"jamesgangnc" <james@[EMAIL PROTECTED]
> wrote in message
news:13s6so0o3qqg69@[EMAIL PROTECTED]
>> Surprisingly, these surround receivers actually do put out 100 watts
RMS
>> each for all 5 channels concurrently, or 85 watts RMS each for 7
>> channels concurre
> If one of those cheap surround sound recievers is putting out 500 watts
> rms then I'm betting it's a class d amp.
Generally, no.
At the 100 wpc level it is still generally cheaper to make a class AB
amplfier than a Class D.
> And that's why the distortion figures suck.
Just because an amplifier is Class D (switchmode) does not mean that it
necessarily has high distortion.
> A good class ab amp will list continuous rms watts for 8 ohms and 4 ohms
> with .1 thd or lower.
That is about specsmanship, not usable performance. Yes, a lot of
receivers
are giving power specs at 0.7% THD and the like. But, if they would back
their power ratings off by say, 10%, then the THD would probably be below
0.1%. There is hardly any audible difference between a clean 100 watts and
a
clean 90 watts. For some reason they want to specify that the amp has 100
wpc, and they are forced to specify more distortion than most are
comfortable with to do it. However, nobody runs an amp flat out all the
time, and in normal listening, the 0.7% THD figure is pretty much
arbitrary.
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