Saturday, November 08, 2014

Whew! So I have to remind myself how HTML works every time I post. Clearly I'm not being active enough, but rest assured, the wheels have been turning in the background. I've got a couple "filler" angles I can exploit, and while I detest the notion of coughing up fluff, if I have to stop and think about how to break a new paragraph something has to give.

Anyway, been tearing down some organs lately and have wound up (literally) wading through piles of interesting parts.

Low tech switch design. Left depicts an open condition, right depicts an operational failure. Easy fix, of course; sort of like brushing the bugs out of an early computer.

Lots of gritty potential.

More 1970s analog drum machine guts!

Daughterboard sounds as follows: #5 = BASS, #3 = SNARE, #4 = CLAVE, #6 = CONGA. Presumably the BRUSH, CYMBAL & SANDBLOCK (?) are handled on the inductor laden side of the main board. I'm a bit apprehensive about snare being built around the same circuit topology as bass & conga (the daughterboards are identical PCBs stuffed with different values), but whatever the sounds I have to thank the good people at Gulbransen for clearly labelling voltage supply points, etc.

I guess I should mention that the lowest daughterboard in that picture is a signal amplifier, not a one shot oscillator. I'm too fond of individual outputs to leave that section alone, but I'm certain it will see use in some capacity.

Once I scrape the dust off this it'll be a snap to try out.

1 comment:

pearshapedhuman said...

I have an identical rhythm machine board here- if you want to go stereo... The big electro on this is a couple years earlier (33rd week/1971).