- Joined
- Jan 30, 2011
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PROS : Size, build quality, versatility, sound quality, DSD support, value
CONS : Micro USB plug doesn’t quite seat correctly, couple of quirks getting bit-perfect working
INTRODUCTION
My audio chain has been very stable of late, my last addition being my HD700s, and before that my Studio V3 Anniversary (DAP) and Dunu DN-1000s. With the addition of the Studio V3, I had pretty much solved all of my remaining audio requirements – good desktop system, good DAP for portable, good headphones – what more could I need?
Then out of the blue, Wolfgang from NuForce contacted me to inquire if I’d be interested in having a listen to their uDac-3. Having never heard any NuForce gear before, I was immediately keen. Even more so when I realised the size and portability of the unit. So, as I was traveling to the US last month, we arranged a suitable address for me to pick up the uDac-3, and for the last month I’ve been putting it through its paces.
DISCLAIMER
I was provided the uDac-3 as a review sample. There is no financial incentive from NuForce in writing this review. I am in no way affiliated with NuForce - and this review is my honest opinion of the uDac-3. I would like to thank Wolfgang for making this opportunity available. When approached, I did offer to return the unit if they so desired. The unit they sent me was “B-Stock” but cosmetically or sonically I’ve noticed no flaws.
PREAMBLE - 'ABOUT ME'.
(This is to give any readers a baseline for interpreting the review).
I'm a 47 year old music lover. I don't say audiophile - just love my music. Over the last few years, I have slowly changed from cheaper listening set-ups to my current mid-fi set-up. I vary my listening from portable (iDevices and Studio V3) to my desk-top's set-up (PC > coax > NFB-12 > LD MKIV > HP). My main headphones at the time of writing are the Senn HD700 and HD600, Beyer DT880, Dunu DN1000 & HAS BA-100 IEMs. A full list of headphones I’ve owned (past and present) can be found in my profile.
I have very eclectic music tastes listening to a variety from classical/opera and jazz to grunge and hard-rock. I listen to a lot of blues, jazz, indie, classic rock, and alternative rock. I am particularly fond of female vocals. I tend to like audio chains that are relatively neutral/balanced - with a slight emphasis on the mid-range. I am neither a bass or treble head (you could argue that I do like clarity though). Current amps = NFB12 and LD MKIV. I also formerly owned several portable amps - the most notable being an Arrow 4G and GoVibe PortaTube. I have also in the past owned Fiio’s E7, E9 and E11.
I have extensively tested myself (abx) and I find aac256 or higher completely transparent. For my portable listening – it has been my preferred format (space vs quality). For home listening, I use my archived FLAC copies, as space is no issue. All of my music is legally purchased (mostly CD – the rest FLAC purchased on-line).
I tend to be sceptical about audiophile ‘claims’, don’t generally believe in burn-in, and would rather test myself blind on perceived differences. I am not a ‘golden eared listener’
SO WHAT IS THE UDAC-3?
The uDac-3 is an extremely small (a little larger than a zippo lighter) high resolution USB powered DAC and amp that is capable of 24/96 decoding, as well as DSD (it does DSD by converting to PCM rather than natively). It also has digital out (so can be used as a USB-coax S/PDIF bridge) and RCA dual analog out (can be used as a DAC to another amp).
PACKAGING AND ACCESSORIES
The unit I was sent arrived in a well-built cardboard retail box with a clear plastic inner mould to display the diminutive uDac-3. The front of the carton lists some of the main points of the unit (eg driverless async mode, works with PC and MAC, DSD playback support). The rear of the carton lists in more detail both features, and also specifications.
Also included in the box is a micro-B USB cable, warranty card, manual, and foldout brochure listing some of their other products. I actually thought the foldout brochure was a nice touch (on the cover it says “May We Recommend”) – I found it more interesting than the manual to tell you the truth. The one thing missing from the manual is instructions on needing drivers for DSD playback – but thankfully these were easy to find on their website.
Note to NuForce (for consideration) - the two accessories I would have loved to have seen with the unit would be a soft cloth carry case – doesn’t need to be expensive, but would protect the unit during transport. The second thing would have been a mini-stand so that it could be easily mounted vertically (if someone wanted to use it in a more permanent setting).
