Singxer SU-6 DDC / USB Audio Bridge Measurements

SU6: https://www.wildismaudio.com/collections/digital-to-digital-converter-ddc/products/singxer-2019-ddc-su-6-3x-i2s

TLDR: The Singxer SU-6 is currently the highest performing DDC I’ve tested.

ChitChat:

The SU-6 is Singxer’s flagship DDC. With USB input, two configurable LVDS I2S outputs, an RJ45 I2S out, BNC, AES, Coax, optical, and clock output support, this product has a lot to offer.

This unit was sent to me by Wildism audio.
It has a few interesting design elements, the first being the PSU. It uses an external 7.5v psu, but not to power the device directly. The psu charges a supercapacitor, which is then used to power the device, and in theory mean the choice of PSU should make 0 difference to performance. This also actually allows you to hot-swap PSU’s, and the device will continue to function for a while after being unplugged.

This is a fantastic device, and the only issue if I had to pick one is that the sample rate maxes out at 384khz/DSD512. So no 768khz (or 1.536mhz) for HQPlayer users unfortunately.
BUT, the performance is what we’re interested in. The audio GD DI20HE I recently tested set the benchmark for high performance digital sourcing……until today…..

(Note: I have a brand-new, latest firmware DI20HE on the way and will be making another post doing some comparisons of performance from SU6 and DI20HE once it arrives. Including looking at the performance of the I2S outputs).


If you’re wondering why a DDC is helpful in the first place you can watch my video on the topic here:

Measurements:


Test Setup:

– Audio Precision APx555 B-Series Analyzer
– AudioQuest Carbon SPDIF, BNC and AES Cables (all 1.5m)
– Stock PSU
– AMD PC USB -> ifi iGalvanic USB Isolator -> ifi iUSB 3.0 hub feeding both APx555 and DDC
– 44.1khz and 48khz real music played through device during measurement
– Coax output used unless otherwise specified

Content and analysis made possible thanks to support from https://headphones.com, and https://patreon.com/goldensound supporters

Jitter:

To measure jitter, the device is connected to the digital input of the APx555, and the analyzer is set to analyze jitter, not audio content.
These measurements do not show audio/analog info, but instead show the spectrum of jitter, ie: time-domain inconsistencies.
This is the primary factor that a good streamer or DDC will seek to improve.

Aaaaaaaaand we have a new top dog!
This is crazy performance. And is showing about 10ps lower jitter than the DI20HE (Though I’ll re-test once the new DI20HE arrives).

Unfortunately I can’t measure the I2S output as the APx555 does not support differential/LVDS I2S. However I would recommend using I2S if you are able to. The SU6 has switches underneath which allow you to customise the pinout to suit almost any dac.

Electrical Noise:

The second issue that a good DDC or Streamer will seek to address is electrical noise. You don’t want noise from your source causing your DAC to perform poorly. Noise can have a direct, audible effect, such as hearing GPU-whine through your headphones/speakers, or it can have indirectly-audible effects. For example, causing clocks in your dac, or other circuitry, to perform sub-optimally.
Some dacs are more immune to this, and some will even have full galvanic isolation to in theory prevent any noise getting through entirely. But many smaller dacs are much more susceptible to it.

Exceptionally low noise levels here, on par with or better than the ifi Zen Stream.

This is clearly an exceptional product, and I really have nothing else to say other than that if you’re looking for a good DDC, get this.

20 thoughts on “Singxer SU-6 DDC / USB Audio Bridge Measurements”

  1. I really like your videos 🙂 I use the SU-6 since it came out. if you upgrade the set pin capacitors on the two LT3042 powering the Oscillators, from 1µ to 22µF you will get at least 10x better jitter performance. The result in clarity of the midd’s is extreme.

    Reply
  2. Interesting… on the DI-20HE thread on Head-Fi, multiple people claim that the DI-20HE is much better than the SU-6… Not measurement wise but auditioning the 2 and going A/B between them.

    Reply
    • Personally swapping between the two they are almost impossible to tell a difference between. Both are incredibly high performing and I really don’t think there’s a wrong choice to be made.

      It’s quite likely that placebo/expectation bias is playing a part. When you’ve got a big heavy box with special regen PSU vs a smaller fairly plain black box, you’d expect the big thicc impressive looking one to be better

      Reply
  3. Hey, I love your videos and just explored the homepage. I am currently using a Singxer SA1 amplifier and a Chord Qutest on my computer. I am thinking about one tof two options:
    1. getting a Singxer SU6 between my PC and the Qutest.
    2. Selling the Qutest and the SBooster + Ultra Mk II and take this money + what I would spend for the SU6 (and a bit more money) and get a Holo Audio Spring instead.

    Any suggestions? Really would appreciate your opinion.

    Reply
    • Stick with the qutest combo unless you like the R2R sound – try before you buy. I had the Holo Audio May and sold it for the Qutest + matrix x-spdif 2 (fed from a JCAT USB XE with a very good power supply). The SU-6 doesn’t need the afformentioned power supply – if I was starting from scratch I’d go SU-6+Qutest. Job done.

      Reply
  4. IMHO the noise on coaxial noise measurement is useless. No one else measures this, it is not clear how it is measured, and it is an unbalanced measurement – which can only go wrong when tinkering with millivolts…

    Reply
  5. Long time viewer first time poster, I had a Holo spring 1.2 v3 and was considering the su1 in the past, now i have an auralic Aries g1 streamer and a Holo may kte on the way, with the may and this source is there any point to this ddc now?

    Reply
  6. Thanks for the great article, really informative!
    After reading this, I am considering going with the following set for source: Bluesound Node (2021) feeding through USB the Singxer SU6 and I2S connection to the Holo Spring 3. I want to get the more user friendly interface to stream my music and BluOS seems to be one of the best in class (I only stream Qobuz and Spotify, I don’t have any local files/library). Would that make any sense or it’d be better to go with the pi2aes (although I’d loose the BluOS opportunity)?

    Reply
  7. Some say that the inputs of the latest Holo DACs are so good that there is little benefit to SQ from adding a DDC. I have heard it reported that the sound might change a little but it would not really be said that it improves, so you might want to explore this with Spring 3 owners who have tried this option before you buy. Magna Hi Fi could advise you on this – they sell both the Spring 3 & the SU6

    Reply
  8. Hey, I really love your reviews and measurements! Could you please test how an SU-6 or SU-2 would improve Jitter on an RME ADI-2 Pro/DAC? This would be awesome, as RME claims that they have an ultra Jitter Free USB implementation. Already waiting for your new content. Hope your move went smooth.

    Reply
  9. Is the Singxer SU-6 and the Bluesound N130 via USB connectivity compatible? Do both devices work flawless in conjunction? Any experience?

    Reply
  10. I am torn between this and the pi2aes. My Problem is that I have to gap aound 7 Meter from the PC to the dac (pontus 2). With the pi2aes its no Problem (lan-pi2aes-short hdmi for i2s to dac..) but for the better measuring SU-6 I Wander if I should Stick the the USB Norm (5meters) and place the su-6 there, of so how do I contunie? What is the most robust Digital Signal for long cable lenght? (AES over xlr?) thanks for any hints!!

    Reply

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