• Wadia 121 Decoding Computer DAC Review

    Many people don't realize it yet but nearly all the high tech devices in use today are computers. Even iPhones and Android based smartphones are just small computers that fit into our pockets and enable us to communicate via voice. I remember the days of analog phones that never needed a reboot. Those were the good old days. Many audio components are no different from small purpose built computers. Some companies suggest their devices are for people who don't want a computer in the listening room or near an audio system. In reality these same companies' products are computers running Linux operating systems disguised as traditional audio components. Good, bad, or indifferent virtually everything is a computer today. Wadia's 121 Decoding Computer follows a long line of products with apropos names. Calling the company's Digital to Analog converters DACs is a bit too simplistic. Wadia writes software that runs on multi-purpose processors to decode and process digital audio. This audio is received, buffered, and processed by Decoding Computers such as the Wadia 121 similarly to conventional computers. To the end user a Wadia Decoding Computer looks, feels, and functions the same as any DAC. Connect a USB cable to the digital input and analog cables on the output and music flows without any user configuration. What happens inside the Wadia 121 Decoding Computer is another story complete with an advanced design similar to Wadia's very high end reference components. The 121 isn't the largest component on the block but is capable of competing at large component levels.






    The Wadia 121 Decoding Computer / DAC


    In an effort to avoid confusing readers let me state that the Wadia 121 is a DAC with a more descriptive name and extra features such as volume control and a headphone output. When in doubt just think of it as a DAC. The 121 is packed with wonderful design and proprietary technologies developed by Wadia. White papers describing much of these technologies read like an engineering geek's dream and music aficionado's nightmare. Four design elements in the 121 Decoding Computer that most computer audiophiles should understand are ClockLink, filtering & D to A conversion, volume control, and the power supply.






    ClockLink

    ClockLink, as opposed to Wadia's ClockLock, pertains only to the 121's asynchronous USB input. ClockLink is all about reducing jitter through oscillator placement, master clocking, and flow control. In the 121 Wadia placed a fixed master oscillator as close as physically possible to the actual DAC chip. This close proximity is thought to be extremely critical for best performance by many respected audio engineers. All computer audio sources connected to the 121 via USB are synchronized to this master oscillator's clock signal. The 121, like other async USB DACs, controls the flow of data from the computer to keep its buffer at an optimal level. In layman's terms the DAC controls show by using its clock and signaling the computer when to send data. This is vastly different from traditional audio sources connecting via AES/EBU or S/PDIF. These traditional sources embed a clock signal into the audio stream entering the DAC causing increased jitter. In other DACs using adaptive USB the DAC must adapt to the incoming data stream without the ability to prevent data under-run or overflow and must adjust to the incoming clock signal. In theory asynchronous USB has the upper hand but sound quality is much more about the product as a whole than one design element.


    Graphic courtesy of Wadia.



    Filtering & Digital to Analog Conversion

    The 121 Decoding Computer uses Wadia's proprietary interpolation filtering system called DigiMaster. This filtering technology reconstructs the analog waveform operating at 4x44.1 kHz. Wadia does this by interpolating four samples for every original sample. Readers familiar with CD ripping interpolation may recognize a tiny bit of similarity in that CD ripping interpolation looks at the original bits on a disc to recreate missing bits lost to scratches in the disc. The process is called interpolation and can be enabled in dBpoweramp via a check box. The DigiMaster system isn't recreating missing bits through interpolation rather filling in gaps between samples to smooth out the recreated analog waveform. According to Wadia the original samples used by the interpolation filter are not changed in any way. The 121 uses a 32-bit DAC integrated circuit for completion of upsampling to 1.4 MHZ and final conversion from digital to analog.



