Search found 40 matches

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: 126105

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: That1580/1510 mini mixer
Replies: 70
Views: 51172

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: That1580/1510 mini mixer
Replies: 70
Views: 51172

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: That1580/1510 mini mixer
Replies: 70
Views: 51172

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: That1580/1510 mini mixer
Replies: 70
Views: 51172

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: That1580/1510 mini mixer
Replies: 70
Views: 51172

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 ...
by weroflu
Sat Nov 18, 2017 4:46 am
Forum: Pro Audio Design
Topic: That1580/1510 mini mixer
Replies: 70
Views: 51172

Re: That1580/1510 mini mixer

The second channel that stopped working, which had previously passed signal at default gain, started acting the same as the other channel ie no signal was passing and then the microphone diaphragm started whining. I figured this had to be a short in the chip itself. Replaced the chip and it's workin...
by weroflu
Fri Nov 17, 2017 1:18 pm
Forum: Pro Audio Design
Topic: That1580/1510 mini mixer
Replies: 70
Views: 51172

Re: That1580/1510 mini mixer

Got real close to finishing today, then problems. 5 channels were working well. I passed signal through all working channels and the preamps sounded really good. I can't remember exactly the sequence of events following but I had phantom on (accidentally) the non-working channel with an sm-57 for te...
by weroflu
Wed Nov 15, 2017 10:45 am
Forum: Pro Audio Design
Topic: That1580/1510 mini mixer
Replies: 70
Views: 51172

Re: That1580/1510 mini mixer

I think you're way overestimating my skills. Actually I did a lot of them wrong, and then did the rework wrong. If you follow sop you just get a stencil (which I did not do), put paste on and hot air them and they should be not so hard. I was using hot air btw and just doing touch ups around the edg...
by weroflu
Wed Nov 15, 2017 6:04 am
Forum: Pro Audio Design
Topic: That1580/1510 mini mixer
Replies: 70
Views: 51172

Re: That1580/1510 mini mixer

Moving along... I stuck a .1u cap in the reset rc, didn't work. Then tried a 22u and it seems to be working. Things got a lot more stable. Next I rewrote a lot of the code on the arduino and android so that only actual gain register data was being displayed. Every change on the android gain display ...