Hi Greg,

tnx2u for your interesting explanations and the schematics
on ABSE, too.

So far, with "real" cathode resistors in such LTPs, I used to use the rule
of thump that the R value of the cathode resistor should be dimensioned so
that the voltage drop across it should equal ~1/4 to ~1/3 of B+ for good
results, resulting in a R (impedance) value high enough to act
nearly like a CSS, giving good balance for both outputs.

This R value - to be more precise the voltage drop across it - has to be
considered when drawing loadlines and deciding on operation points, because
the dropped voltage must be subtracted from the "available" voltage when
looking up operation points in the tube data nomograms.

So, I am wondering how to compute the voltage drop across such a CSS, to
further on compute the voltages available across the load resistor and the
tube rp.

Additionally, you suggested a fixed R + trimmer combo for the
emiiter/source resitors in circuits you posted on ABSE, to get some range
for exactly adjusting the bias due to data variations of the actual SS
parts used. Besides this, how to dimension the circuits you posted for
other currents as in the actual circuit, the original poster asked for?
Without having looked up the circuit he talked about, I suppose because of
mentioning the "Mullard 5-20" (or something like that) a 12AX7 was used,
which has pretty low current (probably well below 1mA per section) at its
usual operation point(s). When using, say, a 6SN7 or 6CG7 in such a LTP
instead, the needed current will be in the 5-10mA range instead. How to
adapt the CSS circuits you posted to such current demands?

Tnx2u!

Tom