Team, i am kind of new to tubes comparing to others, only involved last 8 months or so. I started with Muzishare X7...Push-Pull 4xKT88s.
I also have KEF 105/3 that I renewed painfully, all donuts and capacitors.
I keep reading about SET...so I wanted to try SET and compare.
I am also planning get Tekton perfect 15s if KEFs would be hard to drive with 8W 300Bs etc...
I also build raspberry stream with HAT digital out, trying Ethernet to Digital streaming source.
I have Ares II as R2R DAC.

Muzishare has 2x300bs...I believe those 2 more looks like 300b but they are 274b i think...used as rectifiers. 
I also learned that Cayin is mostly 220v...I am in the USA so 120V is on Muzishares...
@cb3489,
I’m a very happy owner of an 8 watt 300b SET amplifier. The KEF  is a 4 ohm speaker that dips to 3 ohms in the bass frequencies. They recommend 50 watt minimum to drive them. In addition it’s a 4 way speaker with multiple crossovers. In my opinion this is not an ideal choice for a low power SET.

I believe you’ll get much more of the capability and attributes from a 300b SET paired with the Tekton Perfect SET 15 speakers. They are intentionally designed to work very well with low power tube amplifiers.
Charles