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GE 5692 BLACK base?

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Hey guys,

This is my first post, and can almost guarantee it won't be my last as I continue this tube amp diy adventure.

I'm currently trying to source parts for a 300B SET project and came across these tubes a very good price (compared to the red/brown base RCA's).

8e_1.JPG


I'm trying to get the skinny on these tubes as I can't find any information on the web regarding the black base, and the seller unfortunately knows nothing about them either as he picked them up at a hamfest.

I've seen/heard of the RCA/GE Red and Brown base 5692's and are considered the cream of the crop. Hopefully someone here has seen/knows about these obscure black base '5692's. Are these just like the original red base RCA's, or rebranded aftermarket types? If anyone has used/seen these, how do the audio qualities compare to the red base?

Thanks for any help,

-Charlie
 
SY, sorry (and thanks for the quick moderation). Those are the only pics I have.

The seller described them as a 'black base', but they very well could be brown, for all I know.

BTW: I was just reading (yes, I'm trying to do my homework) that this tube was a poor driver choice for the 300B.....sheesh.....whats a newbie to do;)
 
diyAudio Senior Member
Joined 2002
Hi,

Or you could ask the seller what the acid marking on the glass is.

If that doesn't say 5692 then they're rebranded 6SN7GTs at best and can't qualify for the high asking price of the 5692.

Personally I'd only spend my money on the original RCA red base series and I'd still have to test them myself first......

Cheers, ;)
 
Thank you very much for the input. I went ahead and bought them for $6/tube. I'll post more detailed pics when they arrive.

If they turn out to be run of the mill 6SN7GTs, no biggie at that price. Also, kinda glad I didnt spend the big bucks (yet) on the red bases that some feel are "mediocre at best" as a driver for this particular architecture, which dosent 'lock' me into sticking with 6SN7s.
 
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I have used 6SN7 as drivers in a number of commercially successful 300B amplifiers, both SE and PP and they are not a bad choice for driving 300B regardless of the fact that there may be other possibly even better choices.

A carefully designed 6SN7 SRPP running on a 400V supply will swing up to 200Vpp into 100K with <1% thd. For a simple, potentially low cost topology that is fairly hard to beat.

I have done transformer coupled drive using Tango IT and 6CK4, or 45's as drivers - and I still like the 6SN7. I run them at 7 - 10mA in this sort of application.

My 300B SE amplifier uses a 6J5 voltage amplifier and 6SN7 SRPP driver stage and has acquitted itself well against other similar amplifiers.

Truthfully I prefer the 6SN7/6J5 to just about any small signal tube I have tried with the possible exception of the 26. (Too microphonic for most uses.)

The 5687 as well as the ECC99 are other potentially good choices for this application.

I have some black base 5692 lurking around which appear physically identical to the red base 5693 I have lurking around.
IMHO I don't think the 5692 red base is necessarily the best sounding variant of the 6SN7 I have ever heard.

As always your mileage may vary..

Kevin
 
If they have the internal support-rods, then they proably qualify as genuine 5692's. (Can't tell from current pic). I'm only aware of RCA and Sylvania having made versions. So it's likely that if the above is the case, that they might be relabeled RCA's. This would be especially true if the "5692" on the tube is in a "stop sign" label ( = RCA).
 
diyAudio Senior Member
Joined 2002
Hi,

So it's likely that if the above is the case, that they might be relabeled RCA's. This would be especially true if the "5692" on the tube is in a "stop sign" label ( = RCA).

IME not likely.
In all my years I've never, ever come across a GE branded tube that was sourced from RCA.
When RCA had a specific reference then GE usually cross- referenced it with whatever product they produced themselves that was close enough to work without failure.

Cheers, ;)
 
Example 5962, labeled GE, exactly the same internals as the RCA version, frequently including RCA-type "stop-sign" type identifyer, same red-base and everything!
df_1_b.JPG


There were also versions that also seem the same too, but with brown-bases. (Not 100% certain they are the same though).

As well; there was a CBS-Hytron version, (which ended up sort of also being a GE company at the end) but I'm not 100% positive that there were also RCA's, though I suspect that it's not unlikely.


I've also seen (not often though) RCA's (not in the 5962 type though) with characteristic GE identifying dots, though this is rarer.

I think that towards the end of the vacuum-tube heyday, companies would source stock from each other occasionally to make up their own shortfalls. Retooling the machines just for one or two batches was probably considered as hassle.
 
diyAudio Senior Member
Joined 2002
Hi,

Example 5962, labeled GE, exactly the same internals as the RCA version, frequently including RCA-type "stop-sign" type identifyer, same red-base and everything!

Well, I'll be dammed.:dead:

As well; there was a CBS-Hytron version, (which ended up sort of also being a GE company at the end) but I'm not 100% positive that there were also RCA's, though I suspect that it's not unlikely.

Yes, historically I think CBS-Hytron was part of RCA and was later on sold in a deal when Richardson Electronics took over most of the vacuum tube manufacturing businesses.
At least that's what I remember but don't quote me on it.....

Cheers, ;)
 
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Actually it was very common for RCA to make tubes for GE and vice versa, certain types were mainly made by one or the other and they were made under contract. RCA Camden made tubes here in the Northeast for a lot of other vendors, as did Sylvania. Hytron had a plant in Salem and also in Newburyport, I don't know whether or not they were ever affiliated with RCA, I think CBS was their final owner - tooling might have gone to Rich***son as much of it did to sit moldering disused in some warehouse somewhere.
 
diyAudio Senior Member
Joined 2002
Hi,

tooling might have gone to Rich***son as much of it did to sit moldering disused in some warehouse somewhere.

LOL.

I may be wrong about this but I think much of this cross-manufacturing only started late after WW II which may be the reason why those products weren't that common in Europe.
In the late Sixties early Seventies European manufacturers struck the same kind of deal but mostly for the production professional types.

Much of this historic stuff can be found in a book called:

70 Years of Radio Tubes and Valves by John W. Stokes.

(Guess the author wanted to make both the British and American readers happy: tubes and valves....)

Cheers, ;)
 
I got the tubes today and took some detailed pictures. The tubes and boxes are clearly marked as '5692'.

Can any of you experts tell from the internals if these are authentic RCA/GE 5692's, or just the run of the mill 6SN7's?

BTW: The box flaps have what appear to be hand written test results. 75/50, 74/50, 70/50, 70/50, 69/50 (5 tubes). Can anyone tell me what these values mean? I'm guessing the 74 and 75 tested the best and are a good 'matched pair'?

Here are some pics.

TIA

-Charlie

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