TECHNICAL SPECIFICATIONS
The table below lists most of the relevant specifications.
I have asked Wolgang about the impedance rating for the headphone out – he has asked his engineers, but at this stage I am awaiting a definitive reply. I didn’t notice any really glaring frequency issues with any of my headphones (including the 10 ohm DN-1000s), and NuForce recommend using headphones from 16 – 300 ohm. I’m going to take an educated guess – and with a damping factor of 1:8 – estimate that the headphone out is possibly around 2 ohms impedance.
UPDATE - got a reply from Wolfgang at NuForce - the actual impedance on the headphone out is 5.3 ohms. Higher than I expected.
BUILD / DESIGN
The build quality for this little unit is extremely good. The unit consists of a one piece milled body, and matching front and rear plates. On my unit, everything lines up nicely with only a very small lip between the body and end plates. Screws are nicely even and countersunk correctly. Edges are smooth with no sharp corners. The volume pot is an excellent size (not too small), and rolls smoothly – yet has enough resistance to avoid accidentally bumping. It doubles as an on-off switch (rotating fully to the left turns the unit off). The front headphone socket is 3.5mm and the fit with everything I’ve tried has been snug and firm. It has no problem with 3 pole plugs (ie headphone cables with inbuilt microphone) – and does not suffer for cut-out.
At the rear of the unit are 3 gold plated RCA ports – left and right for outputting to another amp, and a coaxial digital S/PDIF port for using the unit as an USB to coaxial converter. The plug sockets are placed nicely apart – and I had no problem with all 3 plugs fitted at once.
The USB port at the rear is micro-B and fits the supplied plug firmly. It also had no issues with 2 other micro USB plugs I had on hand. My only criticism here was that while the USB plug fits firmly, it does not seat fully. I know this is nit-picking, as it doesn’t affect functionality – but even so, having the plug fully seated in the socket would be better long-term for both the unit and the cable.
There is a single LED on the front panel which glows blue when the unit is plugged, and changes to blue-white when engaged (signal being fed).
The NuForce name is nicely engraved both sides of the main housing – so you can orient it whichever way you prefer, and still see the etching (a nice touch).
FEATURES / FORMATS
The uDac3 has a discrete asynchronous USB audio receiver and D/A converter stage, and does have DSD decoding ability. DSD decoding is converted to PCM rather than natively – but I did test this (downloaded some free test tracks from Blue Coast Records to check this), and it worked admirably. It also sounded extremely good – the DSD files were mastered beautifully.
The unit can function as an USB to coaxial S/PDIF bridge – and also tested and confirmed that this works wonderfully as well. The RCA L/R analogue ports allow output to another amp, and I tested this with my LD MKIV tube amp (more on that later). These ports operate a line-out at 2Vrms.
The uDac-3 is fully USB powered – and I had no problems with my netbook, laptop, and two desk-tops. Unfortunately my iPad 2 did not have enough power to run it (via the cck).
The uDac-3 can natively decode bit-rates up to 24 bit, and samples at 32 kHz, 44.1 kHz, 48 kHz, 88.2 kHz, and 96 kHz.
PERFORMANCE
The u-Dac3 was essentially plug and play on all the systems I used – being recognised as “SPDIF Interface 2-uDac-3 Async”. Playback defaulted to 16/44.1 – and interestingly 24 bit didn’t show in the windows mixer – but 32 bit did. I tend to have my system running natively at up to 24/96 – so I changed the settings to 32/96 and after that had no issues. In Foobar’s preferences WASAPI playback didn’t seem to be a workable option – but ASIO showed up as an option – and worked admirably.
In order to have DSD support (Foobar), you need to download NuForce’s own driver plus they also supply a Foobar plugin package and full instructions. This isn’t mentioned in the manuals (but should be). The drivers are easily found at https://nuforce.com/index.php?option=com_k2&view=item&layout=item&id=680&Itemid=2751.
The downloadable NuForce driver can also be used for normal playback.
