Switch power supplies?

[mhuss]

I see Blackstar has a "lightweight" new line out with "no conventional power transformer." It certainly has a very small PT buried in a switch mode power supply (SMPS). I've often thought they'd be a good idea for a tube amp, since the 80s when I first encountered them - potentially halving the iron weight.

Has anyone experimented with higher current switchers? I've built preamps with low current/high voltage SMPS, but nothing that could supply dozens of watts to power tubes.

<snark>Hopefully Blackstar hasn't patented using a SMPS in a tube amp like they patented their variable slope resistor</snark>

[pdf64]

There’s the Crate V33 https://el34world.com/charts/Schemat...te_v33_212.pdf

[Helmholtz]

Nothing inventive with a high voltage high power SMPS.

[mhuss]

There’s the Crate V33 https://el34world.com/charts/Schemat...te_v33_212.pdf

Thanks. (Crate, the paragon of quality. )

Everything in there looks fairly standard from a SMPS point of view - the trick is getting or winding the transformer!

[loudthud]

Just about any desktop computer has a SMPS in the 50W to 300W range. If you can find a dead one, they can, with all due caution, be repaired. The trick to re-winding one is to figure out which winding is used for feedback.

[Mick Bailey]

I don't understand why mainstream tube amps didn't go over to SMPS a long time ago, given their efficiency, broad input voltage tolerance, and low manufacturing cost - though from a repair perspective they are more involved to troubleshoot. I suppose one aspect is that they're very well regulated and maybe too 'stiff'. You'd think that this could easily be designed out to give load-dependant sag.

[J M Fahey]

Yes to both, but Musicians, in theory "revolutionaries" and "free thinkers" in practice are the staunchest Conservatives on Earth.

At least as far as guitars and amps are concerned.

[nosaj]

Walking oxymorons or contradictions.....
nosaj

[mhuss]

It'd be easy enough to add an RC at the output to add some softness.

[xtian]

SMPS is a great idea...as long as they're MODULAR! Meaning, easy to replace as a unit. They're cheap!

[loudthud]

Soldano has released a 30W amp with an external SMPS and a class D power amp. Sorry, no tubes.

Read about it here: https://www.ssguitar.com/index.php?topic=5155.0