power consumption

[Unregistered]

If a piece of equipment's power consumption is stated in amps how do you
convert to watts and vice versa?
I've been looking at different avr's, for example, elite vsx-59txi 725watts, rz-z9 1000watts(1200VA), avr-5803 12.1amps, hk avr-630 1000watts.
How come an avr-630 absorbs more power than a vsx-59txi

 

[Polkfan]

If a piece of equipment's power consumption is stated in amps how do you
convert to watts and vice versa?
I've been looking at different avr's, for example, elite vsx-59txi 725watts, rz-z9 1000watts(1200VA), avr-5803 12.1amps, hk avr-630 1000watts.
How come an avr-630 absorbs more power than a vsx-59txi

This might help:

"This Receiver is more powerful than the other one.
The power game that many receiver manufacturers play can be most misleading. There are so many multi thousand dollar flagship receivers on the market these days that claim over 100 watts a channel times 5 or even 7 channels. Let think about this for the moment and take a look at one of the top receivers on the market, the Denon AVR 5800.

The Denon AVR 5800 claims 170 watts/ch for all 7 channels. If this implies continuous power for all channels driven, than the receiver must consume (170*7) / 0.75 (efficiency factor of class AB) = 1586 watts for the power section alone. This is an impressive claim considering that the common wall socket can only produce 120V*15amps = 1800 watts. This means you must plug this bad boy into its own dedicated line to achieve these power levels, assuming the power supply is up for the task (1200VA power supply featured in this receiver, cannot).

The fuse rating on this receiver is 11 amps. It is common practice in engineering to derate a fuse to 75% of its maximum sustained current ratings. Thus the Receiver should not consume more than 0.75*11 amps = 8.25 amps. That being the case, the maximum power consumption of this receiver cannot exceed 120V*8.25A = 990watts. Since this receiver has one common power supply, it must share with the processor, preamp, etc. Lets assume the processor/preamp consumes 100 watts, this leaves 990 - 100 - 890 watts available for the power section. Take 890*0.75 (efficiency factor) = 667 watts.

667 watts divided into 7 channels equals a whopping 95 watts /ch which is almost half of the specified power ratings! If we don't consider derating the fuse, than the total power available would be 120V*11A = 1320 watts - 100 watts = 1220 *0.75 = 915 / 7ch = 130 watts / ch which are still below the 170 watt/ch ratings.

So you are probably wondering how Denon can get away with this? The answer is; they never claimed the receiver could deliver 170watt/ch with all channels driven. They rate power for each channel driven instead. Again, the average consumer does not know this and thus chooses this receiver based on big power ratings. The point of this exercise to is bring awareness to consumers on how power is rated so that when they compare Receivers/Amps from competing manufacturers, they know if they are making an apples to apples comparison with respect to the power game.

When judging power, look for the following:

Continuous Power / Channel from 20Hz to 20KHz into 8/4 ohm loads
with all channels driven."

Straight from the AH website.

 

[cam]

If a piece of equipment's power consumption is stated in amps how do you
convert to watts and vice versa?
I've been looking at different avr's, for example, elite vsx-59txi 725watts, rz-z9 1000watts(1200VA), avr-5803 12.1amps, hk avr-630 1000watts.
How come an avr-630 absorbs more power than a vsx-59txi

If it is rated in amps, times it by 120. The denon 5803 at 12.1 amps x 120 would have a power consumption of 1452 watts. The yammaha would be reversed. 1000 watts divided by 120 = 8.3 amps. I hate to offend all the yammaha owners out there, but every denon out there has a higher power consumption then it's yammahe counter part. Does this mean better sound, no, does this mean that denon has bigger power supplies, yes.

 

[mtrycrafts]

does this mean that denon has bigger power supplies, yes.

That is a good explanation

It implies more power simultaneously from all channels but when will that even happen?
I don't know of a movie soundtrack that has such demands from all channels at the same instance. So, it is really much ado about nothing.

