[HeadphoneAddict]

I'll be posting my impressions of the uDAC-2 here very soon.  I'll be referring to the original uDAC a lot in this thread as I compare them, and will build on what the differences are more than doing a big review from scratch.  So be sure to get familiar with the original uDAC.  I might start calling the original the uDAC-1 just to keep from confusing people.
 
http://www.head-fi.org/forum/thread/456945/first-impressions-nuforce-udac-usb-dac-amp-with-line-out-and-s-pdif-out
 
I'll tell you right now, the uDAC-2 is not a rehash of the original uDAC with just a higher bit rate that supports.  It's uses an improved attenuator, and the headphone amp has been improved as well.  I will update the first post or second post as I add more data below:
 
-----------------------------------------------
 
IMPRESSIONS:
 
 
The uDAC-2 uses the same 24/96 USB receiver chip as the HDP, and sends the data to the Sabre DAC to be decoded into analog.  The Sabre DAC has some jitter reduction algorithms inside, but the new receiver chip may also be responsible for some jitter reduction.  You can set the computer USB port to 24/96, but it can still decode 16/44 with the USB set to the max allowed.  But it does not up-sample the 16/44 music up to 24/96 with an SRC.
 
From the SABRE DAC the signal goes to the RCA line-out if no headphone is plugged in, and to the Coax S/PDIF out AT THE SAME TIME.  No longer do you have to turn off the uDAC at the volume knob to activate the S/PDIF output, as it is active all the time now.  
 
The RCA line out sounds noticeably better, and whatever flavor the older uDAC was giving the music is not there with the new USB receiver chip.  The RCA line-out (to my ears) now sounds identical to my Pico DAC-only when feeding my ALO Amphora, Woo WA6, or RSA Protector amps.  I honestly cannot tell which one I am listening to in A/B comparisons with the same music, regardless of bit rate.
 
The headphone amp section is improved, with better treble extension/presence and not too forward mids.  The frequency balance is now closer to the HDP than it is to the original uDAC, while retaining it's nice warm tone.  It's still slightly more forward sounding with a slightly smaller soundstage than the HDP.  The headphone amp with 24/96 music is noticeably more detailed than the same music with the original uDAC, and still slightly more detailed when using 16/44 CD rips with both devices.  While the earlier uDAC-2 prototype was being held back by the original uDAC headphone amp, the revised amp in the final production uDAC-2 takes a step above the original amp.
 
The Nuforce HDP is still more detailed and spacious than the uDAC-2, but the uDAC-2 clearly spans the gap between the two products and comes closer to the HDP than the original.  The $65 upgrade price is great, at 50% the cost of a new one.  The only downside I can think of is that uDAC-2 doesn't work with the iPad which wont support a USB DAC that goes higher than 48Khz (with camera connection kit).  But at these prices maybe someone could buy one of each?

 

[HeadphoneAddict]

Post #2 reserved:
 
8/3/10 Q&A:
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Quote:

I'm very curious to know if this uDAC-2 supports Windows volume control. The uDAC-1 did not,but the HDP does. You said that the uDAC-2 uses the same 24/96 USB receiver chip as the HDP so would it be safe to assume it does support volume control within Windows? This is important to me because when someone walks into my room and talks to me, I can press mute on my keyboard to stop the sound instantly without turning the physical volume knob especially if I am playing through my speakers, with the uDAC-1 I could not do this because the Windows volume control had no effect at all.

 
The Mac system volume is not affecting my music volume with the second prototype.  I have to use the uDAC volume knob to control it. 
 
The new volume knob will let me get at least 4-5 dB quieter with my most sensitive custom IEM before any channel imbalance sets in at the low end.  The old uDAC would start to become imbalanced at about 9:15 on the knob, now I can go as low as 8:30 on the volume knob before any imbalance starts.  This is quiet enough to fall asleep wearing my new Westone ES5 (which sound stunning with the uDAC-2 I might add).
 
Quote:

I want to know if you were comparing the two as DACs through another amplifier.

I was using the headphone amps when I said that about the detail and spaciousness.  But the HDP is also more detailed and spacious than my Pico DAC, and I have found that the uDAC RCA out sounds identical when feeding them into a bigger amp.  So, therefore the HDP RCA out should still be better than the uDAC-2 to some degree.  I have not been able to compare the line-outs yet.  It's still clear that the improved headphone amp is not as big of a bottleneck anymore.
 
