watts or ohms

Discussion in 'AV Receivers' started by Giob, Dec 15, 2004.

  1. Giob

    Giob Extra

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    in comparing 2 receivers, 1 has higher wattage (115 vs 85) while the other has higher resistance (8 ohms vs 6). Which would u pick, the one with higher wattage but lover ohms or the other one?

    Thanks
     
  2. Mark Tranchant

    Mark Tranchant Stunt Coordinator

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    A receiver doesn't "have" ohms. The "ohms" figure is a measure of the impedance (think AC resistance) into which the amp can provide the stated power figure.

    It's more a measure of the amps' current-providing capability. Both receivers will probably drive 4-ohm loads with no problem, although you'd need to check this.

    Both figures are largely irrelevant to you, anyway. Pick the one that has the combination of looks, features and sound quality that suits you the best. Unless you're looking for monster volume levels, anything over about 50W rms will suit most homes.

    There's a lot of variability in the way the numbers are measured, too: this makes direct comparison difficult. I've seen a 5.1 computer audio system advertised as 2500W. Reading the small print revealed this to be a PMPO (peak music power output) number, which marketing departments can pluck from the air to suit them - the genuine maximum power output was 2Wrms for the satellites and 12Wrms for the sub...
     
  3. James Phung

    James Phung Second Unit

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    You'll also need to check your speakers and see what ohms they are. Many receivers have problems powering 4 ohm speakers so if you have 4 ohm speakers you might want to check if the receiver can handle it.
     
  4. Giob

    Giob Extra

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    Mark, thanks for the education. so i'm looking at the wrong things.

    James, how can i check if the receiver can handle it?

    thanks guys
     
  5. Paul S

    Paul S Stunt Coordinator

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    I have yet to see a receiver that wouldn't handle both 4 and 8 ohm speakers. I don't think you'll have a problem no matter what speakers/receiver you select.
     
  6. BrianWoerndle

    BrianWoerndle Supporting Actor

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    Watts and ohms are directly related. Theoritically, 100 watts at 8 ohms would be the same as 200 watts at 4 ohms. (most receiver can't double down like that, but some get closer than others). So theoritically the 85 watt receiver should put out 127.5 watts at 6 ohms.

    But remember that is 1 tiny part of what the receiver can do. There are several other determining factors. How many channels driven? At what frequency (1khz, or 20-20khz)?
     
  7. Robert Cowan

    Robert Cowan Supporting Actor

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    you know what the GREAT thing about all this is? you dont need to know this stuff [​IMG] listen to the combo you are planning on buying. if it sounds great to you, and you an afford it, buy it, listen to it, enjoy it, and be happy.
     
  8. Jon W.

    Jon W. Stunt Coordinator

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    I agree with letting your ears decide. Watts mean NOTHING. The Harmon Kardon fans here will tell you that. Put my 120 watt Denon receiver against a 50 watt Krell amplifier and the Denon will lose very badly every time.

    Just a suggestion but....You'd probably get better advice if you revealed the brand and model numbers of the receivers you are considering.
     
  9. Paul S

    Paul S Stunt Coordinator

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    "Put my 120 watt Denon receiver against a 50 watt Krell amplifier and the Denon will lose very badly every time."

    I highly disagree with you Jon W. In double blind carefully matched testing all amps sound the same. There is no difference in audio quality between a Krell and a Denon or any other properly operating amp/receiver as long as they are operated within their designed power range, i.e. not clipping.

    If you are so sure that there is any difference whatsoever, why don't you take the $10,000.00 challenge. Go to the forums at www.audioholics.com and do a search for $10,000, there you will find that the money is offered to anyone who can tell the difference between amplifiers. As a matter of fact, you can take your Krell and put it up against a Denon. I will warn you, many have taken the test, none have walked away with the money.

    Please don't argue with me about how wrong I am. Simply go, take the challenge, and walk away with $10,000 if you can.
     
  10. Shiu

    Shiu Second Unit

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    HK fan knows that HK provides all channel driven power. People consider HK as being honest about their published power rating.

    That said, a 75W pc X 7, 85W X 2 HK model's (e.g. AVR630) spec does not necessarily mean in lab test they will prove to be more powerful than a Denon AVR3805's 120W X 7. In fact if you read HT mag and S&V lab measurements (available online) you will find that the opposite is true, the Denon has much more power. The Denon has much higher 1 & 2 channel driven rating and a little higher in all channel driven rating. Keep in mind too, these two receivers are in comparable price range.

    I compared the sound of my 3805's amp with my 4BSST (300W X 2) in pure direct mode and heard little difference. At first I thought the Bryston sounded clearer and more dynamic. I was in fact, ready to tell everyone how significant the improvement was, looking back I felt a little silly. The fact is, after more careful listening, I was disappointed but I must admit that the difference were only noticeable if I listened very hard at higher volume, and focussed on certain parts of the music. Even then, I am not entirely sure if I simply want to believe I had not wasted my money on the expensive Bryston.

    Jon W, that 50W Krell may not do all that much for you. I will still hook up the 3805 to my old 2 channel Adcom GFA-555, but only because I think it will help prolong the life of the Denon.
     
  11. Robert Cowan

    Robert Cowan Supporting Actor

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    paul,

    do some homework before you make such claims...

    the challenge you elude to is for test tones only, its not for music. test tones are VERY hard to hear differences with.
     
  12. Giob

    Giob Extra

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    Thanks for all the responses I guys. I am learning.

    Jon W is right, I would have gotten better and more direct advice if i specified the receivers brand and model. Thanks Jon W. However, i did learn a lot. Thanks.

