That's probably in the manual, huh? RTFM!
Let's Design and Build a (mostly) Digital Theremin!
Posted: 6/20/2021 5:37:39 PM
Play Hum Misty For Me
Inspired by Hyrtis: https://www.facebook.com/groups/53827181469/permalink/10157833682911470/
Just learning it today (when will I learn?) no outboard reverb or effects, key of C: [MP3]
Posted: 6/20/2021 8:03:36 PM
Another Day, Another DAC
Scored a pretty nice DAC box off Amazon for $10 USD. Some pix of the guts:
Not sure what the extra IC is, a headphone amplifier? Everything is unmarked as usual. Transistor drive to the line out? Power LED is surface mount, you view it through a hole in the back cover.
Looks pretty clean! I like that it has a physical switch to select the digital input. The volume pot has an on/off switch, and it's a little unbalanced and twitchy on the low end, but probably OK for most uses. The D-Lev kicks out a pretty hot signal, so I had to really lower the analog volume knob when plugging headphones directly into this. A bit of digital reduction kept it up out of the unbalanced zone. Oddly, the volume control operates on both the headphone and line outputs. There are literally a trillion ever so slightly different offerings of these things on Amazon and elsewhere, making it a really tough item to shop for (good-by meaningful branding and curating, and lord knows what's actually hiding inside the case).
[EDIT] This looks like the manufacturer: https://mealink.en.made-in-china.com/product/GKNJiCrTbyYc/China-Digital-to-Analog-3-5mm-Stereo-Audio-Converter-Analog-Stereo-Converter.html
Posted: 6/21/2021 8:47:50 AM
Why not to solder your own board? Existing board has jacks in inconvenient places.
I've found WM8731 codec which is easy to solder. It has headphones out amplifier, line in / out, mic in.
On your own board, jacks can be soldered at places you want.
Posted: 6/22/2021 2:22:32 AM
"Why not to solder your own board?" - Buggins
Yes, good idea. I guess for $10 it's hard to beat these things, though they can vary quite a bit internally, and some seem to have muting problems. I've played through one for years now and it's worked quite well. I'm learning KiCad (you have inspired me!) so maybe at some point I'll take this bull by the horns too.
Posted: 6/22/2021 2:36:10 AM
Hold Me Closer Tiny Tuner
Learning KiCad for the D-Lev kits, my first attempt is Roger's tiny tuner display board, which uses 8mm LEDs and 1/2" tall digit (instead of the "normal" 10mm and 1"):
Libraries seem to be a problem when doing this sort of thing, it took me almost as long to find a model for the 7-segment display as it did to do the schematic and layout. Those pin headers above and below it are for a dual footprint and in lieu of the 1" display module (I gave up and punted).
The 3D printed tiny tuner panel can be made the same width as the controller panel (here a quickie 1/2 size proof of concept, warts and all):
The 100 encoders arrived today, my updated knob fits like a glove on them. Roger sent me a textured printing plate, so I'm figuring out how to use that too, along with the PrusaSlicer. So much learning!
Posted: 6/22/2021 2:54:15 AM
Hold Me Closer Tiny TunerLearning KiCad for the D-Lev kits, my first attempt is Roger's tiny tuner display board, which uses 8mm LEDs and 1/2" tall digit (instead of the "normal" 10mm and 1"):Libraries seem to be a problem when doing this sort of thing, it took me almost as long to find a model for the 7-segment display as it did to do the schematic and layout. Those pin headers above and below it are for a dual footprint and in lieu of the 1" display module (I gave up and punted).The 3D printed tiny tuner panel can be made the same width as the controller panel (here a quickie 1/2 size proof of concept, warts and all):The 100 encoders arrived today, my updated knob fits like a glove on them. Roger sent me a textured printing plate, so I'm figuring out how to use that too, along with the PrusaSlicer. So much learning!
The D-Lev Quasquicentennial
is looking beautiful! Having tried your prototype, the tuner is especially clever.
Posted: 6/22/2021 10:56:39 AM
Buggins,Do you have an complete example circuit for SPDIF digital in to stereo audio out? Does this require an external circuit to automatically reset after any drops in the digital input stream?
-- pitts8rh
No.
Eric had some examples of S/PDIF to phones devices from ebay.
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