Last weekend, we helped our friends with their garage sale. They advertised and set up the sale. We brought over our crap, err, our fine pre-owned items and helped out with the sale and watching the kids.

In the middle of everything was this fantastic item.

What's so special about this radio? Looks like a simple AM radio to most, but this ia actually a tube radio.

Sure enough, this is a 5 vacuum tube model AM radio from the early 60s. An explanation is in order. Back in the early days of electronics, vacuum tubes we the key to all modern innovations from radio and TV to amplification of signals.

Like the sound of electric guitars and the speed of microwave ovens? Thank vacuum tubes.

People in their 30s and older will likely remember TV commercial that told you to when your TV broke, you could bring the tubes from your TV for easy replacement. They had special kiosks at the supermarkets for the testing of the tubes.

Vacuum tubes have mainly been replaced by transistors in almost all uses. A few niche markets remain, like broadcasting and audio enthusiasts, but by in large it's a forgotten technology. The 'tube sound' or 'tube amp' refers to the use of vacuum tubes in audio systems. Some people swear by the tube sound, but I can't hear much of a difference between it and a good solid state (transistor) amplifier.

I had a brief education in tubes (or valves as the rest of the world calls them) in college in the late eighties. But they still fascinate me. There's a brisk market on ebay for tube radios, but they aren't worth a lot.

This radio was from the last generation of vacuum tube based radios that were meant to compete with the new transistor based radio arriving on the scene. Transistor radios were smaller and ran off of battery power, unlike the larger tube radios than needed to plug into the wall.

The radio works great. I adjusted the dial, listened to a baseball game on it, and was in heaven.

Best of course is that the schematic diagram and tube callout is on the bottom, ensuring that I can keep this running forever.

Posted by michael at June 04, 2006 03:03 PM