Search found 44 matches

by weroflu
Mon Oct 19, 2020 8:00 am
Forum: Pro Audio Design
Topic: That1580 mini mixer
Replies: 79
Views: 60565

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: 79
Views: 60565

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: 79
Views: 60565

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: 79
Views: 60565

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...
by weroflu
Thu Sep 06, 2018 3:32 am
Forum: Pro Audio Design
Topic: New: A Direct-Coupled Input-Capacitorless Active Mic Preamp
Replies: 122
Views: 143216

Re: New: A Direct-Coupled Input-Capacitorless Active Mic Preamp

uhh just checking in re wayne's comment. I would not let my fail rate influence anyone, mainly because this was my first attempt at qfn. the 1580/5171 were not the cause of any problems. tldr for me was that i made the opposite error as most people in not putting enough solder on the pads. usually n...
by weroflu
Fri Dec 22, 2017 2:15 pm
Forum: Pro Audio Design
Topic: That1580 mini mixer
Replies: 79
Views: 60565

Re: That1580/1510 mini mixer

side project - stereo that 1510, +-9v rails, p48, 10 way switches gain 12db-66db, mint tin size

3d render of better version not yet built
https://1580mixer.shutterfly.com/pictures/70

real
https://1580mixer.shutterfly.com/pictures/70#69
(pots were added later)
by weroflu
Thu Dec 07, 2017 1:11 pm
Forum: Pro Audio Design
Topic: That1580 mini mixer
Replies: 79
Views: 60565

Re: That1580/1510 mini mixer

3d cad case for prototype. I'll soak it in conductive paint then paint some non conductive over that. Hopefully it will fit, but it's not that expensive to 3d print these buggers so one or two misses is ok. I might spring for a stainless steel 3d printed case even though they do co$t. https://1580mi...
by weroflu
Thu Nov 30, 2017 7:51 am
Forum: Pro Audio Design
Topic: That1580 mini mixer
Replies: 79
Views: 60565

Re: That1580/1510 mini mixer

Too scared to permanently solder all the preamp cards into backplane. As of last test everything was working, but I haven''t tested all channels at once. I tried to get some of my old 1510 preamp cards working and stuff them into a case, but I couldn't get proper signal passing. Cooked up an all in ...
by weroflu
Mon Nov 20, 2017 6:07 am
Forum: Pro Audio Design
Topic: That1580 mini mixer
Replies: 79
Views: 60565

Re: That1580/1510 mini mixer

Replaced all the decoupling caps, still no luck. Spi seems to be working properly, gain commands are ok. Audio is passing but gain never changes. Listening through phones it sounds a little distorted and noisy. Louder sounds cause the gain to overload recorder's vu. I was thinking maybe a problem wi...
by weroflu
Sat Nov 18, 2017 10:59 am
Forum: Pro Audio Design
Topic: That1580 mini mixer
Replies: 79
Views: 60565

Re: That1580/1510 mini mixer

Spi is very stable now. Afaik there are no floating logic lines. The only random logic-related thing that happens is sometimes when I hotplug the power jack to my board one channel doesn't reset correctly. A quick proper power cycle corrects it. The current problem is one channel is stuck on a gain ...