Headphone Amplifiers

Sony UDA-1 USB DAC Stereo Amplifier Review

ARTICLE INDEX

Sony UDA-1 USB DAC Amplifier Review Highlights

I review a lot of headphones and headphone amplifiers for Secrets of Home Theater and High Fidelity and I was excited to see how the Sony UDA-1 would perform with several cans, including the excellent NAD HP50.

The UDA-1 is a small, yet versatile USB DAC and amp, able to drive small bookshelf speakers and headphones. The Sony UDA-1 feels best at home in a small office setup and anyone who needs a versatile all-in-one for their computer audio collection should check it out.

Sony UDA-1 USB DAC Amplifier Review

Sony UDA-1 USB DAC Amplifier Highlights Summary

  • • Handles all lossless formats including DSD via its USB input
  • • Has coax and optical digital inputs
  • • Small amp can handle efficient speakers
  • • Great build quality

Introduction to the Sony UDA-1 USB DAC Amplifier Review

Sony has been around my whole life and is one of the top mega-brands of my childhood, sitting amongst heavy weights like McDonalds, Coca-Cola, and Nintendo. I do remember having a Walkman and a handful of cassettes, but I am truly a child of the Compact Disc. I still buy CD’s, albeit not as often as I used to, but the majority of my music purchases are on vinyl or high resolution downloads.

As the CD sections in stores like Best Buy have shrunk down to a couple of racks, it's been clear since iTunes took off that the Compact disc is on its last legs. So as the industry switches to digital downloads, it only makes sense that a company like Sony focus on playing back those downloads rather than clinging on to a dying optical media. At the 2014 CES, it was quite apparent that Sony was directing a lot of talent and engineering into Hi-Res audio. Sony has even made a minimum specification for what qualifies as “Hi-Res Audio.”

SONY UDA-1 USB DAC Stereo AMPLIFIER REVIEW SPECIFICATIONS

  • Design: Two-Channel DAC/Stereo Amplifier
  • Power Output: (JEITA 10% 1kHz 4Ω) : 23W + 23W
  • Codecs: PCM, Dolby 2.0, 5.1, 7.1 (Through HDMI Input)
  • THD+N: 10%
  • MFR: 10 Hz - 100 kHz, - 3 dB
  • S/N: 100 dB
  • Inputs: 1 x Coaxial Digital, 1 x Optical Digital, USB Digital Type 1, 1 x USB Digital Type 2, 1 x Pair Analog Coax
  • Outputs: 1 x Stereo Analog Coax, 1 x Head;phone, 2 x Speaker
  • Supplied Accessories : Remote Control; Instruction Manual; Quick Start Guide; USB Cable
  • Dimensions: 3" H x 8.9" W x 10.4" D
  • Weight: 8.8 Pounds
  • MSRP: $799 USD
  • Sony
  • SECRETS Tags: Sony, DAC, Sony UDA-1 USB DAC Amplifier Review, UDA-1 Review, Headphone reviews 2014, Headphone Amplifier Reviews

Sony UDA-1 USB DAC Amplifier Review

Sony UDA-1 USB DAC Amplifier Review

There is actually a pretty clear definition of what media can be labeled Hi-Res: anything higher than the 44.1kHz/16bit CD standard. This includes sampling frequencies such as 96kHz/24bit and higher, and DSD 2.8Mhz and higher. The file format must also be lossless, meaning if compression is used then no information is lost. DSD, WAV, AIFF, FLAC, and ALAC all support lossless High-Res Audio.

The only question left is how the consumer plays back Hi-Res media, and that’s exactly what the Sony UDA-1 seeks to answer. It connects to your computer, either Mac or PC, via USB and plays back any digital audio format you are likely to have. That signal is made available through a headphone out, standard RCA out, and a 23 watt rated amp. All this can be had in a small, well-built package for just $799. So is the Sony a good buy? Turns out it might need a few tweaks before I can call it a slam dunk, but it does offer a lot of functionality.

