On 11 May 2010 at 15:55, Roger Lapthorn wrote:

> There are several sources in the UK for toroidal mains transformers with
> various step-down ratios. See for example
> http://www.airlinktransformers.com/toroidal-transformers.asp . These
> sell for £12 to £20 for ratings up to 160VA.  They are available up to
> at least 1kVA, but get expensive.
> 

Not sure that mains transformers are appropriate for 9kHz. Probably 
better would be switch mode psu transformers (normally operate 25kHz-
75kHz) and you could probably design what you wanted with readily 
available cores (toroid and other).

73 Dave G3YMC

http://www.davesergeant.com