Saturday, May 23, 2009

x0xb0x SS#01: VCA

The VCA was a reasonably painless step. It was really nice to see the BA662 IC get dropped into place. Seeing it on the pcb starts to give one the sense that the project is taking shape (despite upcoming steps being rather large).

Q31's hFE: 198
(again - based on my faulty meter)

Testing this section gave me some odd results. I was able get a change in sound behaviour but I couldn't say that it sounded like a note. I tested the resistors and got some odd figures here:

r127 (47K) : 39.4 K
r128 (220K): 52.5 K
r129 (2.2K): 20.25 K

The folks on the boards suggest that it's not entirely out of the ordinary and suggested I carry on to the sequencer to trigger notes properly, then troubleshoot again. I'll follow their advice on this one.

The parts for the headphone / mixer are set aside already. I'm looking forward to starting that.

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