More bits of the synth turn up ..

Work has unfortunately got in the way of play lately .. and then the weather has picked up nicely. It's a glorious sunny morning this Sunday, the London Marathon is on, the US Masters later and I spent a chunk of last night putting a schematic of a VCO into Eagle, and crafting a PCB.

So far I have received two boards from Itead Studios:

1) the multifunction VCLFO / ADSR board, and that is going well. I have a second style of DAC - an MPC4922 somewhere to try out - one that isn't £20 a go, but needs an external reference. The small daughter board idea for the DAC should serve its purpose well there.

2) is a dual VCA, 3 channel mixer, noise and sample and hold board. It's amazing what you can squeeze into 100 square centimeters. Quite pleased with it so far - only a couple of niggles on capacitor leg spacing. I must stop assuming that all caps have 2.5mm spaced legs (a mistake I haven't repeated on the VCO)

And so, before putting some clothes on, while the drill battery is charging I thought I would share the VCO design ..

First, the schematic. It's a well-known design based on Ken Smith's excellent VCO. I was going to borrow more of MFOS but this is a great starting point. It's probably not the only VCO I am going to cut a PCB for.

Again, I have stuck to the same format as the other two boards - slighly less than 100mm on each side, and Itead provide 10 (or 11 apparently) PCBs, double sided, thru-hole plated and silk screened in your choice of colour (as long as its green) for $19 US, including shipping. Can't compete with it, except on time, as it does take 2-3 weeks to turn up once the order is placed.