Anyone own 200iq and prefer kt150 over kt88

No, the KT150 were pretty awful in my 200iQ monos - killer slam and weight but completely lacking everywhere else. They can hardly even last 5 minutes of listening before I have to yank ’em out and get some sonic relief. I feel like I wasted time & money trying them.

But I actually like the Tung-Sol KT120 a lot, and even slightly prefer them to stock KT88 Gold Lion most of the time. But it’s a close call, and I see why many prefer the KT88.

I use the VAC Renaissance SE phono stage and it’s amazing. I also auditioned it in non-SE form and that’s fantastic too. Don’t feel like you HAVE to do the SE upgrade (the non-SE is even possibly, maybe, a little warmer and more romantic sounding). My only critique is you might not love the built-in Lundahl SUTs but I have my own SUT collection so that was never a problem (I even prefer a Bob’s Devices 1131 or Sky to the Lundahl LL1931). System is vinyl only!

And I agree with others - if you want to run KT150, get an amp designed especially for them!

Also on phono stage - realize you're already running a 100 Watts/ch tube power amp that will throw out several times the heat of a typical tube phono stage...and you're concerned about heat from the phono stage in that scenario?? 

The VAC Ren phono stages use a sextet of 12ax7 tubes, which just don't throw out much heat. I can't see it ever being a concern. Stages that use 12au7 (yuck) or 6922, add a little bit more heat. But you'd need a stage chok-full of 6N30 like the ARC Ref 3 before it will approach (or exceed) the heat of a tube power amp.