Hello Rodman99999, Yeah it was a thermal sensor thing. Amps just got too damn hot to be housed inside of a closed cabinet. Happened with solid state Audio Research and also with Krell. Learning experience that prompted 2 actions: (1)never put hot running amps inside of a cabinet again. So I moved them out in the room next to the speakers on amp stands. Isn't that pretty much what everybody does anyway? (2)installed a custom ventilation/heat exhaust system in my cabinet. Problem solved.
I really never should have been swayed by the W.A.F. in the first place, but she wanted everything to look all nice and neat inside of a cabinet that she deemed "classy". Any type of free-standing Audiophile equipment rack just wouldn't do. If mama's happy then everybody's happy. If mama ain't happy....well you know what I'm sayin'.
My concerns about what is TOO MUCH heat? stem from the fear of having some kind of "random" thermo-nuclear meltdown due to higher ambient temperatures inside of a closed cabinet. Something self-inflicted that I could control if I knew better. Nothing specific to any such brand or model of gear. Heat is a normal part of operation with many types of electronics and I am aware of that, but my thoughts have more to do with what would be considered by many as "higher" than normal temperatures, and how it may affect the lifespan of certain pieces of gear. I currently have a (tube) preamp, as well as a DAC that both generate signifigant amounts of heat when they've been on for a few hours. Thank God for my ventilation system otherwise those 2 pieces of gear may well have taken a shit by now. The internal temperatures of my custom-built cabinet can range from 80 degrees on a good day, (when the weather outside is cooler), to 100 degrees on a summer day. While that doesn't sound all that hot, it is constant, it is consistent, which is what concerns me a bit. Without the ventilation and heat exhaust system, the internal temp's can easily top 180 degrees. So I am certain the vent/cooling system is working properly. Just pondering the "worst" case scenerio of having 100 degree air constantly present inside the cabinet, and how that may ultimately affect my gear, that's all. B.A.T. and Theta Digital both say no problem. I'm good with that and I believe them. Just wanting to get other Audiophiles' thoughts and input on the subject. Thanks for your response and advice, so far. Peace.