    Variable Level Outputs

    One of my favorite features of the Wadia 121 is its volume control. The 121 user manual states emphatically that this device was design to drive a power amplifier directly. To drive a wide array of amps with varying interconnect lengths Wadia implemented a volume control similar to the Weiss DAC202's coarse analog / fine digital control. The 121 output stage is adjustable to either 4Vrms, 2Vrms, or 1Vrms (the user manual states 0.5Vrms as a fourth level of attenuation). Wadia accomplished this attenuation with a single metal film resistor as opposed to multiple resistor arrays with complex signal paths. Adjusting the output voltage of a DAC can increase resolution of a playback system greatly. Most DAC only allow digital volume attenuation thus reducing bits and eventually resolution. Operating a digital volume control at its highest levels decreases the number of bits reduced. An unadjustable output voltage may require the user to use massive amounts of digital attenuation to reduce volume to a comfortable listening level. This reduces resolution and sound quality. By setting the output voltage lower this same user can keep the digital volume control near its maximum output and not reduce bits in an audible way. The 121 can attenuate a 24-bit signal from a computer by 48dB without losing any of the original information according to Wadia. After setting the output voltage of the 121 all subsequent volume adjustments are done in the digital domain at 0.5 dB increments.



    Power Supply

    The Wadia 121 Decoding Computer uses a switching power supply. When implemented right an SMPS can be extremely good. CA readers may not realize that the $15,500 EMM Labs DAC2X, the best DAC I've heard in my system, also uses a switch mode power supply. Wadia has taken several steps to reduce the effects of such a supply on the 121's sound quality. Placing the power supply outside the physical 121 chassis not only reduces the DAC's size it also reduces EMI and RFI interference from effecting sensitive analog and digital circuits. Internally the 121 has multiple stages of regulation to stabilize the DC power. The master oscillator has its own dedicated voltage regulator providing a clean DC signal for clock stability.

    No single design element, discussed here or elsewhere, is responsible for the sound of a component. Rather it's all design elements when implemented together as a whole greater than the sum of the parts that really matter. This whole is a waveform that enters one's ears for interpretation by the brain as a good, mediocre, or bad sound. This hobby is all about taste. Each person may enjoy a slightly different sonic color or character than the next person. Nobody likes 100% transparency because nobody has heard 100% transparency. Not only that but nobody outside the studio control room can judge accuracy of music reproduced through a given component.







    Listening to the Wadia 121 Decoding Computer


    I listened to the Wadia 121 Decoding Computer ($1,299) in a number of configurations. Most listening was done using my C.A.P.S. v2.0 server running JRiver Media Center v18 and using my MacBook Pro running OS X Mountain Lion 10.8 and Audirvana Plus v 1.3.9.5.2 in Direct Mode. On the audio side I listened mainly through my reference system consisting of a Spectral Audio DMC-30SS Series 2 preamplifier ($12,000) and DMA-260 amplifier ($10,000), and TAD Labs CR1 loudspeakers ($40,000). This system is very neutral and helps me identify differences between products easily. However, the Wadia 121 was likely designed for systems that cost less than my preamplifier alone and systems with different requirements. Wadia advocates a direct connection from the 121 to an amplifier while at the same time Spectral advocates use of its preamp with its amps. The DMA-260 user manual states a high output current capability of at least 180ma continuous is required. That's not an easy task for a small component with small power supply. I listened both with and without a preamp but preferred the sound with the preamp in this playback chain. Both configurations had pros and cons. There was no free lunch simply bypassing the preamp in my main system. At the end of the review period I changed things up considerably by connecting the Wadia 121 directly to a pair of Bel Canto ref1000m monoblock amplifiers ($5,990 /pair) via AudioQuest balanced interconnects. This was a game changer. These amplifiers are not as resolving as the DMC-30SS / DMA-260 combo but from a system synergy point of view they were a much better fit then running direct to the Spectral amp. This Wadia > balanced AudioQuest > Bel Canto combination is a "must listen" for readers putting together a system in this ballpark of size, price, and performance. I also spent a considerable amount of time listening through Sennheiser HD600 headphones connected to the 121's front headphone output. My headphone use wasn't planned but came more from necessity and a desire to listen while at my desk without routing music to my main system. I frequently purchase music online or fire up MOG to sample the new releases of the week every Tuesday. The Wadia 121 works excellent in this capacity as it supports all relevant sample rates from 44.1 through 192 kHz and sounds very good with the Sennheisers.


