My Mini Moog Voyager. Click to go to my web site...

Sunday, July 25, 2010

More prototypes ready to order

I got the sequencer board stuffed and found an error in my schematic. It was in the logic section and was messing with the sequencing. I was able to confirm the flip flop logic is fine. I was not able to fully confirm the internal clock, however, since the production version uses an upgraded voltage controlled clock, I'm not going to worry about it. I did manage to burn up two pots however. Whenever I turned the pot to full CW, the pot smoked. This is weird because when I had a trimmer soldered in, the trimmer didn't smoke. I think in all my unsoldering/soldering around the clock circuit, I must have shorted something which was causing the magic smoke to be released.

So, I've made the corrections to the next version sequencer, I've updated the VCO to be two boards now (see below for details), and the VCF to be two boards. This lets me mount the VCF board parallel to the 14 Hp wide panel which I think will be satisfactory for most euro rack and frac rack users.

The VCO will now be two PCBs with an option to add a third daughter board with output buffers and output "levelers". I'm doing this because I figure there will be those who want the VCO outputs to be +/- 5 volts. As it stands, the pulse is about +/- 7 volts, the sine +/- 6.5 volts, and the saw and triangle about +/- 2.5 volts. This way, I preserve the heart and true Steiner VCO on the two main boards and then can add a third which will allow it to interface better with modern stuff.

The VCO is one of the more complicated PCBs in the system and has a lot of components. I wanted to reduce the size of the PCB in case anyone wanted to mount it perpendicular to the panel or design a slightly narrower panel. I was struggling with this until I thought I could just make the power regulation on a separate board and cut an inch or two off the main board. Right now, the panel is 28 HP but the main VCO board is now 4.5 inches wide and 3.9 inches tall and would fit behind a 23 HP panel, saving about an inch.

I'm going to follow this approach for as many of the PCBs as it makes sense. I'm also going to use the daughter board idea for some of the trigger conversion circuits, too. I think that preserves the ressurection idea for the Steiner system, but also allows a user to integrate it into an existing system with less headache.

I wonder how many people will actually buy/build these modules... I guess even if it's only one, it's worth it to do it right.

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