Much of this will have to do with the accuracy of ratings, both from Bryston and from Stancor. You also have to remember that momentary draws can be quite high when trying to reproduce dynamic peaks. While the 300 watt draw from a 500 watt transformer does follow the "60% rule" that i spoke of in another thread in terms of rated load and draw, i based that on having quite a large ( heavy ) transformer core. Given that i'm not real familiar with the Stancor's, i don't know if they fall into that category or not. I know that their smaller transformers seem to be reasonably well built, but....
Call up Stancor and or look on their website. Look to see what the transformer is rated for in terms of noise reduction / attenuation and internal capacitance.
As a side note, Bryston actually uses a little more filtering in their power supply than many other amplifiers. That is, according to their schematics. Then again, Bryston's were originally designed as Pro Sound amps where AC is typically "worse" than in a home, so they might have taken this into consideration. If you've got an old original 2B, it will have an iron core transformer, not a toroid. This puts you quite a bit ahead of the newer designs in terms of the noise floor of the power supply itself. Sean
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