Anyone else like Vacuum Tubes

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Like this tetrode, which can handle 2MW in class C mode. You can't see the internal bits, but you probably wouldn't want to look at a 10kW filament anyway (600A @ 16.3V).

(Looks sort of like a Dalek...)

And let's not forget specialty tubes such as klystrons and traveling-wave tubes, which, AFAIK, have no "sand" equivalents.


And tubes can withstand overload conditions that would send solid-state devices to an early grave.

Oh, and I've NEVER seen a piece of tube gear suffer the "cascade failures" that sometimes wipe out transistors downstream (and occasionally upstream) from the original failure point.


12BH7's (used as the "voltage amplifier" in many McIntosh amps) weren't in current production last time I checked, and were getting up to $20+ for NOS.

Fortunately, they'll last nearly forever in an MC-30!

The EI example I own is a pre-bombing tube. I have a GE tube that was made in 1993, at the time it was called the last commercially available glass tube. It was made in Kentucky by MPD, and bears a code of 93-03, corresponding to January 1993-production ceased in June. ("03" means third week, so third week of 1993 = January 1993.) I also have a cheap Chinese 12AX7, the type that had sky high failure rates. I figure that most of them went in the trash, so my example should be a collectible one day. I have a number of JAN (US/NATO military) tubes, as well as a Marconi tube from Swedish Army NOS stock. I have WW2 JAN tubes as well.

Chinese 12AX7's as well as Chinese tubes in general have vastly improved in quality as well as tonality. Shuguang 12AX7's are actually considered desireable because of their hi gain and low noise when used in V1 in guitar amps with Bassman/Marshall style circuits. Shuguang EL34BH's also sound good, but all of their power tubes still seem to have cathode poisoning issues.

Fortunately also they don't sell for $150 and > , which are the prices that Mullard, Telefunken smoothplate , Amperex, Boxplate Tung-Sol, and RCA Blackplate 12AX7's now command.

I never did get a Shuguang in my collection. Mine is just generic "MADE IN CHINA" so who knows who made it? THis tube is from around 2000, so fairly old.

Mullards were good tubes. I think I have a Mullard in the collection. I'm not sure if I have a Telefunken. I have a LOT of 6 volt GT envelope tubes, the types that were only used in radios and nowhere else. The goal was to preserve examples of box design and tube silkscreening, so I took virtually anything I was handed. I DID turn down an Amperex tube that was meant for a transmitter, it was glass and HUGE! I didn't have room for it. One guy had a crapload of tubes that had sat in a barn or garage and the boxes were all moldy, I took 3 or 4 of the best preserved ones. Guitar amp tubes are nearly all 12 volts, and are the A- types.

Towards the end of their production, Telefunken branded tubes contracted out to other manufacturers, most notably to Tungsram (Hungary), RFT (E. Germany) and Ei (Yugoslavia). Real Telefunkens can be differentiated from the rebrands by the '<>' in the glass at the center of the bottom of the tube.

FWIW, Amperex had two fabs, their main was was Heerlen, NL and a second fab on Long Island, NYC.

My interest is purely aesthetic. Recently my life-long bachelor neighbor moved out and left a marvelous tube radio in the rubbish. The Missus grabbed the lovely wood cabinet and I filched the innards. I plan to put tiny light bulbs behind the actual tubes so it looks like they're glowing, and have a chip play static and bits of old radio programmes.

Love the idea of creating art with radio tubes ....

Why not just make it functional?

I worked at a Radio Shack (1980's) that still sold some vacuum tubes. We had a tube testing device so people could bring in the tube that they thought might be bad and check it. Newer electronics are easy to take for granted. They just work. Older technology had more of a mystique. They invoked a sense of wonder. Vinyl records are similar in that way. A record that sounded good was easy to appreciate, since so many did not.

Why not just rehab the radio and use it? Chances are all you'll need to do would be to find new tubes for it, and possibly change out any caps that have either dried up or drifted from their values over the years. You may also need to change out the grounding scheme on it to utilise a modern 3 prong cord instead of the 'death cap' and polarity switch.

I wouldn't know where to start ... Frankly, every tube appears to be burnt out, I havent opened the marvelous box that I guess contains the transformer. Don't know how to tell if it's OK.
I will take a pic and post it.

What state do you live in? (PM the answer to me)

When i was about 20 years old, I had an obsession with home audio, and always wanted to be able to compare the difference a tube amplifier made, versus the traditonal amp. I had a really nice system, not super-high-end, but an upper grade, nonetheless. I had a Carver amp, and Definitive Technology speakers, which was the best i could afford at the time. Anyway, I've read many, many, times, how the sound of tube equipment was something that had to be experienced to be appreciated, and sadly, i never had the opportunity. I'm not into audio anymore, anywhere near like I was then, but someday i plan to get back into it, and plan to listen to some tubes someday. I'm so damn obsessive about having the best possible though, that I think I'd have to hit the lottery to buy anything that would keep my OCD at a tolerable level. Damn, those things can get expensive.

Is this a find or what ??? ! !!



Restore such a thing of beauty ???

YES!

I am a part of a popular web forvm on antique radios (you can Google for it) and you set looks to be VERY restorable - and if you are willing to take the time to learn about what you have and are even semi-handy at using a soldering iron, you can do the work yourself.

There are several rules of thumb that I usually go by when I dig into a newly-acquired antique radio, especially one of those wonderful pre-WWII sets:

First - unless I see clear evidence to the contrary, such as chalky white where that mirror-like stuff should be on the inside of the glass (it means that all of the tube's good vacuum has leaked out), I go in on the assumption that all of the tubes will be *GOOD*. They do NOT go bad sitting unused.

Second - SOP is to change out the set's electrolytic filter and wax-paper capacitors as they are almost universally BAD - the electrolytics dry out (unless replaced, a bad filter cap can take the rectifier tube and/or an expensive power transformer down with it) and the wax paper in the other caps rots away from the same cascading acidification reaction that turns old newspaper yellow. That is called 'recapping' the set and is why you *NEVER* 'plug it in and try it out' before such work is done.

Third - read any and everything that you can on the subject, ask whatever questions you can in the radio forvm, be safe and HAVE FUN - the feeling that you will have when that set makes nice noises for the first time in perhaps fifty+ years can't be beat.

Fourth - expect to lay out no more than about $20 for parts for electronically restoring a normal set like that (assuming no unexpected difficulties). They are generally cheap and plentiful and modern replacement capacitors are light-years better in quality and design (and far smaller in physical size) than those useless antiques.

Fifth - once restored to safe and reliable operating condition, it will outperform pretty much any AM broadcast radio available new today and just sound great - it will blow your socks off. These sets were intended to be the centerpiece of the house much like big-screen LDC TVs are now - and fully restored pre-WWII console radios are just as 'at home' in a modern-day living room as they were when they were new in the 1930s. They are KEWL today.

What is the make/model of your set?

Mike