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Confused about power consumption ratings..

Discussion in 'AV Receivers & Amplifiers' started by phils_wicked, Oct 31, 2004.

  1. phils_wicked

    phils_wicked
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    Ok, Im looking into buying a Yammy DSP AX750se. However Ive seen and read a few snippets talking about the tweaks made to the PSU, i.e upping the rating to 400w from 370w.

    Ive found several pics of the back panel of the 750se and all show..

    Model no. DSP-AX750se

    350w

    a pic on superfi's website shows it clearly.

    So I assume Im looking at the correct model, and if so, whats up with the 370w rating i keep seeing?

    Or should I not worry?

    Thanks
     
  2. phils_wicked

    phils_wicked
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  3. BestGear

    BestGear
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    Hi there..

    Yes, power ratings as specified on the rear of amps is certainly one to watch.

    That rating is a nominal or max power consumption -- based on how much power it takes from the mains input - not what it can put out to the speakers.

    Based that amp is probably 70% at best efficient (many are nearer 50%) you get the drift as to what the amp can deliver.

    Many amps are rated at 100w X 5 channels... then check the rear - 300w max...hmmmm does not work out does it!!?!?!?

    The ratings that many amps state are only good for one or possibly two channels driven to that level at any one time - the others will probably be idling along at 20w ish... (whatever.,.).

    For a comparison, have a feel at the weight of the bigger amps around - they will certainly be 70% power supply weight - and will be up to rated power from all of its channels simultaneously. Some Yamahas are 20-30Kg....

    There are lots of power supply tweeks for amps around... easy meat for a cheapo upgrade to a standard amp... but at the end of the day if the basic PSU is not up to the current delivery, you aint going to get full output to all channels simultaneously.

    So - how often are all channels drive to thier max at the same time? not often... so if the power supply has headroom it gives the amp the ability to max way beyond its rated output during peaks... cleanly.

    The days of good old "Hifi Choice" doing its real lab tests (labs are often not in the real world...) to measure all channels driven to limits seem to be gone... I think most mags these days sway depending on who buys lunch...

    Hope that helps...
     
  4. CosmicOne

    CosmicOne
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    don't worry "phils_wicked" i was in the same boat with u from a month or more & i was looking on the power consumption to comapre the RXV650 to the RXV750 & i found that the pics of both on the internet are wrong very wrong.
    anyway from asking the guys hrere with the AX750 they told me it's 440w & when i bought my RXV650 i found its powe consumption 440W.so it's good & don't worry about it.
     
  5. phils_wicked

    phils_wicked
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    Thankyou for your replys :D

    Im off out shopping today, so who knows what I may come back with lol

    Thanks :smashin:
     

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