Nice review. 
 
But this comment is totally incorrect.  "The SU-1 has a lot in common with the Melodious MX-U8 - both are roughly the same size and well built if somewhat industrial in appearance. I actually suspect the two were made by the same people (can't prove it though)."
 
Other then form factor the two have little in common.  Of the three MX-U8's two had major issues right out of the box.  The build quality of the Singxer products looks much better then the Melodious.  The MX-U8 used the XMOS U-8 the SU-1 the latest gen XU208 as well discussed on my XU208 thread.  The SU-1 uses Crystek low phase noise CCH557 clocks for audio - the MX-U8 the Chinese sourced TXCO's.  The isolation scheme on the SU-1 is far more advanced.  I guess they share one thing in common - the use of a Talema transformer.
 
I am glad to see you like the SQ of the SU-1.  After much experimentation - I prefer the F-1.  The F-1 offers a much wider array of LPS power supply options without modification.  It costs less as well.
 
But for a turn key solution the SU-1 is a great audio value.
 
Cheers

Great review.
 
Also thanks for discovering the dip switches on the bottom.

Great review!
If user doesn't need i2s or doesn't care about fully DSD support, he will satisfy with F1. I love my SU-1 with i2s, it processes DSD64, DSD128 and DSD512 flawlessly.

Thank you for the informative review. Nice to know what I purchased I wanted a turnkey solution to use the i2s input on my audio-gd master 11. The su-1 worked perfect right out of the box. I had found the dip switches but left them alone (what does this button do). The su-1 transformed my Bimby / microZOTL setup.

rb2013: Thanks for pointing that out. I don't really know the history of the Melodious but the unit I had was well built and had some design aspects in common with the SU-1 (beyond the Talema). Nothing terribly conclusive though, and it could be that Singxer just liked their enclosure style/layout so they did something similar. I guess I didn't realize the Melodious had so many revisions.
 
But yes it's nice to find a turnkey device that can improve even $5k+ DACs (not all of them, but definitely some).

Hello project86. Thank´s for the review. I would like to ask you a question if you do not mind.
 
Now I have the converter Yellowtec Puc 2 Lite with a DAC NAD M51 ¿You think it may be worth buying the Singxer SU-1? ¿Is there a significant difference difference between them?
 
Thank you very much.

Thanks for a great review!  !!!

I am running Singxer SU-1 into Holo Spring. Just like to confirm that the SU-1 accepts DSD128 without any problem - Opus3's Meeting at the Building by Eric Bibb (http://shop.dsdfile.com/free-dsd-download/).

Just ordered this device and am awaiting delivery. Would you know if there's any benefit on leaving it on continuously? Is there a plus to "warming it up"/ 

Outstanding review!  Thanks for your hard work.  After reading your review I feel more confident about trying an SU-1.