11-06-2020, 03:56 PM
valvekits Wrote:Is there some Ra-a data for push pull I’ve got a few transformers hanging around and probably got some 1j29b 1J24b and 1p24b here somewhere.
They're pentodes. So for Class A, optimum load for a single valve is just 0.9 x HT volts / quiescent Ia. (The 0.9 allows for the fact that anode voltage can't swing all the way to zero b fore going around a 'knee.')
In push-pull, class A, Ra-a is just twice this value.
if you go lower than this, you'll be going into Class AB.
Hope this helps!