Quote:

All the information so far only says the spdif output is active all the time and doesn't say if it can works as preamp (just like the RCA line out) or just bypass the build in dac and amp working as a usb-to-spdif converter (just like the original uDac when the volume is turned off).
 
This was all I was asking.

Digital out does not have volume attenuation.

 
Quote:

Keeping tabs on this thread, I wonder how their upgrade program will go for the current uDAC owners. I really like the forward mids of the uDAC for my headphones (Beyer DT 150, Alessandro MS1i), so i'm iffy about the change in sound sig for the uDAC 2.

 
Jason posted $65 in another thread.  I don't know of that is a special or normal upgrade price.
 
Quote:

 
RE jasonl's post in HPA's uDac-1 thread, advising:
 
"...For the upgrade price, we will offer special upgrade price for people who bought in July. We have to draw the line somewhere so if you bought on June 30, you have to pay the normal upgrade price..."
(link to post)
 
Is anyon - i.e. jasonl - able to advise what this special upgrade price for those who bought in July will be? I'm one of those customers, and although I initially expressed I probably won't upgrade, HPA's initial comments on the uDac-2 have got me interested.

Not sure myself yet.

 
Quote:

I'm a bit confused... What's the point of an S/PDIF passthrough? The whole purpose of a DAC is to convert from digital signals (like S/PDIF) to analog signals (carried by RCA), right? Is it so you can hook the S/PDIF to a home theater receiver and use the receiver's DAC when the uDac is off (like maybe for DTS/Dolby surround) and otherwise use the uDac's DAC when the volume is on? If that's the case, why not just use the computer's digital out?
 
Maybe I'm just rambling on about an inconsequential feature, but I'd like to know if I'm missing anything?

Yes, to feed digital into another DAC that doesn't include USB inputs, or whose USB inputs are limited to 16/48.  Not all computers have digital out.
 

8/12/10:

 
 
I have to say that the synergy of the uDAC-2 with my Westone ES5 is stunning.  With the ES5 it sounds very much like the DACport 24/96, but for 1/3 the price.  The detail, ambience, speed and immersion are top notch and I preferred the ES5 with the uDAC-2 more than my JH13Pro (gasp).

 

It's not that way with all phones or IEM, and with other phones these amps sound a bit different, but this is an IEM that I listened to a lot on vacation this past week.  I've been on vacation since last week and just got back in time for the Colorado head-fi meet, so I'm sorry that my impressions are delayed.  I need to compare all of my IEM and full-size phones again with the uDAC-2 vs DACport, and report back. 

 

8/14/10:

 
 
Quote:

Just curious how did uDAC-1 compare to Icon-1 in terms of just USB DAC and headphone amp?
 

The uDAC-1 RCA out had superior detail and soundstage to the DAC built into the Icon-1, but the headphone amp of the Icon-1 was slightly better with full size phones like HD600 or D2000.  So the best sound was from feeding the uDAC-1 into the Icon-1 analog input and listening through the Icon-1 headphone amp.  For my custom IEM like UE11Pro, JH13Pro or ES3X the uDAC-1 headphone amp sounded a little better than the Icon.  So far the uDAC-2 sounds better with all of these.

 

8/21/10:

 
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Quote:

Just a question about UDAC2 buying.
 
I am a new buyer and have never bought UDAC / UDAC2 (for the matter any DAC/HP Amplifier). Have already bought HiFiMan RE0.
 
Now I have the option to buy UDAC as well as UDAC2. The UDAC2 costs nearly 45% more.
 
My question is, is it worth paying that much premium for the UDAC2 when I do understand that only the receiver chip is new and that I'll be using my Netbook as a source.
 
Since I am not finding many UDAC2 reviews online, I am kind of confused.
 
Any help will be appreciated.

 
Quote:

I do not quite understand the technical jargon associated with DACs. However, I do not think I can extrapolate degree of perceived improvement over the original uDAC from such information. Nevertheless, I shall continue to look forward to this thread for incoming impressions. I am happy that the uDAC-2 has retained the form factor/enclosure of the original. I'd be happy to pick one up after a bit more feedback.
 

