Tube mixing

Wolfie, if the Large Hadron Collider is in use at the time you try this, the result will be a black hole that will eventually suck in the entire known universe.

If the LHC is not in use at the time, I agree with Mlsstl that the result would be a significant increase in distortion. The positive-going and negative-going halves of a symmetrical sine wave, for instance, would most likely emerge no longer symmetrical, as a result of differences in transconductance (Gm) and/or other parameters.

The same thing would apply to using a 6L6 and a 6V6 together as a push-pull pair, probably even more so (i.e., even greater distortion, and/or more rapid destruction of the universe), as Gm and several of their other parameters differ widely. On the other hand, while using a pair of 6L6's in one channel and a pair of 6V6's in the other channel would eliminate the possibility of interaction with the LHC, it would most likely result in a significant sonic mismatch between channels.

Best regards,
-- Al

Wolf, I could understand your consideration of this tube complement (?) implementation if you still resided in the land of Maui Wowie, but what is your excuse now...?

...but it seems to be a way to get the advantages of different tubes ALL AT ONCE!

That's one of those ideas that sounds great if you say it fast enough.

Rather like deciding your next car should have an 8 cylinder engine with 4 cylinders from a Chevy and 4 from a Ford to take advantage of the strong points of each.

That's usually not a good engineering approach. ;-)

Hey...I'm not planning to try this as I assumed there would be good reasons not to but somebody had to ask (actually nobody HAD to ask), and now I know and I feel I've learned something. By the way...I'm sure some near sighted tube head has accidentally stuck similar but different tubes in something, so I feel this thread has performed an important public service.

I think the impedance mismatch alone may be a problem, causing either the push or pull side to have a different load. Even with the same bias load, the frequency response can also be different enough, to possibly overheat the output transformers. I've used two different brands in each side (same number), for a blend that I liked better. This was as much of a difference I have tried. But, I wouldn't risk a totally different tube in each push-pull side.