I noticed that the new Marantz flagship model SR-8012 uses a toroidal power supply. And the new Denon flagship model AVR-x8500h uses a different type of power supply? Does this really matter? or does one type of power supply have any advantages over another?
Both types have theoretical pros and cons. For much larger transformers especially in high voltage/utilities applications I have never seen the toroidal designed used. Toroidal does have one big advantage that can be attractive in audio gear, that is, lower weight to power ratio. Everything else being equal, the more efficient toroidal is better. To summarize, theoretically:
Efficiency & weight - Toroidal type >
Magnetic field induced hum in the audio path - Toroidal type >
Prone to core saturation as related to DC offset/core air gap - EI frame type>
If designed well, the "cons" listed above can be reduced to eliminate any audible effects. For example, my Bryston (2 separate toroids) hums louder than any of my AVRs and my other amps (Adcom, Anthem, Marantz, NAD, Cambridge Audio) hums as quiet as any of my Denon AVRs. I have also heard one of Anthem's top model amp, forgot the number years ago at the dealer, that hummed loudly. I could hear it from two feet away and can still remember that vividly. If you look at the layout of this big Denon, you can see they succeeded in giving the transformer space around it. It also has the typical kind of copper shielding used in the higher end audio power supply transformers. I fully expect this unit will not hum any louder than the Marantz.
Both types of transformers can be found in super high end audio amps. For further understanding, I highly recommend
THIS article, the writer did a great job explaining a technical topic in easy to understand language.
The 51.6 vs the SR8012's 39 lbs probably has something to do with the use of the non toroidal type, in addition to the fact that it is a more powerful (higher VA rating) one, plus two more amps channels.
