Is it tradition that we use linear PSUs for valve amps?

[Paul Uszak]

This question is asked with full respect for the valve community, but I can't get my head round the following...

Is the PSU an important part of a valve amplifier? Would it be wrong /bad to build valve amps with switch mode supplies for high and low voltages? I realise that there is tradition, and that's very important. But there must be those who are only concerned with the valve sound. The source of the electricity might be of secondary importance to them.

Some say that a SMPS puts out weird noise onto the output. Yet most laboratory PSUs are switch mode. Your TV and PC are switch mode. I also understand that Europe has banned linear power supply bricks. If you buy something in Europe that comes with an adapter, no matter how sophisticated or sensitive, it will come with a switcher these days.

Yet the majority of valve amplifiers I see designed run on huge iron transformers, chokes and other assorted inductors*. Why?


* - Don't know about the solid state guys though...

[rayma]

Originally Posted by Paul Uszak

Yet the majority of valve amplifiers I see designed run on huge iron transformers,
chokes and other assorted inductors*. Why?

It's partly tradition, and partly most tube guys not knowing about smps.
PSU-COMP - Power Supply for Tube Amp - PCB + Passive Components

[Paul Uszak]

I don't understand. Isn't that a linear power supply and they just haven't included the huge iron transformer(s) in the picture? It's described as having passive components connected to transformer(s) via 18 gauge wire. If it was a switcher there would in all likelihood be an on pcb mounted transformer. Probably yellow. They're always yellow...

[rayma]

Originally Posted by Paul Uszak

I don't understand. Isn't that a linear power supply and they just haven't included
the huge iron transformer(s) in the picture?

Yes, this is about the farthest most tube gear goes with solid state power supplies,
but it's still linear regulation.

[JMFahey]

Originally Posted by Paul Uszak

This question is asked with full respect for the valve community, but I can't get my head round the following...

Is the PSU an important part of a valve amplifier?

Yes, VERY important.

Would it be wrong /bad to build valve amps with switch mode supplies for high and low voltages?

YES.
They are too stiff; voltage dropping under load is an important part of tube sound, at least for Guitar and Bass.
So much so, that some of the very few SS amps "approved" by hardcore Tube players add thatn on purpose.
There is a famous Guitar amplifier (used by Metallica , Korn , Rammstein, Evanescence, and 1000 others) which even gives the user the option to switch between very saggy Tube rectifiers and stiffer (but still saggy) Silicon diodes, for different flavour.
That feature is SO important that the amplifier is called the Mesa Boogie Dual Rectifier, go figure.

An externally hosted image should be here but it no longer works. Please upload images instead of linking to them to prevent this.

click twice for maximum image size and check the back pnel, you will see:
* 2 x 5U4 tube rectifiers; the silicon diode ones areinside
* the 3 diode type selection switches for differentb combinations
* it even has a Bold/Spongy switch which makes the supply even saggier.

I realise that there is tradition, and that's very important. But there must be those who are only concerned with the valve sound. The source of the electricity might be of secondary importance to them.

As you see, it is important.

Some say that a SMPS puts out weird noise onto the output. Yet most laboratory PSUs are switch mode. Your TV and PC are switch mode.

All 3 are very poor examples.
Lab supplies sit on a bench; in TVs and PCs you find puny little poor quality amplifiers driving cheesy speakers and the main device is not Audio but something else, either killer colour image of the latest soap opera or computing/gaming/NET surfing, etc. ; a guitar amp has **microvolts** sensitivity and stages amplifying that must share chassis space and ground with the SMPS.

I also understand that Europe has banned linear power supply bricks. If you buy something in Europe that comes with an adapter, no matter how sophisticated or sensitive, it will come with a switcher these days.

Tube amps are not powered from bricks.

Yet the majority of valve amplifiers I see designed run on huge iron transformers, chokes and other assorted inductors*. Why?

Read above.


* - Don't know about the solid state guys though...

[DF96]

Originally Posted by rayma

It's partly tradition, and partly most tube guys not knowing about smps.

Yes. I would not know where to start on designing an SMPS, and I don't think you can buy a suitable one for valves like you can for lower voltage (or buy a high voltage transformer).

[SY]

See the Audionics/Berning BA-150 for use of switchers 40 years ago. Likewise the TF-10 preamp. There have been many examples since.

[AllenB]

Does a vibrator supply count?

[wintermute]

I had one of those in an old valve car radio Allen!

Funny the things you see close together on the front page of the forum SMPS for valve design

Tony.

[AllenB]

Yes, I have one also, somewhere.. I don't much care for the idea in a car, and the parts were not that interesting for other purposes so it remains.

Although I might spend months on a linear supply for home use if it were for a car I'd probably go switched and focus on the preventative, ie filtered from all angles and whatever it takes.

Charging my phone is enough to throw out weaker FM stations.