• S/PDIF Battle: Mutec, Singxer, Lynx, Rednet, Et Al.

    August 4, 2016 Luckbad 8

    I am a born skeptic. Until I heard a properly good amplifier with legit headphones, I didn’t think they were necessary. Until I heard a good R-2R DAC against a theoretically-good Delta-Sigma DAC, I thought all DACs sounded essentially the same.

    As I’ve progressed in my audiophilia, I am left with few frontiers to conquer when it comes to convincing myself to spend money on audio products. Cables and USB to S/PDIF converters are perhaps the last bastion for me.

    Note that I won’t be talking a lot about specifics for any of the S/PDIF converters here. There’s ample information on their websites about technical data, features, and prices. If I listed all of the information here, this entry would become far too long. Do your research and come back here for one user’s opinion.

    I started my journey into S/PDIF conversion with some common converters. The Gustard U12 was hardly an improvement over the USB in my DACs. The Audio-GD DI-2014 seemed like maybe it was slightly better, but it was hard to say. The Audio-GD DI-U8 felt like a slight improvement over that. The CIAudio Transient MKII was around the same level as the DI-U8.

    I breeze right by all of those converters because they had one thing in common: while I could convince myself that I was hearing some slight improvements in my (at the time) Audio-GD Master-11, I didn’t ever feel they were worth the money to keep in the chain. The simple USB gizmo known as the UpTone Regen did as much for the Amanero Combo384 in that DAC as any converter I tried.

    The journey continued. I eventually discovered how much I love tubes, and my beloved Master-11 went to a new home. I also found that I really enjoyed the sound of non-oversampling DACs, and ultimately found MHDT Labs. They make non-oversampling tube DACs with R-2R chips. I love the heck out of them, and they also benefit quite a bit from good S/PDIF input over USB. After finding MHDT, I embarked again on my journey of S/PDIF conversion.

    Not to be put off from spending too much money, I heard about a couple of pro audio contenders: The Mutec MC-3+ Smart Clock USB and Mutec MC-1.2. The MC-3+USB is a re-clocker and USB interface rife with features (many that I’ll never use), and the MC-1.2 is the little brother that doesn’t re-clock.

    When I first plugged my system (now a modded MHDT Labs Atlantis going to the ampsandsound Mogwai amplifier) into the Mutec MC-3+USB, my smug look born of my belief that I’d hear little difference was wiped away immediately.

    The Mutec MC-3+USB was the first USB to S/PDIF converter that I could unequivocally state audibly improved the sound of my system. Everything got smoother, more effortless, more expansive, and extension and separation seemed to improve. The effect is still subtle, but it is on the order of two completely different DACs rather than something extremely minor.

    The Mutec MC-1.2 was also very good for the price, but simply can’t satisfy after hearing its big brother. It’s a bit less smooth, a little swooshy and airy at the top in comparison, and less hard hitting. It’s better than the previous crop of converters I tried out, but can’t measure up against the much more expensive MC-3+USB after you’ve heard it.

    Thus began a spending spree to find the the right S/PDIF converter. I wanted to find the best at the top of my price range as well as the most practical devices that I’d be happy with.

    I grabbed some non-USB solutions first. The ESI Juli@ XTe, Lynx E22, and Focusrite Rednet 3 were among the contenders.

    The ESI is in the realm of the mid-priced USB S/PDIF converters. It lacked what I’ve come to understand as digital hash (swooshy feeling to the sound, almost like you’re rubbing together dry napkins inaudibly while listening to music). But it also didn’t work wonders with the soundstage or separation, and was outdone by the Mutec MC-1.2 in this regard.

    Next up was the Lynx E22. This is a no-nonsense PCI Express card that is built for pro audio. No digital hash, no glare, very good dynamics and separation. It’s a touch less smooth than the Mutec MC-3+USB, admittedly, but it’s also cheaper and it’s an internal card for my PC, which gives it some bonus points for taking zero space. This is an outstanding value and is a one-piece solution that outdoes most USB devices.

    Now comes the Focusrite Rednet 3. It’s a Dante-based converter intended for professional audio use. It is the first audio-over-IP device I’ve tried. I directly connected it to my computer’s ethernet port. Immediately, I was faced with issues. It doesn’t work out of the box at all because the installed firmware doesn’t work with the latest software. So I had to go download the firmware update and install it. Twice, for good measure, because the Rednet software doesn’t trust you and does it again after the device is detected for the first time.

