Wrong group...I know...but since the people here seem to be "all knowing"....
I have the innards to an old Magnavox stereo...there are five or six glass tubes that were working fine the last time the stereo was plugged in.
Are tubes still common, or are they hard to find?
I hate to throw them away if someone could use them.
What should I do with them?
Tubes are like machine tools. they arent as common as they were. You cant get them at sears anymore. But they are available in every city
they are over $10 plus per tube usually but still available
if youre screpping the agnavox and you know an electronics hobbyist they would likely be happy for the parts but it isnt in itself a windfall
I'ma musician and electr> Wrong group...I know...but since the people here seem to be "all > knowing"....
Jim Newell wrote: (clip) What should I do with them? ^^^^^^^^^^^^^^ Put them on Craig's List.
Post this to rec.audio.tubes, and include the type numbers off those tubes (if they're no longer readable, the model number of stereo).
But beware: if you think the signal-to-noise ratio is bad here, you ain't seen nuffink :-) There's several perpetual flamewars running on that group.
Bill
to contact me, do not reply to this message, instead correct this address and use it
will iam_ b_ No ble at msn daught com
Fair Radio Sales in Lima Ohio used to be a good place to get tubes, they even had tested used tubes for a discount. I don't know but they probably have a web site. What I did with an old FIsher console is gut it and install a more modern stereo. The cabinet then had extra room to store CDs.
"lens" wrote: (clip) What I did with an old FIsher console is gut it and install a more modern stereo. The cabinet then had extra room to store CDs. ^^^^^^^^^^^^^^^ I think it's really cool to have modern audio stuff in a really old cabinet. If I could find one, I would love to use an old upright phonograph cabinet.
The Russians have take up making tubes. Israel too IIRC.
There is a pretty big market for high end audio tube equipment, as is and rebuilt with modern caps and resistors for lower noise. There are even a lot of outfits making new stuff. Heck you can still buy new, high end turntables. Those folks only want new, premium tubes.
Check out e-bay prices before you decide it's worthless. In fact it might be worth selling it there, complete or as parts.
If anyone wants original parts for vintage equipment -
I know this place, Antique Electronic Supply. They have everything down to knobs, screws, and grill cloth.
Dunno about Israel, but the Russians never _stopped_ making tubes. They never got their semiconductor processing techniques up to the level of the US, so they had to stick with tube technology for their military equipment.
And there was an additional benefit..one the Russians were fully aware of. Tubes are not affected by EMP during an nuclear exchange.
Gunner
"A prudent man foresees the difficulties ahead and prepares for them; the simpleton goes blindly on and suffers the consequences."
- Proverbs 22:3
Incorrect - They *ARE* affected, just not as catastrophically as solid-state stuff.
You sure about that, Gunner? Both semiconductors and tubes operate by behavior of charge carriers in the presence of local fields. Tubes use higher potentials, but they are also physically larger with much longer charge migration paths. Hardened military semiconductors are made a lot differently from consumer stuff and smaller stuff is a lot easier to shield with given weight penalty. The parts of a system most vulnerable to EMP are interconnects, i.e. cables of any length.
This is an interesting one, and not sure of the correct answer. In early days, tubes WERE a lot harder to zap - early CMOS stuff fried if you looked at it sideways. Plus, static buildup etc on antennas didnt help - there was a story, probably apocryphal(sp) that in the 1st gulf war, the fancy solid state comms gear fried in the static induced by dust storms, and the old Collins etc tube based stuff was hauled out of storage. (Just happened to be a few warehouses of it left - I think it was near the ones holding all the WW2 Harleys...)
The other story is when a Russian pilot defected to Japan in his MIG (something) in the 70's - the Yanks were AMAZED at all the tube gear in it so came up with the EMP theory. Another theory is this was an elaborate dis-information scheme by those dastardly Russians........
So, would love to know the current state of this one - interesting, if nothing else. BTW - I just picked up a an old Collins ARC51BX UHF airborne transceiver, 70's vintage - it has a tube front end..... (and a tube PA).....full of precision machinging and castings, a JOY to behold for the sheer beauty of its construction....
Andrew VK3BFA.
PS - my metalwork is getting better, got "how to run a lathe" by Southbend, and lots of books from the local library. And a bigger hammer...
The cables are the driven antennas, they're basically immersed in whatever electric fields that occur locally. The larger the field, the larger the induced voltages.
The problem happens when the currents that flow along the cables (both external, on the sheilds, or internal when the sheilding is absent or inadeqate) go places they're not supposed to and create potentials larger than allowed.
Aside from actual physical damage to conductors from overcurrent (which would of course be identical for solid state vs. hollow state electronics) the largest problem is exceeding the reverse breakdown voltage for semiconductors I would think.
It's pretty tough to damage a vacuum tube that way, they can be broken down internally by overvoltage, briefly, and will still function just fine afterwards. My personal guess is there's two orders of magnitude between tubes and semiconductors in EMP resistance. Anything over a couple of hundred volts will exceend the PRV rating for signal devices, but a transient of around 10KV won't smoke a tube. Some of them (not all, obviously!) even *run* at that level.
Jim
The other thing that amazed people was that that MIG was made of steel foil, not titanium, not aluminum.
The theory of the day was that the Russians needed interceptors that could get to the point of incursion quickly and in great numbers, to simply overwhelm the overly clever Americans, so the Russians built large numbers of cheap interceptors. Thus the steel airframes and vacuum tube avionics.
And one should not underestimate vacuum tubes. The most feared of the close-in antiaircraft systems of the Vietnam era, the ZSU-37 Gun Dish, had a vacuum tube aiming computer.
Joe Gwinn
Indeed. As I recall...a defector brought in the first Mig-21..and the boffins were rather non plused to discover most of the fire control etc etc was using tubes.
Gunner
"A prudent man foresees the difficulties ahead and prepares for them; the simpleton goes blindly on and suffers the consequences."
- Proverbs 22:3
Okay, so I'm late and catching up, but Gunner wrote on Mon, 06 Feb 2006 20:25:04 GMT in rec.crafts.metalworking :
Plus the use of a lot of Stainless steel where the Americans had used Titanium and other exotics.
tschus pyotr
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