AS A DAC
The first thing I did for critical testing was to set-up the u-Dac-3 feeding my LD MKIV (full OTL tube), and also set-up my NFB-12 the same way. I then volume matched both amps to within 0.5 dB using an SPL meter and a 1kHz tone. I then A/B’d both units (sighted) using a switching box with dual inputs and single output. The uDac-3 showed limitations of its diminutive size, and was a very pleasurable listening experience with a variety of test music from Dire Straits / Steely Dan to Tchaikovsky and Vivaldi. Using the LD MKIV for both sources – there was very little if any difference at all – which is a testament to the uDac-3.
At this point I should mention that the volume pot on the uDac-3 does control gain on the RCA outputs (I understand this range is about 6 bB gain). I generally ran it at around 12-1pm on the pot, and this provided more than ample output for the Little Dot.
The uDac-3 was surprisingly detailed for such a small footprint – and very similar to the output from the NFB-12. It has a nice linear bottom end, with a full mid-range, and slightly mellow (yet still detailed) upper end. If anything – it just gets out of the way and lets the music shine.
Main headphones used for this testing were DT880 and HD600.
AS A DAC/AMP COMBO
For testing this time, I compared directly to NFB-12, and once again volume matched carefully. Switching was a little more cumbersome this time, as I had to plug and replug. This time I mainly used my HD700, as well as my DN-1000 and BA-100 IEMs.
When testing the IEMs, I had to take the volume pot a lot lower than with the full sized headphones – but noticed no channel imbalance in doing so. Both IEMs performed admirably with no signs of hiss (I wasn’t sure what to expect with the 10 ohm Dunus). As mentioned earlier, I have asked Wolfgang about the impedance of the headphone-out, as I suspect it may not be ideally suited to the Dunu’s – which exhibited a slightly more flabby bottom end than they normally do from other sources. I suspect that some of this could be from a slightly mismatched damping factor. The BA-100s (at 36 ohm) were fantastic, as were the HD700.
My overall impression was that the uDac-3 is relatively neutral overall, with a slightly warmish tilt to the bottom end and mid-range. It’s subtle – but very pleasant. The detail levels remained extremely good overall – and whilst the NFB-12 may have just topped it overall with slightly more transparency, once again the comparison was extremely close between the two.
On power – with the BA-100s, the pot was at around 9 o’clock (switch off occurs between 7 and 8). The HD700s were comfortable at anywhere from 10-12 position. My 250 ohm DT880s needed about 11-1pm on the pot. The volume can crank all the way to 5pm – but you’d deafen yourself before attempting this with the headphones I have. So there is plenty of good clean power available – and at no time did I encounter any hint of clipping or distortion.
CONCLUSION
Looking at the uDac-3’s small size and simple design, you’d be forgiven for thinking that this is more toy than serious sonic device. But looks can be very deceiving, and I’m pleased to be able to report that the uDac-3 is a seriously good DAC/amp combo at its price point (USD 125.00 MSRP) – especially if you’re cramped for space, or looking for an easily transportable device. It was a welcome addition to my recent 2 week global business trip – especially as I had just picked up the HD700s whilst in New York, and this gave me the perfect platform to enjoy them.
I now use the uDac-3 almost every day at work (paired with my DT880). It is a revealing yet slightly warm and friendly signature that just does its job and lets the music shine.
The real litmus test is would I recommend this amp to my family and friends – and to that I would say yes with no hesitation.
I did offer to return the unit to NuForce after I’d finished the review, however - because of the shipping cost and the fact that it was B-stock, Wolfgang invited me to keep the unit and I am very grateful for their generosity. If they hadn’t, I would have bought one myself – my office would simply not have been the same without it!
Wolfgang and NuForce – thanks for the opportunity. I shall be keeping a very close eye on your progress in future, and I have no doubt that your higher end products will be on my radar at some stage in the future.
CONS : Micro USB plug doesn’t quite seat correctly, couple of quirks getting bit-perfect working
uDac-3 From NuForce (front panel) | uDac-3 From NuForce (rear panel) |
INTRODUCTION
My audio chain has been very stable of late, my last addition being my HD700s, and before that my Studio V3 Anniversary (DAP) and Dunu DN-1000s. With the addition of the Studio V3, I had pretty much solved all of my remaining audio requirements – good desktop system, good DAP for portable, good headphones – what more could I need?
