A couple of questions

[Shane]

As a newcomer to the valve world and a general ignoramus could someone answer a couple of questions for me?

1) If toroidal transformers are such a good idea in transistor amp. power supplies, why aren't they a good idea for valve amp. outputs?

2) Do all the valves you use date from the '20s to the '50s, or is there someone out there designing new valves? If not, why not? Have we lost the art?

Thanks everyone.

[Global]

I'll have a go!

Yes, toroidal transformers are a good idea for PSUs because they are compact for their power, have minimal stray fields and can be run close to saturation hence efficient. They are also a very good idea for output transformers BUT the design considerations for OPTs means that they are difficult to wind, must be larger than their PSU brethern and hence are more expensive for a given quality than E/I transformers. Meno van der Veen designs excellent torroidal OPTs which are sold by him (forget the web site) and Plitron (www.plitron.com) q.v. for more info.

There is a reasonable manufacturing facility, having regard to the market, for new valves using existing designs. The effort of designing, tooling and manufacturing a new valve could not possibly pay back in today's market except perhaps in ultra-costly niche markets.

Mark