[Elecraft] Leakage Flux from Toroidal Transformer

[Jim Brown]

On Tue, 20 Apr 2010 07:22:33 +0100, Ian White GM3SEK wrote:

>Obviously the answer will also depend on the quality of design and 
>construction, not only in the transformer but also in the rest of the 
>amplifier, because flux leakage is also affected by the external 
>connecting wires. For the lowest possible flux leakage, it is important 
>to minimize the physical size of the 'coupling loops' created by the 
>connecting wires, especially if the stray magnetic fields can also 
>interact with a steel chassis.

I never bothered to figure out why, but the first family of Crown audio 
power amps that used toroidal power transformers had BODACIOUS levels of 
leakage flux that could drive you NUTS in a live situation, when they 
coupled into line level audio circuits. We had to solve that by physically 
rotating them. 

73,

Jim K9YC