[Phlogiston]

Can anybody tell me the difference between the 7AC base (6L6) and the 7S (8417) base? Look the same to me.
 
I wanted to try some tube rolling on my new project and can't see why they speced the bases different.

Blog/story to follow - Super MP3 adaptor -

[Ron Ramirez]

Agree, 7S and 7AC look the same to me as well.

Only, tube type 8417 is listed as having an 8LY base on my favorite online tube database, NJ7P.org?

Edit: Duncan Amps shows 8417 as having the same pinout as 6L6. I'm not familiar with the 8LY designation.

Edit #2: RCA tube manual RC-30 shows the 8LY designation as having pins 1 and 3 tied together (plate). Otherwise the same.

[Phlogiston]

Ok. I see that now on RM. My 1966 RCA tube manual (25) does not list the 8417, so I got the base off of another site. I guess that site is wrong. Still I wonder why 7S and 7AC are drawn the same - and we might never know.

So I don't think that I'll try that tube.

Thanks