Donald Christensen has written an homage to the vacuum tube. He notes that many young engineers aren’t aware of the rich history of the vacuum tube. He writes, “Some [young engineers] may even believe that aside from a few special-purpose tubes (magnetrons, klystrons, photomultipliers, and CRTs for example), tubes are no longer manufactured and are found only in museums.”
He should have also included some links to information on the “All-American Five” radio he refers to, but they are easy to come by on the Net. Here are a few links:
- Fun With Tubes – the All-American Five
- Wikipedia – All American Five. This article not only describes the AA5, but lists several variants.
- History of the AA5
David N8SRE says
The All-American Five is a really interesting design. It speaks to both the cleverness of its designers and the relatively weak product liability laws of the time. ;) I have one that, as originally wired, had the entire bottom of the radio — a steel plate — “hot” whenever the radio was plugged in! Pretty astounding. It works quite well for such a simple design, though. It’s not exactly a radio you’re going to be doing broadcast band DXing with, but I use it to listen to local stations every day, and it doesn’t have any trouble separating stations in an area that’s fairly crowded with them. Older tube receivers almost always have a heavy treble roll-off in the audio stages, and I find the resulting tone pretty pleasing for listening to talk radio.
I’ve also seen four-tube versions that leave out the IF amp. I haven’t used any of them but I can’t imagine they performed very well.
Bill Quinn says
Dan: This is a question. I got back the other day a Emerson’s Model ED-354 from a person who repair the radio. One of the problem I was having with the radio is that 5Y3G tubs became very physical hot very fast. All the problems with the radio have been fix. But 5Y3G tube still become physical very hot fast. Is this normal? Or what did the person forgot to do? Thank you for taking time to read my e-mail. Bill Quinn
Dan KB6NU says
Hmmmmm. Good question. Tubes do get hot. You might want to measure the filament voltage and make sure it’s 5V. A higher voltage might cause it to run hotter, I guess.