 

[av_phile]

If it is rated in amps, times it by 120. The denon 5803 at 12.1 amps x 120 would have a power consumption of 1452 watts. The yammaha would be reversed. 1000 watts divided by 120 = 8.3 amps. I hate to offend all the yammaha owners out there, but every denon out there has a higher power consumption then it's yammahe counter part. Does this mean better sound, no, does this mean that denon has bigger power supplies, yes.

With all things equal, having a larger, heftier power supply can be indicative of the power reserves available to the amplifier circuit. It is often not possible to defeat the laws of physics to do so. But having said that, the use of Torroids can effectively bring the wieght down by abut 25% for the same current and voltage requirements. Torroids are theoretically more efficient in conducting current between its primary and secondary configuration compared with regular EI types. That is why, most powerful SS amps use Torroids. They can have more power for the same weight as one using EI transformers.

You could offend yamaha lovers out there, the same way I did when I questioned the power specifications of their beloved Z9. And I don't offer apologies for what I think has no basis whatsover to offend. People often put things in the wrong perspective. You can enjoy the sound of your gear, whatever the brand is. Those are perceptions and I have no quarrel with that. But finding fault in its over-hyped power specification is another. I totally agree with Polkfan above. THose specs, while they can follow whatever measurement standards they find convenent for their marketing purposes, the net effect is that they can mislead people who are often interested more in the power numbers game and not knowing how to read and interpret technical specs. Power specs in advertising brochures are a promise to the consumer. If they shout 100watts PER CHANNEL in a 7.1 or 9.1 receiver, they better deliver that. Because that is what may have prompted the customer in buyng the product, among other things. It hardly matters if ALL channels are driven. Or if only 1Khz was used. Or whether you would need need all that in your listening levels. OR if there are ever any DVD material out there that requires that much. These are entirely beside the point. What is outright offensive is their brashness in publishing over-hyped specs to mislead unwary consumers. When those specs start attracting customers to their wares because it shouts 100WPC, those measurement conditions can be a fine print the customer couldn't care less to read at all. And that is my caveat against most of those consumer receivers out there. You only need to compare their power specs against reputable brands that use CONSERVATIVE power ratings to see what I mean.

 

[av_phile]

That is a good explanation

It implies more power simultaneously from all channels but when will that even happen?
I don't know of a movie soundtrack that has such demands from all channels at the same instance. So, it is really much ado about nothing.

It probably will never happen.

But that's entirely beside the point. The power as it is PUBLISHED in a BROCHURE to attract customers initially should correspond to the REAL power it can deliver as promised by that brochure. I think you can do that without any problem with CONSERVATIVE power ratings - something many consumer receivers probably haven't heard about in their quest for mass market leadership. It's often much ado about nothing for people who couldn't care less if they get hoodwinked or not.

 

[av_phile]

If a piece of equipment's power consumption is stated in amps how do you
convert to watts and vice versa?
I've been looking at different avr's, for example, elite vsx-59txi 725watts, rz-z9 1000watts(1200VA), avr-5803 12.1amps, hk avr-630 1000watts.
How come an avr-630 absorbs more power than a vsx-59txi

The HK AVR-630 is rated CONSERVATIVELY as compared with the other brands. That's why it can have more electrical power input for its conservatively rated output power, relative to the others. You can always draw that same observation comparing many over-hyped brands with more conservatively rated brands. I have a stereo power amp that consumes 1200 watts for a mere 2 channels rated conservatively at 250wpc into 8 ohms. I think that same electrical power is eaten up by many receivers claiming more than 170wpc for 7 channels or 9 channels. It's called CREATIVE marketing. They can create the needed power on the whim from air or something to attempt, much as they try, to deliver on their quesitonable promises for 170wpc.