There are several improvements in the uDAC-2 over the original uDAC.  
 
(1) Improved USB receiver chip that can decode in full resolution your 24/96 high bit-rate music like what you might buy from www.hdtracks.com or www.linn.com
 
(2) This new USB receiver chip does a better job decoding the music even at 16/44 CD-quality bit-rates, so the RCA line-out now sounds very much like my more expensive Pico DAC-only (I couldn't tell the difference when switching between the two DACs).
 
(3) An improved headphone amplifier combined with upgraded DAC which results in a more naturally balanced and transparent sound out of the headphone amp - the sound is now less forward in the mids and not rolled off in the highs.  I have heard the prototype uDAC-2 which had upgraded DAC but with the original headphone amp, and the old headphone amp was holding back the performance of the upgraded DAC.  However, the upgraded headphone amp now allows one to hear and appreciate the improvements in the upgraded DAC.  
 
(4) An improved volume control, where I can listen to the music several decibels quieter than with the original uDAC before going low enough to get channel imbalance between L and R channels.  For people with very sensitive IEM, this allows a wider range of volumes that you can listen to the music.
 
 

 

[size=large]8/28/10 Update:  [/size]

 
[size=large]I have been listening to my new Westone ES5 custom IEM a lot lately, and I'm pretty sure now that I prefer the uDAC-2 with them slightly more than my 24/96 DACport.  The uDAC-2 sounds slightly warmer and fuller or more complete than the DACport when driving the ES5, with a wonderful sense of transparency and space.  The ES5's performance via uDAC-2 is more engaging and involving than via DACport, or DACport/Pico DAC feeding the balanced Protector amp.  I know, I wasn't expecting that either.  The ES5 sound great with the other gear, but I just find the sound signature when paired with the uDAC-2 to be preferable.  The ALO Amphora is even better with the ES5, and it sounds pretty much the same whether I feed the Amphora from the uDAC-2 or with the Pico DAC-only.[/size]
 
[size=large]Right now the uDAC-2 is connected to my Macbook Pro and feeding my Audioengine A2 speakers, and I can simply plug in the ES5 to shut off the speakers and listen via IEM.  Before when I was using the DACport I'd have to unplug the speakers from the headphone-out in order to connect my IEM, and if I forgot to turn down the speaker volume them I'd get blasted with noise as I pulled the plug.  The original uDAC RCA line-out didn't sound this good with the A2 speakers and I tended to use the DACport more, but now the uDAC-2 RCA out is almost as good driving the A2 as the DACport has been.[/size]
 

9/2/10 update:

 
Most of my impressions of the DBA-02 written in LFF's DBA review thread were done with me using the uDAC-2 as source and amp.  It was a very nice pairing of gear with good synergy.  http://www.head-fi.org/forum/thread/484569/review-fischer-audio-s-dba-02/1155#post_6813070.  
 

9/17/10 update:

 
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Quote:

Originally Posted by replytoken /img/forum/go_quote.gif

Larry,
 
Thanks for the great review and follow-up posts.  I am doing a bit of system rearranging, and now find myself looking for a DAC to do triple duty.  The wife and I are setting up an office in a spare bedroom, and I thought that a desktop system with very small speakers and a headphone jack would be nice for my HD-600's or Ety ER-4's.  One option may involve moving a tube headphone amp/preamp into the office.  But, I may just take the plunge into PC audio and use a DAC with my laptop or netbook to keep it simple.  The third use for the DAC would be to hook my computer up to my main system when I am in the living room.  I initially started looking at DACs up to $500, but that led to $600 and then $1,000.  I could spend this much, but as this is my first DAC and I am just getting my feet wet with PC audio, I thought the uDAC-2 might allow me to see how much I will actually use my PC as a source at a reasonably affordable price.  
 
But, I have two concerns.  
 
(1a) Can the uDAC-2 drive the HD-600's, and (1b) is it up to the task of feeding a two channel system with a tube preamp and a solid state amp?  I know the latter questions will depend on the computer and the source files, but am I asking too much from an affordable DAC?  
 
(2) Also, I was concerned about having the volume pot in the path of the RCA outs when feeding my preamp, but it appears that any DAC with a true line out is gong to be much more expensive.  Any thoughts?
 
