Search found 50 matches

by weroflu
Mon Jun 07, 2021 11:48 am
Forum: Pro Audio Design
Topic: That1580 mini mixer
Replies: 92
Views: 206088

Re: That1580 mini mixer

can't do the polarity digital because signal is still analog at that point. the adc happens after the virtual earth summing: 5x2 analog mixer>> stereo analog buffer for adc >>stereo adc>>mcu>>microsd i thought about what you're saying (sorta) with nixing the 1240's. pro: save a stage, less noise pro...
by weroflu
Sun Jun 06, 2021 4:47 am
Forum: Pro Audio Design
Topic: That1580 mini mixer
Replies: 92
Views: 206088

Re: That1580 mini mixer

one preamp card is built but have not passed audio yet. i have some beta code for a linear audio meter loaded, have not gotten around to making it log yet. i paused building due to: spending some months trying to turn this from an analog mixer into a mixer/stereo adc/stereo recorder. right now the d...
by weroflu
Mon Feb 01, 2021 4:49 pm
Forum: Pro Audio Design
Topic: That1580 mini mixer
Replies: 92
Views: 206088

Re: That1580 mini mixer

Lots of progress. 328p mcu working, oled display working, mini joystick working, power supply working, and mcu section of the channel cards is working. Wayne you will like this new power supply, it is half the size of the last one. Double sided board about the size of two thumbnails New board order ...
by weroflu
Wed Dec 09, 2020 12:13 pm
Forum: Pro Audio Design
Topic: That1580 mini mixer
Replies: 92
Views: 206088

Re: That1580 mini mixer

1.2k bias straight from the datasheet.

I don't have mute on this version.
by weroflu
Mon Dec 07, 2020 10:47 am
Forum: Pro Audio Design
Topic: That1580 mini mixer
Replies: 92
Views: 206088

Re: That1580 mini mixer

Boards ordered. First next step is just a physical dimension test on the jacks and edge connectors. I caught one error, which might turn into a positive... I rearranged the phantom blocking caps, which were previously 22uf - as I understand it this about the low end of what you want. I can only fit ...
by weroflu
Sat Nov 21, 2020 5:37 am
Forum: Pro Audio Design
Topic: That1580 mini mixer
Replies: 92
Views: 206088

Re: That1580 mini mixer

Oled: Show me how I can use lcd in a smaller footprint than what I'm using now. I managed to squeeze the 6th channel back in by offloading the p/s onto a mini card. Getting close to a board run and then I saw the That 6261, hmmm. It wouldn't be hard to add a master channel with gain/attenuation now....
by weroflu
Mon Oct 19, 2020 8:00 am
Forum: Pro Audio Design
Topic: That1580 mini mixer
Replies: 92
Views: 206088

Re: That1580 mini mixer

c12,14.16 gone. Metering will be done post unbalancing right before the 5k mixing resistors. Going with attiny84 somethings on each channel card, 10 leds, will try to emulate an lm3916 with the mcu. low current leds and peak metering should not be too much of a current draw. (led color render is mes...
by weroflu
Sun Jun 14, 2020 9:44 am
Forum: Pro Audio Design
Topic: That1580 mini mixer
Replies: 92
Views: 206088

Re: That1580 mini mixer

JR I would like to have even simple metering as you suggested but there is not a lot of board space left. Adding 5 mcu's is a lot just to drive the led's. I'll keep thinking on it. Meantime here is an attempt at digital switching for phantom, polarity and lcr pan. Also attaching the backplane schema...
by weroflu
Wed May 13, 2020 1:34 am
Forum: Pro Audio Design
Topic: That1580 mini mixer
Replies: 92
Views: 206088

Re: That1580/1510 mini mixer

JR I have not ignored you, just busy working on the power supply before I get into the switches. The previous version p/s used an ltm8049 micromodule (with bga footprint) for the opamp rails and the TI tps7axx low noise +-regulators. I did have room on the board to go this way, but decided to try to...
by weroflu
Thu May 07, 2020 5:46 pm
Forum: Pro Audio Design
Topic: That1580 mini mixer
Replies: 92
Views: 206088

Re: That1580/1510 mini mixer

Onto version 2.0 https://1580mixer.shutterfly.com/pictures/103 changes from the initial prototype: -implement wayne's excellent suggestions from post #11 current summing his lcr pan scheme -digital switching of pan,phantom, phase, gain control -replace bluetooth/android interface with mini oled/5-wa...