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Comment by hilbert42 | Hacker News Reader

"I realize that each time it flickers to life could be its last. How does one go about finding ancient tubes nowadays? Where are the parents with the know-how to fix such things anymore?"

Fixing it is non-issue. Almost evey part will be available if not a direct replacement then a close substitute. Even new electrolytic capacitors can be made to look like old parts by burying them in the case of the defunct part.

As for tubes, it's almost certain they'll be standard octals (they were commonplace by 1941), and there's any number of them around both new-old stock and secondhand.

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An AM-only radio of that period almost certainly uses the "All American Five" set of tubes. All of which are still available.[1]

Note that many of those things are a hot-chassis design. The chassis is directly connected to one side of the power line, so there is a shock hazard. On some units, the shafts of the controls are live.[2]

[1] https://www.tubedepot.com/products/american-5-tube-set

[2] https://geojohn.org/Radios/MyRadios/Safety.html

"Note that many of those things are a hot-chassis design."

Right, hot-chassis was mainly a US phenomenon due to its 110/115V supply. It was very rare in other countries such as in Europe, UK, NZ and Australia that used 220/240V because of the danger. If memory serves me correctly, I think hot-chassis was banned in some countries such as Australia. Of the 220/240V countries some European ones did permit H-C but such sets were rare.

Thanks to guitar players, lots of tubes are being manufactured new these days for old amps. There may even be new tube amps being made.

Amplifier tubes have only a little overlap, if any, with the tubes you will find in a typical AM radio like the one described. Maybe the rectifier or the output tube.

There is still (!) plenty of old stock of radio and television tubes out there, however.

Yeah, see my comment re the 6J8G.

> There may even be new tube amps being made.

There are. I had the resident guitar expert at work pick me out a cheap-but-decent guitar+amp combo for my son, and the amp ended up being a 1-watt tube amp

Right, but I'm not so sure about superhetrodyne-specific tubes such as pentagrid and triode-heptode converters like the 6J8G (perhaps I'm wrong, I've not followed the matter that carefully lately).

Reckon the demand wouldn't warrant tooling up (and they're messy complex tubes to make).

Right, super popular for death metal guitarists, for some reason.

Tube amps are really the default type of guitar amp for every genre. I can name hundreds of guitar players famous for playing tube amps, I don't think I can name a single one known to play solid state amps.

>I don't think I can name a single one known to play solid state amps.

Dimebag Darrell and Buckethead are two names who come to mind, favouring the even response of solid state over the more-dynamic valve amps. If we include pre-amplification such as guitar pedals, solid state is everywhere - a DS1 or a Rat gives that even response for big gnarly cold distortions. Then there's the Boss HM pedal which spawned a whole genre of it's own when players used it as a pre-amp for that unique "chainsaw" sound.

So, you're right that most players opt for valves at the amplification stage, but solid state is all over guitar music.

With digital simulation, things are slowly changing and a lot of players now use digital amps on tour as a matter of convenience, even big names. This has been debated to death on guitar forums, but some would argue that digital is now undistinguishable from the tubes.

>This has been debated to death on guitar forums, but some would argue that digital is now undistinguishable from the tubes.

I find that it's impossible for the average listener to identify the difference in recorded music, especially if there's a lot of distortion in play, but I can entertain the idea that it's a detectable difference.

As someone who moved from solid-state and digital amps to tube amps I find there to be a huge difference in terms of dynamics and response, which massively influences the way I and others play. I can't imagine Jeff Beck or Gary Moore getting the same results with non-tube amps, since their playing relies so much on dynamics and physically feeling and moving air in the room.

edit: for live touring, though, it's so much more efficient to use digital or solid-state options for size, weight and reliability, if it doesn't directly impact the artist's ability to perform

I have never used a top line modelling amp, like kemper or whatever...but I immediately play better through my tube amps than lower end digitals (Katana or whatever). It is dynamics as you say. Anyone would prefer to hear me play (as if) through a valve amp (vacuum tubes are called valves in Britain). Valve amps are still the default option for higher end enthusiast amps, although modeling is taking over with pros for convenience

As compute power continues to improve, so does simulation.

Yeah, I would expect modern software able to do the job for all but extreme cases. Basically, custom Amp mods.

I don't want to be that guy but I think you are thinking of Doom Metal / Black Metal.

Seriously. The author is smart enough to get their piece published in the LA Times. You would think they know how to search YouTube for "how to repair old radio".

I was going to write that expertise in one area doesn't necessarily transfer to competence in another, but then it occurred to me: Perhaps the radio is still running off the same valve that his father installed in 1978 and that is part of the emotional value that it holds for him.

If your father fixed something for you, it could feel like a betrayal of his memory to hire someone to fix it again for you.

Though personally, if I had the deep emotional connection with it, I'd want to fix it myself (almost certainly with assistance from some amateurs who know the radio).

Give a man a fish vs teach a man to fish :/

You're never going to "teach a man to fish" on how to keep his one, mostly-reliable, tube type radio going. You can teach him to switch tubes, but eventually it's going to get more complicated than that, and you can only get so much experience from a touch of help every few years.

Whilst it doesn't happen very often it never ceases to amaze me that some of those old radios will still work after being switched off for about half century.