 

[realistic]

Same old rant on power ratings by av_phile. H/K is not 'conservative' because they rate their receivers with all channels driven and the other manufacturers are not deceitful because they rate their receivers for two channels driven.

If the Z9 is rated 170wpc, that means EACH channel is capable of 170 watts. It DOES NOT mean that each channel can deliver 170 watts at the same time UNLESS THEY SPECIFICALLY STATE THAT...and they don't. The blame is on the consumer who does not read the specs and draws their own faulty conclusions.

 

[Yamahaluver]

Let the Yamaha bashing begin again, how can one listen to a non musical amp like Rotel and even comment on Yamaha is beyond my comprehension. Since Yamaha is not made or priced for snobs, it would never be good no matter what. Call about being subjective, if this isnt so, dunno what is.

Oh! Well! Here we go again...................

 

[toquemon]

I Own A Yamaha Rx-v1400 With Yamaha Ns-300 Front Speakers, I Agree With You That Yamaha Is Not Made Or Priced For Snobs (i Think Yamaha Has More Quality Than Denon, Hk And Onkyo Togheter), But I Can't Understand Why You Say That Rotel Is Not Musical. What Do You Mean With That?

 

[mtrycrafts]

Same old rant on power ratings by av_phile. H/K is not 'conservative' because they rate their receivers with all channels driven and the other manufacturers are not deceitful because they rate their receivers for two channels driven.

If the Z9 is rated 170wpc, that means EACH channel is capable of 170 watts. It DOES NOT mean that each channel can deliver 170 watts at the same time UNLESS THEY SPECIFICALLY STATE THAT...and they don't. The blame is on the consumer who does not read the specs and draws their own faulty conclusions.

Very well stated. Exactly what this is about.

 

[mtrycrafts]

how can one listen to a non musical amp like Rotel


Please, why do you think this is the case? You think the specs reflect your statement? Perhaps a DBT comparison?

 

[Rÿche 1]

(i Think Yamaha Has More Quality Than Denon, Hk And Onkyo Togheter)

Hilarious...

 

[toquemon]

The truth sometimes hurts. I don't know if you have seen amps lately, but Denon amps have PLASTIC instead of ALLUMINIUM in their front panels. The look of the HK amps is like a Christmas tree and the Onkyo amps are sounding terrible. I have had two Onkyo amps and the difference is from hell to heaven. The only mass market manufacturer that is taking responsability of new product creation, quality construction, and sound quality is YAMAHA.

 

[Unregistered]

One can find something to dislike about EVERY brand of receiver. Your assertion that Yamaha is the best, bar none,is an opinion - nothing more.

One area where Yamaha is severly lacking is basic usability. Simple things are extremely complex, compared to Onkyo where simple things are simple. Look at the large number of threads on Yamaha 'dynamic range compression' - very few understand what each setting does. Compare that to Onkyo - off, low, high; ie simple. How do you invoke DD-EX processing to a non-ex soundtrack on the yamaha? Read nine pages of threads on how to do it. Onkyo, press the 'ex' button.

In the end it comes down to personal preference. All major brands sound similar. The room and speakers make far more difference on sound quality than a receiver so useability is tantamount and at that Yamaha fails miserably.

 

[toquemon]

Ok

One can find something to dislike about EVERY brand of receiver. Your assertion that Yamaha is the best, bar none,is an opinion - nothing more.

One area where Yamaha is severly lacking is basic usability. Simple things are extremely complex, compared to Onkyo where simple things are simple. Look at the large number of threads on Yamaha 'dynamic range compression' - very few understand what each setting does. Compare that to Onkyo - off, low, high; ie simple. How do you invoke DD-EX processing to a non-ex soundtrack on the yamaha? Read nine pages of threads on how to do it. Onkyo, press the 'ex' button.

In the end it comes down to personal preference. All major brands sound similar. The room and speakers make far more difference on sound quality than a receiver so useability is tantamount and at that Yamaha fails miserably.

