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Old 10-29-2010, 10:38 PM
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'40's Admiral 78 rpm suitcase phonograph

The other day, I came into possession of this '46-'47 Admiral automatic 78 rpm suitcase portable record player. The amp uses 3 loktal tubes and there are two knobs on the front. One is for power/volume and the other is a motor switch. I fired it up and the amp will, of course, need a recap. The record changer operates as far as the mechanism goes; but, will need a new idler wheel and cartridge. In all my years of collecting, I've found lots of radio/78 phono combinations and mulit-speed phonographs; but, I don't recall finding too many 78 rpm phonograph only models.

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Old 10-30-2010, 06:02 PM
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The 33-1/3 RPM LP was tried in the early thirties and dropped after two years. The first successful introduction was in 1948 by Columbia, with the 45 by RCA shortly thereafter. So when your player was made, the only thing available to play was the 78RPM record.

It's interesting that the case looks very much like the familiar three and four-speed players popular throughout the fifties and sixties.
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Old 11-26-2010, 12:02 PM
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I had the cartridge rebuilt by west tech services and I bought a needle from Ed Crockett because I wasn't thinking about a new needle not being part of the cartridge rebuild. In the future, I'll know to purchase a new needle when having a cartridge rebuilt. Last night, I put it all together and I must say that for a basic 3 tube record player with a 5" speaker, it sounds real nice. I had to go with a 2 mil "all speed" sapphire needle, as that's all Mr. Ed had; but, it still sounds decent. If anyone has one of these old 78 rpm record players or radio/record player combinations, I'd highly recommend spending the extra money to have the original cartridge rebuilt. In the past, I've modified these players to use a more modern, lower ouptut ceramic cartridge and the results are not as good. I have several radio/phonograph combinations to restore and I will be having the original cartridges rebuilt in those.
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Old 11-26-2010, 12:56 PM
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Be careful, as the vast majority of those phonographs had hot chassis. There is no power transformer and thus no isolation from the power line. They take certain precautions but still it's possible to get some current through your body. You probably have a 50A5 output tube, a 50Y5 (?) rectifier and, in some units, a 14A6 or something as a driver. Many didn't even bother with a driver and depended on a high output cartridge to drive the output tube.

I may even have a Sams on that model; I have a few books of old stuff. As for speed, the 33-1/3 speed was used by radio stations to get longer play but there were no commercially available records at that speed until after WW II, and when they did become available they had narrower grooves, necessitating smaller styli.
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Old 11-26-2010, 01:57 PM
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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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Old 12-04-2010, 08:53 PM
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Quote:
Originally Posted by radiotvnut View Post
Then, there were the later Arvin metal midget sets that had a cap between circuit ground and chassis; but, those could still be dangerous.
Many years ago, I had a metal-case Arvin 540T 4-tube radio. It worked, and well as I recall, but I think it could very well have been an accident waiting to happen due to the metal cabinet. I never got shocked from it, but I'm sure the external antenna terminal could have been charged with line voltage -- even with a blocking capacitor between it and the chassis, which I am sure it had. If anyone were to touch that terminal and a grounded object at the same time while the radio was plugged it (it wouldn't have to be switched on), they would receive a shock they would never forget -- if the shock didn't kill them first.

If I still had that radio today (it is long, long gone, having been lost in a move 38 years ago ), I would certainly have replaced that cap with a modern one before I even thought of using the radio again. Those old paper caps can't be trusted after a certain length of time, which of course is why everyone here on VK (and AK as well) warns anyone trying to restore any kind of vintage or antique radio or TV not to trust the original caps to be usable after 40-50 years or more, especially the 3-section can type(s) in the power supply. While I am against so-called "shotgun" recapping of vintage/antique radios, TVs or other electronic devices using capacitors unless the goal is to restore absolute peak performance, I do agree that, at the very least, the filter cap and any blocking capacitors be replaced as a matter of routine.

Another problem the metal-cased AC/DC 3-, 4- and 5-tube radios had was poor or no insulation between the cabinet and the chassis; those that did have such isolation usually had rubber grommets between the mounting screws and the chassis. While these grommets did a passable job of insulating the chassis from the cabinet when the radio was new, they do harden and deteriorate over time, eventually losing much if not most of their efficiency as insulators. I also remember reading somewhere here in this forum of the ill-advised practice of omitting those grommets altogether when the radio was reassembled after repairs were done. The radio will work without them, but without the insulation between the chassis and the cabinet, the metal case will be charged with the full line voltage, creating, once again, an accident waiting to happen if the cabinet and a grounded object are touched simultaneously. I shudder to think how many people were injured or even killed by these radios because of this potential hazard.
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