Receiver power rating

Discussion in 'Archived Threads 2001-2004' started by Aaron Rosenfeld, Dec 12, 2002.

  1. Aaron Rosenfeld

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    I was looking through the manual for my Panasonic SA-HE200 today and I noticed something odd. In the specifications section, under the power heading, it said power consumption: 350 watts. Whah!? This receiver rates itself as 130W x 6 (Granted this is at 6ohms, but still). What exactly is the 350 measuring? I had my friend look up the same number on his Sony STR-DA3ES and it only had 420 Watts. What is going on here?
     
  2. Paul Clarke

    Paul Clarke Supporting Actor

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    Hi Aaron,
    Here we go again. If you do a search on related topics, you'll understand. [​IMG]
    There are a great many misconceptions about the power ratings of various receivers. The most common one is that any given receiver will output what is listed as its' manufacturers power rating across all channels. This is not the case and rarely will you find it in low-mid level receivers. There are a handful of known brands who do deliver what they promise as they are designed and built to do so from the start. H/K, NAD, Arcam, Rotel, etc. fit the bill and are considered conservative. High end receivers, by and large, have no issues in this regard.
    Since full power is rarely needed across all channels simultaneously, the much more common method of power rating is to list the maximum of what each channel is capable of delivering in isolation, that is 1 channel. It may seem misleading but it is legal. If this is of concern to anyone the rule is to look for 'all channels driven, 20Hz-20kHz'
    One of the easiest methods of determining whether or not a given receiver is rated as delivering the quoted power with all channels driven is to question the consumption figure which you have done. Obviously the HE200 does not deliver anything like 130Wx6 simultaneously. There is also the matter of impedance which needs to be factored in. If the HE200 were rated for 4 Ohm speakers (which I do not think is the case), the roughly 60Wx6 maximum would apply here as well. Which would mean that at 8 or 6 Ohms total output (?Wx6) could likely be even less. But as the receiver is rated at 6 Ohms the full potential remains 350W at 6 Ohms.
    I'm sure many will tell you not to fret over such things and they are partly right, IMO. How a given receiver sounds is far more important than specs. and many good to great pieces have been made with specs that might seem questionable in some regards. But I am in the camp that generally regards good specs as a precursor to good performance.
    Just my $.02
     
  3. Aaron Rosenfeld

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    Thank you very much for your lengthy and detailed reply. I did do some minimal searching before I posted a new thread, but I wasn't able to find anything. I figured that the truth lied somewhere near what you just said. The only thing that surpised me was that one of the Sony ES models had the same defficiency. Now maybe this is just me, but I figured the ES series was fairly "high-end". Thanks for the help.
     
  4. Paul Clarke

    Paul Clarke Supporting Actor

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    Aaron,
    Actually the situation is even worse as far as power actually delivered to the speakers themselves. There is a certain amount of available power that is used for other things in receivers so the attrition rate between other demands and system losses and inefficiencies can reach as high as 20-30%. That leaves 70-80% available for your speaker set.[​IMG]
    As to the ES line most are quite capable of delivering the goods but like most others Sony rates their power by the 1-2 channel method and multiplies.
     
  5. mark alan

    mark alan Supporting Actor

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    Just for everyones edification, here is the standard that all manufactures must base their power output claims on. If people really think that the claims are inflated, they should file a complaint with the Federal Trade Commission.

    16 CFR §432.2 Required Disclosures.
    (a) Whenever any direct or indirect representation is made of the power output, power band or power frequency response, or distortion characteristics of sound power amplification equipment, the following disclosure shall be made clearly, conspicuously, and more prominently than any other representations or disclosures permitted under this part: The manufacturer's rated minimum sine wave continuous average power output, in watts, per channel (if the equipment is designed to amplify two or more channels simultaneously) at an impedance of 8 ohms, or, if the amplifier is not designed for an 8-ohm impedance, at the impedance for which the amplifier is primarily designed, measured with all associated channels fully driven to rated per channel power. Provided, however, when measuring maximum per channel output of self-powered combination speaker systems that employ two or more amplifiers dedicated to different portions of the audio frequency spectrum, such as those incorporated into combination subwoofer-satellite speaker systems, only those channels dedicated to the same audio frequency spectrum should be considered associated channels that need be fully driven simultaneously to rated per channel power.

