Question About Watts.

[huma]

Maybe I'm not understanding this correctly, but would appreciate the clarification. I'm looking at a few models with their wattage claims vs the watt power consumption. Whats the difference?

Sony STR-DE998
110w x 7 channels
power consumption: 400w

Yamaha HTR-5890
140w x 7 channels (890w total on yamaha's website)
power consumption: 500w

Harman Kardon AVR-235
50w x 7 channels
power consumption: 890w... wtf?

Another question. If I only use 5 channels out of 7, what happens to the power reserved for the extra channels?

 

[Buckeyefan 1]

Maybe I'm not understanding this correctly, but would appreciate the clarification. I'm looking at a few models with their wattage claims vs the watt power consumption. Whats the difference?

Sony STR-DE998
110w x 7 channels
power consumption: 400w

Yamaha HTR-5890
140w x 7 channels (890w total on yamaha's website)
power consumption: 500w

Harman Kardon AVR-235
50w x 7 channels
power consumption: 890w... wtf?

Another question. If I only use 5 channels out of 7, what happens to the power reserved for the extra channels?

Good question. Manufacturers rate wattages differently. Peak power consumption is different than average or continuous. Wattage is one of the least beneficial stats to go by when reviewing/shopping for receivers.

Take a look at the weight of the unit. You'll get a great idea of the size of the transformer (unless it's digital) as well as the heat sinks. My rule of thumb as a lot of you know is 33lbs. You'll get a nice beefy unit no matter what brand you pick if the unit weighs 33lbs or more. I don't think any THX certified units weigh under 33lbs.

 

[annunaki]

I say stay away from the Sony. The have weaker amplifier sections based on my prior experiences. The other two are quite good, and would perform very similar to one another. Unless of course, you like tons of DSP modes. Then the Yamaha wins.

 

[scasarano]

I have a sony now and it sucks. But feel free to buy it on Ebay!!!

 

[Ron Temple]

I'm no expert, but I've read that analog receiver's amps are about 50% efficient, so based on consumption they can put out about half what they take in. So the HK takes in 890 and puts out 445/7, which is pretty close to their conservative rating they publish.

I'm sure there are some design issues that allow more output.

Just my .02

 

[anamorphic96]

Maybe I'm not understanding this correctly, but would appreciate the clarification. I'm looking at a few models with their wattage claims vs the watt power consumption. Whats the difference?

Sony STR-DE998
110w x 7 channels
power consumption: 400w

Yamaha HTR-5890
140w x 7 channels (890w total on yamaha's website)
power consumption: 500w

Harman Kardon AVR-235
50w x 7 channels
power consumption: 890w... wtf?

Another question. If I only use 5 channels out of 7, what happens to the power reserved for the extra channels?

Keep in mind as well. That all the receviers listed except for the Harman Kardon will only output that power into 2 channels driven at the same time. The other channels can output the power that is rated but not all 7 channels at the same time. Only 2 channels.

The HK however from what I understand can output there specs with all channels driven at the same time.

As stated above wattage specs are very misleading. Most of us are only ever using a few watts when watching movies. The big climaxes are what use the power. Even then maybe only 20 to to 40 watts get used. Especially if everything is crossed over at 60 to 80hz and youre not watching things at lease breaking levels. This lets the sub do most of the work.

Buckeye is correct in that weight is very good measure of the receivers ability. The heavier the amp section the more current it's typically able to output.

On a side note stay away from Sony receivers. Sony tends to have the weakest amp sections on the market.

 

[j_garcia]

Another thing to look for is the receiver being rated at 1kHz rather than 20Hz-20kHz. I don't think any of those listed were measured this way, but Sony's lowest models are notorious for this, giving a MUCH over inflated power rating. Even THX Select receivers are only rated for the output on individual channels, not with all channels driven. AFAIK, only THX Ultra receivers are actually tested with all channels driven. H/K tends to be "honest" about their power ratings, unlike many manufacturers. IMO, it is easiest to tell if the rated power is true or not, just by listening to them.

 

[mtrycrafts]

Maybe I'm not understanding this correctly, but would appreciate the clarification. I'm looking at a few models with their wattage claims vs the watt power consumption. Whats the difference?

Sony STR-DE998
110w x 7 channels
power consumption: 400w

Yamaha HTR-5890
140w x 7 channels (890w total on yamaha's website)
power consumption: 500w

Harman Kardon AVR-235
50w x 7 channels
power consumption: 890w... wtf?

Another question. If I only use 5 channels out of 7, what happens to the power reserved for the extra channels?

You cannot extrapolate a power rating to power consumption figures. Two different methods of calculating two different measurements.

The first reflects what the amp will do per channel RMS continuously. Unless an amp states all channel driven simultaneously, it is for one or two channels simultaneous capability. And, in reality, that is how the musical signal is or a movie audio signal is, there is not a signal to all channels at full power at the exact same time so there is no real need to rate them that way.

Consumption is measured much differently calculating inefficiencies, etc.