So I've been trying to source some small single channel transformers (power). Currently I use EI core dual bobbin's and they work very well, but the hum is a problem. I wanted to try James Transformers OA core because they appear to be very high quality and sport a shield between the windings.
Anyway, if someone/s can point me in the direction where to order better EI dual bobbins, or ideally OA core toroids with a shield between windings, would be much appreciated.
Your sharing is quite useful to my new project. Thanks a lot.