6x8

[ernie_jr]

looks like this tube could be used inplace of 6an8 with wiring changes. any thoughts about this tube?
thanks,
ernie

[DummyLoad]

likely no. shared cathode & dissimilar elements. you don't mention what the application is.

6AZ8 looks to be same as 6AN8 w/ different pining.

6CM8 looks like could be made into 1-1.5W p-p geetar amp.

6KT8 2.5W high Gm pentode with hi-mu triode.

6EB8/6GN8 may be workable as 4-5W p-p - the triode section looks similar to 1/2 12BZ7. 6HF8/6JE8/6JV8/6LF8 also look interesting.

6JZ8 looks interesting... 1/2 12AU7ish triode and a 7W beam pentode in a compactron envelope. if i built an amp using this tube, i'd have to call it the JeZabel. looks like it might make a nice 12-14W p-p amp.

6LR8/6LU8 - 14W pentode and hi-mu triode - compactron envelope - beam pentode seems to be troublesome to shake an audio plan out of without a squirrel-ey PS. perhaps a FWVD recto and 1/2 tap w/ C-LC filter for the g2 supply. 

careful and neat layout is likely a must - from past experience, most of the TV triode/pentode envelopes like to squeal when used in audio apps.

[PRR]

What he said: shared cathode.

6AN8 is still only $10. Why bother with other tubes?

[jjasilli]

I accidentally cornered the market on these tubes when I acquried a Cordovox accordion amp & tone amplifier.  I've been meaning to use the 6X8 for something sooner or later.  One issue with the pentode section is extremely hi output impedance, so it should probably drive the triode section as a buffer.  Here's a clever use of the tube as a paraphase PI:  http://www.dogstar.dantimax.dk/tubestuf/paraph.htm

If you have 6X8 tubes anyway, I could see it as a pentode 1st stage > triode tonestack driver > paraphase PI > power tubes.

[ernie_jr]

i have  some of the tubes and i am looking for some place to use them. always have to keep building something.
ernie