I use MA-1 Mk 3.3 with Soundlab A3. I do not find the heat from MA-1 excessive. Yes there are a lot of tubes there, but they do not heat so much. Since I started to listen music on tube amplifiers, I’m having troubles to listen solid state. Atma Sphere amplifiers will give a very smooth and relaxed sound to your stats. Go for it ! And upgrade to 3.3 ! It’s worth every cent.