E1DA Cosmos ADC

[onlyoneme]

Ridiculous prices...

 

[IVX]

Well, I've ordered a Cosmos ADC Grade B + the Hifime isolator now, so in a week or so we'll know if it works or not! Cost (including shipping for the isolator and 25 % VAT): €305, compared to €343 for the Cosmos ADCiso (Grade A?) only. (From Audiophonics.)

Ok, our Aliexpress has ADCiso grade B for $179.

 

[IVX]

IMO, APx500(BTW, it is possible to deceive APx500 with a fake HW key) today is useless even for 1/10 price if we have REW for free. I didn't see a difference between REW and AP2700 more than 1/3db, and usually, REW is more pessimistic.

 

[oal]

Thank you, pls try to compare DR(THD+N@1kHz -60dbfs A-weighted) tests, ADC vs ADC+Scaler(gain +20..+26db). ADC+Scaler outerforms APx555b for 7db in the DR test of Meizu HiFi DAC.

@IVX , To be honest, since I purchased Cosmos Scaler as an input buffer, I overlooked the gain feature that gives Scaler its name. I compared DR tests.

TOPPING D30Pro 1kHz (actually 999.76Hz as FFT length is 64k) -60dB to ADC. THD+N = -58.2dB, hence DR = 58.2 + 60 = 118.2dB.

Next, TOPPING D30Pro 1kHz -60dB to Scaler +25.527dB to ADC. THD+N = -71.4dB. DR = 71.4 + 60 = 131.4dB. If I am not mistaken in my measurements, it is awesome.

This is the comparison of ADC (Red) vs Scaler+ADC (Blue). Clearly, the noise fllor to the signal is lower with the Scaler.

 

[onlyoneme]

What was the reason to use 25.527 dB gain instead of 26.078?

 

[IVX]

oal, if you want to see the THD+N results A-weighted online, without extra calculations, please try AW calibration file for REW.
BTW, I see your DR is 134db(A) with Scaler, that's actually so-so for 4x DACs with 130db(A)* of each, where is 136db(A) expected.
* Cirrus competitors told me that Cirrus cheated with DR in their cs43131/198 i.e. DAC switches its gain at about -20dbfs level, and deceives DR test but 0dbfs exhibits the DAC has real DR about 118-120db(A).

 

[Music1969]

IVX is a genius.

I can't wait for little class D Cosmos power amps (??) to go with a Cosmos DAC (??)

 

[oal]

What was the reason to use 25.527 dB gain instead of 26.078?

No specific reason. I just chose one of +20..+26db gains to check the effect. Attached is the measurement of +26.078 gain.

 

[onlyoneme]

Ok, I thought I've missed something important about these gain levels, as I used +26 dB for -60 dB signal to measure my ADI-2 but results were not so spectacular.

 

[onlyoneme]

 

[onlyoneme]

 

[oal]

oal, if you want to see the THD+N results A-weighted online, without extra calculations, please try AW calibration file for REW.
BTW, I see your DR is 134db(A) with Scaler, that's actually so-so for 4x DACs with 130db(A)* of each, where is 136db(A) expected.
* Cirrus competitors told me that Cirrus cheated with DR in their cs43131/198 i.e. DAC switches its gain at about -20dbfs level, and deceives DR test but 0dbfs exhibits the DAC has real DR about 118-120db(A).

@IVX, Thank you for pointing this out. I used the AW calibration file this time. Is this A-weighted now?
I did not know about the the cheat by Cirrus.

and this is DAC 0dBFS. THD+N or real DR is about 118dB.

 

[oal]

Ok, I thought I've missed something important about these gain levels, as I used +26 dB for -60 dB signal to measure my ADI-2 but results were not so spectacular.

Perhaps my too-good-to-be-true results are due to the cheating.

 

[misureaudio]

I've just received a Cosmos ADC and a Cosmos APU. I tried the ADC with no problems, fine device indeed. Just one doubt. As You can see in the photo, I ordered a grade A but it looks like there is a B on the board. In different sites online, an A is on the board, for a grade A ADC.

Am I wrong?

Thank You in advance.

 

[IVX]

oal, you can see the same 134.3db(A) all is correct.

 

[IVX]

misureaudio, I testing Cosmos ADC twice, the first time I marking the PCB A; B; 0. Next, I test the unit after assembling, sometimes B marked unit becomes A.

 

[misureaudio]

misureaudio, I testing Cosmos ADC twice, the first time I marking the PCB A; B; 0. Next, I test the unit after assembling, sometimes B marked unit becomes A.

Thank You,
So mine should be considered grade A as I ordered at Audiophonics.

 

[BKDad]

Topping E50 DAC (unbalanced) > Cosmos Scaler > Cosmos ADC (non-iso version, but using external ADUM4166 based isolator)

Limited by the DAC. When I used a Cosmos APU in place of the Scaler, the 3rd harmonic measured the same as shown above. My E50 sample obviously isn't as good as the one Amir reviewed. A Topping D10s (unbalanced) DAC measured about the same distortion, but the noise is considerably worse.

Overall, not much to complain about with the Cosmos measurement tools!

 

[IVX]

BKDad, the problem is the uncalibrated DAC unit, not a big deal to reduce H3 for a single unit and send that to review. If the manufacturer did promise to calibrate each unit you have reason to be unhappy because you paid for the calibration extra money. If not, all is fine

 

[IVX]

Perhaps my too-good-to-be-true results are due to the cheating.

remember, the cheating isn't proved technical way and came from the competitor's side. What we can see is -130db(A) noise/130db(A) DR from a tiny and cheap DAC with ridiculously low power consumption for such a noise level(550nVrms(A)). On the other hand, THD+N is -115db at 0dbfs i.e. typical for such cheap and low-power DAC.