If you're looking for a cool running ARC amp, The only ones available are the 100.2, 150.2, and 200.2. These are all class T designs which means they utilize digital switching. I have a ARC D-240 MKII amp and a LS-9 preamp. Both are solid state. The preamp runs cool and sounds great. The amp runs very hot as do most ARC amps. The SS ARC class T amps that run cool can be very expensive on the used market because they are relatively new. If you can deal with one that is older and runs hotter, you can save significantly.