Encapsulated (potted) Toroidial Transformers

[mitch57]

Do encapsulated (potted) toroidial transformers perform better then non encapsulated (potted) toroidial toroidial transformers? I've heard that potted transformers are quieter and less subject to humm/buzz.

It also seems that potted transformers are a more standard feature on higher end amplifiers. Although I have seen a Krell with a non potted transformer.

So.... What's the deal?

[Glen B]

Mitch, I only just saw your post today. Toroids that have just the center filled in with potting material are also technically called "potted." This center potting may help reduce some noise and provide a solid mounting means. Toroids that are totally encapsulated should in theory be quieter than ones that are not, however, you can find exceptions that are very quiet (like the Equi=Tech Q type transformers for example). It all depends on how well the transformer is designed and wound. One other thing, don't be fooled into thinking that every toroid you see with the pretty cover is encapsulated. You may simply be looking at a center-potted transformer in a metal can.