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Does size matter?

Discussion in 'AV Receivers & Amplifiers' started by scrapbook, Oct 19, 2003.

  1. scrapbook

    scrapbook
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    I have had a slimline Sony Amp for about 3 years and I am now thinking of investing in a new 6.1/7.1 one.

    Can you clarify for me the main difference between say a slimline amp and a full size amp...is it just a case of a bit more oommpph?

    If you compare for instance the Pioneer 501 slimline receiver and the Pioneer 712/812 there doesnt appear to be much difference in the specs....so why are most amps so damn big?
     
  2. hornydragon

    hornydragon
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    main difference is the amp circuits slimline use combi amps big meaty ones proper amps less efficent and far more waste ful generate a lot of heat so a lot of the big box weight is heat sinks for the power amp stages! See Class A Class A/B and Class D amplifier descriptions
     
  3. Garrett

    Garrett
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    Generally it is to give more room for the heat since you have a mass of amplifiers in one box, but does not the 501 have only one set of analogue input?
     
  4. alexs2

    alexs2
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    Another big space/weight item is obviously the power supply in most amps,and in general as the power output rises,so does the mass of the power supply.

    One exception to this is amps using switch-mode power supplies,which are more compact than traditional designs,and a good example of this is the Linn Klimax(daft name)power amp which despite measuring 35cms square and only 6cms high,turns out around 300W.

    You also have to remember that a pair of amps with relatively similar specs may be very different....e.g.a relatively low priced AV amp rated at 100W per channel may just about manage that with 2 channels driven into a simple load,and may then have problems delivering the rated power with all channels driven,or into low impedances or difficult loads.
    A similarly rated Krell or Levinson will continue to deliver more and more power into lower loads without problems,usually doubling output as impedance halves.

    It all comes down to how much you want to pay,and how important power reserve and load tolerance are to you,along with sound quality.
     
  5. scrapbook

    scrapbook
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    So to in layman's terms......

    in comparing the Pioneer 501 with 712/812 which have similar specs at similar price - basically you get more bang for your bucks due to the extra amplification that the 712/812 carries?
     
  6. alexs2

    alexs2
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    If you compare the specs of the 3 receivers carefully you'll see the differences....the 501 is rated at 100W into 6 ohms,and at a very audible 10% THD,whereas the others will do so into an 8ohm load,at much lower rated distortion levels...basically,as you've said,the extra bang for your bucks comes in the form of better,and more rugged amplification.
     
  7. hornydragon

    hornydragon
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    Trust me 10% THD is crap 0.1 THD is good 0.05 is very good the best amp push 100Watts + at o.o5 THD thats why high quality amps are rated a lot lower than they can go because they are rated at very low THD levels.
     
  8. alexs2

    alexs2
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    I think that's what I've been saying! :)

    You may also find that a lot of the best high powered amps(Krell,Levinson etc) will not only deliver far in excess of their rated power,but will also do so at or below their rated distortion figures etc.

    As far as the various Pioneer receivers here are concerned,the only reasons for buying the 501 as compared to the others would be on cost or appearance grounds,and the latter will lead to disappointment eventually.

    It's often better to accept a good,lower powered amplifier,than a relatively poor,and on paper at least,higher powered amp that struggles to deliver music you can listen to.

    Within their obvious power limitations,some of the nicest sounds I've heard have come from very low powered(8-20W)Class A SET valve amps...I certainly wouldn't recommend something like that for AV use,but only to illustrate the point.
     
  9. scrapbook

    scrapbook
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    All very interesting this - I would imagine alot of people like myself just compare amps by the 80w output etc!

    I have just looked at my Sony instruction manual, out of interest -

    The rated power output at stereo mode is quoted as
    8ohms 1khz 0.30% THD (80w)

    How does that compare with the Pioneer quoted at
    8ohm 1khz 1% THD (100w)


    I assume not very well??
     

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