Shielding power transformer or shielding power transformer + PSU PCB

[Whoops]

Hi.
Just a quick question. I'm building the Fripholm TG1 zener limiter. I have some aluminium strips lying around I could use for shielding. And was wondering if it's better to shield...:

Aluminium is not good for that task

(A) ...the whole power supply (incl transformer and PSU PCB)
or
(B) ...if I should shield just the toroidal power transformer.

THe PSU doesn't need shielding only the transformer

It's 1mm thick Aluminium. Should be fine for shielding right?

Not really.

Best solution to shield Toroid transformers, and I've tried many, is the transformer shielding sheet from Don Audio, this one:
https://www.don-audio.com/trafo-shield
"two grain-oriented-steel layers that effects double shielding around the toroid and 6-times shielding on the overlapping to eleminate horizontal radiation hum and noise of toroidal trafos."

It's easy to apply, just wrap it around the transformer.




Toroid transformers have less EMI emission than starndard EI transformers, although they still radiate enough to induce hum in a circuit.
The trick with Toroid is:
1) Listen to the circuit with headphones while turning the toroid in a circular motion around it's screw axe, find the point where the Hum induced in the circuit is least possible, screw the toroid in that place
2) after that Wrap a Don Audio Trafo shielding sheet around the Toroid

After these 2 steps the circuit will be pretty silent and the magnetic radiation tremendously reduced

 

[Whoops]

Also found this guy mummified behind the front panel. Bug in the system or the secret of a great amplifier?

Like Schwarzenegger said what "an Ugly Motherf..."

 

[CJ]

you need a mag camera for analyzing stray fields, can't be more than $23,000

or get a hall sensor for a buck and send it thru an opamp,

 

[wrentema]

Thanks for all the great info. Lot of the stuff is above my head. But I’m watching and learning

 

[Whoops]

Thanks for all the great info. Lot of the stuff is above my head. But I’m watching and learning

What I wrote is not "above your head" for sure and it completely solves the problem
have fun

 

[wrentema]

What I wrote is not "above your head" for sure and it completely solves the problem
have fun

Correct I can manage that I was regering to the other posts too..