    Overall the sound reproduced through the Wadia 121 ranged from good to very good. The best sound was had when listening to headphones and using Audirvana Plus in Direct Mode on the Mac. Even lossy 320 kbit/s MP3 was very enjoyable while sitting at my desk. Listening through my Spectral preamp and amp produced the best main system sound followed by the direct DAC to amp connection via balanced XLR cables. Connecting the 121 directly to my DMA-260 amp didn't sound as good as the aforementioned configurations but this is also an extremely rare setup not likely to occur in the real world. The sonic character of the Wadia 121 was very different from other DACs I've had in my system in recent memory. I attribute this to Wadia's unique design and proprietary technologies. My favorite aspect of the 121's sound quality is its lack of warm tube coloration. Granted this is a complete solid state design, but that hasn't stopped manufacturers from injecting a bit of warmth in the past. I am usually annoyed by tube warmth within minutes. Readers like me should audition the 121 for a refreshing tubeless sound. Playback of Rock and Pop was right in this DAC's wheelhouse. Seal's Killer (acoustic version) sounded really good through the 121. The vocal on this track was right up front and didn't require a DAC with ultimate resolution and delicacy to reproduce with great effect. Similarly playback of Tower of Power's Diggin' On James Brown was a great track to turn up the volume and enjoy. All the horns, drums, and backing vocals contributing to the chorus produced a fun and engaging sound through the 121.


    Continuing with some of my favorite popular recordings I had a blast listening to Suzanne Vega's Headshots, The Black Key's Sister, Fiona Apple's Limp, and The Doors' The End at 24 bit / 96 kHz high resolution. Headshots had very forward sounding bass right from the start while Suzanne's crystal clear vocal was set out in front of the speakers. This track and others like it with a bit more "production" than traditional audiophile recordings were handled with ease by the 121 Decoding Computer. Sister from The Black Keys was another track I turned up considerably to feel the punch of the drums and enjoy great new Rock n' Roll through the 121. With the volume still at an abnormally high but enjoyable level I moved to Limp from Fiona Apple. From the strange sounds starting the track to the percussion solo at 2:07 to the horns during the chorus the 121's reproduction didn't disappoint. Jim Morrison's dark vocal throughout The End and the seemingly endless repetition of keyboard and drums at 24/96 high resolution sounded really good but not so good that I got lost on Jim's 11:38 musical journey. My experience listening to these recordings through both the full Spectral and Wadia / Bel Canto configurations was very enjoyable.


    Playback of some of my favorite audiophile type recordings through the full Spectral system revealed the weaknesses of the 121 Decoding Computer. No component is perfect nor without a color of its own. Randi tytingvåg's Red or Dead was a bit forward, a bit flat, and lacked a bit texture that I'm used to albeit with DACs costing thousands of dollars more than the inexpensive 121. The vocals were right up front and crystal clear as was the guitar. Other instruments had pop to them as if they stuck out a bit too much or at least more than I'm use to hearing. The sound was very reminiscent of solid state electronics without a touch of unnatural warmth. The Kansas City Symphony's version of Passacaglia at 24 bit / 176.4 HRx high resolution requires a playback system that can reproduce the delicacy of fine violins and minute sounds at low levels. The 121 struggled with this track. It reproduced sound more like a melting pot (all sounds gelled together without differentiation) than a salad bowl (every instrument is a distinct sound with delineation). This level of reproduction is expected from a component far down the line from Wadia's reference decoding computers. The huge horns and cymbals in a display of wonderful dynamic range isn't easy to reproduce as well as the best DACs in the business.


