Cosmos APU a notch+LNA $70 to outperform APx555b for $30000

[matulo_g]

I got no problem to register on Discord yesterday. Two steps verification is required on most of the platforms now.
M

 

[PMA]

If you are willing to give away your phone number to some strange blog/game platform, then it is your choice.

 

[staccatiss]

If you use a VPN with a server in some other country then it might work better.

 

[staccatiss]

If you are willing to give away your phone number to some strange blog/game platform, then it is your choice.

Just enter 123 123 4560

 

[matulo_g]

Big Brother knows more about you then you can imagine...

 

[BamboszeK]

If you are willing to give away your phone number to some strange blog/game platform, then it is your choice.

This strange platform has 350 milion users globally and currently is one of most popular messaging apps. Mostly popular in gaming community, but gained lots of users during pandemics due to remote lessons. Sony and Microsoft tried to acquire them, but without success.

 

[IVX]

4000pcs of switches were burned during wave-soldering )) Switches supplier said - it is a production problem, oven is too hot and PCB time inside is too high.
The soldering contractor says this is a part issue, their wave-soldering process is standard )) So, I going to buy 1000pcs of PCB + 4000pcs switches more and try again..
In my opinion, it is the soldering contractor's blame, I gave them PCBs and parts, they said -Ok, pay me money. I did, so who should control the soldering for all given parts?

 

[1audio]

That's ugly. Who made the switches? Was the problem obvious when the board went through the machine? Is rework an option? I hope its not too bad a setback.

 

[IVX]

The switch is Taiwanese KKG, yesterday I ordered small PCBs for switches again. and new switches as well. The rework is more costly.
The problem was detected by disappearing the click when you shifted the handle of switch.

 

[1audio]

The vendor seems good quality. They would not last long if the parts failed easily. I hope this doesn't get caught in the china taiwan animosity.

 

[IVX]

yeah, KKG is Ok. We used a few years ago Chinese jacks 2.5/3.5mm and had some rate of problems, after I switched to KKG, I forgot about these issues at all.
But KKG 4x more expensive.

 

[IVX]

I did test 7pcs APU and gave Sunny to sell on our Aliexpress. All have H2 and H3 <-150db @5Vrms 1Khz.

 

[IVX]

Hey, if I understand correctly, Cosmos APU+Cosmos ADC+RIAA combo outperforms "Ultra high spec. opamp MC/MM phono" at least for distortions, noise and RIAA accuracy(I never seen if DSP filter was less precise). Please, correct me if I'm wrong
https://www.diyaudio.com/community/...p-elliptic-filter-line-headphone-amps.362390/

Cosmos APU+Cosmos ADC+digital_RIAA, 250uVrms input 10ohm source.

 

[BamboszeK]

Well, as stated by author, THD of his preamp is limited by test system.

11. Unmeasurably low (limited by measurement system) distortion at rated output, including harmonic and many tone.

 

[IVX]

Maybe, but IMO doesn't look so because his H2 is covered by the noise floor. Probably his ADC was cray noisy, something like 16 bits. lt1115 has the same 1nV/Hz^.5 as THAT1510, so the result shouldn't be 8db worse indeed.

 

[matulo_g]

The hunt for the lowest THD + noise is IMO for RIAA preamp pretty useless - compare it with noise/hum/thd of the mechanical MC/MM pickup system of the turntable...

 

[IVX]

exactly, I would like to try the first mod of my turntable as adding the balanced wiring. Under my apartment I have a few teslas charging every evening, and I very well know when looking on the FFT. A balanced MM->APU cable will help for sure.

 

[IVX]

30pcs available on our Aliexpress shop

 

[IVX]

Guys, I prepared a new Cosmos ADC FW with DSP RIAA EQ for vinyl ripping geeks. All Fs are supported from 44.1 to 384, but RIAA only with no subsonic so far, and RIAA isn't controllable by Cosmos_Tweak app yet. If anyone is interested in trying let me know.

 

[1audio]

I tried to get an APU but Alibaba's payment system was too cumbersome and the last available was gone by the time I got through it. Next time.