Archived from groups: rec.audio.high-end (More info?)
Rui Pedro Mendes Salgueiro <rps@rena.mat.uc.pt> wrote:
> Yamaha seems to have some strange habits about reporting power.
> Theirs subwoofers are also specified at 10% THD, which I suspect
> is a way to present the highest Watt value they can. But what is
> obvious is that this amplifier doesn't give more power into
> 4 ohm than into 6 ohm. Probably the impedance switch changes the
> supply voltage to the output of the digital amplifier ?
> This article:
> http://www.yamaha.com/yec/products/PDFs/RX-Z1_gear_guide.pdf
> has a graph (page 2) which might be useful to understand this,
> although a digital amplifier might behave in a different way.
> As you see the manufacturer may chose to quote a moderate power
> with very low distorsion (0.04% at 35W in the case of the Yamaha
> RX-SL100) or an higher power, but with a lot more distorsion
> (0.9% at 70 W or 10% at 75 W).
> If you check the manual of this amplifier:
> http://www.yamaha.co.jp/product/av/prd/dspav/rx-sl100/img/rx-sl100.pdf
> http://www.yamaha-service.de/service-download/owners_manual/audio/RX_Serie/RX-SL100/RX-SL100_m.pdf
> you will find a whole bunch of different numbers including one
> higher than what I posted above:
> " Maximum Power (EIAJ) for Front, Center, Surround, Surround back
> 1 kHz, 10% THD, 6 & ...................................... 100 W "
This site reprints some bench-test results on receiver performance, including Yamaha
http://www.geocities.com/Area51/Hollow/3401/ratevsac.htm
--
-S.
"They've got God on their side. All we've got is science and reason."
-- Dawn Hulsey, Talent Director
Rui Pedro Mendes Salgueiro <rps@rena.mat.uc.pt> wrote:
> Yamaha seems to have some strange habits about reporting power.
> Theirs subwoofers are also specified at 10% THD, which I suspect
> is a way to present the highest Watt value they can. But what is
> obvious is that this amplifier doesn't give more power into
> 4 ohm than into 6 ohm. Probably the impedance switch changes the
> supply voltage to the output of the digital amplifier ?
> This article:
> http://www.yamaha.com/yec/products/PDFs/RX-Z1_gear_guide.pdf
> has a graph (page 2) which might be useful to understand this,
> although a digital amplifier might behave in a different way.
> As you see the manufacturer may chose to quote a moderate power
> with very low distorsion (0.04% at 35W in the case of the Yamaha
> RX-SL100) or an higher power, but with a lot more distorsion
> (0.9% at 70 W or 10% at 75 W).
> If you check the manual of this amplifier:
> http://www.yamaha.co.jp/product/av/prd/dspav/rx-sl100/img/rx-sl100.pdf
> http://www.yamaha-service.de/service-download/owners_manual/audio/RX_Serie/RX-SL100/RX-SL100_m.pdf
> you will find a whole bunch of different numbers including one
> higher than what I posted above:
> " Maximum Power (EIAJ) for Front, Center, Surround, Surround back
> 1 kHz, 10% THD, 6 & ...................................... 100 W "
This site reprints some bench-test results on receiver performance, including Yamaha
http://www.geocities.com/Area51/Hollow/3401/ratevsac.htm
--
-S.
"They've got God on their side. All we've got is science and reason."
-- Dawn Hulsey, Talent Director
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