Freed 38166 Lang PEQ Transformer

[PRR]

> screen grounded on one end only or both ends?

"Both ends" would make a shorted winding. Bad.

Conceptually we could wrap metal foil, being careful to insulate the overlap (so not a shorted turn).

In a wire-winding room we can "make a foil" by laying wire (we got a ton of it!) shoulder to shoulder all the way across. Yes, any crap landing at one side may have to travel through many feet of wire to reach a drain wire at the other end. But for crap coming "through air", any length of wire is "nothing" to the crap current.

 

[jetbat]

PRR. 'Shorted turn, bad'. It's painfully obvious now that you said something. I had never heard of a shield of wire before and did not think of it that way.  Also I have not wound a transformer that had a shield before so I have not even thought about keeping it from becoming a shorted turn. It is interesting to think how the resistance of the wire will interact with the low pass filter created with the shield.

CJ. Thanks. Is the former/bobbin made of cardboard? Could you estimate the thickness? Is there any insulation between the winding layers such as kraft paper?

Scott.