GE 5692 BLACK base?

[kstylianos]

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).



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]

Charlie, any chance you could get a close-up pic showing the internals?

[kstylianos]

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

[SY]

Without seeing the insides, it's tough to tell if they're just relabelled 6SN7 or genuine 5692. You might ask the seller for a better pic...

[fdegrove]

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,

[kstylianos]

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.

[Original Burnedfingers]

Quote:

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.


Ya, you outbid me I needed two of them.

[kevinkr]

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

[kstylianos]

I dont need all 5.

We can work something out if I can test and find a good pair.

[Original Burnedfingers]

Quote:

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.)


I just love the 26. Its just to damn bad I can't get the hum out without resorting to battery packs to run the 26's heater.