Then out of the blue, Wolfgang from NuForce contacted me to inquire if I’d be interested in having a listen to their uDac-3. Having never heard any NuForce gear before, I was immediately keen. Even more so when I realised the size and portability of the unit. So, as I was traveling to the US last month, we arranged a suitable address for me to pick up the uDac-3, and for the last month I’ve been putting it through its paces.
DISCLAIMER
I was provided the uDac-3 as a review sample. There is no financial incentive from NuForce in writing this review. I am in no way affiliated with NuForce - and this review is my honest opinion of the uDac-3. I would like to thank Wolfgang for making this opportunity available. When approached, I did offer to return the unit if they so desired. The unit they sent me was “B-Stock” but cosmetically or sonically I’ve noticed no flaws.
PREAMBLE - 'ABOUT ME'.
(This is to give any readers a baseline for interpreting the review).
I'm a 47 year old music lover. I don't say audiophile - just love my music. Over the last few years, I have slowly changed from cheaper listening set-ups to my current mid-fi set-up. I vary my listening from portable (iDevices and Studio V3) to my desk-top's set-up (PC > coax > NFB-12 > LD MKIV > HP). My main headphones at the time of writing are the Senn HD700 and HD600, Beyer DT880, Dunu DN1000 & HAS BA-100 IEMs. A full list of headphones I’ve owned (past and present) can be found in my profile.
I have very eclectic music tastes listening to a variety from classical/opera and jazz to grunge and hard-rock. I listen to a lot of blues, jazz, indie, classic rock, and alternative rock. I am particularly fond of female vocals. I tend to like audio chains that are relatively neutral/balanced - with a slight emphasis on the mid-range. I am neither a bass or treble head (you could argue that I do like clarity though). Current amps = NFB12 and LD MKIV. I also formerly owned several portable amps - the most notable being an Arrow 4G and GoVibe PortaTube. I have also in the past owned Fiio’s E7, E9 and E11.
I have extensively tested myself (abx) and I find aac256 or higher completely transparent. For my portable listening – it has been my preferred format (space vs quality). For home listening, I use my archived FLAC copies, as space is no issue. All of my music is legally purchased (mostly CD – the rest FLAC purchased on-line).
I tend to be sceptical about audiophile ‘claims’, don’t generally believe in burn-in, and would rather test myself blind on perceived differences. I am not a ‘golden eared listener’
SO WHAT IS THE UDAC-3?
The uDac-3 is an extremely small (a little larger than a zippo lighter) high resolution USB powered DAC and amp that is capable of 24/96 decoding, as well as DSD (it does DSD by converting to PCM rather than natively). It also has digital out (so can be used as a USB-coax S/PDIF bridge) and RCA dual analog out (can be used as a DAC to another amp).
uDac-3 compared to my iPhone 4 | uDac-3 beside my Seiko |
PACKAGING AND ACCESSORIES
The unit I was sent arrived in a well-built cardboard retail box with a clear plastic inner mould to display the diminutive uDac-3. The front of the carton lists some of the main points of the unit (eg driverless async mode, works with PC and MAC, DSD playback support). The rear of the carton lists in more detail both features, and also specifications.
Retail box front | Retail box rear |
Also included in the box is a micro-B USB cable, warranty card, manual, and foldout brochure listing some of their other products. I actually thought the foldout brochure was a nice touch (on the cover it says “May We Recommend”) – I found it more interesting than the manual to tell you the truth. The one thing missing from the manual is instructions on needing drivers for DSD playback – but thankfully these were easy to find on their website.
All of the accessories | Micro-B USB cable |
Foldout brochure | Foldout brochure |
Note to NuForce (for consideration) - the two accessories I would have loved to have seen with the unit would be a soft cloth carry case – doesn’t need to be expensive, but would protect the unit during transport. The second thing would have been a mini-stand so that it could be easily mounted vertically (if someone wanted to use it in a more permanent setting).
