The 6.3v tube filament line on the tabletop Stromberg wasn't working so I acquired a replacement from eBay. The seller said it came from an electric organ and had been powering about 25 tubes, so it's more than beefy enough to light up the 14 or so in the radio. First I tested it at low voltage, mainly to see which end was which as there were no markings on the casing. I then hooked it up to the radio; there was a faint signal there briefly before a loud sputtering swamped it. The noise was unaffected by the volume control so I have to assume it is the fault once again of the power transformer, this time the high voltage line. This line goes directly to the rectifier tube, a 5U4G. I looked online for some circuit diagrams that include this tube to confirm what transformer I need to hunt down on eBay. On my travels I found this Japanese company's site which had some very good info, as well as a very charming explanation of a tube power amp:
"Mr. Amp is told like "Hey I am going to send you the audio signal" after the power is on to replay music. Mr. Power Source says "Ok then let's work! First I will make rice!" Mr. Amplifier says "The signal is small, so let's make it bigger". Then Mr. Output is like "Oh OK OK. Here I can shake Mr. Speaker by pulling out power! Here we go! Tada! Look! It's a good sound, isn't it?"
10 years ago
