I was looking up the 6F6 as I have two old radio chassis, one missing the field coil speaker (darn) and someone was felling a bunch of 6F6's. They look to be the same other than the heater draw and the 375V pentode and 350V triode specs on the 6F6.
http://www.r-type.org/pdfs/6k6gt.pdf
https://frank.pocnet.net/sheets/127/6/6K6GT.pdf
https://frank.pocnet.net/sheets/127/4/42.pdf
http://www.r-type.org/pdfs/6k6gt.pdf
https://frank.pocnet.net/sheets/127/6/6K6GT.pdf
https://frank.pocnet.net/sheets/127/4/42.pdf
The 6F6 evolved from the old type 42, while the 6K6 IS a type 41 stuffed into an octal base and envelope. Both types had round plates. Both were made in metal envelopes although I have never seen any. I do have some metal 6V6's.
That statement was perfectly valid in the late 40's and early 50's when these tubes were common.
Much of what was being manufactured in the 50's and later was mix and match from what the tube companies were making, especially the 6K6GT.
I have a few 6F6's but haven't really messed with them. All have round plates.
I have seen 6K6GT's with 6V6GT plates inside, and found some with 450 mA heaters instead of 400 mA, so I suspect that they were 6V6's with a suppressor grid instead of beam plates. All the 6K6GT's that I pulled from scrap HP 200 series audio oscillators had oval plates. I used to stuff the oval plate 6K6GT's into guitar amps made for 6V6GT's to get a different sound. Never had one blow up.
That statement was perfectly valid in the late 40's and early 50's when these tubes were common.
Much of what was being manufactured in the 50's and later was mix and match from what the tube companies were making, especially the 6K6GT.
I have a few 6F6's but haven't really messed with them. All have round plates.
I have seen 6K6GT's with 6V6GT plates inside, and found some with 450 mA heaters instead of 400 mA, so I suspect that they were 6V6's with a suppressor grid instead of beam plates. All the 6K6GT's that I pulled from scrap HP 200 series audio oscillators had oval plates. I used to stuff the oval plate 6K6GT's into guitar amps made for 6V6GT's to get a different sound. Never had one blow up.
Darn 41, 42, what is the difference? 😉
I built a Tweed styled amp with 6K6's and had them running at 350V with no problem, a Champ with proper cathode resister at 350V also. I pulled up the 41 and 42 datasheets, Easier to compare with them both from GE. The 6F6 is just a little beefier, I am guessing my transformers should be no problem for the 6K6's if I don't pick up the 6F6's that are being sold here.
I built a Tweed styled amp with 6K6's and had them running at 350V with no problem, a Champ with proper cathode resister at 350V also. I pulled up the 41 and 42 datasheets, Easier to compare with them both from GE. The 6F6 is just a little beefier, I am guessing my transformers should be no problem for the 6K6's if I don't pick up the 6F6's that are being sold here.