Zener V drop and PS capacity / rating

[chopstuck]

What effect do zener V+ drop devices have on current capacity of power transformers ?

My example is an old Zenith 6BQ5 console that ran another tuner chassis- without that chassis the B+ runs high.
I used a low power zener and a mosfet to cut the V+ from 375 to 330 vdc.
The big transistor does get more than warm when left on an hour. Nothing too scary but what effect would it have on the power supply's ability to deliver current when needed ?
Is there a formula to figure out the current consumed by the dropping method and subtract that from the original transformer rating ?

My amp sounds a bit constipated and I'm wondering if the PS is stretched too thin..

Marc

[M Fowler]

Here is the link to a previous discussion we had.

https://tubeamparchive.com/viewtopic.ph ... ight=zener

I would think as long as you have the correct type of zener diode of the correct voltage rating, the diode should be expelling the heat to the chassis for reverse anode and some heat may occur in the PT from pushing the voltage through the zener.

I don't have any formula.

[tubeswell]

I don't see how the zener would steal current from the B+ supply in a way that would somehow be to the detriment of the tubes. The zener has to be big enough to survive the voltage drop x maximum-current equation, that's all.

[M Fowler]

Need to determine your plate voltage and adjust the dropping string accordingly.