Toroidal transformers

[MoonBassAlpha]

Why are these not used in Valve amplifiers? (or are they these days?) I'd have thought it would help in the trend to make stuff lighter and probably have a lower noise floor.

[RandomBass]

Toroids in valve amps? This will just go round and round in circles...

[MoonBassAlpha]

Let's stick to the core issue please.

[Dad3353]

Stop winding us up and answer the question..!

[taunton-hobbit]

Jokes aside, I have an (overworked) amptech down here (Devon) who has designed a 400watter using valves and torodial trannies, so it can be done.....

[Bill Fitzmaurice]

[quote name='MoonBassAlpha' timestamp='1448981103' post='2919766']
Why are these not used in Valve amplifiers?
[/quote]Price, and demand, which are closely related. Aside from valve amps high voltage transformers are rarely used, so there's no economy of scale. Take a look here, you can count the number of 400-500v secondary toroids with no fingers:
http://www.hammondmfg.com/182.htm

[Dad3353]

I think it's basically just a question of economics. The raw materials and build techniques for traditional transformers are less costly than the more sophisticated materials and winding techniques for 'doughnuts'. High quality efficiency and weight were not, back then, major considerations for makers of amps, in general (one or two exceptions, of course...), and the final selling price was a more important factor. Anyone, back then, ordering a 200w amp had a van, and maybe roadies, plus a couple of 4 x 12 cabs of birch ply. Heavy..? Of course it's heavy. The more it weighed, the more it was considered 'quality', 'durable', 'rugged' etc. There are, nowadays, several makers of valve gear using toroidals; the few I've seen are very good. Worth the difference..? Why not, but it's not a huge factor, I'd suggest. The old Partridges still retain their mythical edge for connoisseurs.

[Handwired]

Weber use them in Mywatts.

[taunton-hobbit]

I have Mathias amps with Partridge Transformers, and one that is a Matamp 're-creation' using Sowter.....
Hate to burst any bubbles, but they sound identical (& excellent)........

[RandomBass]

I think there was a relatively inexpensive Ashton branded 300w valve amp that used a toroidal as the mains transformer, but maybe not for the output side.

[Pentode]

[quote name='taunton-hobbit' timestamp='1448998226' post='2919973']
I have Mathias amps with Partridge Transformers, and one that is a Matamp 're-creation' using Sowter.....
Hate to burst any bubbles, but they sound identical (& excellent)........


[/quote]

Sowter transformers are quite simply superb pieces of work!