OK, YOU'RE RIGHT ABOUT THAT.

 

[Yamahaluver]

how can one listen to a non musical amp like Rotel


Please, why do you think this is the case? You think the specs reflect your statement? Perhaps a DBT comparison?

Specs dont make or reflect the sound character, if that was to be the case, all pianos from different manufacturers should sound allike, there should be no difference between a Yamaha, Steinway or a Baldwin but those who play them know very well the subtle difference in the sound and use it accordingly.

toquemon,

My opinion of Rotel exactly represents and reflects the subjective and biased nature of this very debate and therefore, in my opinion, the Rotel sounds like garbage just like to others, Yamaha sounds thin, harsh and bright.

 

[WmAx]

Monkey eggs!

If one piano really sounds different than another, it will most certainly measure differently. The same goes for an amplifier.

-Chris

Specs dont make or reflect the sound character, if that was to be the case, all pianos from different manufacturers should sound allike, there should be no difference between a Yamaha, Steinway or a Baldwin but those who play them know very well the subtle difference in the sound and use it accordingly.

 

[Karp]

There is no perfect receiver. At the risk of fanning the flames (what the heck.. it's fun to argue), I'll add my 2 bits:

IMO, the Yamaha tops every receiver for driving moderate loads in home theater applications. It has the best DSP's in the buisiness.It has very good DAC's. It's room optimizer is also pretty good. I would not want to try to drive 4 ohm speakers with one though. It's power supply is mediocre.

Pioneer has decent DSP's (not as good as the Yammy), and possibly a weaker power supply than the Yamaha. It has a very neutral sound, which is nice, but overall I am not really impressed with them.

Onkyo is very innovative, easy to use and have slightly better power supplies than the Yamaha. I think they are a great bang-for-the-buck Amp.

HK has the most robust amplifier section, but I think they are cheesy looking and don't have a lot of features. Its room optimizer sucks, but you can set the sub crossover separately for each set of speakers, which is really nice.

Dennon has a great power supply (not quite as good as HK), has good DSP's (not as good as Yamaha), but it has the best DAC's and a very good room optimizer.

This is what I gathered from spending hours reading spec sheets, reviews, user opinions.. ect. Take it with a grain of salt. I had a Sony receiver, which basically sucked. I read everything I could and listened to each one of these amps before choosing a Dennon 2805. I chose it because it had the features that I wanted in the price range I was looking at. It also sounded better to me than the other receivers I looked at, although I couldn't A/B it against the HK or the Onkyo.
Each one of these receivers does something or has something better than the others, and does some things worse. I think it depends on what priorities the buyer has. I would have probably been happy with any of these brands - none of them were bad receivers in the price range I was looking at.
Enough ranting.. I'm gonna go grab a fire extinguisher in anticipation of the flames heading my way!

 

[av_phile]

Same old rant on power ratings by av_phile. H/K is not 'conservative' because they rate their receivers with all channels driven and the other manufacturers are not deceitful because they rate their receivers for two channels driven.

LOL You better do some research and find out exactly what CONSERVATIVE means. Rating ALL the channels in a multichannel gear IS conservative and rating a multichannel receiver or amp with only one or two channels is over-hyped and, thus, totally deceitful to unwary consumers who would think they are getting a receiver rated for all channels.

If the Z9 is rated 170wpc, that means EACH channel is capable of 170 watts. It DOES NOT mean that each channel can deliver 170 watts at the same time UNLESS THEY SPECIFICALLY STATE THAT...and they don't. The blame is on the consumer who does not read the specs and draws their own faulty conclusions.

And precisely because they don't specifically state that is what makes their claims dubious to say the least. A spec as advertised is a promise to the consumer who EXPECTS his gear to perform as promised. Stating that it is a 170wpc is presicely that. If it cannot deliver what it is capable of doing. Then you just got duped. A wrong customer impression engendered by such a hype doesn't make them any less deceitful.