Thought I'd create a thread for a bit of SMSL love I've been using a SD-793II for the last 2 years to feed my powered Yamaha HS5 from PC Optical, it's done a brilliant job and sounded pretty good for the price point. However time has come for an upgrade, and I needed more power to run my new 660S. I'd already decided on a balanced setup as I'd already converted a lot of my headphones to 2.5mm to get the extra juice from my portable Fiio Q1mk2. I'd been scratching my head for some time regarding which route to go; Aune S6, Topping D7Xs, Schiit Jotunheim etc. But in the end it came down to budget. Enter the SU-8 and SAP-9 for less than £280 for both shipped.. SMSL info is pretty lacking, SAP-9 product page is minimal and the SU-8 does not even have a page, specs can be found on Amazon.. But love him or hate him I stumbled across Zeos reviews for both and they sounded like they'd do the job. ***Videos contain swears*** SAP-9 - https://www.youtube.com/watch?v=-CV1V6FwGUY SU-8 - https://www.youtube.com/watch?v=gSTMx_nsyU8 So mainly for the lack of a long USB I'm running optical from my PC, set to 24bit/192kHz to the SU-8. Custom XLR cables from the lovely people at OIDIO SOUND into the SAP-9. My monitors are hanging off the SU-8 RCA (RCA to XLR cables). Sounds pretty good to me, the DAC out to the HS5 has a nice clarity in the detail and soundstage. The SAP-9 seems very capable, plenty of power for the 660S and I've not noticed any issues despite the mediocre THD figures. It does get a bit bright at very high volumes. It looks like there may be a matching Amp for the SU-8 "coming soon" (video 40s in the SH-8), might be one to keep an eye out for..