Wadia 121 Decoding Computer Review

June 20, 2012

I have reviewed several USB DACS – the High Resolution Technologies MusicStreamer II+ ($349), the Furutech ADL GT40 ($525), the Music Hall dac25.3 ($599), and the Benchmark DAC1 HDR ($1895). Each has its own unique feature set and comes in at a different price point. The Wadia 121 USB DAC ($1299), which is the subject of this review, is unique among them in that it will play 192/24 high-resolution files over USB. Regular readers will know that I am not convinced that 192/24 audio files have a sonic advantage over 96/24 audio files, but that is based on a spectral analysis of a handful of high resolution files and playback on systems which may not be sufficiently resolving to reveal the differences. In these matters, perhaps it is better to be safe than sorry and seek out a USB DAC with such capability, provided you are willing to pay the additional cost of entry both for the hardware and (especially) the software. The good news is that such capability need not cost an arm and a leg, and the additional cost may provide a better all-around performer at the lower sampling rates, where most of your music likely resides.

The Wadia 121 is the same size and has the same cosmetic appearance as the Wadia 151 PowerDAC and the Wadia 171 iTransport (8″L x 8″ W x 2.7″H), and they can be conveniently stacked atop one another. The case is black, bead-blasted aluminum, and appears very rugged. Fit and finish are excellent. On the left side of the front panel are the blue power LED and the 1/4″ stereo headphone jack. Plugging in a pair of headphones disables the analog outputs on the rear. In the center, toward the bottom, all but invisible, is the IR receptor for the aluminum, wand-like remote control. Center right is a series of six vertical blue LEDs which indicate volume and balance. You will need to press the volume up button on the remote several times before the next volume LED lights up as volume is adjusted in small increments. On the far right are two series of of six vertical LEDs. The first indicate the incoming sampling rate – 44.1kHz, 48kHz, 88.2kHz, 96kHz, 176.4kHz and 192kHz. The second indicate which source is selected and whether you have chosen to invert phase from the remote. The indicator lights can be dimmed remotely, which is great because they are really bright. One small nit is that the power LED is a different size and color of blue than the other LEDs. I would have chosen to use the same LEDs for all inidcators.

On the rear panel are the connectors for the external power supply, and the inputs and outputs. There are five digital inputs – AES/EBU, coaxial on BNC, coaxial on RCA, Toslink, and asynchronous USB. The Class A output stage has both balanced and unbalanced analog connections, which is a real plus, particularly since the Wadia can drive a power amplifier directly. Since all inputs are upsampled to 1.4MHz/32, volume can be adjusted in the digital domain without throwing away bits of resolution. Think how much money you’ll save by not having to buy a preamplifier. It’s also one less box and one less pair of interconnects. You have just freed up a ton of money to spend on better speakers.

Audio signals are processed using Wadia’s patented DigiMaster upsampling and filtering technology, which is a software based solution that runs on powerful DSP chips using a 12th-order polynomial Spline curve fitting to generate up to 63 new samples for each original sample. This is the same technology Wadia uses in its mega-buck digital products trickled down to something that is actually affordable. It is why they refer to the 121 as a decoding computer instead of simply a DAC.

I listened to the Wadia 121 driving my Meridian 557 power amplifier directly, and using my Meridian G02 preamplifier as an intermediary, both in an all balanced pathway. I could not hear any differences. It is a testament to the transparency of both the G02 and the 121′s digital volume control. I also listened to the Wadia 121 drive a PrimaLuna Prologue Premium integrated tube amplifier (review forthcoming) directly though its home theater bypass inputs, and though it standard line level inputs. Here the Wadia 121 driving the Primaluna’s amplifier stage directly had the edge. It was slightly quieter than when run through the PrimaLuna’s preamp circuitry and tubes. For my listening sessions, I used the Wadia 121 through the Meridian G02. Speakers were the Magnepan MMGs (review also forthcoming).

The first thing to do was to test the Wadia 121′s ability to pass high resolution over USB. My setup is a MacMini with 16GB RAM using iTunes and Pure Music playback software. I first cued up the 192/24 version of The Eagles Hotel California. Since I had previously been listening to 44.1/16 audio files, I was greeted by a dialog box on the screen saying the Wadia 121 was changing to 192/24, followed by a relay click on the Wadia 121 and the indicator light changing to 192. The file played perfectly. I next cued up a 176.4/24 version of Mahler’s Symphony No. 8. Again, the change from 192/24 was visually announced on-screen, followed by a relay click and a change in indicator light. The same held true when changing to 96/24, 88.2/24 and 44.1/16. I put files recorded at various sample rates in a playlist in no particular order, and the Wadia 121 made the switch seamlessly as the files played. Clearly, the Wadia 121 works without a hiccup.

