[sdiy] Drumfire DF500 mods on the bench

[Metrophage]

Aiieee!!! Why so many projects at the same time?!

I finally got around to messing around with this synth, which I got in
the spring. There was a nasty dent on the top right corner, which I
hammered out. I needed to replace two broken pots there. Now it looks a
hell of a lot better, still a bit scuffed but there is no trace of the
dent. I needed to fiddle with the audio bus wires to get the mixed outs
working.

Very raw machine!

I had to try FMing the drum sounds together. Connecting one of the
oscillators on the second board (bottom 47k under 2nd 324) to one on
the first board (left of the 39k resistor between 2nd 324 and 1st 308),
through a 1M pot sounds quite wild! Jumpering the freq pots 1k ground
resistor improved the low frequencies.The sweep control makes for some
fun modulations. A bit of an envelope here might be even better, I'll
try it.

The noise source on the DF500 is WAY louder than the oscillators. Also,
of the five identical PCBs, only one has the dual op-amp IC5. This is
the noise source for all five modules. I flipped the second PCB out,
with cutting of two traces and moving the noise input wire, I was able
to use the blank area to make a noise filter. After the noise range
switch I tried a 10k attenuating pot, though I suppose I'll compare a
few other values for this. So now the noise is less likely to overwhelm
the drum tones. The low frequency pops also make a fun modulation
source for the VCOs.

If I really go off the deep end, I might make a tiny S&H board. Scary
bleepcore drums!

CJ


		
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