Mike - Problem with switching power supplies is that most of them are designed to save money and space and not to improve performance. REF1000 for instance in improved version REF1000m has additional power supply with a lot of capacitors on separate board. I believe that with the same resources (cost and space) better PS can be achieved in switching than linear technologies.
I remember that there was an argument that high frequency can modulate audible frequencies on nonlinear (at this range) transducer - tweeter. Argument is valid under condition that tweeter membrane can move at 500kHz - not likely.
Larger Icepowers have a little lower carrier frequency than small ones and therefore lower -3dB frequency (50kHz vs. 60kHz). It is because stronger Mosfets are slower. Wide frequency range is necessary to provide smallest phase shift in audible range. Even with 60kHz amplifier shows about 30deg phase shift over 5Hz-20kHz.
This is first avalanche of class D amps (remember first SS amps?). Next generations will have faster Mosfets, higher frequency range, better power supplies and better noise filtering. I see it as technology of the future.
Magfan - this Zobel, can be improved as well. In Icepower it is simply common mode choke two filtering capacitors and one resistor. This Zobel network is responsible for time/power limitations and available power at higher frequencies. In practice musical power is only few percent of peak power (unless one listens to sine-waves)and high frequency energy is minimal. Should I pay for larger Zobel toroid to allow high frequency power that would make me deaf? Thanks for the link to IRF primer. I read opinion that full bridge sounds like very good tube amp while half bridge sounds more like high quality class AB amp (less tubey).
I remember that there was an argument that high frequency can modulate audible frequencies on nonlinear (at this range) transducer - tweeter. Argument is valid under condition that tweeter membrane can move at 500kHz - not likely.
Larger Icepowers have a little lower carrier frequency than small ones and therefore lower -3dB frequency (50kHz vs. 60kHz). It is because stronger Mosfets are slower. Wide frequency range is necessary to provide smallest phase shift in audible range. Even with 60kHz amplifier shows about 30deg phase shift over 5Hz-20kHz.
This is first avalanche of class D amps (remember first SS amps?). Next generations will have faster Mosfets, higher frequency range, better power supplies and better noise filtering. I see it as technology of the future.
Magfan - this Zobel, can be improved as well. In Icepower it is simply common mode choke two filtering capacitors and one resistor. This Zobel network is responsible for time/power limitations and available power at higher frequencies. In practice musical power is only few percent of peak power (unless one listens to sine-waves)and high frequency energy is minimal. Should I pay for larger Zobel toroid to allow high frequency power that would make me deaf? Thanks for the link to IRF primer. I read opinion that full bridge sounds like very good tube amp while half bridge sounds more like high quality class AB amp (less tubey).