Circling back to Mahler’s Symphony No. 8, this contemporary recording is of the London Symphony Orchestra led by Valery Gergiev on the LSO’s own label. The symphony is also known as The Symphony of a Thousand because it is scored for an enormous orchestra, choir and soloists (extended orchestra, double choir, boys choir, three solo sopranos, two altos, one tenor, baritone and bass), a trend beginning with the fourth movement of Beethoven’s Symphony No. 9 and realizing its full expression in Mahler. The recording was made in St. Paul’s Cathedral, and instead of the imaging having laser-like focus, as can be the case in smaller venues or with aggressive multi-miking, the sound is enveloping, if somewhat homogenous. The first movement of Part II, marked poco adagio, the longest, and, in my estimation, the most beautiful of the symphony, sets the opening landscape for Mahler’s interpretation of Goethe’s Faust: Part II. The instrumentation is sparse, consisting primarily of woodwinds, accented by pizzicato bass and violins, naturally, if distantly, captured. The soundstage is vast, with particular emphasis on depth. Closing your eyes, the rear wall disappears. The very high notes for the flute and oboe, which can have a tendency to sound piercing on lesser components, here are rendered smooth and polished. The choir is haunting and chant-like. I was transported.

For those interested, shown below is a spectrum analysis of one of the Mahler movements I downloaded from HDtracks. The sharp 35db spike to the right is centered at 20,835Hz. The rise and fall to the right of it, between approximately 23,000Hz-55,000Hz represents noise from noise shaping. Note that such noise level exceeds that of the music between 5,000Hz-20,000Hz. It appears that this file is a PCM conversion and downsampling of the original DSD file from the SACD. Although I did not hear these anomalies, the spectrum analysis makes a case for the use of cables from Transparent Audio or others which roll-off high frequencies. Just to be clear, these are issues with the audio file itself and not the Wadia 121.

Bonnie Raitt has recently released a new album, her first in seven years. Titled Slipstream, it has received universal acclaim, many calling it her best since Luck of the Draw in 1991. Although my favorite of her albums is Nick of Time from 1989, Slipstream has been in heavy rotation here since I picked up my copy. Yes, I still purchase CDs. Aside from a limited number of high resolution files, where else are you going to get uncompressed digital music? Although I have used iTunes for computer playback of audio files for nearly a decade, I have never downloaded a single file from Apple. I have an iTouch, but there is no music on it. I use it solely for apps. I know I am an outlier, but there you have it.

Back to Slipstream, it is almost incomprehensible that Bonnie Raitt is 63. She plays slide guitar like nobody’s business. For the up-tempo songs like Used to Rule the World, the beat is driving from the kick drum and bass, propelling the song forward at a near frantic pace. Cymbal crashes shimmer as they decay. The album has jump. A jazzy blues song like Million Miles channels Mose Allison, demonstrating both her broad perspective and versatility. A ballad in the break-up tradition like You Can’t Fail Me Now gives her an opporunity to slow down the pace and highlight her strong, but plaintive voice. She appears dead center with instruments surrounding her in their individual spaces. Similarly, in Standing in the Doorway, on which guitarist Bill Frisell joins her, the kick drum and bass, both centered, set the pace, the guitar solo is restrained, and her voice is reach out and touch her real. I’m not sure it gets better than this.


There now must be hundreds of USB DACs, a growing number of which can process audio files over USB with sampling rates of 176.4kHz and 192kHz. Faced with the sheer number of alternatives, and the inability to audition more than a handful – if you are lucky enough to be able to audition any at all – before purchase, how does one go about selecting one? Reading reviews is helpful (I hope), but I think a proven track record of producing high quality components is perhaps even more important. Here Wadia, well known for producing some of the finest digital playback equipment available since the earliest days of the medium, has brought its considerable talents to bear in producing a DAC which is operationally bullet-proof at an unexpectedly modest price. This is not simply another DAC-in-the-box with off-the-shelf parts and a marketing slogan, but a component with highly sophisticated software realized in DSP which has been decades in the making, coupled with an analog section which, to my ears, is completely transparent. And with no separate preamplifier needed, your budget for speakers has just doubled. I can’t recommend it highly enough.

- Frank Berryman

Contact Information

Wadia Digital
3900 Annapolis Lane North
Plymouth, Minnesota 55447-5447
Telephone: (763) 577-0593

Associated Equipment

Analog Source: VPI Scout; Dynavector 20X2; Musical Surroundings Phonomena II
Digital Source: Meridian G08; Mac Mini; Halide Design Bridge and DAC HD; Amarra and Pure Music
Preamplifier: Meridian G02; Meridian G68ADV
Power Amplifier: Meridian 557
Loudspeakers: Magnepan MMG; Meridian DSP5500
Cables: Digital: Meridian; USB: Wireworld Starlight; Analog: Mogami/Amphenol (RCA), Mogami/Neutrik (XLR); Speaker: Mogami/Audioquest (BFA/banana); Power: Volex/Marinco
Headphones: Etymotic ER-4S
Accessories: GIK acoustic treatments; dedicated 20 amp circuit; Audience aR2p power conditioner