I've had my DT50-112 less than 2 days. I'm playing at very low volume, low power setting, class ab, voicing III. I notice a smell, which I think is paint or varnish (or tolex?) at a temperature close to melting or burning, but it could be an electronic component too (I'm not an expert in odors).
The guy I bought the amp from claimed to have only used it for 2 hours, so at first I thought it was maybe a normal break-in kind of smell. But when I touched the metal amplifier housing in the rear after playing a couple of hours, it was very hot. Not hot like a muffler pipe, but hot enough that if you needed to hold your hand to it for whatever arbitrary reason, you wouldn't do so for more than 2 seconds without leather welding gloves.
Upon removal, the power tubes look mint to me. The screws did not appear to have been loosened previously, however, one of the transformers has a couple screwdriver dings in it--could be a factory thing, but I think that seldom occurs at the factory (even a Chinese factory).
So is this kind of heat normal? (If so, I'll just get a fan.) My previous tube experience has been with a vintage Dual Showman, and I never was concerned with heat buildup. But with this amp, with basically only 2 tubes, maybe it runs much hotter in order to get that tube vibe?