Champion 600 -- with an EL84 tube?

[madzub]

Has anyone installed an EL84 power tube in place of the 6V6 in their Fender Champion 600 amp?

If so, did you use a tube adaptor (like a Yellow Jacket) or did you change the socket?

If going the socket route, what circuitry needs to be changed? Looking at bias charts for the two types of tubes, it seems they line up pretty much the same, but do the screen or grid resistors need to change?

And, how does the sound differ?

[HTH]

Cathode resistor for a single EL84 is in the region of 220R, for a single 6V6 you'd want 470R.

I'd install another socket for the EL84 and have a DPDT switch to lift the cathodes of each to turn the valves on/off. The other half of the switch could be used to switch cathode resistors - I'd just parallel another 470R with the existing one for the 6V6 so you get around 220R for the EL84 setting.

As for tonal differences, the EL84 will be raunchier/dirtier with less bass and more midrange.