SET amp recommendations for Zu Definition II's

I would use the Coincident Technology Frankenstein's at 8 watt/channel and MSRP $5,000. Thy are as clean as a whistle and surprisingly powerful sounding. If one needs more tube power the Coincident Technology Dragon's at 70 watt are also great.

I have been using a Yamamoto A-09S, 300B amp for last 2 years with my Def IIs. I have had no desire to change. I did demo the Art Audio PX-25 before I bought the Yamamoto. I thought it matched up very well. I have seen them for sale here at pretty reasonable prices.

There are Komuro amps here on sale; should be good enough.

Schw, the Mastersound 845 amps are excellent. Lots of grunt. The Conincident Frankensteins are crystal clear. Both are great choices. I'd echo what Glory said. Sean Casey at Zu currently has my Mastersound Compact 845 on loaner duty. He'd probably be able to answer any questions as to how it performs with most any Zu speaker.

The Frankensteins will also run closer to 6K than 5K. If you go that route, you should strongly consider the upgrade to the Shuguang Treasure 300B tube, which puts it at about 5999. With that kind of money invested, going with the better tube is pretty much a no brainer in my eyes. Again, talk to Sean Casey. He'll be able to tell you better than we will. The Franks are "only" 8 wpc, but it's a damn strong 8 wpc. If you want to split your ears, you may want to go higher, but you likely don't need it with the Def Mk II's. The built in subs raise another issue with the Def Mk II's compared to my Essence. Sean will be able to answer those queries for you.