[Phil Allison[_3_]]

"John L Stewart"

( snip )

Depending on the loading conditions of a triode power stage, from 2/3 to
4/5 of this ripple voltage will be applied to the load. Unfortunately,
most loudspeaker systems have one or two
resonance's below 100 HZ. One of these could be at or near the power
frequency. Presto!! We have objectionable hum in the listening room.

Figure One illustrates an ordinary center tapped full wave power supply.
Two sides of the HV winding measured 38 & 40 ohms.


** FFS - just add 2 ohms to the 38 ohm winding.

Problem gone.

Dodgy 5U4s etc not withstanding.

SET amp loonies sure are a bunch of neurotic old women.



..... Phil