Switched Mode Power Supplies

[JottoSW1]

OK.

Can you power a large valve power stage using this type of power supply.

If not why not and vice versa.

I'm interested why not , primarily ...

[Downunderwonder]

To watt end?

[Suburban Man]

Technically speaking there’s no reason why you can’t design a switched mode power supply to power anything, including a valve amp. The obvious reason switch mode has become popular is that despite being inherently more complex (and expensive) than a linear psu, it’s far less heavy. So, apart from sheer cussedness, why would you put a lightweight expensive power supply in a big heavy valve amp? I can imagine that in a practical design shielding might also be a problematic. 

[Downunderwonder]

Maybe you could switch mode the input supply but sfa to be done about the output transformer. It would take a big lump of transformer out of the equation that says it's too heavy to bother with but it would still be blimmin' heavy.

[Chienmortbb]

It would remove one of the really heavy transformers from the amp. Sadly you cannot remove the output transformer but you would make the amp several Kg lighter. Of course if you take out that much weight you will more than half the heft.......

[agedhorse]

Sure it’s entirely possible. The real challenges is the cost of development, testing and global safety/EMC certification for a component that’s very low production volume. 

[gilbjd]

Peavey made a 300W valve bass amp in 2009 with a switch mode power supply. Do a Google search for "Peavey VB-3".

[JottoSW1]

I will have a look for the Peavey

[agedhorse]

53 minutes ago, JottoSW1 said:

I will have a look for the Peavey

Just note that there were some reliability issues, and I don't think that they support them anymore. This should factor into your decision.

[JottoSW1]

Only ever seen one for sale few years ago

[JottoSW1]

All of my remaining Amplifiers are alive and well at present except a positive grid we talked about a while ago  . I  do not envisage buying any more