DAC discussions

[RPI4 Rambler]

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Thanks Tim. 
Off topic. .................................. snip ............................... Forget the usual HATS though (Allo, Justboom, HifiBerry etc) and generally any DAC equipped with TI's 51xx DAC chip. .................................. snip .................................. For a HAT, I can strongly recommend (UGeek) Aoide's DAC II HAT though one would need customized versions of Moode or Volumio (no kernel support). You will need to get these custom Moode and Volumio versions from Github or Sourceforge ......... snip ............

Yesterday, 03:55 PM --> Now, even more off topic!

Nice stuff for sure, the USBridge SIG alone is $ 240. The Shanti another $ 160..... snip ...... The Aoide Hat retails for around $ 50.


Cheers,
marco

Aoide DAC HAT... not a hit with AudioscienceReview folk: https://www.audiosciencereview.com/forum...-hat.8662/

Of course they have not reached the sofistication of the Power Bank testing employed by Archimango (no expenses spared) but they are striving...

All the above is 'off topic', please accept my apologies.

Ouch, so it would seem. Ok, the OT continues. Time for me to start looking for my own measuring gear. I wonder which drivers Amir used. The HAT is specifically designed for (a modified version of Volumio) but it should work with generic drivers, which it doesn't (I seem to recall a driver named Audiophonics ES9018K2M or some such). On Github there's an installation routine to make it work on other systems, but even then it will not even run on a stock Volumio (or Moode) system with manually installed drivers. BTW: on Amir's site you can also find reviews of "USB cleaners", "Power Cleaners", "Jitter Killers". Those reviews reveal the truth as does stuff on Archimago's blog. 

It will not fit Ropieee and the combination with the Aoide; it really is designed for Volumio, so there's more going on than just the drivers.  The measurements are so far removed from the DAC chip's capabilities, with THD+Noise of 18% (!) it must be audible. Which it isn't in the right setup. So while my "defense" may sound lame, I really think the cause lies in the system + driver setup, or he had a broken sample. FWIW: these are the official specifications:
Line out:

Frequency Response: 20Hz ~ 20KHz +/- 0.1dB

S / N: -119dB +/- 1dB

THD + N: -120dB

DNR: 127dB

 

Headphone out:

Frequency Response: 20Hz ~ 20KHz +/- 0.1dB

THD + N: 0.0021% (16ohm load)

Output level: 138mW (+ 4dB gain)

SNR: 93dB

PSSRR:> 100dB
CMRR: 69dB

Which is in line with the DAC chip's specs. A designer must work very hard to yield the measurements Amir got. With these results you'll hear the noise through speakers or headphone when idling. I can assure you it doesn't. Moreover, with Amir's measurements, it is easily outperformed by the RPI's embedded DAC.


Cheers,
marco