Mixed tube output KT66 and EL84

[allsavy]

Hi I'm looking for suggestions for what will be a mixed tube amp with 2 EL84s and 2 KT66s in parallel push pull.
The amp is an experiment, point to point wired and can go anywhich way.
At this stage I have both sets of output tubes set up for cathode bias operation and have three (so far) preamp sockets to play with.
My goal with mixed tubes is to get combine a fat lead tone from the KT66s with some more defined tone from the EL84s. To further exemplify this I am considering using two phase inverter circuits, a long tail pair for the 84s which I might change to fixed bias for more definition, and a paraphase for the 66s (I heard that the paraphase these can sound cool when pushed).
The amp is presently is setup for tube rectification (5u4gb) but I'm considering installing another PT with SS rect to serve the 84s and leave the 66s with the tube rect. Might run the 66s in triode mode to better match the level of the 84s. ???
Side note: max B+ voltage will be lowish 300v-350v

I'm not sure how the the OT (a single PP OT intended for 6v6) will fit in with the Pwr amp topo. An alternative is an old heavy 4,8,16 ohm PT intended for x4 6L6). Thoughts on mixing the signal from each pwr section would be appreciated.

As for the preamp section I'm thinking marshall 18 watt topo and fender super 5D4 (the paraphase pi) with each going through the full compliment of output tubes.

Suggestions are welcome.
thanks. Savy.

[mooreamps]

You're on the right track. But consider the high end for plate voltage for the EL-84's is around 300 volts ; for the KT66 {or 6L6 it's around 600 volts}. I just don't think the KT power tubes and the 6L6 really don't sound good until the plates are above 500 volts.

So, perhaps a better match would be a pair of 6V6 with the EL-84's if you intend to have all of them drive the same O/T. If so, you could run them in mixed mode ; class A for the 6V6 and and class A/B for the EL-84's.


-g