Well, most of AP users I know used that to measure the THD+N, SNR/DR but not to "control an impedance". In that respect, Cosmos APU + Cosmos ADC or any just Ok ADC outperforms APx555b 2x times, and more being hundreds of times cheaper. Of course, Cosmos APU isn't an equivalent replacement for AP - no generator, only 2 frequencies 1kHz, and 10kHz are available for the THD+N test, and some ADC anyway is needed. However, if some DIYer can't buy APx555, I gave him a chance to see the THD+N@1kHz down to -134db if any newcoming DAC will provide that. Amir ASR will report about such DAC - "well, again the SINAD is 124db, let's try to control an impedance instead" )) Why? Just because APx555 isn't ready for such low distortions measurement. L7 did measure Topping SE90(ES9038Pro perhaps a golden sample) THD+N with APU and got L-126/R-127db, APx555b again found its limit -124-125db. What about the new Hypestream IV ES9039, again -124db? ))
The same or even worse regarding the Dynamic Range test. APx555b shows AES17 DR 123..124db(A) for the $13 Meizu HiFi DAC CS43131 based. 6db worse than Cirrus claimed. Knowing that, Cirrus Logic, Inc. staff prepared a special appnote about how to measure SNR/DR of this a few dollars DAC with "state of the art" APx555b $30000 analyzer. They recommend to solder some LNA to help a noisy AP reach the real level of modern tech. Cosmos APU(in fact just THA1510!)+your laptop audio input will show AES17 DR 130..131db(A).. Isn't it ridiculous?
The same or even worse regarding the Dynamic Range test. APx555b shows AES17 DR 123..124db(A) for the $13 Meizu HiFi DAC CS43131 based. 6db worse than Cirrus claimed. Knowing that, Cirrus Logic, Inc. staff prepared a special appnote about how to measure SNR/DR of this a few dollars DAC with "state of the art" APx555b $30000 analyzer. They recommend to solder some LNA to help a noisy AP reach the real level of modern tech. Cosmos APU(in fact just THA1510!)+your laptop audio input will show AES17 DR 130..131db(A).. Isn't it ridiculous?
I read the comments about USB type-C reliability on the website and I thought, maybe you could make it compatible with this or something similar?
https://www.amazon.com/Cablecc-Type-C-Locking-Connector-Standard/dp/B075S3C7QB
https://www.amazon.com/Cablecc-Type-C-Locking-Connector-Standard/dp/B075S3C7QB
Sorry for the off-topic, guys, I have an interesting and I bet unexpecting upgrade for your Cosmos ADC 
I found that just by the new FW is possible to expand the sampling frequency up to 768kHz. However, the modulation noise isn't as cool as at 384k but quite Ok for the frequency response tests up to 380kHz, with the correction file in REW(the analog input response is limited by the 1st ord LPF at 180kHz). To get 705k and 768k Fs work Windows needs Comtrue ASIO installed, that's a weird installation method found by our dear StaticV3(pls search the cosmos in our discord channel). Mac, Linux, and Android users should have no problem. The FW contains DSP RIAA as well, so don't be surprised if at the middle of the volume slider you'll get the RIAA EQing Min Volume = STEREO, Max = MONO, as usual.
I found that just by the new FW is possible to expand the sampling frequency up to 768kHz. However, the modulation noise isn't as cool as at 384k but quite Ok for the frequency response tests up to 380kHz, with the correction file in REW(the analog input response is limited by the 1st ord LPF at 180kHz). To get 705k and 768k Fs work Windows needs Comtrue ASIO installed, that's a weird installation method found by our dear StaticV3(pls search the cosmos in our discord channel). Mac, Linux, and Android users should have no problem. The FW contains DSP RIAA as well, so don't be surprised if at the middle of the volume slider you'll get the RIAA EQing Min Volume = STEREO, Max = MONO, as usual.
Ok so we found finally a solution although I don't understand how that is possible because the chip you are using isn't supporting 768k according to the manufacturer, but good if it works!
:)Are you saying we can get 768k on Linux too, how?
But the ZIP file is corrupt, I tried to unpack it on Linux.
Please repack the file with 7-zip, not that other SW.
https://www.7-zip.org/
Hm, here is the Cosmos ADC thread as well and nobody complained about the file, pls try to download there https://www.audiosciencereview.com/forum/index.php?threads/e1da-cosmos-adc.27038/page-34
And google drive https://drive.google.com/file/d/1IHqKmcZ6f7NlnNiRyYGV0rmsPSnynyrT/view?usp=sharing
And google drive https://drive.google.com/file/d/1IHqKmcZ6f7NlnNiRyYGV0rmsPSnynyrT/view?usp=sharing
I didn't test that with Linux but should work. How I make CT7601CR work like CT7601PR I mentioned in ASR thread and here https://www.diyaudio.com/community/threads/2020-choice-of-usb-audio-bridge.351441/
Linux is capable of up to 1.536MHz sample rate. I have used 768kHz full duplex without any issues.
Users complained that Cosmos ADC L2R delays are not aligned. https://www.audiosciencereview.com/...ds/e1da-cosmos-adc.27038/page-37#post-1393575
If anyone cares I have a new FW to fix that issue.
If anyone cares I have a new FW to fix that issue.