How tall are kt66 tubes in real life?

[deci belle]

I'll check those out to see how tall they are, their current draw and the socket wiring (compared to 6L6)! Thank you, LeoGnardo!

[Leo_Gnardo]

I'll check those out to see how tall they are, their current draw and the socket wiring (compared to 6L6)! Thank you, LeoGnardo!

Pinout's the same, filament figure 1.6A per tube. Can't say I've ever seen "tall" 6550's, glass is generally wider than 6L6, some versions like early TungSol are "shoulder" tubes. GE states a length of 4 inches max "seated height", add another 5/8 inch for pins.

Much the same for their relative KT88. These days, some consider them interchangeable.

Seems KT66 are the ones to watch out for with tall glass envelopes. Why they're made that way, who knows? A holdover from 1930's build style is all I can guess.

Should be mentioned, KT66 also have a high filament current draw compared to standard 6L6. Spec sheet says 1.3 amp, compare to 0.9 A for 6L6.

Good luck with your project!

[Jammin'John]

Yea,you can see in the picture of my amp that the 66's are taller than the 88's.

JJ

[big_teee]

A little off track, but do KT66s sound that much better than a good 6L6?
I've had a lot of 6L6s, and EL34s, but no experience with KT66s.
T

[deci belle]

I only know KT66 tubes were in the Marshall jtm45, and I wanted to try those in my big tweed amp head, biGT! I made the 5F8a chassis' tube socket centers extra wide to account for KT66 tubes, knowing that I would need to get a taller cab, eventually.

Hmmm, I know my PT can handle the filament draw of the KT66's 1.3A, but I'll have to make sure about 1.6A for each 6550A, LoeGnardo~

GE states a length of 4 inches max "seated height", add another 5/8 inch for pins.

That's the exact figures for the short-bottle 5U4GBs I keep a look out for on the tweed head I have right now. They juuuust fit when installing!!

[Jammin'John]

MidRange

A little off track, but do KT66s sound that much better than a good 6L6?
I've had a lot of 6L6s, and EL34s, but no experience with KT66s.
T

They are thicker sounding with more bass,woody mids,very clear highs.
I run the Shuguang in a Tweed Pro http://www.cnjradio.net/fenderamps/pro_5e5-a_schem.gif and Low Power Tweed Twin http://www.cnjradio.net/fenderamps/twin_5e8-a_schem.gif

I like them better but YMMV.

JJ

[deci belle]

Nice, JJ— thank you for pointing out those characteristics and for making the the recommendation!

[pdf64]

A little off track, but do KT66s sound that much better than a good 6L6?
I've had a lot of 6L6s, and EL34s, but no experience with KT66s.

Yes, my experience / perception is they've each got their own response to being overdriven; KT66 seem very smooth and clear, almost as if they compress more than distort.
I found that aspect a bit confusing until I got used to them.