    (b) In addition, whenever any direct or indirect representation is made of the power output, power band or power frequency response, or distortion characteristics of sound power amplification equipment in any product brochure or manufacturer specification sheet, the following disclosures also shall be made clearly, conspicuously, and more prominently than any other representations or disclosures permitted under this part:

    (b)(1) The manufacturer's rated power band or power frequency response, in Hertz (Hz), for the rated power output required to be disclosed in paragraph (a) of this section; and

    (b)(2) The manufacturer's rated percentage of maximum total harmonic distortion at any power level from 250 mW to the rated power output, and its corresponding rated power band or power frequency response.


    16 CFR §432.3 Standard Test Conditions.
    For purposes of performing the tests necessary to make the disclosures required under §432.2 of this part:

    (a) The power line voltage shall be 120 volts AC (230 volts when the equipment is made for foreign sale or use, unless a different nameplate rating is permanently affixed to the product by the manufacturer in which event the latter figure would control), RMS, using a sinusoidal wave containing less than 2 percent total harmonic content. In the case of equipment designed for battery operation only, tests shall be made with the battery power supply for which the particular equipment is designed and such test voltage must be disclosed under the required disclosures of §432.2 of this part. If capable of both AC and DC battery operation, testing shall be with AC line operation;

    (b) The AC power line frequency for domestic equipment shall be 60 Hz and 50 Hz for equipment made for foreign sale or use;

    (c) The amplifier shall be preconditioned by simultaneously operating all channels at one-eighth of rated power output for one hour using a sinusoidal wave at a frequency of 1,000 Hz; provided, however, that for amplifiers utilized as a component in a self-powered subwoofer system, the sinusoidal wave used as a preconditioning signal may be any frequency within the amplifier's intended operating bandwidth that will allow the amplifier to be driven to one-eighth of rated power for one hour;

    (d) The preconditioning and testing shall be in still air and an ambient temperature of at least 77°F (25°C);

    (e) Rated power shall be obtainable at all frequencies within the rated power band without exceeding the rated maximum percentage of total harmonic distortion after input signals at said frequencies have been continuously applied at full rated power for not less than five (5) minutes at the amplifier's auxiliary input, or if not provided, at the phono input.

    (f) At all times during warm-up and testing, tone loudness-contour and other controls shall be preset for the flattest response.
     
  6. Yogi

    Yogi Screenwriter

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    Take the receivers total power consumption and divide that by the total number of channels it has and then further take 70% of that number (typical Class AB amplifier efficiency). That would give you the number of watts the receiver would be able to output continiously in each channel.

    So in your Panasonic's case the maximum power it will deliver continuously to each channel would be ([350/6] x 0.7 =) 40W. There is no mystery involved here. The manufacturers claim those ridiculous ratings without specifying if its the rated output at 1 Khz or 20-20Khz, for 1 second or for 10'th second etc etc. Dont be fooled by those numbers.
     
  7. Chuck Kent

    Chuck Kent Supporting Actor

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    IMO, when comparing power use versus power output, we're talking about apples and oranges...

    Power consumption (watts = voltage X amperage) of a receiver is spec'd based on 120 volts AC. I don't know what voltage is common for speaker outputs but I'm fairly certain it's not 120 volts AC. If this is so, can a valid comparison be made from what the unit draws from the wall and what it pushes to the speakers?

    Even if one did come up with a yardstick to compare these 2 measurements on an equitable basis, does it mean anything? Many class A amps idle at very high input wattage consumptions and often deliver only small amounts of output wattage. But they are often the most well thought of amplifiers available.

    An inverse perspective would be automotive sound amps. They can create much more output wattage than what they consume. Yet I don't think many of us consider them, quality-wise, to be superior to what we have in our living rooms.

    Bottom line is that I don't feel that comparing these 2 types of measurements means a great deal (if anything)...
     
