EMI absorbers for transformer noise

What would be some recommended materials for lining my amp’s inner walls with, especially around the transformers (2x 650VA)?
I’m getting phono stage hum from the amp at around 2ft away. I’m guessing the turntable grounding wire is picking up most of this as its placement greatly affect the hum intensity, so would also like tips on what to use as a proper ground wire.

Do you get the hum if you move the phono stage more than 2ft. from the amp or are you hearing transformer hum?

If the former, its vastly easier to put some distance between them vs. trying to shield the transformers.

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Well, I can’t currently afford longer high-quality interconnects.
I’d like to shield the transformers anyway, I don’t want them leaking to any part of my system, however negligibly.
What would be a cost-effective EM absorbant for mains freqs?

You could try this stuff. It costs pennies because it’s not audiophile. I used art on my switch, when I had one.

Over here they sell it on Amazon for £30 ($40) for 1.8 sqm.

1.8sqm of the Oyaide stuff would cost $3,490.62, but you’d probably get a discount.

I had the same issue because I actually stacked my phono stage on my turntable power supply. A bit stupid. I moved them apart and hum is gone. The expensive cables issue was solved by using cheap cables that I found in the attic.

Hmm. It occurred to me that constricting the fields of the transformers could affect their intended performance, isn’t that right? I wonder what the optimal radius for shielding placement would be to prevent any issues.

Can’t I simply place a thick enough plate of a suitable metal between the amp and phono stage?
I need to divert the magnetic field in a very divisive way so that very little gets over the edges of the plate, think of a vacuole in the flux being essentially created behind the plate. I don’t actually want to warp the magnetic fields inside the amplifier because when you think about it, shouldn’t a proper big toroid have all the rights to be a toroid, at its effective radius, with an evenly distributed flux.