TECHNICAL SPECIFICATIONS
The table below lists most of the relevant specifications.
| Input : | USB 1.1, 2.0 compatible |
| Native Bit Rate : | 32, 44.1, 48, 88.2, 96 kHz, 24-bit |
| Output (line out) : | Analog RCA output = 2Vrms |
| Output Impedance (headphone out) | 5.3 ohms |
| 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 |
| Power : | USB Bus Powered, 80 mA/5V |
| Dimensions : | 68 x 38 x 21 mm |
I have asked Wolgang about the impedance rating for the headphone out – he has asked his engineers, but at this stage I am awaiting a definitive reply. I didn’t notice any really glaring frequency issues with any of my headphones (including the 10 ohm DN-1000s), and NuForce recommend using headphones from 16 – 300 ohm. I’m going to take an educated guess – and with a damping factor of 1:8 – estimate that the headphone out is possibly around 2 ohms impedance.
UPDATE - got a reply from Wolfgang at NuForce - the actual impedance on the headphone out is 5.3 ohms. Higher than I expected.
BUILD / DESIGN
The build quality for this little unit is extremely good. The unit consists of a one piece milled body, and matching front and rear plates. On my unit, everything lines up nicely with only a very small lip between the body and end plates. Screws are nicely even and countersunk correctly. Edges are smooth with no sharp corners. The volume pot is an excellent size (not too small), and rolls smoothly – yet has enough resistance to avoid accidentally bumping. It doubles as an on-off switch (rotating fully to the left turns the unit off). The front headphone socket is 3.5mm and the fit with everything I’ve tried has been snug and firm. It has no problem with 3 pole plugs (ie headphone cables with inbuilt microphone) – and does not suffer for cut-out.
uDac-3 front panel | uDac-3 rear panel |
At the rear of the unit are 3 gold plated RCA ports – left and right for outputting to another amp, and a coaxial digital S/PDIF port for using the unit as an USB to coaxial converter. The plug sockets are placed nicely apart – and I had no problem with all 3 plugs fitted at once.
USB plugged into rear - the gap is one of the rare faults |
The USB port at the rear is micro-B and fits the supplied plug firmly. It also had no issues with 2 other micro USB plugs I had on hand. My only criticism here was that while the USB plug fits firmly, it does not seat fully. I know this is nit-picking, as it doesn’t affect functionality – but even so, having the plug fully seated in the socket would be better long-term for both the unit and the cable.
Great build quality - blue LED when no signal | LED changing to blue/white when signal present |
There is a single LED on the front panel which glows blue when the unit is plugged, and changes to blue-white when engaged (signal being fed).
The NuForce name is nicely engraved both sides of the main housing – so you can orient it whichever way you prefer, and still see the etching (a nice touch).
FEATURES / FORMATS
The uDac3 has a discrete asynchronous USB audio receiver and D/A converter stage, and does have DSD decoding ability. DSD decoding is converted to PCM rather than natively – but I did test this (downloaded some free test tracks from Blue Coast Records to check this), and it worked admirably. It also sounded extremely good – the DSD files were mastered beautifully.
The unit can function as an USB to coaxial S/PDIF bridge – and also tested and confirmed that this works wonderfully as well. The RCA L/R analogue ports allow output to another amp, and I tested this with my LD MKIV tube amp (more on that later). These ports operate a line-out at 2Vrms.
The uDac-3 is fully USB powered – and I had no problems with my netbook, laptop, and two desk-tops. Unfortunately my iPad 2 did not have enough power to run it (via the cck).
The uDac-3 can natively decode bit-rates up to 24 bit, and samples at 32 kHz, 44.1 kHz, 48 kHz, 88.2 kHz, and 96 kHz.
PERFORMANCE
Test gear - the uDac-3 tiny amongst them all |
The u-Dac3 was essentially plug and play on all the systems I used – being recognised as “SPDIF Interface 2-uDac-3 Async”. Playback defaulted to 16/44.1 – and interestingly 24 bit didn’t show in the windows mixer – but 32 bit did. I tend to have my system running natively at up to 24/96 – so I changed the settings to 32/96 and after that had no issues. In Foobar’s preferences WASAPI playback didn’t seem to be a workable option – but ASIO showed up as an option – and worked admirably.
