In article i,
Iain Churches wrote:
Fairly typical of AF valve circuits. Hum.

A common misconception.
With a properly designed PSU C-L-C-R-C and with
attention paid to layout and ground buss, one can build
valve power amps with no hum or thermal noise even EAS
(ear against speaker) And it plays music to please the
most discerning ears.

My 50W PPP tube amp has a noise floor of 80µV
that's -106dB

That's not typical.

--
*If you think nobody cares about you, try missing a couple of payments *

Dave Plowman London SW
To e-mail, change noise into sound.