845 PP Prototype

[artosalo]

This won't change the results already obtained. RMAA has sufficient (frequency) resolution for these measurements.
Or what is your idea about better resolution ?

 

[artosalo]

2.5Vpp ripple is a lot for a single ended voltage stage with 6db PSRR like a common cathode amp

Yes it is. For the entire front end stages of a tube amplifier some 1...10 mV should be the target.

In earlier discussions (2.5 Vpp) I have meant push-pull output stages only.

 

[Bigun]

to what extent is the gnfb relied upon to reduce audibility of residual hum ?