SCF -- 1st Attempt...

Having a go at Tim Stinchcombe's Switched Capacitor Voltage Controlled Filter. I got a bit overly entusiastic and grafted Tom Henry's front end to the 4046 from his VCO into it... Not so successful, a closer look at what is happening inside the 4046 and it becomes a bit more apparent that I should have left it alone! Anyway it shouldn't be too hard to put it back to the original design...

0.2% THD

Have just made a PCB for Thomas Henry's new VCO based around a OTA & a 555 Timer. It's pretty clean layout without too many links and roared into life immediately. The only issue with the board was i forgot R46 which biases the sawtooth. As it was in the next room I did drag in this Audio Spectrum Analyzer to help adjust the Sinewave purity adjustments and got down to a pleasing 0.2% THD ~ the peak-to-peak amplitude is a bit low for the sinewave compared with the triangle/ramp/pulse so may try tweaking up the input to the OTA by changing R34? Still need to do the 1V/octave adjustment so need to look for that last 2K tempco I have somewhere...

DX7

Accidentally bought a rather sad Yamaha DX7 off e-bay as a non functioning, "for parts" unit. I don't think that there is too much wrong with it and it did come with a spare cover & LCD display. I have stripped it down and started cleaning it up. This has included sandblasting the base which looked a bit like it had been dragged down the road behind a car… I plan to get it powered-coated this week and then start to get all the bits back into it...

Paper Hellfire

This is a bit old but it shows the transformer...

Timber!

A very long time between drinx! Not really sure where the last year has gone but hopefully things will start to crank back into action over then next few months... This is a start... The local council verge collection yielded a new keyboard for Forbin from a Kawai MR270 electronic piano. It is rather nice as being wood, nicely balanced and weighted. The electronics is shot but an AVR doing the scanning and a MIDI feed and we are back in business with 88 keys of goodness!

Brown Turds

I have used what has been euphemistically referred to as Brown Turd capacitors on the Hellfire board. I had to laugh when I saw then called that at a local website, Evatco. The pace is slowly picking up after the holiday. I didn't really plan for Nick to be peering at you through the wires it just turned out that way...

Hellfire Front Panel

Slowly getting there... Off on holiday in a couple of days so this won't get finished for a while... did stuff up the hole for the switch...