In order to have DSD support (Foobar), you need to download NuForce’s own driver plus they also supply a Foobar plugin package and full instructions. This isn’t mentioned in the manuals (but should be). The drivers are easily found at https://nuforce.com/index.php?option=com_k2&view=item&layout=item&id=680&Itemid=2751.
The downloadable NuForce driver can also be used for normal playback.
AS A DAC
The first thing I did for critical testing was to set-up the u-Dac-3 feeding my LD MKIV (full OTL tube), and also set-up my NFB-12 the same way. I then volume matched both amps to within 0.5 dB using an SPL meter and a 1kHz tone. I then A/B’d both units (sighted) using a switching box with dual inputs and single output. The uDac-3 showed limitations of its diminutive size, and was a very pleasurable listening experience with a variety of test music from Dire Straits / Steely Dan to Tchaikovsky and Vivaldi. Using the LD MKIV for both sources – there was very little if any difference at all – which is a testament to the uDac-3.
uDac-3 - about to feed the Little Dot MKIV |
At this point I should mention that the volume pot on the uDac-3 does control gain on the RCA outputs (I understand this range is about 6 bB gain). I generally ran it at around 12-1pm on the pot, and this provided more than ample output for the Little Dot.
The uDac-3 was surprisingly detailed for such a small footprint – and very similar to the output from the NFB-12. It has a nice linear bottom end, with a full mid-range, and slightly mellow (yet still detailed) upper end. If anything – it just gets out of the way and lets the music shine.
Main headphones used for this testing were DT880 and HD600.
AS A DAC/AMP COMBO
For testing this time, I compared directly to NFB-12, and once again volume matched carefully. Switching was a little more cumbersome this time, as I had to plug and replug. This time I mainly used my HD700, as well as my DN-1000 and BA-100 IEMs.
The tiny uDac-3 with the NFB-12 |
When testing the IEMs, I had to take the volume pot a lot lower than with the full sized headphones – but noticed no channel imbalance in doing so. Both IEMs performed admirably with no signs of hiss (I wasn’t sure what to expect with the 10 ohm Dunus). As mentioned earlier, I have asked Wolfgang about the impedance of the headphone-out, as I suspect it may not be ideally suited to the Dunu’s – which exhibited a slightly more flabby bottom end than they normally do from other sources. I suspect that some of this could be from a slightly mismatched damping factor. The BA-100s (at 36 ohm) were fantastic, as were the HD700.
My overall impression was that the uDac-3 is relatively neutral overall, with a slightly warmish tilt to the bottom end and mid-range. It’s subtle – but very pleasant. The detail levels remained extremely good overall – and whilst the NFB-12 may have just topped it overall with slightly more transparency, once again the comparison was extremely close between the two.
On power – with the BA-100s, the pot was at around 9 o’clock (switch off occurs between 7 and 8). The HD700s were comfortable at anywhere from 10-12 position. My 250 ohm DT880s needed about 11-1pm on the pot. The volume can crank all the way to 5pm – but you’d deafen yourself before attempting this with the headphones I have. So there is plenty of good clean power available – and at no time did I encounter any hint of clipping or distortion.
CONCLUSION
Looking at the uDac-3’s small size and simple design, you’d be forgiven for thinking that this is more toy than serious sonic device. But looks can be very deceiving, and I’m pleased to be able to report that the uDac-3 is a seriously good DAC/amp combo at its price point (USD 125.00 MSRP) – especially if you’re cramped for space, or looking for an easily transportable device. It was a welcome addition to my recent 2 week global business trip – especially as I had just picked up the HD700s whilst in New York, and this gave me the perfect platform to enjoy them.
I now use the uDac-3 almost every day at work (paired with my DT880). It is a revealing yet slightly warm and friendly signature that just does its job and lets the music shine.
The real litmus test is would I recommend this amp to my family and friends – and to that I would say yes with no hesitation.
I did offer to return the unit to NuForce after I’d finished the review, however - because of the shipping cost and the fact that it was B-stock, Wolfgang invited me to keep the unit and I am very grateful for their generosity. If they hadn’t, I would have bought one myself – my office would simply not have been the same without it!
Wolfgang and NuForce – thanks for the opportunity. I shall be keeping a very close eye on your progress in future, and I have no doubt that your higher end products will be on my radar at some stage in the future.
