DC chokes, Anode (Plate) chokes and single ended output transformers require a small gap between the E’s and the I’s to prevent core saturation due to the large DC flux.
Our latest development is to use copper as a gap material. Whereas we would normally use a plastic spacer of the correct thickness, we have been investigating the use of other materials. Copper sheet seems to fit the bill very well, and we have already shipped several chokes using copper as the gap material
This picture shows the gleaming copper revealed when we push back some of the I’s.
Copper can be used in chokes and in single ended output transformers, where it may prove to be a positive listening experience compared to plastic.
Copper is a true engineering solution to the gap spacing. It is true that there is no scientific reason to use anything other than plastic, but copper seems to bring something to the party subjectively.
We will be adding this as an option to all chokes and single ended output transformers for those with discerning tastes.