...Chassis Heat? My full rig consists of two vintage Marshall tube heads, each over two individual 8x12 full stacks. Both were bought new back in the day, and I've been employing them in my current rig configured as Master / Slave since 1992. More on the rig configuration later... The heads are: * JCM 800: 2204 50 watt, single- channel (bought in Philly, 1984); * 30th Anniversary: 6100, 100 watt, triple- channel (bought as 8x12 full A/B stack from a metro Denver retailer in 1992). Not too long ago, I brought both heads to an outfit here locally to have them each re- tubed and biased. Wound up having to lay out $800+ in three trips total, with regard to addressing work needed, both in terms of initial repairs done, and consequential follow- up repairs in dealings with said outfit. This primarily centered around the anniversary head. Some problems were identified and addressed initially, however the 6100 wound up with more problems cropping up during and following the initial trip to this vendor. The 30th anniversary head now has been re-tubed and biased twice by these gentlemen, but now -- with 'original ills' taken care of; it seems that the chassis physically produces a great deal more heat than I recall having previously encountered prior to taking the two heads into their shop. Regardless whether on standby or during normal use, both situations present the same overheating conditions even after a mere 40 minutes or so. It gets to the point where the front left chassis panel becomes a good deal too hot to the touch. The 2204 does not produce excessive heat in the range the 6100 is experiencing. I want to note as well the 50 watt / 2204 chassis cabinet does not have a vent grill on the top, whereas the 100 watt 6100 does. The high heat has not produced any malfunctions to date; I'm lucky in that regard, I believe. Has anyone else seen this condition? The 6100 head sports seven (7) 12AX7 pre tubes with four (4) EL34 power tubes and a mutha of a power transformer. It'd indicate to me that this 6100 head should run somewhat hotter than the 2204, being 100 watt with a sh*tload of valves, as compared to the 2204's three (3) 12AX7s with two (2) EL34 power tubes @ 50 watts. Some of what the technicians there have told me regarding configurations and use are outright whoppers. If she needs to go to the shop again, well... it's not going back to these folks, withstanding completion on their part of all warranty work which has popped up while in their possession (and I'm not completely firm in that regard). I'll leave things here at this point for now; any input from the members is welcome and encouraged. THANKS!!