Go to Page 2: Design and Setup

 


The Design and Setup of the Sony UDA-1 USB DAC Amplifier

The Sony UDA-1 is a compact and dense little unit, surprisingly heavy for its size. You have your choice of either black or silver finish and I must say the silver does have that pleasant nostalgic feel of classic Sony gear. I was sent a unit in the black finish for review and it looks sleek and inconspicuous.

Sony UDA-1 USB DAC Amplifier Review

The build quality is top notch and reminiscent of the Sony ES line of products. This isn’t purely a USB DAC, the UDA-1 also features a 23 watt amplifier to power a pair speakers - the UDA-1 is specifically tuned for the Sony SS-HA3 bookshelf speaker. Given its smaller stature, the almost 9lb weight is quite surprising, especially given the fact that on the bench it only puts out around 12 watts into 8 ohms before clipping.

Sony UDA-1 USB DAC Amplifier Review

For inputs the UDA-1 has one USB port in the front for use with a flash drive, a USB input on the back along with coaxial and optical digital inputs. There is also one analog RCA input. For output, there are high quality speaker posts in the rear and a ¼” headphone out in the front and one RCA line out. The front Type-A USB input allows for easy playback of music files off of a flash drive, but is limited to 44.1/48kHz 16 bits. The rear Type-B USB is used specifically for streaming Hi-Res audio from a computer.

Sony UDA-1 USB DAC Amplifier Review

The focus of this unit is clearly on USB and Hi-Res Audio, so my testing consisted of using a PC via USB as the source. I played back a potpourri of file formats from compressed mp3 to uncompressed 192/24 FLAC and DSD.

If you are on PC, a Sony driver is needed to run full USB 2.0 Hi-Res audio. This is a quick download and easy install. Also needed is a player like Foobar2000 and the ASIO support plugin. Foobar makes it a cinch to find and install this component and it took me less than 5 minutes to get up and running. Adding DSD support to Foobar2000 takes an additional download and install of an ASIO proxy and Foobar SACD plug-in. There are a couple settings that need to be adjusted as well, but it was straight forward. I do hope in the future, none of this kind of setup is required to properly enjoy Hi-Res audio. If you are a Mac user, the process is plug in play with software like J River.

Go to Page 3: In Use

 


The Sony UDA-1 USB DAC Amplifier In Use

My preferred setup for the Sony UDA-1 was situated on my computer desk, in USB mode, and hooked up to a variety of headphones that ranged from the HiFiMAN HE-400 and HE-6, NAD HP50, and Audeze LCD-X. The UDA-1 is marketed as a versatile all-in-one intro into Hi-Res Audio with flexibility in mind, so the beastly Audeze and HiFiMAN planar magnetics were a bit of a stretch for this unit. If you are planning on running high impedance, high-end headphones, then the UDA-1 is not up to the task. However, the less revealing, but still rock solid, NAD HP50 headphones are a great match with the Sony UDA-1. I will say, the audiophile in me couldn’t resist also setting up the UDA-1 to output to a few high-end headphone amps as well in order to use the planar magnetics. In that case, the UDA-1 functioned only as a DAC.

Firing up Foobar2000 I simply added my entire music collection to the playlist and flipped on random playback. My first impressions of the UDA-1 were simply, that everything sounds great. Joni Mitchell at 192kbps MP3, 44.1/16bit ALAC Yann Tiersen, 96/24 FLAC Smashing Pumpkins; they all sound very good through the UDA-1.

Joshua Radin’s “You Got Growin’ Up To Do” starts with a quick soft strum of guitars both far right and left and then enters center stage, Radin and Patty Griffin, sounding full and lifelike. Those guitars are so tangible, they might as well be in the room with you.

M83’s “Intro” from their incredible album Hurry Up, We’re Dreaming is as dynamic as I have heard it. Turning on the DSEE (Digital Sound Enhancement Engine) has the slightest smoothing effect, but it isn’t very noticeable. If your equipment sounds a bit bright, the DSEE might calm things down the slightest bit. Generally with headphone listening, I kept the DSEE off.

