Solid state rectifiers in valve amps?

[walpurgis]

I see many valve amps with valve rectifiers, but there are some about with solid state rectifiers.

Are there arguments in favour either way?

Strikes me that as long as a clean power supply is created, it shouldn't matter which is used.

[Marco]

I noticed quite an improvement when I went from valve to SS [MOSFET] rectification in my Croft preamp - most definitely an upgrade. 99% of the time, however, it's been the other way round: valves win.

Many others who've carried out the same mod (with a Croft amp) have arrived at the same conclusion. Indeed, Glenn himself recommends it as an upgrade.

Marco.

[User211]

I've got a solid state rectifier I can plug into the valve rectifier socket in my Lampizator Big 7 DAC, which has been modified internally so extensively it is nothing like the original Lampizator unit.

That aside, I never use it. Because it doesn't sound better than the valve rectifiers I have. And I have a lot of options. Most of the time I use a Westinghouse 5U4G.

[User211]

Photo of said rectifier, cos it's cool.
https://uploads.tapatalk-cdn.com/20260912/eb2306971b606a1e6535d0938bac93a3.jpg

[User211]

I thought it was solid state. It's not, it's a metal envelope vacuum tube. No wonder it gets so frigging hot!.

Sorry about that. So ignore what I have said, basically, apart from the Westinghouse sounding better.

[Barry]

I have a couple of solid-state full-wave rectifiers built into a octal base unit. They look similar to this:


https://www.mikehillservices.com/_webedit/cached-images/22-75-0-800-wide.jpg

The original idea was to try them in a pair of Quad II valve monobock amplifiers, or in a Radford STA-15 III amplifier. However I never did get around to doing it. I still have them somewhere; all I can remember is they were made in the UK.

[walpurgis]

A thought that crossed my mind. Are there any SMPS equipped valve amps?

I guess some may describe that as a travesty. I'd find it interesting! :)

[Macca]

Depends on what you mean by a 'valve amp.' There's some amps with valve buffers that use SMPS power supplies but power section is solid state.

[Ali Tait]

Used to have a WAD stereo chassis PP 300B (The Tim De P design) that used a GZ34. Using different makes was good way to tweak the sound. By far the best was a NOS Mullard, I was lucky to get hold of some boxed GPO examples. Great valves. Is it just me, or does anyone else love the smell of old valves in boxes? Like old books.

https://i.postimg.cc/0rQbjGcS/Whats-App-Image-2026-09-13-at-12-00-25.jpg (https://postimg.cc/0rQbjGcS)

[Barry]

Used to have a WAD stereo chassis PP 300B (The Tim De P design) that used a GZ34. Using different makes was good way to tweak the sound. By far the best was a NOS Mullard, I was lucky to get hold of some boxed GPO examples. Great valves. Is it just me, or does anyone else love the smell of old valves in boxes? Like old books.

https://i.postimg.cc/0rQbjGcS/Whats-App-Image-2026-09-13-at-12-00-25.jpg (https://postimg.cc/0rQbjGcS)

Is that a GZ34 valve? All the GZ34 valves I have seen (Mullard as well as other manufactureres) do not have 'shoulders' of the glass envelope:


https://i.ebayimg.com/images/g/Mb4AAeSwtAZqgW6U/s-l1600.webp


https://i.ebayimg.com/images/g/ldEAAeSwtI5n5Yum/s-l1600.webp



Agree with you regarding valves used by the GPO, they always used, and expected the best samples as reliability was paramount.

[Pigmy Pony]

Looks like it says CV378.

[Ali Tait]

Sorry, typo on my part, meant GZ37. Had 34 in my head as that's what my Modwright phono uses.

[walpurgis]

Depends on what you mean by a 'valve amp.' There's some amps with valve buffers that use SMPS power supplies but power section is solid state.

Yes, true, but I was thinking more along the lines of an amp using a couple of pairs of EL34 or KT88 valves or similar. Something 'beefy' :).