--Ken

(1a) The uDAC-2 can drive the HD600 to decent levels and sound good, but a desktop amp will bring them closer to their full potential.  If you like to play very loud, you'll want something more powerful to feed the uDAC-2 into.  
 
(1b) It does a nice job feeding a larger amp like my Woo WA6 or eXStatA from the RCA out, and should do well with your two channel rig mentioned above.  The RCA out seems to keep up just fine with my other $200-400 mid-fi DAC's like iBasso D4/D10, HR Micro DAC and Pico DAC-only.  The uDAC-2 is more detailed and spacious than any of my DAC's using the PCM2702E Japan or lesser chips.  Plus, if you have a nicer DAC that doesn't do USB, like in a home theater receiver, it does a nice job of supplying S/PDIF coax digital into your HTR from your computer.
 
(2) Even if the volume control was holding the uDAC-2 back, it still somehow keeps up with the other more costly DACs above that don't have variable line-out.  In the $50-$150 price range you could get a hotaudio or Headstage USB DAC with no volume control, but I haven't heard them and can't compare.  The Super Pro DAC707 via optical and with an upgraded PSU is at least as good as the uDAC-2, but the USB performance is not quite as good as via optical, and with the stock PSU it's still at a similar price as uDAC-2.  There are many other DAC's in that price range you could consider, I just haven't tried many of them. 
 
 
 

10/23/10 update:

 
In previous posts I mentioned that I could not control my uDAC-2 volume with the Mac's OSX system volume, but in fact it was because my Prototype uDAC-2 from June was going bad.  A replacement has fixed the issue, and I can use the Mac OSX volume control to adjust the volume playing through the uDAC-2, as you can with the HDP.  
 
And, the original prototype from May still works as it should, it's just that the May version still has the original headphone amp from the uDAC-1 and I didn't want to use that one as long as the second prototype was still working.  After the replacement I pulled out the first one for testing, and you guys were right about the volume control working since the beginning.
 
11/30/11 Update:  post #820
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uDAC-2 SE Impressions:
 
I'm finding the uDAC-2 SE is a bit more open and transparent sounding, and a little more refined sounding than my original uDAC-2.  This might be a result of better jitter reduction or extra micro-detail, I can't say.  The differences are hnot huge, but I find the overall experience a little more immersive than the original uDAC-2.  My SE has an excellent volume pot, with almost no extreme low volume channel imbalance with sensitive IEM.  It is silent with my IEM, and can play quiet enough with my ES5 to sleep while listening to soft music.  
 
It works great out of the box with Mac OSX 10.6.8, and doesn't need any assynch drivers to be installed.  However, it is a little more finicky when trying to run it on my Macbook at the same time as a powered 8-port hub with 5 or 6 other 24 bit USB DAC's (original uDAC-2, Audioengine D1, HDP, DACmini, DACport, Apogee mini-DAC).  Sometimes if I plug in one too many 24 bit DACs then I get static in the music (same with my original uDAC-2 and HDP).  The other DACs listed seem to be immune to this. Someday I'll try another hub to see if that is my problem.  Fortunately I usually only have the DACmini, Apogee, and uDAC-2 SE plugged into the Macbook at the same time, and have no issues.  I leave the D1 plugged into the family iMAC where we have more room for a bigger DAC/amp but no extra outlets to plug one into the wall. 
 
In comparison to the $399 DACport, the uDAC-2 SE is a little more intimate and forward sounding (closer to the performers, smaller venue), but the tonality is now almost a match.  However, power wise it seems to have a little easier time driving my HE-5 LE right now than the DACport which do better with my HE-500.  The desktop amps still have more power, but the uDAC-2 (regular and SE) has plenty for me (and slightly more than the D1).  The SE is probably closer to the Audioengine D1 in presentation than it is to the DACport, but the D1 can't play quiet enough with my sensitive IEM for sleeping with music.  And with the D1 I can hear some quiet line noise in the background in between songs with my most sensitive IEM like ES3X and ES5 (that I can't hear with headphones).  The system volume doesn't affect the D1, but the uDAC-2 can be controlled that way, which is nice occasionally to have.
 