    The previous two paragraphs detailed my experience with the Spectral DMC-30SS Series 2 preamp between the Wadia 121 and my Spectral DMA-260 amp and the direct Wadia to Bel Canto configuration. I listened to the previous tracks and Ottmar Liebert's Not One, Not Two at 24/96 via a direct DAC to Spectral amp connection as well. On all tracks the sonic character was the same and I heard mixed results. On the plus side I heard more low level detail without the preamp. The negative impact of the direct to Spectral amp connection was both less fullness and a loss of texture. Ottmar's guitar strings sounded a bit off to me without using the Spectral preamp. However, I am used to the sound of this recording through my DMC-30SS Series 2. I won't say a direct DAC to amp connection was wrong as my experience with a different DAC to amp config was very right. I will say this direct to Spectral amp configurations was my least favorite and not recommended.


    One additional weakness I heard while using the Wadia 121 was a lack of air and space on some recordings. Diana Krall's Almost Blue was devoid of air and space around the piano in the first 40 seconds of the track. At the end when Diana says, "Almost me, almost you, almost blue" there was no air around her vocals and I didn't hear much separation or depth between the vocal and bass finishing off the track. It's a different sound than I am used to but it was still nice. I'm willing to bet most people without the ability to hear the best DACs on the market wouldn't even notice what I consider the weaknesses of the 121. The concept of relativism is very appropriate.


    Relativism: The doctrine that no ideas or beliefs are universally true but that all are, instead, “relative” — that is, their validity depends on the circumstances in which they are applied.

    The American Heritage® New Dictionary of Cultural Literacy, Third Edition
    Copyright © 2005 by Houghton Mifflin Company.
    Published by Houghton Mifflin Company. All rights reserved.




    Conclusion

    The Wadia 121 Decoding Computer is more than competent and competes with products double, triple, and quadruple its size. Think size doesn't matter? It does when designing audio components. Squeezing more electronics into a smaller box, dampening vibrations, and isolating the delicate analog and digital circuitry is much harder with a tiny form factor. Much of my experience with the 121 was heavily influenced by the component configuration and type of music I selected for playback. The 121 isn't an all-out-assault that enables listeners to hear things on a classical recording they've never heard previously. Fortunately in most system connecting the 121 directly to an amplifier will produce great results. What separates the 121 Decoding Computer from the rarefied air of great but greatly expensive DACs is reduced depth, air, and low level detail when reproducing the best recordings from labels such as Linn Records, Naim, and Reference Recordings. Despite a few anticipated weaknesses I thoroughly enjoyed my time with the exceptionally well designed Wadia 121. Its good sound quality enabled me to enjoy most of my favorite music from old to new Rock n' Roll and everything in between. The Wadia 121 Decoding Computer is recommended for readers putting together high performing yet sensible systems or looking to take an existing system to another level. New computer audiophiles seeking their first entry into this wonderful next phase of high end audio can't go wrong by starting with the 121. They may never need another digital to analog converter.














    Product Information:

    • Product - Wadia Digital 121 Decoding Computer
    • Price - $1,299
    • Product Page - Link








    Specifications:

    • Digital Inputs: AES/EBU (XLR), Coaxial (RCA & BNC), Toslink Optical, USB B
    • Input Data Rates: 44.1kHz, 48kHz, 88.2kHz, 96kHz, 176.4kHz, 192kHz (up to 24 bits)
    • Operating Systems: Apple Macintosh Apple OS X 10.6.4 and newer, Windows, Linux Kernel 2.6.33 or newer
    • Analog Outputs: One Pair Balanced (XLR), One Pair Unbalanced (RCA)
    • Dimensions: 2.7 x 8 x 8 in., 6.68 x 20.32 x 20.32 cm
    • Finish: Black Powder Coated Aluminum








    Associated Music:









