Search found 50 matches

by weroflu
Wed May 17, 2017 3:48 pm
Forum: Pro Audio Design
Topic: That1580 mini mixer
Replies: 92
Views: 211346

Re: That1580/1510 mini mixer

LIttle update. 5 cards done and working, but not rigorously tested yet. Just from quick testing with a 57 the preamps sound great. Waiting on the drv135 board. I added a cypress usb uart to the rfduino board and was able to squeeze in a microusb footprint on the chassis, waiting on that board as wel...
by weroflu
Fri May 12, 2017 5:32 pm
Forum: Pro Audio Design
Topic: That1580 mini mixer
Replies: 92
Views: 211346

Re: That1580/1510 mini mixer

Haven't yet checked the power rails. I got stuck on these qfn32's again. FInally got one more done after a zillion tries, either not enough solder on pads, too much on the thermal or something else. Card #4 has the 5171 on, it seems the rest of the populating is fairly easy once that's done. Card #5...
by weroflu
Wed May 10, 2017 9:39 am
Forum: Pro Audio Design
Topic: That1580 mini mixer
Replies: 92
Views: 211346

Re: That1580/1510 mini mixer

Nope spoke too soon. Very low level rhythmic clicking audible if I turn up the headphone volume. 3-4 per second. Forgot I enable bluetooth broadcast in preparation for the next round of coding torture. RFduinoBLE.advertisementInterval = 250 hmm, 250ms x 4 sounds about right. Disabled bluetooth broad...
by weroflu
Wed May 10, 2017 8:04 am
Forum: Pro Audio Design
Topic: That1580 mini mixer
Replies: 92
Views: 211346

Re: That1580/1510 mini mixer

Update Two channels now working pefectly through the whole signal chain, preamplifier, spi gain set, pan and sum, no noise. edit: the clicking was caused by something on the summing card. I reseated or replaced, can't remember, the lme49720 and that did it. I have tentatively decided to stay with th...
by weroflu
Sun May 07, 2017 4:23 pm
Forum: Pro Audio Design
Topic: That1580 mini mixer
Replies: 92
Views: 211346

Re: That1580/1510 mini mixer

I noticed the 5171 and 1580 seemed to be a little too warm. With no load they are peaking at 50c and 55c respectivelty, after about 5-6 minutes.
by weroflu
Sat May 06, 2017 12:34 pm
Forum: Pro Audio Design
Topic: That1580 mini mixer
Replies: 92
Views: 211346

Re: That1580/1510 mini mixer

I didn't mean to say that I was offering new information about the pad, I'm reading intently. It was sort of a mis-edited post that came across like I came up with the idea. I'm still trying to wrap my head around some concepts but they are slowly sinking into my thick skull. The pico is not even 12...
by weroflu
Sat May 06, 2017 4:28 am
Forum: Pro Audio Design
Topic: That1580 mini mixer
Replies: 92
Views: 211346

Re: That1580/1510 mini mixer

It looks like to me that you need a pad at the output of the DRV134 and run the PicoScope out near FS. Run picoscope sign gen full scale (2v) to increase s/n ratio ? Already too hot for the mic input, but add in gain of 2 from the drv134 and it needs a pad. 600ohm output of the sig gen into 10k inp...
by weroflu
Fri May 05, 2017 12:03 pm
Forum: Pro Audio Design
Topic: That1580 mini mixer
Replies: 92
Views: 211346

Re: That1580/1510 mini mixer

I bypassed the preamp and just fed the picoscope sig gen sweep back to 10x probes. First file is Y axis set to average. Second file is Y axis set to peak hold.

I don't know the answer to how does p.s. produce attenuated 1mV signal.
by weroflu
Fri May 05, 2017 10:50 am
Forum: Pro Audio Design
Topic: That1580 mini mixer
Replies: 92
Views: 211346

Re: That1580/1510 mini mixer

<<You have an unbalanced PicoScope output feeding a DRV134 which then feeds the balanced mic input with gain.>> Correct. I think attenuation is not necessary because the sig gen output range is 1mV - 2V. The output of the preamp is connected to 10x probes which attenuate the signal by a factor of 10...
by weroflu
Fri May 05, 2017 9:41 am
Forum: Pro Audio Design
Topic: That1580 mini mixer
Replies: 92
Views: 211346

Re: That1580/1510 mini mixer

Picoscope signal generator 20hz-20khz sweep, into drv134, into preamp card, output post pan/pre summing into scope

Still getting frequency dependent gain unless i'm not measuring correctly. Gain is set to 30db, which is what I see here from about 600hz-20khz.