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 electronics repair guy amongst other
talents/hobbbies/jobs
Jim Newell wrote:
There is an active market for these used and/or obsolete parts. If your
tubes are the usual 7 or 9 pin all glass tubes, they probably have price
tags of a few dollars each when you buy them on-line.
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The console stereos are so big and clumsy that you can't even give them
away. Smaller self contained radios from the 50's and 60's have value.
Complete units prior to the 50's have substantial value.
Jim Newell wrote:
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.
tubes have numbers on them that say what they are (like 6v6 or 35w4 to
pick two you might find in your amp) - there is a news group with
"radio+phono" in its title - offer them there and someone will take
them off your hands, maybe even take the whole thing - the poiwer
transformer will be worth something, as will some of the other parts
of the amp - maybe the amp itself is needed by a collector of such
things (personallly, I like older electronics than that, or much
fancier, but there are those who do collect such things)
Bill
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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 -
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a lot of links,
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
Gotta say would have been interesting to see the entire USAF RAF and CAF
with the exception of the A-10 reduced to having the handling
characteristics of a flying cement truck
Gunner wrote:
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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