Quote:
Originally Posted by Merlin
It is a bit counter intuitive yes. The actual ripple signal appears across both or course, but the ratio of the two impedances determines the amplitude of the ripple signal. When ra is high, so too is the ripple amplitude, which is fed into the OT.
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It's counter intuitive because it's just not true. If almost all the ripple appears at the anode of the valve that's fine.
As an example let's say there's 50Vp-p ripple on the supply, the anode impedance is 100K and the reflected speaker impedance via the transformer is 2K. The ripple voltage will appear across this potential divider in proportion to the impedances. That is 49Vp-p ripple at the anode and 1Vp-p across the transformer.
I have treated impedance as resistance and ignored reactances in this example since it will have negligible effect on the result.
To explain it another way, the transformer is connected between the anode (lots of ripple) and HT+ (lots of ripple) so not much ripple across transformer. If the load was connected from the anode to 0V then the load would see lots of ripple.