Is a switched mode supply feasable for tube amplifiers?

[twinsen]

switched mode power supply tube amplifiers

Hi all

I was wondering, instead of these massive transformers, would it be feasable to use switched mode supplies for the HT in tube amplifiers? In fact one could even generate the other voltages too...they would be far more regulated...

Lets say, 1200v @ 200mA?

I havent found anything on the web, which makes me think there is a reason as to why it is not an option....

I found one in Elekt*r but that was for an audio amp where the anode voltage is only 300v odd...

 

[probert]

Hi Twinsen,

I was wondering about it as well, and I didn't find an exact answer.
I've asked some older guy, who has practice in tube technology, and they said : just a big electrolyt capacitor (or a tube regulated power supply ??) will do that job perfectly, because it has a kind of a "soft" response for the dynamic load. You may not even need a strong regulated power supply, that keeps preciselly constant supply voltage (just take a look at a penthode output characteristics), but eliminating hum remains important on the other hand. In this case, why not trying a non regulated, but properly filtered switchmode PS at first.
I think, You will get the answer by building a switchmode power supply for
a tube amplifier and listening it. (At that case, would You please inform me about Your results?

probert

 

[flatulent]

yes

Yes. It has been done. In the old days ham equipment for use in automobiles had a switching power supply for the tubes in the equipment. Heath Kit had them as well.

It is probably economic resons that it is not done for mains operated equipment today.