[bcowen]

.

 

[Zachik]

Contest time.

Whoever can identify this tube first gets an all expenses paid trip for 2 to Belize for only $8995.00:

I am guessing it is a trick question, and the answer is not the obvious Frankie?!

 

[bcowen]

.

 

[attmci]

Nope. Good guess though.

188 is GE
The photo had been PSed.

 

[bcowen]

.

 

[attmci]

Good eye! And you're half right. It is GE labeled but wasn't made by GE. But no PS'ing involved (I have a reputation already for sucking at that). It's the real deal. But what tube type?

Most of the loktal tubes were made by Syl (to compete with the RCAs).
There are also National ones. So you scored a National 7n7?

 

[ilikepooters]

7AF7?

The round plates seem a bit of a giveaway, and reportedly better sounding than 7N7 types.


Question is, i'm too lazy to read up, but do they share same pinout as 7N7? or need another adaptor?

 

[Ripper2860]

7N7 and 7AF7 share the same pin configuration and are drop-in replacements for 7N7. I agree that the pic looks like a 7AF7 but could be a 14AF7 if Bill is being devious.

 

[bcowen]

.

 

[bcowen]

.

 

[Zachik]

Ding Ding Ding!!! 'Pooter wins! I'll PM you my address, send me a check, and as soon as it clears I'll get your Belize tickets OTW to you. LOL!

Same pinout as the 7N7 (so same adapter), just a lower gain version. But not much lower -- amplification factor of 17 versus 20 for the 7N7 (which is the same as a 6SN7). Cannot perceive any volume difference through in the Lyr, probably due to the hybrid output topology. Interestingly, the 7AF7 has only half the heater current of the 7N7, but not half the gain This tube sounds really good, and I suspect (as you suggest) that the round plates have something to do with that. I still prefer a true Frankie right at this point, but I haven't put much time or really put this one through its full paces just yet. I'm going to listen to it through the weekend, and then put a Frankie back in and see what develops.

@attmci , not sure if this was made by Sylvania or National Union. I suspect it's a Sylvania, but haven't seen enough of these around to come to any conclusion.

Bill - I am curious, what is the difference between 7F7 and 7AF7 ?
7F7 can be easily found on eBay. 7AF7 seems a lot more scarce... At least at the moment... (@Ripper2860 did you go to eBay and quickly buy ALL 7AF7 tubes?! )

 

[Ripper2860]

(@Ripper2860 did you go to eBay and quickly buy ALL 7AF7 tubes?! )

I plead the 5th...

BTW -- 7F7 is closer to a 6SL7 than 6SN7. 7AF7 and 7N7 are virtually identical except that 7AF7s seem to be all shorter glass and round plates and are more closely aligned with 6SN7.

 

[bcowen]

.

 

[Ripper2860]

For those visual folks ...

7F7 / 6SL7



VS

7N7 / 6SN7



VS

7AF7

 

[Zachik]

So, bottom line:
7AF7 can be used with Lyr 3 (and 7N7 adapter).
7F7 should not, because amplification factor is way too high ?