Is It Possible ?

[skynyrd]

Is it possible on a amp running 6 6L6 tubes to mod it to run 2 EL34`s and 2 6L6`s at the same time ?

[R.G.]

Yes.

[Chuck H]

What R.G. didn't elaborate...

Is that the OT primary impedance for a 6x6l6 amp is likely suitable for 2x6l6's and 2xel34's. If you use one of each tube type on each end of the OT primary and supply each tube type with the appropriate bias (with separate supplies if needed) then it is possible to run 2x6l6's and 2xel34's in an amp designed for 6x6l6's. And FWIW mixing tube types on the same OT has been done many times.

Chuck

[skynyrd]

Thanks guys, have kind of tossed around the idea of having that done for a while I love both 6L6 and EL34 sounds and always wanted to mix the 2.

[stokes]

Mesa has been doing it for years in the simul-class amps.They use what amounts to an ultra-linear OT with the screen taps connected to the plates of two of the tubes to give a slightly lower plate voltage to that pair.

[Chuck H]

Mesa has been doing it for years in the simul-class amps.They use what amounts to an ultra-linear OT with the screen taps connected to the plates of two of the tubes to give a slightly lower plate voltage to that pair.

More likely a slightly different primary impedance. I don't think the +V would be much lower with the tiny DC resistance of the additional windings. Clever too. I've never examined the simul-class circuit but it seems like a good way to do it. Not neccessarry considering the lee-way in OT primary impedance as it relates to guitar amps, but clever anyway.

Chuck