Btzquabc,
We are an ATC dealer and believe it or not a 22watt tube amp will drive the ATC SCM 19 well. A Cayin A 88t is a nice push pull amplifier and the ATCs are actually quite easy to drive.
We have shown the ATC SCM 19MK II with a 50 watt Naim Unitlite which sounded terrrific obviously the amp was a bit low powered and you could not get ridiculous volume out of that setup, howerver, in our smaller demo room 18 by 14 with a 10 foot celing, the combo produced satisfyiing volume.
The reason people generally use bigger amps with the ATC is very simple the louder you play them the better they sound. ACT plays loud with no distortion or compression, which is one reason they are used in most recording and mastering facilities.
So we would say go for it, there are better tube integrated amplifiers but the Cain is a nice sounding unit and well made for the price.
Dave and Troy
Audio Doctor NJ