  8. Yogi

    Yogi Screenwriter

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  9. JohnSer

    JohnSer Stunt Coordinator

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    Just for some comparison, my new HK520 is rated at 78W at idle, 694W maximum (2 channels driven) VS my older Onkyo 575X is 325W 3.9A. The Onkyo might be average rating, though.

    The other way to compare is weight. HK520 is 35lbs, while the 575X is 28lbs. Most of the HK weight is its large transformer.

    I don't know what the wattage and ratings were on the DD ready 5x100 Pioneer, the Onkyo replaced, but it didn't come close to the sound of the Onkyo or HK.

    The Onkyo was a noticeable improvement over the Pioneer. The Pioneer seemed brighter and lacked the detail of the Onkyo. The HK was a less dramatic improvement, with a stronger, tighter bass, with slightly cleaner highs.

    JohnS
     
  10. David MW

    David MW Auditioning

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    Ok, now I've got a question. I posted a few weeks ago about the power claims of the Panasonic HE-100K - the next model lower than the Panasonic HE-200K. All of this got me researching the issue further, and this is what I found:
    Sound & Vision magazine found that the HE-100K (which claims 100Wx6 at 6 ohms 40Hz-20khz) actually delivered 70Wx6, all channels driven, real world watts (before clipping). (It delivered 78W with only 5 channels driven.) Obviously, the 100Wx6 at 6 ohms is a marketing ploy to show more watts per channel because most people don't notice 6 ohms versus 8 ohms, although it is allowed under FTC rules. Sound & Vision testing procedure, as I understand it and read it on their website, is at 8ohms, all channels driven. S&V defines the clipping point as .3% THD+N.
    If this is true, then the Panasonic HE-200K - which is rated 30 Watts higher per channel than the HE-100K - should definitely be able to produce more than 70W to all 6 channels at an 8 ohms load.
    I'm not an expert (and don't claim to be). To further the discussion and continue learning, I'd like to know what everyone thinks about this. Am I understanding this correctly or is there something about Sound & Vision's testing that I don't understand?
     
  11. Yogi

    Yogi Screenwriter

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    Also from what I remember S&V tests the output at 1 KHz and not the full spectrum (20-20KHz). Usually the full spectrum rating is about 20% lower than the 1 KHz rating. So according to that the 70Wx6 should only be 56Wx6 @ 20-20KHz. Also I think S&V tests the amps to 1% distortion which is beyond clipping for most SS amps. So real world outputs before clipping will be even lower although I dont know by how much.

    There is an article on S&V website thats titled something like 'how we test amps'. That discusses in detail about their amp output testing procedure.
     
  12. David MW

    David MW Auditioning

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    Yogi, you are right that Sound & Vision does test at 1khz (or as they say 997hz exactly). They think that this is a more realistic test, as they think it would be very unusual for an amplifier to put out less power at lower frequencies, and unrealistic for an amp ever to have to power all channels at 10khz or more(ear splitting level).
    They also set the clipping point at .3%THD+N rather than 1% THD+N, as they agree with you that under certain conditions 1% might be noticeable.
    Under these conditions, the Panasonic HE-100 tested at 78W for all five channel, and 70W for all six channels. Based upon Panasonic's own ratings, I think that the HE-200 is likely to be 25% higher than this.
    As someone still learning about audio and shopping, I have wanted to seperate hype and marketing from reality. I have looked at Harman Kardon receivers, Onkyo, Marantz, etc., brands that are generally considered better than Panasonic. While there may be many reasons to purchase those brands (such as the interface on the HK, which I love), I'm not sure power is issue.
    Sound & Vision under the same testing criteria found that the Harman Kardon-AVR510 (an older model) was rated at 70W and tested at 74Wx5 under the same criteria as above. This is less than the Panasonic HE-100 for five channels. The Denon AVR-2802 also tested with less power than the Panasonic (61Wx6).
    This is not to say that the Panasonic is a better receiver than the other receivers. To me many other factors enter into that equation, but unless I am understanding something wrong (which is very possible!),odds are that the Panasonic HE-200 (based upon the tested HE-100) will provide more than 70Wx6 of power before a clipping point defined as .3% THD+N.
     

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