How would you introduce tubes into this SS system?

If you live in a cold climate, that Cayin will make an excellent space heater.

Before you buy a Cayin product be aware that they no longer have a USA distributor and the manufacturer in China will not communicate with users. I have two dead A100T integrated amps that sit unused for want of repairs/parts availability. FWIW.

Huh. What about VAS Audio? He can get parts. 

He used to be the distributor. He is the one who wouldn’t repair nor could he get the parts I needed for my service tech. His intentions may have been good but I got the impression that Cayin in China couldn’t care less. FWIW I think that support for product has been a major weakness for some Chinese brands in the USA. Cayin isn’t the only one. The USA (ex) distributor for Consonance tells pretty much the same story. I bought the Cayin as they were ’point to point’ and I believed any service tech could handle them, but what I found out dealing thru VSA was they/ I could not get a schematic (or just wouldn’t pass it on, same difference to me) and were unable to get the parts I needed from China. So I have two amps which can operate with a single input since I bypassed the input selection chip/remote control, etc. But hey, they ’work’ like a basic amp with a volume control if I ever need one. The nail in the coffin for me, if that all isn’t enough, is that both amps failed due to a blown heat resistor after about 4 years of operation and should have been easily repairable.

I made an offer on the speakers, and he's going to ship them! The amp seems great, but now I'm a little gun-shy about the lack of tech support and parts. You all have been extremely helpful so far (except secretguy, but that seems to be his M.O.), so thank you for your help!