Hello to all,

I am building a Stereo Power Amplifier with Dual Toroid Transformer (Each rated at 400VA). Each transformer for each Channel. I would like to confirm whether or not this method will be of any good in creating a shield between the Amp Boards & the EMI generated by the Transformers.

I have made a Virtual 3D design to explain properly on how i plan to do it.
I would put a Barrier between the Amp Boards & the transformer using 1mm thick Steel plate between them. The height of the plate will be exactly as the chassis wall, so that when i put the top cover of the chassis, it will create a closed enclosure for both the transformer from all sides.

Will this method do any Good to shield the amp boards from Electromagnetic waves being emitted from the transformers? Or is it just a waste of time to make these Barriers?

Best Regards,
Lubnan

 

Steel is a pretty good material for shielding magnetic flux so the barrier will help. If you still get too much noise you can add a second steel shield or add a better shield material like mu metal.

 

Torroid transformers have a very low external field (which is why they are preferred for audio amplifiers) so your shielding approach should be more than adequate.

 

Beware your screen can act as a shorted turn, make sure you put a thin layer of insulation between the top of the steel walls and the case's top and bottom. They also have a high inrush current so might blow a 10A fuse.
Frank

 

Copper foil is sometimes easier to work with then steel and can help

 

As mentioned Torioid's do not radiate like EI transformers, with two in proximity to each other you can also position one at right angles to the other to decrease it further.
Max.

 

Copper foil is sometimes easier to work with then steel and can help

Welcome to AAC.

Congratulations, you have practiced the arcane art of necromancy, the revival of a long dead thread. Likely the OP (Original Poster) has solved his problem in the years that has passed, or thrown it away, or something.