6360 & QQE03/12 & QQE02/5 have common screen grids, so the two tetrodes cannot be triode connected individually for splitter service.The driver could be replaced by a 6360 tube with some minor changes.
Not really an option with minor change ...
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I did a quick simulation, the 6N6P gets virtually the same plate and cathode voltages, no schematic changes needed.
The EL95 tube, which is actually half of the ELL80 tube, is very linear in the triode connection, something like a 6V6GT-triode connected in a small package and a replacement for the ECC82, which is not that and which is very bad, especially if you consider that it is a paraphase to the phase turner, where relatively large distortions are added in the second stage of the turner. E80CC would certainly be the best, but it is expensive and difficult to obtain, and with the use of an adapter, it is possible to use EL95, PL95 and even the original ELL80 if by any chance it is obtained. I don't have it documented anywhere on paper, because I serviced Davoli-Krundal amplifiers quite a long time ago, but I remember well that the output transformers, and the output stages of those amplifiers with EL500/EL504 in general, worked very linearly and with very low distortions (so real HI-FI !) in the frequency range from ~30Hz to 16kHz above half of the maximum power. So from an amplifier with Pout~60W, more than 30W can be expected, which can be classified under strict HI-FI criteria.
60W rating is not a good figure alone. One needs to see at which frequency. Usually if frequency is not specified it means @ 50Hzb but still it's a guess.Yes, that's what I'm worried about too. The trafo is certainly rated for 60w
Assuming 50Hz the power rating at 30Hz is barely 22W. If it's 60W at 80Hz it will be even less. Measure the (external) size to make a better guess.
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