The GM70 is now a 211

I think Nic Wilshire is working on a GM70 and looking for a driver with high
transconductance, low Ra and mu around 35. Like you I'd use a 6SN7 type for low
distortion and tonal accuracy, and in fact I've invested heavily in 6SN7, 7N7,
7AF7, 6J5G, 6P5GT, 2C22, 7193, 76, 56, 37, 27 etc - the whole family back in
history. I tried out a 6SL7 for the first time in the amp I'm working on now
which is a real departure from my point of view. I can't help feeling that
valves get more 'lush' sounding as you progress up the mu ladder through 6N1P
to ECC83 - not something I really welcome. I had to use a higher mu valve for
the simple reason I only had one socket available! Outputs are parallel PP
12b4, a nice discovery because they sound great. A bit like driving a 2a3 (-40v
bias). I have a 6.6K OPT in the amp - not sure what the 12b4s want to see.
Chris Found suggests downloading the PP calculator from Tubecad - have you
tried it? Andy

=== Andy Evans ===
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