Shielding a transformer is something I have been interested in but I have only looked into ready made cases which are hard to find and usually not sold individually. Now I am planning on fashioning some myself. Looking at step ups that show when I do a search I see they are usually aluminum cases with shielded transformers inside or on top and rca connectors for the in and outs. I've decided instead of making small cases for individual transformers I will make a larger case/shield combo with rca connectors shielding both transformers. There will be some shielding seperating the transformers so there is no crosstalk between them. Not sure if there would be but I will add this as a precaution. The shielding will consist of different types of metals layered to increase their effectiveness. This is an article I found from 1938 called Magnetic Shielding of Transformers at Audio Frequencies.
http://www3.alcatel-lucent.com/bstj/vol ... -3-416.pdfLots of useful information in there. This is where I found the layering of different types of metals to increase efficiency. They say to use layers of Permalloy and Copper. This just happens to be what the modern Texas Instruments TI-Shield is made with. The TI-shield uses 49 Permalloy which is 49% nickel. I have ordered two sheets of 8" x 10.50" x .004" Ultraperm 80. That should be plenty for multiple layers. The Ultraperm 80 is 80% nickel which will give it a higher amount of shielding. I will buy some copper sheet from the hardware store. I would like to have the outside case made from steel if I can find what I need.
Attached is a diagram of the TI-Shield.
Any thoughts or input will be appreciated.
Scott