Using single tube of Dual

[wrenchone]

I was thinking of using the nice, low Rp, high power triode of a 6CY7 or a 6DR7 as a cathode follower, but have no real use for its hi-mu roommate. In such a situation, does one just let the unused tube of the pair float, or would it be better to ground all the unused bits?

 

[Tubelab_com]

does one just let the unused tube of the pair float

Thats what I do, and have seen done on some commercial equipment.

I was thinking of using the nice, low Rp, high power triode of a 6CY7 or a 6DR7 as a cathode follower

Or just use a 6S4 or 12B4.

 

[wrenchone]

I have both the 6S4 and the 12B4A, but the power triodes in the 6CY7 and 6DR7 are nicer, like smaller versions of the big triode in the 6GF7. I wish they were available as singles. Also, if I stick an active current source under the 6CY7 or 6DR7 big triodes, I won't need to do any extra biasing to speak of.

 

[Tubelab_com]

I know what you are saying. I have used the 6DR7 and the 6DE7. Don't have any 6CY7. My favorite is still the 6EM7 (octal). The low Mu triode is great, but the high mu section varies a bunch from tube to tube.

 

[wrenchone]

All the more reason to have the little guys sit out the game...