which means that I need 18 VCOs... This will surely take a lot of time and money to finish, so I don't expect to complete the project for some years (if it is ever finished at all...)