I fix old stuff. I play with electricity. And I love it.
Now that my hobby of 15 years is starting to become a bit more than just a hobby, I wondered if anyone here on the Kos was interested in hearing about it.
I’m inspired by writers like Major Kong and Denise Oliver Velez and Darksyde and the many others of you who have taken the time to write about your areas of expertise or interest. My own has been antique tube radios.
Radio technology is fascinating for many reasons. Most people in this hobby tend to be engineers and love the nuts and bolts. That’s fun, of course, but for me the real fascination is the social history angle. Radio was the fast-evolving technology of its day that changed everything, much as computers have done and continue to do for us today… but at a slightly slower and less frantic pace. In a matter of ten years, radio went from being something the local nutty professor played with in his basement to being something everyone had to have. The radio industry enjoyed booming growth even during the depths of a depression, expanding from a handful of companies in the 20s to hundreds in the 30s.
At the same time, of course, people needed something to listen to, and in that same decade radio broadcasting went from a few news shows speckled here and there to an entire industry of sports, music, and drama. Radio brought us the soap opera and the sitcom. It gave us the modern news cycle and brought the entire world (via shortwave) into the American living room.
From a design standpoint, radio went from a collection of parts mounted on a board (early 20s) to a box with knobs on it (late 20s) to an ornate decorator statement in wood (30s) to an ornate decorator statement in plastic (40s and 50s) to a box with knobs on it (60s) to… a collection of parts mounted on a (circuit) board (post-60s.) The 30s and 40s are my particular favorite time and I hope to share why in upcoming installments.
As I mentioned above, I restore tube radios. When I tell people about this, they usually express incredulous amazement that such old things can still work. They can, and do, because the circuitry of antique radios is simple and robust. I’d like to start off this series by answering a few of the most frequently-asked questions about tube radio restoration:
Q: Are these for real? Aren’t there circuit boards or something hidden in there?
A: Yes, they’re for real, and no, no trickery. All of my radios work on their original circuitry.
Q: Where do you get the tubes?
A: When a lot of radio repair shops went out of business in the 60s and 70s, they sold their stock to people like me. Since there were so many replacement tubes manufactured and there are relatively few antique radios left, the supply isn’t likely to run out. We trade, buy from each other, and keep each other supplied. There are online shops that sell tubes as well. As a last resort, there’s eBay.
Tubes can sit forever in storage and not go bad. Since the inside is a vacuum, there’s no oxidation or degradation of components. The only way to kill a tube is to A. break it, or B. run it to the end of its service life.
Due to demand from audiophiles for audio output tubes for amplifiers, some manufacturers in China and Russia are actually making tubes again. They simply re-opened the shuttered factories and started up the lines. Here in the USA we scrapped everything, so we can’t do that. However, there’s also skill involved, since many of a tube’s components need to be hand-assembled. The new tubes from Russia and China frankly kind of suck… but maybe in a few years they will get better.
Q: So tubes rarely go bad?
A: Correct. 90% of the tubes I test on old radios are perfectly fine. It’s the capacitors that are always the problem. The old capacitors were made of wound-up foil-backed paper, sealed with wax. With time, the wax hardens or melts and the capacitor shorts out. Original caps in antique radios had a service life of about five to ten years. Electrolytic capacitors were filled with fluid which dries out or leaks and they short or go dead in twenty or so. These ALWAYS have to be replaced. Luckily, modern capacitors are much more reliable and last a long time, and since they go under the chassis, the external appearance of the radio isn’t affected.
Q: Aren't some parts hard to get for these?
A: Yes. The hardest things to get are usually trim pieces specific to certain radios (like Zenith dial pointers,) bezels, and grille cloth. Speakers can be hard to match. If you have an old radio and the speaker cone is badly torn or even missing, DO NOT throw away the speaker! It can easily be re-coned or repaired, but if you toss the basket (the metal part) and the output transformer (the metal box attached to the basket,) you’re in a world of hurt.
That said, there are hobbyists and small companies out there manufacturing some replacement parts (knobs, chassis washers, dial windows) so it’s not always tough to find replacements.
Q: Hey, I just found this great old radio at a flea market! I’m going to plug it in and see...
A: NO! STOP! Never plug in an old radio until it’s been looked over by someone who knows what they’re doing! At worst, you’ll be running stuff way out of tolerance and fry your transformer (expensive) or some tubes, or even start a fire. Most likely, you’ll hear a very loud buzzing (due to dead filter caps.) At best, the thing will miraculously work… but not for long. There is also no difference in ease or cost of restoration between a radio that plays, a radio that buzzes, and a radio that seems completely dead. Buy it because you like it, and don’t worry, we can fix it.
Q: What can I get on these, reception-wise?
A: With few exceptions, all of them get AM. Many are also able to receive shortwave, often on multiple bands. FM as we know it wasn't widely available until the late 40s.
Yes, there’s plenty to listen to on shortwave. True, much of it is nutty people with cheap transmitters, but there are plenty of governments and commercial stations that broadcast on shortwave. My wife and I like to tune in to NHK Japan at nights (shortwave can have practically unlimited range under the right conditions.)
There's also various ways to make your old radio play exactly what you like. You can buy a small AM transmitter (FCC compliant, micro-power, antenna length under three feet, range of about 100 feet.) It's also possible to fit most antique radios with auxiliary inputs to which you can connect a phone, CD player, MP3 player, computer, etc. directly. You can also get Bluetooth installed.
Q: Bluetooth? For real?
A: Yup! Isn't old technology grand?
Q: Do these work as well as modern radios?
A: Yes. In some ways, even better. Warm tube sound resonating from a carefully-built wooden or cast Bakelite cabinet sounds wonderful. In some cases, though, these old radios can be subject to interference that wasn't around back in the day, like smart meters and florescent lights.
So, that’s the first installment. Take the poll below to help me understand what you want, and thanks for reading!
Monday, Mar 6, 2017 · 1:31:59 AM +00:00
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Hatrax
Thanks for putting me on the Community Spotlight! Like many of you out there, I’ve been pretty depressed these past few months and have taken solace in work and hobbies. I’ve toyed with the idea of doing this for a while now, but wondered if it was the right thing to do in light of the serious stories out there. I’m glad now that I did. I’ll try to make this a weekly or bi-weekly thing. Thanks again!