Harman Kardon 7550 is rated 60amps but my outlet is just 15 amps!

stangjason
stangjason Posts: 341
edited September 2011 in Electronics
I'm asking this in another audio forum but I thought I might find a person that understands this if I look in more than one place. So what's the deal? Is the 60 amp rating bogus or is there a way that 60 amps is accomplished?
Pioneer vsx-1120k, B&K Sonata series video-5 amplifier, Polk Rti8, Fxi3, Csi5, and HSU VTF-1
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  • PrazVT
    PrazVT Posts: 1,607
    edited September 2011
    An 'amplifier' contains transistor circuits that do exactly that ... increase current or power etc., depending on the design. I'm being very high level here as I hated my 3 years of electrical engineering in college lol.

    I'll let someone more technically inclined explain it better..but I think I'm in the ball park. Also, if you do a quick google of "amplifier increases current" one of the first links answers that question for you.
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  • disneyjoe7
    disneyjoe7 Posts: 11,435
    edited September 2011
    Without being too complicated, it's due to voltage transformers and capacitors in the power supply storing electrical juice for later use.

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  • stangjason
    stangjason Posts: 341
    edited September 2011
    PrazVT wrote: »
    An 'amplifier' contains transistor circuits that do exactly that ... increase current or power etc., depending on the design. I'm being very high level here as I hated my 3 years of electrical engineering in college lol.

    I'll let someone more technically inclined explain it better..but I think I'm in the ball park. Also, if you do a quick google of "amplifier increases current" one of the first links answers that question for you.

    Yeah if you get too technical I might fall asleep. Actually what you are telling me is what I suspected but I didn't know exactly how it worked so I just asked a wide open question.

    Thanks,
    Jason
    Pioneer vsx-1120k, B&K Sonata series video-5 amplifier, Polk Rti8, Fxi3, Csi5, and HSU VTF-1
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  • PrazVT
    PrazVT Posts: 1,607
    edited September 2011
    No probs - the thought has crossed my mind as well (the specifics), but I never bothered to delve into it. I still recall the final project in my electronics 2 class where we actually had to design an amplifier (using the modeling software) and get it work within certain parameters ...ugh. Ok time to block that memory out again.
    Dali Optikon 1Mk2
    NAD D3020 V2
    Schiit Bifrost 2/64

    ..the rest are headphone setups.
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  • stangjason
    stangjason Posts: 341
    edited September 2011
    On a side note I've been looking around and I noticed that my old H/K AVR 635 that I sold has a very similar amp section and weight to the 7550. Now I really can't wait till I get my 7550 because I really miss the smooth and POWERFUL sound of my old 635 with exception of it's lack of Mastered Audio and HDMI.
    Pioneer vsx-1120k, B&K Sonata series video-5 amplifier, Polk Rti8, Fxi3, Csi5, and HSU VTF-1
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  • Schurkey
    Schurkey Posts: 2,122
    edited September 2011
    stangjason wrote: »
    I'm asking this in another audio forum but I thought I might find a person that understands this if I look in more than one place. So what's the deal? Is the 60 amp rating bogus or is there a way that 60 amps is accomplished?

    Wall outlet rated for 15 amps at ~115 volts rms. (Peak voltage is around 170.)

    Stereo amp rated at 60 amps, probably around 50 volts rms. Between the transformer trading voltage for current, and the short-term energy storage in the power supply capacitors, a short-term burst of output is easy enough.

    Consider that there's NO "duration" spec: the 60 ampere burst is of an unspecified duration, and into an unspecified resistance (load.)

    Which means that the duration is so short, and the load is so close to "zero" ohms as to be musically insignificant.

    This is a game many amplifier manufacturers play; and apparently the FTC allows them to mislead customers. The FTC needs it's **** kicked for inaction.

    NOBODY who advertises crazy ampere output of a music amplifier will publish the test protocol...because they'd "out" themselves as deceptive advertisers.



    When folks would ask what the "ampere output" of an Aragon amplifier was, they'd say "whatever you want it to be"; they could design a test protocol that would produce whatever staggering ampere spec you wanted...if the load resistance was low enough, and the duration was short enough. The only quantitative spec they'd give is whatever the rating for the rail fuses was--often 10 amps + and 10 amps -; for a total of 20 amps long-term.
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