Constrained layer damping tape on toroidal transformer?

If you can’t remember eat more fish. 🐟 🐠 🐟 🐟

Ironically, perhaps, mu metal, a high permeability low frequency alloy commonly used to shield/absorb magnetic fields of transformers, including toroidal transformers, contains ferrous metal. Not sure I would pay too much attn to a ferrous nut. Or ferrous bolt for that matter. Besides as I already commented, bolts on transformers is a rather dumb idea, with the exception of shipping the component, quite unnnecesasry and bad for the sound. 

My solution is multi pronged. Remove bolts or at lease loosen them. The only purpose for the bolts as far as I can see is to hold the transformer when the component is shipped.  Place the transformer on pure natural cork square, thickness 0.25”

Next, remove almost all screws holding the printed circuit boards to the chassis, at a minimum loosen them. Use small pure natural cork squares to shim the printed circuit boards, isolating the PCBs further from the transformer.

Next, use 3” or 4” lengths of pure natural cork 1/8” thickness to weave like a serpentine wall around and through stacks of capacitors to reduce their vibration.

Finally, wrap the large transformer with two (count em!) thicknesses of mu metal to shield everything in the component from the very toxic magnetic field generated by the transformer. One thickness of mu metal is 75% effective. Two thicknesses of mu metal separated by 1/4” is 92% effective.

As Bob Dylan says at the end of all his songs, good luck.

Geez, you’re still trying to argue that? Get real! 

Uh, the transformer is not “live”. I use mu metal to wrap transformers and trust me, mu metal is conductive.

Even if the transformer was “live” which it's not, you could wrap it with constrained layer damping tape since the non-conductive viscoelastic layer is the side that touches the transformer.

Place the viscoelastic material under the transformer. Thus it will be constrained by the transformer. Loosen or remove bolts to isolate it from the chassis. Problem solved! 🤗