[Boatanchors] Filament transformer needed

[Lee Buller]

Glen,

You might try re-winding a old frame E and I transformer.  If you have one that has a core large enough, you just have to figure the turns ration and rewind it.  Take it apart...save the primary...dump the secondary...then use #12 wire or multiple #12 wire...and wind as many turns as you need acordingto the turns ration.  At the half way point, put in your center tap.  I think there was an article in QST in the 60s or 70s about doing this.  You have to take your time getting the E and I laminations apart.  I used a small chisel and gently tapped them apart.  Getting started was difficult, but soon it worked well.  Then, putting it back together was not much fun either and I could not get the last couple of E and I laminations in.  Oh well, I just used it anyway.  Worked.  I used Shellack to put it all back together again.  I did bake it in the oven for an hour or so at 300 degrees to get the Shellack even and I don't know if that helped.  Of
 couse you need to measure if you got the winding right and the center tap right.  It did "buzz" quite a bit under load but after a few hours it became quiet.

I did this when I was a poor college student....with no money.

Lee - K0WA


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