The 23 watt amp inside the UDA-1 is designed for a small setup and, with that in mind, I hooked up a pair of Epos ELS-3 bookshelf speakers. While not a huge sound, the UDA-1 was more than capable of driving the Epos to loud levels. The bass response on Daft Punk’s Tron soundtrack was full, deep and well controlled. When listening to speakers off the Sony UDA-1, the DSEE was actually a bit more apparent. Engaging it smoothed out some of the harshness in lower res mp3 files, but it is was still a subtle change. Overall, with the Epos speakers I tended to prefer the DSEE on.

Unfortunately, where the Sony UDA-1 falls short is with.. Hi-Res audio! When I A-B’d a 16bit/44.1kHz lossless version of John Williams’ Jurassic Park to the HDTracks release of the 20th Anniversary 24bit/192kHz version, I could barely tell a difference via the Audeze LCD-X and UDA-1 headphone out. There was a slight increase in dynamics, but the clarity and liveliness I have come to expect from that Hi-Res version remained about the same between the two. Via the Epos bookshelf speakers it was nearly impossible to tell which recording was 24/192. This is not meant as a slam against Hi-Res audio, because I know I have heard a difference in file formats. In fact, I ran the RCA line out from the UDA-1 to a high performance ALO Studio Six headphone amp in order to bypass some of the electronics within the Sony. In this test I was able to easily identify the hi-res version of track seven “Welcome to Jurassic Park.”

I used the DSD downloads of David Elias to test the UDA-1 with DSD files. In part due to a quality recording, the DSD clearly sounded better than your standard 256kbps MP3. David’s rich tonality played beautifully through the Audeze LCD-X headphones with wonderful clarity. As to what sounded better, the 88.2/24-bit FLAC or the original Pure DSD 2.8MHz recording, I did indeed prefer the DSD version. The bass had more depth and punch, and the acoustic guitars were a step more dynamic and tangible than the FLAC version. However, this review is not a debate about audio formats as I have heard plenty of wonderful FLAC recordings that aren’t even available on DSD. The real point here is that the Sony UDA-1 can handle anything and everything in your digital music collection.

Go to Page 4: On the Bench

 


The Sony UDA-1 USB DAC Amplifier On the Bench

Measurements Section by Dr. David A. Rich

No schematic was supplied so it was not possible to correlate the measurements to the parts used inside the unit. Measurements were made with Audio Precision APx 585 and APx 582 test instruments by Chris Heinonen. Use of these was generously provided by Audio Precision.

Digital measurements are made with an SPDIF input on a coax cable. Except as noted below the test signal was dithered with a 24bit depth and a sampling rate of 192k samples /sec. The analog output was taken from the fixed line output jacks. The volume control and associated preamp gain stage are not part of this measurement and this should yield better SNR and distortion.

The output level (1kHz) at digital full scale was 2.3VRMS which is slightly higher than the standard value of 2.0VRMS. Channel balance was 0.6dB. Signal to Noise ratio was disappointing at 100 dB (16.5 bits equivalent) relative to 2.0VRMS. For the SNR test was band-limited from 20Hz to 20kHz.

Sony UDA-1 USB DAC Amplifier Review

The frequency response is extended to 50kHz. The strange peak above 10kHz will not be audible but it is hard to understand at what point in the analog chain it is introduced. Crosstalk (graph not shown) was an excellent -100dB at 1kHz rising to -70dB at 20kHz

Sony UDA-1 USB DAC Amplifier Review

Full scale THD is low at 0.002% up to 500Hz but then starts to increase significantly to 0.05% at 20kHz.

Sony UDA-1 USB DAC Amplifier Review

The distortion components of the 1kHz full scale signal (8 dBV) are seen above. The 2nd harmonic is at -91dB (0.003%) relative to full scale. The 3rd harmonic is at -95dB relative to full scale (0.002%).

Note the strange spectral lines spaced 1kHz apart starting at 500Hz. At -125dB (0.00006%) relative to full scale they would not appear significant. Still the unexplained origin of the signals leads to the possibility that they would become significant using tests designed to look for non-harmonic behavior in an oversampling DAC (IC). More information can be found on this in my introductory article on DAC ICs.

