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Yep, this is a three tube amp with a cap connected between circuit ground and chassis. I have a '48 Decca children's 78 rpm record player that's about as basic as you can get. No tone control with a high output cartridge driving the output tube. And, the chassis is directly connected to one side of the AC line. Which means the metal volume control shaft is hot, as well. It's hard to believe that something like this that was made for children actually passed UL inspection. I don't think it would do so today. Years ago, I had some '50's era radio and TV servicing magazines and there was an article in one of them concerning the dangers of hot chassis radio and TV sets. In the article, it mentioned that a young man had his hand on a metal cased hot chassis TV and he then touched something else that had a return path to ground. Unfortunately, he was killed instantly. The main focus of the article was to make sure that technicians replaced all insulating material between the chassis and cabinet and to perform other safety checks to make sure the outside of the set was safe to touch. When cheap "AC/DC" radios first hit the market in the early '30's, most of those used a hot chassis with hot control shafts and I think some of these even had a metal cabinet. Then, there were the later Arvin metal midget sets that had a cap between circuit ground and chassis; but, those could still be dangerous.
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11-26-2010, 01:57 PM
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