    Then it started working, albeit with the caveat that all music must be piped to it at the same sample rate. And my was I impressed. The Rednet 3 sounds absolutely outstanding. Despite the bad taste in my mouth from the early frustrations, it’s the best of the bunch. I did start to experience some occasional dropouts, but I eventually tracked it down to JRiver because foobar2000 wasn’t causing the issue, so I switched media players.

    Weaknesses? Well, it’s not user friendly. It can’t change sample rates on the fly. It’s a double rack height massive red behemoth. And, it takes over your ethernet port unless you buy a separate card for it or use wireless. Plus, it ain’t cheap. The reward for all of the sacrifices is an amazing sound. No digital hash, incredible extension, wonderful dynamics, top notch separation.

    So I sold it.

    What? Yeah, I couldn’t deal with the size or redness. Am I an idiot? Probably. I also didn’t feel like spending another $100 to get AES output since it doesn’t come with breakout cables, nor did I want to spend the money for a good internal ethernet card. Will I go back? If they ever make a Dante-based Rednet device that sounds just as good and is intended for personal audio use (and is much smaller), absolutely.

    I settled in at home with the Lynx E22 going to the Mutec MC-3+USB as a re-clocker. Much smaller footprint than the Rednet and it sounds nearly as good to me as the Rednet 3 alone.

    All of this madness at home made me miss the devices at work, so I experimented with some more economical options rather than using a four-figure device there.

    That led me to try the Singxer F-1, which uses the new XMOS XU208 USB converter as opposed to the XMOS U8 in many of the other devices I’ve tried (including, I believe, in the Mutec).

    It garnered significant praise over at Head-Fi, and I found that it was indeed warranted. This sub-$200 device was nearly as good as the Mutec MC-1.2 at less than half the price.

    It shares some of the weaknesses of other USB devices in a similar class though, with that slightly swooshy USB sound that I’ve developed an aversion to. People have solved that with all sorts of UpTone Regens, cables, linear PSUs, and other decrapifiers. I’m not willing to go to such great lengths (pun intended) to clean up a USB chain. So off it went to a new owner.

    But I was intrigued by the performance to price ratio, so I ordered a Singxer SU-1. It uses the same converter but has more outputs and a Talema transformer inside.

    I was not disappointed with the results.

    The Singxer SU-1 is absolutely outstanding, especially with consideration for the price. It’s definitively superior to the Mutec MC-1.2 and all other USB to S/PDIF converters I’ve tried apart from the Mutec MC-3+ Smart Clock USB. In my “modest” (MHDT Labs Canary to a Garage1217 Project Sunrise III) work setup, its not discernibly inferior to the Mutec at all. Differences can be heard in my home setup, but they are hard to hear.

    So, this wandering sojourn has led me to a promised land. My wallet suffered in the process, but I’ve sated my curiosity and found some incredible devices.

    Here’s my subjective ranking of the various devices I’ve spent a fair amount of time with when used alone (adding more into the chain just confuses matters):

    1. Focusrite Rednet 3
    2. Mutec MC-3+ Smart Clock USB
    3. Lynx E22 (Update: AES mode w/ AES out actually seems slightly superior on the Lynx vs. the Mutec above)
    4. Singxer SU-1
    5. Mutec MC-1.2
    6. CI Audio Transient MKII
    7. Singxer F-1
    8. Audio-GD DIU8
    9. ESI Juli@ XTe
    10. Audio-GD DI-2014
    11. Gustard U8

    There’s a gap in performance between #4 and #5. Below #4, I tend to experience some degree of digital hash or other imperfections. Below #7, I don’t know that it’s worth buying unless your DAC has particularly bad USB (or none at all).

    Best S/PDIF Device

    • Overall: Focusrite Rednet 3
      • This is overall the best sounding S/PDIF converter. It’s large, pricy, gaudy, not user friendly, and requires an ethernet port. But dang does it sound great. If you’re willing to deal with the annoyances, this is the best sounding device I’ve heard to date.
    • USB: Mutec MC-3+ Smart Clock USB
      • This sounds nearly as good as the Rednet and is much smaller. It can also use USB input without the digital hash of many other devices. If you want what USB has to offer in a single device, this is what you should be looking at.