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    Comments 34 Comments
    1. ted_b's Avatar
      ted_b -
      Chris, nice review, as is expected. Quick shout out to using Headshots!! Yes, it's been one of my demo tracks for years. I love Suzanne Vega, but especially her years with her husband/producer, Mitchell Froom. His and Tchad Blake's production/engineering of her stuff is a lot of fun.
    1. 32REASONS's Avatar
      32REASONS -
      Hi Chris,
      thanks for the review, I had a try also, but still I could not get any better feeling and dynamics, specially the sound presence (even more if using one of the different power improvements that exist on the market today) when compared to the Italian YOUNG 32bit,...I feel wadia is nice, but costs more than the YOUNG and offers not more for that... I better invest that difference on improving my USB cable.
      cheers!
    1. cvision123's Avatar
      cvision123 -
      Quote Originally Posted by 32REASONS View Post
      Hi Chris,
      thanks for the review, I had a try also, but still I could not get any better feeling and dynamics, specially the sound presence (even more if using one of the different power improvements that exist on the market today) when compared to the Italian YOUNG 32bit,...I feel wadia is nice, but costs more than the YOUNG and offers not more for that... I better invest that difference on improving my USB cable.
      cheers!
      In my understanding, all m2Tech products (except the HiFace 2) operates in bulk mode. Thus, USB cable shouldn't have any effect on the sound. The HiFace 2, which is based on the XMOS interface, might lead to another story then. I've been using the M2Tech for more than 6 months and I would suggest you to be careful in your investment into different USB cables.
    1. Garf's Avatar
      Garf -
      Under "Listening to the Wadia 121 Decoding Computer", second sentence:

      "Most listening was done using my C.A.P.S. v2.0 server running JRiver Media Center v18"

      Is that a typo? I did jump to the JRMC website to look for a beta release!

      This item looks interesting, especially the volume control. The one item that drives me crazy on my system is low volume listening, I am forced to use digital volume control via JRMC.
    1. The Computer Audiophile's Avatar
      The Computer Audiophile -
      Quote Originally Posted by Garf View Post
      Under "Listening to the Wadia 121 Decoding Computer", second sentence:

      "Most listening was done using my C.A.P.S. v2.0 server running JRiver Media Center v18"

      Is that a typo? I did jump to the JRMC website to look for a beta release!

      This item looks interesting, especially the volume control. The one item that drives me crazy on my system is low volume listening, I am forced to use digital volume control via JRMC.

      No typos here :~)

      You should try a 121 in your system. The volume control is really neat.

    1. Blake's Avatar
      Blake -
      Thanks for the review Chris. I liked that fact that you were able to test it with some of the highest level components money can buy and give us a sense of perspective- what we get and don't get with the 121 compared to the very best, playing the best recordings available. Of course, as you mention, everything is relative. The 121 will not compete against the very best DAC's in the world but within its price range, I feel the 121 is worthy strong consideration.

      I am using a Wadia 121 direct to a Bel Canto REF500S via USB in my main system and I absolutely love it. So much so, that my terminal "upgrade-itis" disease is in full remission. All my time and attention these days is devoted to finding and obtaining great music, without a thought toward my gear, which for me is nirvana.
    1. The Computer Audiophile's Avatar
      The Computer Audiophile -
      Great to hear Blake. That's what this wonderful hobby is all about.
    1. Puma Cat's Avatar
      Puma Cat -
      Quote Originally Posted by The Computer Audiophile View Post
      Great to hear Blake. That's what this wonderful hobby is all about.
      Thanks for the review, Chris. Thorough and well-written.

      I really enjoy my 121 and for me, it will likely be the point where I stop for quite a while. I don't know how much run-in time you had on your evaluation unit, but I will say that the Wadia continues to improve considerably over 3-4 months of continuous use (300-400 hours), much like the Schiit Bifrost, which I also hope you will review at some point in the near future.
    1. antigrunge's Avatar
      antigrunge -
      Agreed, usually when individual tracks sound less than the Full Monty, polarity is wrong. Chris, did you try to swith polarity in Audirvana on Diane Krall? The Wadia doesn't seem to offer the feature which for a company boasting about Digital Done Right is a bit of a let-down.

