Showing posts with label electronics. Show all posts
Showing posts with label electronics. Show all posts

Sunday, May 24, 2009

x0xb0x SS#01: Headphone

This was another painless step in the process. There's nothing to really test just yet according the documentation. That will follow once the I/O is in place. It's also nice to see the volume pot in place.I couldn't resist snapping a better pic of the BA662 I have too. I'm looking forward to hearing this amplified. The LA4140 also looks ancient despite being new old stock. It just looks vintage alongside some of the other old ICs. Note that I'll also be building the wiring for the jumpers.

Q33's hFE: 200 mfm*

Total time on this: about 2 hours to sort parts, build it, snap pics, and write this.

* My Faulty Meter

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.