udac-3, anyone have one?
Oct 14, 2013 at 1:59 PM Thread Starter Post #1 of 20

shaocaholica

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Seems like theres zero interest/discussion on this DAC but being new to all this it seems like a good package considering its async, bus powered, spdif + line out and has a built in amp.
 
Is there something horribly wrong with these guys?
 
Oct 14, 2013 at 3:50 PM Post #2 of 20
Output :Analog RCA output = 2Vrms
Dynamic Range:90 dB
S/N Ratio :98 dB
THD+N :0.05%

Digital Output :Coaxial RCA 75-Ohm
Headphone Output : 80 mW x 2 @ 16-Ohm
 
At the price it looks okay but you should note that it is 24 bit in name only, its actual resolution is a tad over 16 bits. NuForce got a reputation in the past for misleading specs both with items supplied to mags such as Stereophile and with items independently measured elsewhere so how reliable these figures are is an open question, but at $125 you cannot complain too much. If that distortion figure is on the line out it is a little high, unlikely to be audible though.
 
Oct 16, 2013 at 8:57 PM Post #3 of 20
I got an interesting reply from Nuforce support:
 
 
Date: Wed, Oct 16, 2013 at 3:03 AM
Subject: NuForce uDAC-3 power filtering
To: salesteam@nuforce.com

Does the NuForce uDAC-3 do any kind of power filtering on the USB 5V input?
Does it even matter considering its design and other components?

Thanks.
Dear Customer,

 
Dear Customer,
The uDac does not have any power filtering, and, is in fact susceptible to noise generated through USB.
 
Best Regards,
Nuforce Support

 
I'll give them credit for being honest.  I guess this might also constitute similar design goals at this price point but Schitt also commented in their sponsor forum thread that the lower priced but less featured Modi does have USB power filtering.
 
Oct 25, 2013 at 2:59 PM Post #4 of 20
I've got one in house. So far I'm liking it. I wish I had a udac2 to compare against. I used to have one, but sold it long ago.
 
Oct 27, 2013 at 1:35 PM Post #9 of 20
On top of that, does it show up as async?

 
I fail to see why you are so obsessed with the USB transfer mode. The actual audio parameters I included above show that it's audio performance is Ok but nothing exceptional, for example the dynamic range tells you that the DAC is not capable of accurately rendering a 16 bit signal without noise i.e it has less than 16 bits of resolution, in fact slightly under 15 bits to be precise, if that quoted figure is on the Line-out rather than on the headphone out (impossible to tell but likely as manufacturers will always post the best numbers they can and the analog headphone out will always be noisier !) it is frankly pretty bad though probably still capable of largely inaudible noise levels. If the measurement was taking using a 24 bit signal (again likely) then the noise figures are even more unimpressive. As for the benefits of Async transfer (1) nobody has done any actual controlled listening tests to determine whether the benefits are audible, (2) to date our best empirical research on jitter audibility indicates it is not a problem until it reaches very high levels which are very rare in competent kit and (3) the actual spec'd audio performance of the UDAC-3 renders the point entirely moot as its jitter contributes to the noise/distortion as defined.
 
Again for $125 what do you expect !
 
Oct 27, 2013 at 2:24 PM Post #10 of 20
   
I fail to see why you are so obsessed with the USB transfer mode.
 
Again for $125 what do you expect !

 
Because its an advertised feature?  Reguardless of if its audible or not you expect advertised features to be true and the history of nuforce here has not been flawless.  And AFAIK that feature, as inaudible as it is (I'm not arguing with you here!) is typically not available at this price/feature point.
 
 
Edit: I'm not quite sure what your actual point is.  Are you saying its an all around crummy DAC based on its published mfg specs?  Are you saying its pretty good for its price tier?  Or are you saying that most everything in its price tier is mostly sub par?
 
Oct 27, 2013 at 3:44 PM Post #11 of 20
  Hey Armaegis. Does your driver show up as 16bit?

 
I can play at 16/96, but haven't been able to get it to play any 24/96 files yet. However, I'm not sure if this is the device itself or my software (J.River v16) being weird, because I have trouble getting my HDP to play 24bit via usb as well, but it works via coax and optical. (using the usb-spdif bridge in my LPS)
 
 
edit: actually it does 24/96 using direct sound instead of wasapi
 
 
On top of that, does it show up as async?


I'm not sure how to check for async. The device name shows up as async, but that's not really indicative of anything.
 
Oct 27, 2013 at 3:57 PM Post #12 of 20
I'm not sure how to check for async. The device name shows up as async, but that's not really indicative of anything.


There's an old thread here about it:

http://www.head-fi.org/t/546092/confirming-whether-your-dac-is-asynchronous-as-claimed-or-not

I haven't read it all and I'm not sure if the methods discussed check whether async is actually being used vs just supported as all async capable interfaces should support fallback to adaptive but it's a place to start.
 
Oct 27, 2013 at 4:12 PM Post #13 of 20
Early impressions/notes... it's about on par from my memory of the uDAC-2. Decent sound, lots of gain (seems to do well without distorting at least), nice solid feel to the unit. Gain might be too high with iems, but I haven't tested those yet. With a Munitio Pro40 which is quite sensitive, there's barely much room for me to play on the pot
 
Compared with the HDP, well, the HDP is clearly a league above. Most noticeable is the uDAC-3 bass is looser. Almost feels like a bass boost but I don't think it is. It's a bit much with cans that are already flabby, but those lean in the bottom end don't mind it.
 
Coax output works just fine. I've been feeding that into my HDP without issue.
 
It is not immune to interference/noise from other usb devices. I tried playing music while transferring a movie on an external hard drive and music was constantly interrupted by clicks and pops.
 
With a modded T50rp (actually a transplanted driver) I can get to 3 o'clock on the pot before clipping. Volume is at the top end of comfortable listening for me at that point. I prefer to have it closer to 12 o'clock. With more sensitive cans I'm more around 10.
 
Oct 27, 2013 at 5:55 PM Post #14 of 20
   
Because its an advertised feature?  Reguardless of if its audible or not you expect advertised features to be true and the history of nuforce here has not been flawless.  And AFAIK that feature, as inaudible as it is (I'm not arguing with you here!) is typically not available at this price/feature point.
 
 
Edit: I'm not quite sure what your actual point is.  Are you saying its an all around crummy DAC based on its published mfg specs?  Are you saying its pretty good for its price tier?  Or are you saying that most everything in its price tier is mostly sub par?

 
It's measured performance is what it is Async or not, having async will not alter it's relatively high noise and distortion levels. Not that these are really a problem and the specs are probably accurate, as they are pretty ho hum, Nuforce does have access to measuring equipment (at least since the UDAC-2 business)  while I am not convinced that audible superiority is in any measure correlated to price it is rare to find anything from a smaller manufacturer at such a low price that will measure particularly well. I have a pair of $90 Fire Phoenix DAC-02 DAC/Headphone amps, their spec'd performance is superb
 
Dynamic Range 127dB
THD + N <0.002% (-94db)
SNR:> 110dB
Headphone output: MAX 14dBV (5V) 
- THD + N <0.003% (-90db)
 
do I believe this - well certainly not the SNR or Dynamic Range. The THD  maybe, there are certainly similarly priced DAC/Amps at that price that have measured about the same on harmonic distortion but generally SNRs on the headphone sections of such cheapies will be nearer 90db than 110db
 

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