Sunday, August 1, 2010
VCO output, triggers, and sequencer
First, here are schematics for the VCO output buffers and the trigger convertors. I'd love comments if you think these could be done better. The output buffers are specifically setup to even out the gain of the VCO and will have onboard trimmers to do this. The triangle and sawtooth are about 2-3 vpp, the sine is about 12 vpp (if memory serves) and the pulse is about 14 vpp. The idea is to amplify the saw and triangle to 10 vpp, and attenuate/buffer the sine and pulse to 10 vpp. The pulse also has a DC offset at 50% duty cycle hence a DC offset on the first opamp for the pulse.
The trigger convertor has 8 S-Trig to V-Trig convertors and 8 V-Trig to S-Trig convertors. The idea is this can be its own module with jacks, or it can be piggybacked on the EG, Sequencer, or any other board which needs it. Instead of wiring right to the panel jacks, the user can put this board between and interface it seamlessly with current V-Trigger modules.
Nyle has checked out the voltage controlled clock circuit for the sequencer and will next check the gate/hold circuits. He also has an idea to eliminate the three Germanium (Thanks Ian :) ) diodes and replace them with a standard silicon switching diode. One less archaic part to source.
I'm working on project pages. When all done, I will have general instructions and some specific details for each board. I also want construction photos where appropriate and calibration instructions. If there are more specific things you think will help, let me know.
Last, I've been re-working the PCBs all week. I'm very happy with all of it. The sequencer is awaiting Nyle's last testing, but the others, VCO, VCF, VCA, EG are ready to go.