Don't forget the rimlock type ECC40.
With specs similar to the 6SN7, it's a very sweet sounding tube and useful in
many applications.

I have some but haven't tried them yet. I was worried about the Ra=11. My
current amp input circuit is a voltage amp DC coupled to a concertina, no
global feedback, so I was speculating where to try the ECC40, or indeed the
E80CC. I suppose as the first stage with cathode bypass. I have a rather nice
6J5 there right now, and a 12B4 in the concertina. Not shabby.

=== Andy Evans ===
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