    Here's why i asked the question: I got 3 offers to buy pre-owned receivers. A YAMAHA RXV450 ($280), an Onkyo TXSR 502 ($303) and an Onkyo TX-DS484 ($178). I just wanted to know which one would have the best bang for the buck. I'm no audiophile and could hardly differentiate sounds (or maybe i just havent heard them so i think i wouldnt know the diff.) just wanted value-for-money.

    I was thinking of including the specs but maybe you guys would know which one will get the unanimous vote as the the most value for money receiver.

    tnx /G

    PS. (the other problem with the specs i collected is that they are not consistent, eg one site says 75 watts, another (onkyo site) says 115Watts per channel min. into 6 ohms, 1Khz, JBTA.)
     
  13. Robert Cowan

    Robert Cowan Supporting Actor

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    give yourself a bit more credit. 99% of my customers say "im not an audiophile, i cant hear a difference". 100% of those people are surprised when they easily hear differences between gear when its properly demo'ed. give yourself credit, demo the stuff. understand what $500 would get you compared to $300. just get a feeling of what sounds like what.
     
  14. Jon W.

    Jon W. Stunt Coordinator

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    I think you guys kinda took what I said the wrong way. At normal listening levels I don't think they're would be much difference in audible "sound quality" between my 3805 and a Krell although I think their would be a difference. The big difference would come when running my towers full range at near clipping levels. I'm talking about current reserve. Watts mean nothing without current reserve is what I'm saying. I'm not a highly educated person so this is only my opinion FWIW. I bi-amp my towers atm but would like to get a decent pair of monoblocks (not Krell cause I'm not rich)someday so I can run them full range. I have NHT VT-2.4 towers and they are "current" hungry speakers.

    My Harmon Kardon comment meant that if people went by wattage then no one would buy HK because they rate their wattage different than other brands. I never said anything about My Denon against a HK.

    Now having said that, Onkyo and Yamaha are both quality brands, I'd go with the one that has the most features that you would find beneficial and not pay much attention to their rated wattage and of course listen to them if you can. Some may say you can't hear a difference but I have had 3 receivers and I could tell them all apart. I had an Onkyo 105wpc that sounded very good but the Denon sounds a little warmer IMO. I had a Kenwood 110wpc before the Onkyo that had no bass output whatsoever to full range towers. I could pick it blindly for $10,000 all day long against my Denon by just playing a 30Hz test tone through my towers running full range.
     
  15. Paul S

    Paul S Stunt Coordinator

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    Robert Cowan: The challenge as described in an Audioholics thread: (It specifically states MUSIC NOT TEST TONES)

    Take ANY two amps (Amp 1 and Amp 2).

    The amps are tested to find their linear range (i.e. where they operate w/o distortion or clipping).

    The linear range of the less powerful amp is selected (so that 10-watt tube amp isn’t driven into clipping while going up against the $10,000 SS amp)

    Adjustments are made for the input sensitivity of each amp.

    If necessary, the amps are EQ’ed to sound the same, apparently some amp makers boost/cut certain frequencies to give their amp a distinctive sound.

    The person taking the challenge decides which amp gets EQ’ed. Yes, you can take a working flea market find, have it EQ'ed, and compare it to a Halcro.

    The person taking the contest listens to ANY music they want for however long they want, but the guy running the contest requests that they keep it limited to a few hours.

    The person taking the contest can use ANY available commercial speakers; as long as the speakers use cones and the amps being tested can power them.

    There will be 2 listening sessions of 24 trials. If anyone can tell the two amps apart 100% of the time, they walk away with $10,000.
     
  16. Robert Cowan

    Robert Cowan Supporting Actor

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    paul, ok, i was thinking about something else... sorry.

    i understand the point of eq'ing, but it seems like it would make it much harder to tell the difference. i wonder why you can only use cone speakers, not planars? 100% of the time is the BS part. we are human, and arent perfect. 90% of the time would be adequate. you have to look at statistics and say what is enough of a positive correlation... of course 50% is just guessing, but 90% or so is definite...
     
  17. Paul S

    Paul S Stunt Coordinator

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    Robert, to put it mildly, from the extravagant claims made by high end amplifier/receiver owners in regard to how much better high end equipment sounds than the standard garden variety of receiver/amplifier, it should be a piece of cake to tell the difference between amps/receivers 100% of the time. After all, who couldn't tell the difference between a Lexicon and a Radio Shack???? The audible difference may be far less than you think. (as long as neither amp is driven into clipping)

    As to specifying that no electrostatic speakers be used it is really quite simple. Most amps/receivers don't have the required power to drive electrostatic speakers properly. Electrostatic speakers such as Martin Logan require a lot of amplifier power.
     
  18. Robert Cowan

    Robert Cowan Supporting Actor

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    paul,

    sounds like its too controlled of a test...

    i know about planars, and thats why i asked... mine use a LOT of power, but dont necessarily drive the amp until clipping. however, different amps sound different due to power delivery. so, maybe thats why they werent included, it would be too easy [​IMG]
     
  19. Paul S

    Paul S Stunt Coordinator

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    I think you sort of missed the main point a bit Robert, which is simply: If it is that hard to distinguish a difference between receivers/amps, are you really getting your money's worth on high end equipment. If you are purchasing it for the vanity of owning it, I suppose you are. However, if you are purchasing it to get better sounding audio, you might not be getting what you are paying for.

    If I were to look at only one point in an audio system to improve sound quality it would be speakers.
     
  20. Robert Cowan

    Robert Cowan Supporting Actor

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    Paul,

    i understand what you are saying... its just that if you limit them to exactly the same power output, the same eq'ing, and the same gain, etc... with only cone speakers, i would have to agree, they would sound the same. however, power, eq (or flatness), and ability to drive difficult loads is what makes amps different. that is what you pay for.
     

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