Is this an excellent value?

I'll probably get ripped for saying this, but what the hey.  Why would any one want to buy an upstart Chinese amp/preamp from someone who wants to get rid of it when you have so many safer choices of quality equipment in the same price range???

Yaqin is a fine manufacturer for budget minded enthusiasts. I would not let their poor and very cheap hybrid designs infer anything about their all tube designs, but I'm not sure I would spend that kind of money on a SET design from them. 

Yaqin is my my only recommendation for budget tube amps because I've heard enough of them now to know they are good values. All of those amps were push pull though, where transformer quality is not as paramount as it is with SET. I would expect these amps to completely fall apart with a 4 ohm load, much like my Shuguang amps do that are listed above. My favorite saying for those is that they never found an 8 ohm speaker that they didn't like, but they also never found a 4 ohm speaker that they did. 

When i picked up MastersounD I fully realized how this statement was not true for all SET designs. Speakers that made my Shuguang fall apart were handled triumphantly by the Compact 845. With that said, even the Compact 845 can have limitations and not shine in every application. Such is the case with every amp. 

If you are wanting to experience a high powered single ended amp and keep price reasonable, the MastersounD BoX should be high on your list. It offers more power at 35 watts and higher quality transformers. it has the balls of a good 845 amp and retains the single ended sound in a Pentode configuration. The BoX would run you about $500 more than the Shuguang separates but would offer a lot more in terms of sound quality, speaker options, and a lower noise floor with blacker backgrounds. 

I use Heresy IIIs with a Dennis Had SEP amp with something like 12 watts per side...maybe 10 with my current KT77 tubes. He seems to be making only lower power SETs these days, including a recent listing (Ebay...the only source for new Had stuff, although I bought mine used) for a 2 watt PC SET "45"...I like the added headroom of my massive 10 watts, but can’t recommend these amps enough...hand made, absolutely beautiful sounding little gems. Otherwise the Coincident Audio Dynamo 34SE II seems like a cool little amp. Also, I wonder where the Heresy III "96db" rating info comes from as, although I’ve seen mention of Klipsch spec exaggeration here and there, is there an actual measurement out there somewhere that disproves the 99db spec? I wanna know, but don’t care all that much as my experience with the Heresy III is all good, and they’re far more efficient than anything I’ve owned other than pro audio stuff.