I've switched them on expecting fireworks—the plates in the 5Y3G/T or 80 rectifiers glowing red hot because the electrolytic caps had shorted to deck—but no they actually still worked.

What's more I've even had some of those ancient wet electrolytic caps (the 1930s-style 8μF/400V types in vertical cans mounted on the chassis) actually work.

Mind you, I certainly don't recommend you do that—do as I say not as I do (I'm rather gung ho about such matters and rather enjoy the fireworks). Be warned, you can not only blow up the rectifiers but also the power transformer and that'll likely be much harder to replace than the tubes.

I recall several years back being so shocked that some of those old wet electros still worked that I pulled the top seals off several and stuck my multimeter in the electrolyte and noticed that essentially there was no voltage between the electrolyte and the case. I even stuck my finger on the Al foil and could feel very little until I pushed hard and then suddenly whammo—ouch. A fascinating exercise, it's an excellent illustration of how good aluminum oxide is as an insulator and dielectric.

Please don't try this unless you are as mad as I am—and even then don't do it!

Electronics (and machines in general are weird).

My car dies in a month if I don’t start it because of parasitic drain.

My 1969 deuce and a half fired up after two years with zero problem at all.

I have ancient computers that work fine and much much newer ones dead by capacitor.

Had that problem myself. Parasitic drain is shitty bad design—full stop! The only things that should drain when the car's not being used are the clock and or the radio's memory and they only take flea power.

Franky, I'm pissed off with much modern elecronics (I used to work in the prototype lab for a large multinational electronics company and crappy design like that wouldn't get past the breadboard stage let alone make it into production).

It's doubly annoying because I know it is possible to design storage systems that do not require energy - every computer manufactured in the last 30 years has had them!

That will never stop reminding me of the Pterry quote.

Radio of Theseus

That's rather unfair. Whilst I cut my teeth on old radios like that (which were essentially obsolete when I was a kid), and their operation is second nature to me, I know many electronics people brought up on transistors, ICs and 5-Volt supply rails that wouldn't know where to begin fixing one. For starters, plate voltages upwards of 250V scare the shit out of them.

Anything involving the mains can be a worry to them.

However, it can also pass quickly! I have mentored a few of these people over the years. It is funny!

I worry about burning up a chip, and they worry about getting zapped!

We share experiences, fix or build a few things and it all works out fine.

And therefore have to omit that poetic line?

How long can a vacuum tube survive sitting on a shelf? Decades, apparently, but centuries? Millenia? What's the diffusion rate of air through the glass envelope?

Also, wouldn't keeping the tube filament temperature stable maximize longevity? In other words, couldn't leaving it on be better than using it once a day?

No. The old caps in there will be overdriving the tubes. It will die pretty quickly.

"and there's any number of them around both new-old stock and secondhand."

I believe there are even a company or two manufacturing new.

There are about 10 companies that still make vacuum tubes for a variety of products. There is also stock you can find on eBay or at ham radio festivals pretty easily. There are even customers who make crystals for old rigs like the Hallicrafters and Drake lines.

one may not need to find ancient valves - my little (65-year old) brother builds valve amplifiers and repairs valve radios as a hobby, and seems to do ok. only problem that as far as i can see, many valves are apparently sourced from russia (i don't know about this definitively).

Russians and other ex soviet countries kept manufacturing tubes well after the west stopped. They're often great quality military grade parts, a lot better than the Chinese remakes and fakes one can find at the usual online places. The same applies to germanium transistors and diodes, passive parts etc: excellent quality at very reasonable prices. Those who currently don't want to, or can't, buy from Russian sellers, can find the same items at various shops in western Europe: Bulgaria, Czech Republic, Ukraine (some shops still active and worth helping), Romania, Poland, etc.

You know, it depends how desperate one gets. I have longtime friend who occasionally repairs ancient B&W TV sets, not from the 1950s but earlier 40s and even late 30s. When he couldn't get new picture tubes he simply invested in vacuum pumps and necessary tube components and snipped the necks off the tubes and rebuilt them—and they worked perfectly OK.

I reckon he was mad to attempt it but I have to eat humble pie because he became so expert at it. And what's more, he did all this in his backyard shed at home!

yeah, my bro doesn't, AFAIK, buy from russia direct. but even if you buy from UK suppliers, you are still indirectly supporting the russian economy. i haven't brought this up with him - we have enough disagreements about politics as it is.

Well you are maybe placing a few bucks in some English person's pocket where there was already money long gone to the Russian economy, and reminder that most people in Russia don't even support the war so it's not like you are making an impact outside of buying an Englishman tea after he already paid a Russian for his... idk what they prefer to drink over there other than Vodka. :P

Even in Russia, it's mostly a cottage industry, they aren't shipping thousand's monthly and definitely are not funding a war machine from that small investment, it also costs them raw resources when they do eventually manufacture. War has a way of getting funding much greater than from it's exports.

yeah, they’re playing up the “can’t fix it again” angle for the melancholy feeling.

Maybe. They may feel that way themselves.

Edit: I feel that way about my Apple Platinum 8 bit computer. It was the machine I started on, and I learned a ton! Great little computer. And of course, it can be fixed!

But, I flip that switch, hear that 1Khz beep and do not look forward to the day coming when I do have to fix it.

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