    Best Bang-for-the-Buck S/PDIF Device

    • USB: Singxer SU-1
      • No digital hash, nearly as good as the Mutec that costs more than twice as much. It’s a no-nonsense device, but it sounds outstanding. This is what I’d recommend for most people. It’s an obvious and discernible improvement over the USB input in any DAC without breaking the bank at $400.
    • Other: Lynx E22
      • Again, nearly as good as the Mutec, and perhaps slightly better than the Singxer (they trade blows). This requires a PCIe slot in your computer, but it’s outstanding and reasonably priced. If you have space in your computer for it and don’t want to occupy any space externally, this is your best bet. It also comes with the peace of mind that you’re not going to get any digital hash because there’s no USB involved.

    I’ve personally opted for the bang-for-the-buck options. At work, I’m using the Singxer SU-1. At home, I’m using the Lynx E22. Currently, it’s not hooked up to the Mutec to make sure I can live without it before it goes away to the highest bidder.

    My chains after much money was spent and a considerable gear shrink occurred to reduce the cost and footprints of my setups:

    Lynx E22 → Sonic Frontiers SFD-1 MKII SE+ [6н23п-ев]  → ampsandsound Mogwai aka “Gizmo” [6н9с МЭЛЗ металл.цок., 6п3с-Е] (Home)
    Singxer SU-1 → MHDT Labs Atlantis [6н26п] → Garage1217 Project Sunrise III [6н6п] (Work)

    Note: I have a Sonic Frontiers SFD-1 MKII SE+ on the way. I let go of my non-SE+ version a while back and missed it. It will be equipped with 6н23п-ев tubes. This DAC benefits greatly from a solid S/PDIF converter and sounded excellent with the Lynx E22 when I had it.

    Note: I heard from the folks at Kitsune Hifi that they’re now the US distributor of Singxer, so you can grab the Singxer SU-1 from the good ol’ US of A. Mention Basshead.Club and you might get a discount–I don’t get any kickbacks and I’m not sure how much you get off. Anyway, grab it from them if you’re getting one!

    Update: I swapped the Lynx E22 to output in AES mode instead of S/PDIF going into the Sonic Frontiers SFD-1 MKII-SE+. This elevated the Lynx further. At this point, it’s likely better than the Mutec by itself, and might be approaching the Rednet. At minimum, it’s more reliable than the Rednet 3 ever was for me and sounds nearly as good. Highly recommended.

    Categories: Gear, Reviews

    8 thoughts on “S/PDIF Battle: Mutec, Singxer, Lynx, Rednet, Et Al.

    • dogears says:

      Thanks for the summary 🙂 I noticed no Yellowtec PUC2 though.

      • Luckbad says:

        Wasn’t able to get my hands on several options, but these are generally more current and people I trust rate most of them above Yellowtech, Audiophileo, etc.

    • klh007 says:

      Good to see Kitsune distributes Singxer now, great combo with Spring L3 using I2S.

    • mcr says:

      As a new owner of Audio GD’s NOS-11 I have been wondering how SU-1 with I2S output to NOS-11 would match against those higher ranked gear?
      It’s been said those Audio GD gear sounds best using I2S so if I would get, say Mutec MC3+, I would lose that I2S output option but probably gain something with reclocking of Mutec.
      NOS-11 does not have AES input while Mutec or AOIP devices are mostly missing I2S output.

      I guess going first with Intona USB isolator would be a nice start upgrading source signal. Ahh, what a mindfuck.

      • Luckbad says:

        I’d ignore the Intona and go straight to the Singxer SU-1. I2S is a great input, and the Singxer is nearly as good as the Mutec for far less money (and probably better based on I2S).

        • mcr says:

          Thank you for your opinion on the issue. Ignoring Intona sounds interesting since it has got lots of recommendation, even with chained usb gear.
          I was leaning strong towards i2s output, this just encourages my thoughts. I’ll just get SU-1 and see/hear what happens next 😉

          While I’m already here, do you have any experience regarding cables in i2s use? Is it worth investing any pricier cable than regular HDMI-cable?

          • Luckbad says:

            Get a very short i2s cable. Something like this:

            • Dave says:


              I really enjoyed your writeup. I have an Aurender N100h server and it has only USB output. I have been using the Mutec MC-3+ USB for about a year and I agree that it is a great product. About 2 months ago, after reading your analysis, I bought a Singxer F-1 to test against the Mutec. I am having a hard time telling them apart. They’re so close, the F-1 seems like a real bargain. Even with Stax headphones, I really can’t tell them apart.


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