I had a little time to tinker with Eagle again yesterday, and the result is a 40% smaller dual VCA. I've now put parts on both sides. I had to remove the separate CV input and trimmer outputs - instead of the trimmers you can put four 510 Ohm resistors on the board. The physical size (excluding pins) is now 27.3 * 16.8 mm.
I must admin that I like the original a little better as it had labeled pins and a nice big Xonik logo on it, but this one is very cool for being so small.
Saturday, August 23, 2014
Thursday, August 21, 2014
VCA works as expected
I tested the dual VCA today. Except for a mixup of output pin 1 and 2, it works as expected. At 10V the amplification is just slightly higher than 1. The VCA is linear, so at 5V it looks roughly like 50% amplification
VCA hooked up to the bread board. The two 1k trim pots are for adjusting the symmetry around 0V. |
Response at CV=10V. The outermost triangle wave is the output, and it's slightly larger than the input. |
Response at CV=5V, the output is about half the size of the input. |
Thursday, August 14, 2014
7 saw controller board populated
I finished populating the 7 saw controller board tonight. It has not been tested yet but it looks good :-D
I didn't have any 22k 0204-size resistors, and I can't find any 3M3 or 4M7 resistors anywhere in that form factor, so I used normal 1% metal film ones instead. It looks a bit wonky but will work fine.
I have yet to test both the dual VCA and this board so not sure it works yet...
I didn't have any 22k 0204-size resistors, and I can't find any 3M3 or 4M7 resistors anywhere in that form factor, so I used normal 1% metal film ones instead. It looks a bit wonky but will work fine.
I have yet to test both the dual VCA and this board so not sure it works yet...
7 saw controller board |
tiny LM13700 based dual VCA |
Silk screen looks great :-) |
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