Super TLDR: The modified SU-1 performs very well, but from a value standpoint doesn’t make sense when options like the pi2aes and SU6 exist.
I’d really like to compare this to a stock SU-1 and also the newer modified SU-2 which has replaced this.
ChitChat:
The Singxer SU-1 is a fairly affordable digital to digital converter / USB Bridge, and this particular unit is a bit different. This is not the stock unit, but has instead been modified to use SoTM’s ‘sCLK-EX’ clock board, which is the same clock board used in the SMS200 Ultra network streamer.
It has also been modified to accept a direct 12v DC input instead of the standard internal linear power supply.
Savolax on Audiophilestyle kindly sent this unit to me alongside a farad linear power supply and Uptone ultracap 1.2, to test how the PSU might affect performance.
This was a great opportunity to try out a modified SU-1 to hopefully compare to a stock SU-1 later (if you have one you’d like to send in please let me know!)
DISCLAIMER:
This is a heavily modified unit and will not directly represent the performance of either a stock SU-1 or the sCLK-EX board itself, please treat this article as something of curiosity and nothing more.
Measurements:
Test Setup:
– Audio Precision APx555 B-Series Analyzer
– AudioQuest Carbon SPDIF Cable (1.5m)
– Farad Super3 and Uptone UltraCap power supplies
– 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.
Very good performance here for both 44.1khz and 48khz.
Not at the same level as the DI20-HE or the SU-1’s bigger brother the SU-6, but still very good, and does beat the pi2aes slightly.
The difficulty here is that the SU-1 is an older unit and the price/performance argument isn’t particularly good. The pi2aes is much cheaper and offers roughly the same performance, and the SU-6 is about the same cost as this package would have been if purchased new, but offers substantially better performance.
Though, to be clear, the point of this article isn’t to say whether you should buy this, in fact magna no longer makes this modified version, as it has been replaced by the SU-2. It is just because quite frankly this is a very interesting product and offered the opportunity to test the impact of different power supplies on a good DDC.
The above shows the performance with the Farad PSU, and below you can see the impact on performance of using the ultracap instead.
Performance impact is incredibly minimal, with peak/RMS measurements being basically identical to the farad within margin of error and moment to moment variation.
BUT, what the pictures don’t show is that performance was actually slightly more consistent with the ultracap.
Jitter measurements (and in fact most measurements) are not absolute figures, they change from moment to moment and you should NEVER take any of the measurements posted here or elsewhere as ‘absolute’. A dac having ‘123dB SINAD’ is often dependent on when you take the screenshot, and can be affected by silly things like if you have your hand near the device!
For this reason among others, its usually best to look at the FFT and actual behaviour, rather than trying to put a fixed number on things. And always take measurements with a pinch of salt, as it can be quite easy to make a product look good or bad depending on how the measurements are taken.
Regardless, with the Ultracap both peak and RMS figures fluctuated less than they did when running on the Farad.
Electrical Noise:
Usually this unit has an internal linear PSU. However this modified version accepts 12v DC input, and Savolax has loaned me his Farad PSU and Uptone UltraCap PSU.
The Farad is a high quality linear power supply. Whereas the ultracap is actually a bank of supercapacitors with LT3045 regulators. The idea being that you can use any PSU you like to feed/charge the supercapacitor bank, and then your device runs from the supercapacitors, not the host PSU.
This is also what the SU-6 does internally, and in theory should offer excellent performance.
Exceptionally low noise levels here, RMS levels are about the same as SU-6, different only in moment to moment variation. Though the SU-6 does have a fair bit lower audible-band noise than the SU-1. Both are excellent however.
What about the Farad PSU?
Still very very good! The audible band levels are sliiiiightly lower with less spurious activity in the 5khz-20khz region, but for the most part very very similar.
Subjectively, I could not reliably discern between the two PSUs, and you’d be happy with either.
I’ll update this post later with additional measurements taken using a ‘mediocre’ PSU to see how the SU-1 performs there.
This is a very interesting product, and does perform well. However for the cost other options make more sense currently. Hopefully I’ll be able to get the SU-2 with modified clock board in as I think that could be a very interesting comparison.