[James W. Johnson]

Yeah I know that specs generally mean nothing or at least not much but still I have to wonder how broad the UL rules are for listing these specs.

I know for a fact that Denon and Harman Kardon list the maximum current draw at the rated output for their receivers. The 7200 uses a max of 1050 watts and the Denon 5800 uses 12amps , 120v x 12 amps is 1440 watts.
On the other hand Yamaha does not say how they come up with their wattage rating , they simply have on the RX-Z1 "Power consumption 650watts"

Now what do we know about the Z1 and 5800? Hard evidence by Sound and Vision is this:
The Denon 5800 is rated at 170x7 and S&V measured it to put out 138x5/118x7 with all channels driven with .05% distortion.
The Yamaha RX-Z1 is rated at 130x6 and S&V measured it at
117x5/109x6 with all channels driven and a very low .015%
distortion.

How much power does the Denon put out at .015% distortion? I'd wager that these two amps are fairly similar if you were shooting to keep the distortion figures the same.

Yet the Denon uses 1440 watts and the Yamaha uses 650watts , so either they have a very broad range for rating their receivers or these two designs are very different. Perhaps Yamaha's amp is indeed nearly 3x more efficient then the Denon?
I know these are just ratings and should be disregarded for the most part but I would like to know a little bit on how these companies come up with these numbers.

Anyone care to comment?

[Wayne A. Pflughaupt]

Actually James, specs are extremely meaningful – like THD, frequency response, S/N ratio etc. - but that’s not what you’re looking at here. Don’t make the mistake of confusing power consumption with power ratings.

The latter, as you can guess, is how much the amplifiers put out. As you have noted, sometimes the manufacturer’s watts-per-channel specs can be a little optimistic, but generally not tremendously so. For instance, the difference between Denon’s 170 watts and S&V’s 118 watts is probably no more than 1dB at best.

The former is how much power the receiver uses. This includes not only the amplifier sections, but also things like the displays, all the LED’s, the digital processors, etc. Modern receivers have much more circuitry than their stereo counterparts of yore, so they consume more power.

Bottom line, pay more attention to the watts-per-channel specs than the power consumption info.

Regards,
Wayne A. Pflughaupt

[James W. Johnson]

Thanks Wayne but something is amiss when the Denon Flagship uses over 1400 watts of power , in other words it has to work almost 3 times as hard as the Yamaha to put out about the same amount of power. Either they are blowing up their power consumtion (funny but perhaps this particular figure is not regluated ? ) Sorry but digital displays , DSP chips and tuners dont go thru 800 watts., the amplifer is by far the largest power consuming piece of a receiver...by way far.

I spoke with Yamaha today and they assured me that their numbers are honest for the working/wattage numbers. He also said he believed his (Yamaha's) amplifers were indeed abit more efficient hence the cooler operating temps. and lower overall power consumption. Being someone who went from a Sony ES piece to a Yamaha RX-V3300 I can attest to the cooler running temps.

[dale^g]

when the HK7200 was bench tested it came up with 145 watts per channel...name another receiver that has 45% more power than stated by manufacturer.

[James W. Johnson]

Ah yes , but what was the distortion level? One thing interesting about the 7200 is that Harmon Kardon did not give it a 4ohm rating and they do not recommend driving 4ohm speakers with it....what a brute eh?

My RX-V3300 is rated to drive 5 channels simutaniously at 4ohms each if I so choose. Now I am not saying the HK7200 cannot drive 4ohm speakers but it was not given that rating and if you call HK and ask , they will tell you not to use hard to drive speakers.

[Wayne Ernst]

Quote:

when the HK7200 was bench tested it came up with 145 watts per channel...name another receiver that has 45% more power than stated by manufacturer.

Actually, it was 142 watts -- and only 5 channels were being driven during that particular test. But, I own an AVR-7200 and will never be able to use all of the power that it can provided.

[Wayne Ernst]

Quote:

I spoke with Yamaha today and they assured me that their numbers are honest for the working/wattage numbers.

Isn't that kind of like calling up Yugo and asking them if their vehicles are good? Sure, you get the following answer: "Yes, sir. Our vehicles are fabulous."

My point? Manufacturers can't be fully trusted. I love reading reports and tests on gear to see how far off the specs are during the actual test vs. what the manufacturer stated.

[James W. Johnson]

I agree, perhaps I should have elaborated. It was not just a "oh yes our specs are correct" ..."ok , thank you sir , good day." conversation.
No , call Yamaha up and ask to talk to a technical support person and the odds are you will get a very knowlegable adult who actually knows a thing or two about electronics. I spent a good 15 minutes on the phone with a tech support guy and we talked about all of the above in detail.

Call Sony support up and you usually get some snot nosed punk on the other end who doesnt know anything
at all about anything. Instead they have some sort of system where the "tech support" guy just enters your complaints as keywords and he then goes on to tell you some basic troubleshooting that most people have figured out before they even would call tech support. They do not have the ability to use their mind. Yamaha is not like that...not in my experience so far anyways.

[dale^g]

Quote:

My RX-V3300 is rated to drive 5 channels simutaniously at 4ohms each if I so choose.

most people who have demanding 4 ohm speakers choose seperates to power them.

Quote:

My RX-V3300 is rated to drive 5 channels simutaniously at 4ohms each if I so choose.

try choosing some "hard to drive" 4 ohm speakers with your yammy at reference levels and watch it shut down and curl up in a fetal positon. not to say that the HK7200 wouldn't do the same thing but i'm just saying receivers arn't made to drive demanding 4 ohm speakers.

[JohnSer]

James, I suspect the yammie rating is an average, while the Denon is a max rating. Given they are both class AB amps there shouldn't be a great deal of difference between power consumption, especially by the factors you are describing. If the yammie is one of the new digital amps or rail switching classes, that might explain the difference. If that was the case, I would go with the tried and true class AB. JMHO.

JohnS

[James W. Johnson]

It depends, actually there are many receivers availble that are more than capable of driving difficult loads
to reference levels. I have been in this hobby for a long while and seperates are not going to take over anytime soon. In fact I no longer have a desire to have them because most modern receivers deliver enough power for my needs.