i have the BAT REX and yes it puts out some heat. The upside is that the sound is glorious, euphonious and I am able to listen at all volume levels both low volume and high volume. It has lots of features, the remote is easy to use.
The downside is that your electric bill will go up (I leave it on most of the time, and only turn it off if I am away for the weekend or gone for 24 hours). And I do not have the heat on very much in my listening room in the winter. I like a cool room so the preamp is just about right. I know it's a warm preamp but never too hot to touch. But all the heat come from the REX as my Krell EVO 402 is never more than barely warm.
The downside is that your electric bill will go up (I leave it on most of the time, and only turn it off if I am away for the weekend or gone for 24 hours). And I do not have the heat on very much in my listening room in the winter. I like a cool room so the preamp is just about right. I know it's a warm preamp but never too hot to touch. But all the heat come from the REX as my Krell EVO 402 is never more than barely warm.