      Quote Originally Posted by ted_b View Post
      Chris, nice review, as is expected. Quick shout out to using Headshots!! Yes, it's been one of my demo tracks for years. I love Suzanne Vega, but especially her years with her husband/producer, Mitchell Froom. His and Tchad Blake's production/engineering of her stuff is a lot of fun.
    1. HiFiGuy528's Avatar
      HiFiGuy528 -
      You have the new version without two headphones outputs.
    1. The Computer Audiophile's Avatar
      The Computer Audiophile -
      Quote Originally Posted by antigrunge View Post
      Agreed, usually when individual tracks sound less than the Full Monty, polarity is wrong. Chris, did you try to swith polarity in Audirvana on Diane Krall? The Wadia doesn't seem to offer the feature which for a company boasting about Digital Done Right is a bit of a let-down.
      The 121 has a phase button right on the remote and a phase indicator on the front panel.

      As part of my routine when reviewing components I check phase right away.
    1. Nocompression's Avatar
      Nocompression -
      Chris, are you saying that you tried switching the polarity for the individual recordings as you played them ?

      I seem to recall reading ,on more than a few occasions ,that there can be a pretty wide variance as to how the polarity is set on recordings even from the same label.
    1. 32REASONS's Avatar
      32REASONS -
      Quote Originally Posted by cvision123 View Post
      In my understanding, all m2Tech products (except the HiFace 2) operates in bulk mode. Thus, USB cable shouldn't have any effect on the sound. The HiFace 2, which is based on the XMOS interface, might lead to another story then. I've been using the M2Tech for more than 6 months and I would suggest you to be careful in your investment into different USB cables.
      REGARDING THE USB CABLE:
      Theoretically, USB cable shouldn't affect the sound quality when transmission is bulk mode. BUT... USB also makes a ground connection which could inject noise in the system if the cable is poor quality.
      And we know all about how important the noise and the power supply is...and the BAD effects that can have on sound.
    1. The Computer Audiophile's Avatar
      The Computer Audiophile -
      Quote Originally Posted by 32REASONS View Post
      REGARDING THE USB CABLE:
      Theoretically, USB cable shouldn't affect the sound quality when transmission is bulk mode. BUT... USB also makes a ground connection which could inject noise in the system if the cable is poor quality.
      And we know all about how important the noise and the power supply is...and the BAD effects that can have on sound.
      Please stay on topic. If you want to discuss USB cables start a thread in the forum.

      Thanks.
    1. Alkan's Avatar
      Alkan -
      My 121 has burned 400 hours plus and my nowadays "critic listening" is through a Stax earspeaker powered by its own amp. And? It's fantastic!
      I am very happy with this marriage and it doesn't matters if I was listening the powerful "The Kennedy Experience", the classy Patricia Barber "Mythologies" or the dynamic Boulez "Pli Selon Pli", my system gives me all those little orgasmic pleasures so well-known to music lovers.
      I am a Wadia addicted and this DAC doesn't disappointed me - specially for that price.
    1. mav52's Avatar
      mav52 -
      Chris, one question the volume if this unit is not connected to a pre-amp is only controlled by the remote ? no volume adjustments are on the unit correct ?
    1. The Computer Audiophile's Avatar
      The Computer Audiophile -
      Quote Originally Posted by mav52 View Post
      Chris, one question the volume if this unit is not connected to a pre-amp is only controlled by the remote ? no volume adjustments are on the unit correct ?
      Correct Mav.
    1. dman's Avatar
      dman -
      Thanks for the review Chris. I have been waiting to hear your take on it. I am another owner who is very pleased with the DAC after coming from a Rega Apollo. For me the direct connection was better then going through my Parasound P3 preamp so I encourage people to try it both ways especially if they have a more modest preamp.
    1. buffalobill's Avatar
      buffalobill -
      The 121 is a nice sounding DAC but the bright blue LED lights is an unexpected distraction.
    1. The Computer Audiophile's Avatar
      The Computer Audiophile -
      Quote Originally Posted by buffalobill View Post
      The 121 is a nice sounding DAC but the bright blue LED lights is an unexpected distraction.
      I think the capability to turn off all the lights would be a great feature on the 121. The lights are a bit bright.