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flimflammed on RCA black plates 12AT7's

WhiteSE

WhiteSE

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I bought what was supposedly a quad of NOS RCA Black Plate 12AT7's. Of teh 4 tubes, only one has the RCA clearly on it in white with the 12AT7 in the rectangle atop of the tube. One tube is clearly labeled 12AY7 CBS HYTRON, one tube has no visible markings and the top plate is a double plate, the 4th tube has 12AT7 stamped 2/3's up the tube in white with no box, and has a large USA stamped in white also.

enclosed is a pic...are any of these actually an RCA Black plate? they are square getters, while I always see black plates as round getters and red RCA writing.

4tubes.jpg
 
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Well... you oughta be able to trade a 12AY7 for a couple of 12AT7s, if it's good. For the rest, try 'em and see!
 
What is the identfying feature on black plates? letter color, square/round getters? something else?
 
WhiteSE said:
What is the identfying feature on black plates? letter color, square/round getters? something else?
Click to expand...

Err...the identifying feature should be black plates! (We're not talking about the mica insulator discs, but the outside electrode of the vertical structures) I can't tell from your photo, so I had a scrabble through my box o' tubes and found what I think are a RCA black plate (which has white lettering and a square getter), a RCA grey plate with a square getter, a RCA grey plate with side getter and, just for fun, an Amperex Bugle-Boy (just in case anyone wonders what that means!). Oh, and these are 12AU7's, not AT's, but should be illustrative. As you found out, taking snapshots of tubes is pretty hard, especially if you have a crap camera like I do, but here are my best efforts:

L-R, pic 1, black plate, grey plate (both top getters),
L-R, pic 2, grey plate RCA side getter, Amperex Bugle-Boy

The black-plate is smooth looking and, well, black! The grey plates are more of a matte-finish. I make no claims for merits of the various variants, sonic or otherwise, I just have a box o' tubes!

--Bob
 

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Well, the guy agreed to refund me anyway....what a jip,,,I guess he lied about what he had...
 
Hey-Hey!!!,
The old white labeled RCA stuff is usually pretty nice. I used the 12AT7 as the driver( last in line ) on a pair of MC75's I had and they were as good as Tele's. I wish I had as many as I have of the Tele ECC81's....:(

In my sack of tubes, pulls from Tek 502's mostly were 27 of them. Since I could use a smile or so, I will probably put them on ebay and see how nutsy folks get over the 'Diamond on the Bottom' effect.

I have some old Amperex which look quite similar to the RCA's save for the Philips codes etched in. If I had anything which took 12AT7's I could conduct a shoot-out.
cheers,
Douglas
 
Hm, if the ones with square black getters and white lettering are considered blackplates I might have to do some eBaying myself... I've got a good 100+ of the damn things stashed away at my parents' house and at least that many more available next time I go visit my grandparents. I never really gave 'em a second thought as being desirable, they were just miscellaneous tubes from my grandpa's days at a TV station that I'd sort through when I needed one...
 
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