The noise floor of the graph is -130dB. As explained in other reviews I have written this is not the SNR but is related to it. The noise floor of the spectral plot is dependent on the frequency span (bin width) used to produce each point on the X axis. So many points appear on the X axis it looks continuous.

Since the bin width is not standardized you cannot compare this noise floor between measurements made on different equipment even if the test instrument comes from the same company. For the Audio Precision the bin width is adjustable. Other options on the AP can also change the appearance of the noise floor in a spectral plot.

You can compare the plot with other measurement sets made by Chris Heinonen. The SNR value is independent of the test instrument used but you need to scale it to the referenced full scale level which for our reviews is 2VRMS. I am bring this up now since DAC boxes have become the most coming component for which detailed measurements are presented in reviews.

Power supply noise was low with the maximum level at -110dB at 60Hz (graph not shown).

Sony UDA-1 USB DAC Amplifier Review

The spectra of a mix of 19kHz and 20kHz -6dB down shows low levels of IM products but unexpected spectral lines, not predicted from the IM equation, are seen across the band at -115dB. These may be related to the spectral lines spaced 1kHz apart starting at 500Hz seen in the 1kHz spectral plot above.

Sony UDA-1 USB DAC Amplifier Review

A 1kHz signal reduced to -60dB full scale is relatively free of discrete spectral lines above the higher than average noise floor reflective of the 101dB SNR of this product. The strange spectral lines seen in the full scale plots above are not seen.

Sony UDA-1 USB DAC Amplifier Review

Moving to an investigation of the DACs linearity performance for low signal levels we see the performance of the DAC is below average in the level linearity plot above. The deviation is up 1dB for a signal level of -98dB and is up 3dB at -102dB. These numbers indicate the linearity is starting to degrade for signal slightly below 16 bits equivalent. A mid-grade DAC (IC) would have the curve shifted to the left by 3dB, and a top grade DAC would shift the curve by more than 10dB.

Sony UDA-1 USB DAC Amplifier Review

In the time domain, a 16 bit un-dithered signal at -90dB distinctly shows the 3 discrete levels of this signal. Some of the ringing is the impulse response of the digital reconstruction filter and some is it is noise.

Sony UDA-1 USB DAC Amplifier Review

The effect of the relatively low SNR of 101dB is more clearly seen in the time domain plot above which extends the bit depth of the signal shown in the last plot to 24bits.

Power Amp

Sony UDA-1 USB DAC Amplifier Review

Only one graph is needed here. The amp produces 0.02% distortion until the clipping point of only 12 Watts average into 8 ohms. The graph above is for a 1kHz signal. Increasing the signal to 10kHz produced a similar graph with little increase in THD before clipping (not shown).

Go to Page 5: Conclusions

 


Conclusions about the Sony UDA-1 USB DAC Amplifier

The Sony UDA-1 feels most at home in an office or bedroom system. The built-in amplifier will not power every speaker, but does a decent job with bookshelves in a small room. This versatility is the highlight of the UDA-1. It plays back any of the current Hi-Res Audio formats, from 24/192 PCM to DSD, along with MP3 and other compressed formats. It offers fine performance with low and mid-tier headphones along with the afore mentioned speaker option.

With High Resolution Audio downloads gaining presence, it makes sense to invest in a DAC that can handle any format an album might be available in. Stores like HD Tracks and Acoustic Sounds Super HiRez have a catalog to choose from and are growing weekly. It likely won’t be long till one of the giants like Amazon, or iTunes offer High Resolution Audio as well. With the Sony UDA-1 you can enjoy increased fidelity now and feel confident in its ability to handle everything down the road.

For $799 I wish Sony had opted for a better DAC, but with the other functionality offered in the UDA-1, choices have to be made. For the computer audio generation the Sony UDA-1 offers a lot of versatility in a small package and fills a niche in their High Resolution Audio lineup.