AudioCircle
Audio/Video Gear and Systems => All Solid State => Topic started by: Falcon on 13 Apr 2021, 11:31 pm
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I don't attach a lot of emphasis on having an amp that can double wattage output from 8 ohm to 4 ohms, but I do respect companies that accomplish that. I was looking at the rated output for the M22 and it claims the same output, 300 watts from 8 to 4 ohms. I'm wondering what kind of output circuits don't up the output at all when halving impedance? Could this be a negative attribute for this amplifier?
They rate the "Dynamic" output wattage as almost doubling when impedance is halved. I've read somewhere that the dynamic wattage ratings can be ignored, more a selling point than anything else. What are your thoughts on that?
Thanks!
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This is NAD's way of saying the amp is load agnostic.
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It's a class D amp, they output the same regardless of load. The IHF dynamic load is measured at 1kHz with 1% distortion. Hope that helps.
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It's a class D amp, they output the same regardless of load. The IHF dynamic load is measured at 1kHz with 1% distortion. Hope that helps.
:scratch:
I see other class D amplifiers that increase with lower impedance.
NAD has rated power into 8 and 4 ohms the same for a long time, even with their class A/B amplifiers.
C272 from 2003-07
https://nadelectronics.com/wp-content/uploads/2017/03/Data-Sheet-C-272-Stereo-Power-Amplifier.pdf
:dunno:
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From Stereophile measurements of the amplifier (V1) that I assume you are asking about:
Fig.4 indicates that the THD+N reaches 1% (our usual definition of clipping) at 340Wpc into 8 ohms (25.3dBW). Fig.5 shows that the M22 clips at 400Wpc into 4 ohms with both channels continuously driven (23dBW), while with just one channel driven (fig.6), the amplifier clips at 570W (24.55dBW). Even into 2 ohms, the NAD M22 managed to output 700W (22.4dBW) with just one channel driven.
NAD's Masters Series M22 amplifier measures extraordinarily well. It is the very model of a modern class-D amplifier!—John Atkinson
https://www.stereophile.com/content/nad-masters-series-m22-power-amplifier-measurements
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From those last quoted numbers it would appear that the amplifier is power supply current) limited such that it starts to “sag” into lower impedances.
dave