I build this filament transformer from an old Zenith TV tube type transformer.
I took out all the I E 's wound sum 17 AWG kapton magnet wire for primary and secondary to gets me 7.5ct Vac at 21 Amps with a 120 Vac primary. I sexfilar wound the secondary with the sixth strand for a center tap.

I built this 3 years ago and finally getting around to putting the HF QRO amp put together. Back then it made a great vibrator for those old hockey games. Now that it has aged the vibrator has gone.

But alas when hooked up to my 4x1 to getter the gas out I had it near my Midland police radio that is converted to 2 meters, and the 60 hz from the transformer was getting into the audio output of the radio.

I got a spot on the RF deck for it.

I'm afraid that running 21 amps through the secondary will induce counter emf in the shield and heat things up more, I don't need no more heat Although I was thinking about using a peltier module if things get to hot.

So should I shield the windings with a copper or aluminum shield, or I could run it from 440 Hz least I wouldn't get reports of hum on my signal

tyvm in advance
73 de n8zu