Once I left it on for a few hours but it was idle, no music and it was up there with the temperature....... Mcintosh guy said to leave it on with no connections to troubleshoot other issues........ but it still gave off some noticable heat, it's warmer when hooked up and having music run through it. I noticed the transformer and heatsinks were warm, the autoformers were not. It was a demo that sat around for 3 years with out being used, out of the box but never connected or turned on.
MC352 owners
Hello there, I just had my Mcintosh MC352 biased and checked out but it still runs a little hot..... I put an electric thermameter on the heatsink and it read 92 degrees. Chuck at Mcintosh said it should be fine but I'm wondering if your amp runs that hot too. It gives off heat like a small tube amp.