For those with full size phones and no IEM, the decision becomes more of do you want a smaller size, with coax S/PDIF out and a little more power, or do you need optical input instead of the coax out.  Sound-wise you wont find a lot to complain about with either.  And, as before, the line out sound quality with any of these is excellent and rivals that of my more expensive Pico DAC (in detail and sound signature).
 
 

 

[vkvedam]

Interesting, looking forward to your in-depth impressions.

 

[kite7]

I'm very curious to know if this uDAC-2 supports Windows volume control. The uDAC-1 did not,but the HDP does. You said that the uDAC-2 uses the same 24/96 USB receiver chip as the HDP so would it be safe to assume it does support volume control within Windows? This is important to me because when someone walks into my room and talks to me, I can press mute on my keyboard to stop the sound instantly without turning the physical volume knob especially if I am playing through my speakers, with the uDAC-1 I could not do this because the Windows volume control had no effect at all.

 

[Ypoknons]

Let's see how much better that volume control is

 

[vunjick1]

May i know is the latest version uDAC-2 supporting the iPad (via camera connection kit) as the previous uDAC did? anyone actually did a test to confirm that please? i'm very soon to getting the uDAC-2 for my iPad, if it really not working then will be a waste. Thanks!

 

[Lil' Knight]

*facepalm*
Right in the first post ...

 

[Farnsworth]

This should answer your question.
 
Quote:

 

Originally Posted by HeadphoneAddict /img/forum/go_quote.gif
 
The only downside I can think of is that uDAC-2 doesn't work with the iPad which wont support a USB DAC that goes higher than 48Khz (with camera connection kit).  But at these prices maybe someone could buy one of each?

 

 

[grokit]

Lol

 

[kite7]

 
Quote:

 
The Nuforce HDP is still more detailed and spacious than the uDAC-2, but the uDAC-2 clearly spans the gap between the two products and comes closer to the HDP than the original. 

I want to know if you were comparing the two as DACs through another amplifier.

 

[miyinan]

 
Quote:

 
From the SABRE DAC the signal goes to the RCA line-out if no headphone is plugged in, and to the Coax S/PDIF out AT THE SAME TIME.  No longer do you have to turn off the uDAC at the volume knob to activate the S/PDIF output, as it is active all the time now.  

Does this mean that I can now use the uDac-2 as a dedicated Dac using the s/pdif output to an amp? If I am not mistaken, the original uDac was only a usb-to-s/pdif converter when turning it off and using the s/pdif out, which means the built-in dac got bypassed.
 
If the uDac-2 can now preamp out through the s/pdif output, the $65 upgrade is definitely worthwhile.

 

[.Sup]

Thanks for your impressions Larry

 

[Yikes]

Does anyone read anything?

The uDAC has stereo RCA line outs, plug those into an amp and wa-la! The amp will then drive whatever it is that you normally drive with it. The uDAC also had a SPDIF output that was activated when you turned the volume to the off position.

The new uDAC-2 has pretty much the same basic feature set (with changes in details - like the SPDIF is now active regardless of the volume controls position). It appears that the changes are primarily performance oriented (24/96 Khz via SPDIF, better volume pot, better headphone amp (although how it's better remains at this point a mystery). All this info is either in Larry's post or Nuforces announcement, if you lazy members would bother to actually read the thread.

 

[KnightK]

Will be looking forward to see if upgrading is worth it. Thanks for the awesome reviews, HPA, and keep 'em coming

.

 

[miyinan]

 
Quote:

Does anyone read anything?

The uDAC has stereo RCA line outs, plug those into an amp and wa-la! The amp will then drive whatever it is that you normally drive with it. The uDAC also had a SPDIF output that was activated when you turned the volume to the off position.

The new uDAC-2 has pretty much the same basic feature set (with changes in details - like the SPDIF is now active regardless of the volume controls position). It appears that the changes are primarily performance oriented (24/96 Khz via SPDIF, better volume pot, better headphone amp (although how it's better remains at this point a mystery). All this info is either in Larry's post or Nuforces announcement, if you lazy members would bother to actually read the thread.

All the information so far only says the spdif output is active all the time and doesn't say if it can works as preamp (just like the RCA line out) or just bypass the build in dac and amp working as a usb-to-spdif converter (just like the original uDac when the volume is turned off).
 
This was all I was asking.