Low heat alternative to FIRSTWATT J2 ?

@zd542
The J2 doesn’t use any MOSFETs. It uses JFETs throughout. That’s where it gets it’s unique character from. All Pass Labs amps use feedback. That’s what Su-Sy is. First Watt amps are a mixed bag with the F7 using both negative and positive feedback.
You're not likely to find anything that sounds quite like a J2 on account of those big power JFETs. The unique thing about them is that they have conduction curves that resemble triodes whereas MOSFETs and BJTs resemble pentodes. 

The J2 and F7 are the two I am considering.

The reason the First Watt sounds like it does is its class A. Class A makes more heat; you're not going to find a cool running amp that is class A, so if you like the sound I would find a way to deal with the heat. Putting it in a refrigerator BTW will not work- the refrigerator has to get rid of the heat and will do so via its heatsink system.

One simple solution is to have a vent placed in the room above the amplifiers locations. The vents are then ducted to a fan that blows the air outside if needed. This system can be very effective and is cheap.

I would hire a cute girl to fan myself and the amp before I got rid of my F6 .

I would think as long as you have the amp on a simple floor amp stand you would be fine.