SMSL SU-2: a dumb, wasted opportunity

[crabbos]

It's a bit of a niche product, for sure, and it took some finagling to get it up and running. I ended up using my iBasso DX260 MK2 with its included SPDIF to coax cable and then running balanced XLR to my Burson Soloist GT4. I've gotta say - I'm really impressed with how good it sounds. A USB input would make it more versatile for the desktop, but at the same time, I've been enjoying the distraction-free "music only" nature of this setup.

 

[Solveit]

the existence of this dac is godsent for me. for $80 you could use them out of something like a minidsp flex digital/shd studio and get balanced xlr out connections to subwoofers with xlr input. maybe another one to the power amp as well. perfect in-between solution for someone who swaps active and passive speakers from time to time

I have two of those running SPDIF with nanoDIGI and very happy with AC power to get rid of the USB powered Dacs that searching for an fiktive ground and creating noise.
Dead silent now.

 

[Johnkeizer]

I regard the su1 as one of the great bargains in hifi.

 

[Roland68]

It's a bit of a niche product, for sure, and it took some finagling to get it up and running. I ended up using my iBasso DX260 MK2 with its included SPDIF to coax cable and then running balanced XLR to my Burson Soloist GT4. I've gotta say - I'm really impressed with how good it sounds. A USB input would make it more versatile for the desktop, but at the same time, I've been enjoying the distraction-free "music only" nature of this setup.

Just get a PO100 for USB; you can even connect it directly to the SU-2 using an RCA-to-RCA adapter. With an optical cable, you even get free galvanic isolation.
That still makes it cheaper than any other balanced DAC with USB of comparable quality.

I regard the su1 as one of the great bargains in hifi.

For me, it's clearly the D1 and especially the SU-2, for the reasons mentioned above.
I've never had any problems with clicks, pops, or dropouts with the D1 and SU-2, probably because they're simply more advanced devices than the SU-1.

 

[hikkiDO]

It actually looks intentional rather than a design oversight. The SU-2 seems positioned as a pure digital DAC stage, assuming you’ll pair it with a dedicated USB interface (like a DDC). By removing USB, SMSL avoids: PC electrical noise (ground loops, switching noise), and dependence on USB controller quality (e.g., XMOS implementation). Inputs like AES or coax are often preferred in higher-end chains because they provide better isolation and clocking when used with a good transport.
So while USB is definitely the most common input for casual use, this design is more aimed at users running a separate digital transport or streamer, not direct PC/tablet connections.