How can the power output exceed the power input????
ward91
Posts: 338
How can the power output exceed the power input????
Hello all, i have wanted to know this for a while , some of the avrs on the market have rated power outputs (continuous or rms) that are more than the rated power input in watts , how is this ??
For example i have a borrowed denon avr 1509 and the rated power input in watts is 360 . and the sums rated power outputs are (75w*5ch) = 375w @ 8ohm . or (110w*5ch)= 550w .
How can this be ??
Cheers ed :-)
Hello all, i have wanted to know this for a while , some of the avrs on the market have rated power outputs (continuous or rms) that are more than the rated power input in watts , how is this ??
For example i have a borrowed denon avr 1509 and the rated power input in watts is 360 . and the sums rated power outputs are (75w*5ch) = 375w @ 8ohm . or (110w*5ch)= 550w .
How can this be ??
Cheers ed :-)
ELECTRONICS
arcam cd93
linn wakonda
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arcam cd93
linn wakonda
MC2 MC450
Teac ud h01 DAC
SPEAKERS
Tannoy DC6 t se .
Post edited by ward91 on
Comments
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Two things.
One, usually "75w x 5ch" is with only one or two channels driven. It's a cop-out, and blatantly dishonest, but almost all of them do it.
Two, for instantaneous power, you could technically exceed the input power thanks to capacitors and whatnot.If you will it, dude, it is no dream. -
Bobman, "If this is true, which 2 channels would get the main power?Polk Audio Surround Bar 360
Mirage PS-12
LG BDP-550
Motorola HD FIOS DVR
Panasonic 42" Plasma
XBOX 360[/SIZE]
Office stuff
Allied 395 receiver
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RT8t's & Wharfedale Diamond II's[/SIZE]
Life is one grand, sweet song, so start the music. ~Ronald Reagan -
I think the trick is to understand the ratings used. I could be wrong, but most AVRs aren't rated for full output with ALL channels driven. I.e., the fronts may be driven at that level, but the surrounds are at much lower levels. If all channels drew 'full power' continuously the power supply would obviously not be able to deliver.
Then there is the difference between rms continuous power (based on simple sine wave at a specific frequency) and music power (which is a more complex signal with transients that are significantly greater than the average power draw.) With a well designed amp, there are reserves in the PS which will allow the amp to deliver clean transients that are perhaps 5 times the level of the rms continuous power rating.
It get really complicated!
Cheers. JimA day without music is like a day without food. -
I don't understand the question....
Basically, the rating is saying that if you have all five channels connected but only one or two are being driven, you will get 75 watts on those channels. If you are driving all five you'll get significantly less on all of them. I don't believe there's any kind of "priority".If you will it, dude, it is no dream. -
A more legitimate way is that amps use large capacitors. Some expensive power supplies / surge protectors have giant coils that allow for up to 50 amps of current... now this can only be used for a very short period of time as the capacitors will run out and then recharge.
It is possible for output to exceed input in short bursts.My Iron Man training/charity blog.
HT:
32" Sharp LCD. H/K dpr 1001 to Outlaw Audio 7900 to Polk LSi + Paradigm Studio center. Hsu DualDrive ULS-15. PS3/Wii. Outlaw 7900. -
Bobman, Thanks I think I understand now, forgive me for the dumb question, Im still learning.......If im watching a movie in DTS or DD and all 5 channels are being driven with my Pioneer 816 rated at 110 wpc I may only be delivering half that amount to all 5 channels....am I on the right path?:)Polk Audio Surround Bar 360
Mirage PS-12
LG BDP-550
Motorola HD FIOS DVR
Panasonic 42" Plasma
XBOX 360[/SIZE]
Office stuff
Allied 395 receiver
Pioneer CDP PD-M430
RT8t's & Wharfedale Diamond II's[/SIZE]
Life is one grand, sweet song, so start the music. ~Ronald Reagan -
Knucklehead wrote: »Bobman, Thanks I think I understand now, forgive me for the dumb question, Im still learning.......If im watching a movie in DTS or DD and all 5 channels are being driven with my Pioneer 816 rated at 110 wpc I may only be delivering half that amount to all 5 channels....am I on the right path?:)
Yes sir, that's about it. Luckily, chances are you're RARELY driving all five speakers at once.If you will it, dude, it is no dream. -
Thanks, I understand the use of seperate amps a little more now, and whadda ya know, I have pre-outs.:DPolk Audio Surround Bar 360
Mirage PS-12
LG BDP-550
Motorola HD FIOS DVR
Panasonic 42" Plasma
XBOX 360[/SIZE]
Office stuff
Allied 395 receiver
Pioneer CDP PD-M430
RT8t's & Wharfedale Diamond II's[/SIZE]
Life is one grand, sweet song, so start the music. ~Ronald Reagan -
The guy at denon said that “mains is different” and the amp does give the specified power to all channels driven . still none the wiserELECTRONICS
arcam cd93
linn wakonda
MC2 MC450
Teac ud h01 DAC
SPEAKERS
Tannoy DC6 t se . -
So the answer is "It can't..." or did I miss something?
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Didn't one manufacturer have 'power steering'?Main Surround -
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Den - Rotel RSP-1068 / Threshold CAS-2 / Boston VR-M60 / BDP-05FD -
So the answer is "It can't..." or did I miss something?
Nope, you are correct. Receivers are not rated for 5 or 7 channels driven simultaneously, only 2. -
Didn't one manufacturer have 'power steering'?
Yes, the Carver AV-705x 5-channel amp has it. There may be others.Sony 60'' SXRD 1080p
Amp = Carver AV-705THX 5-Channel
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Music/Video Streaming = Netgear NEO550
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speakergeek wrote: »Nope, you are correct. Receivers are not rated for 5 or 7 channels driven simultaneously, only 2.
well , my normal amp the Cambridge 540r has specs for all channels driven but the L/R power is higher if only L/R are driven. (limitation of continual psu output ?)
"80W per channel @ 8 Ohms all channels driven/100W per channel @ 8 Ohms 2 channel ".
and the power consumption is higher than the output. at 850w .ELECTRONICS
arcam cd93
linn wakonda
MC2 MC450
Teac ud h01 DAC
SPEAKERS
Tannoy DC6 t se . -
The efficiency cannot be more than 100%. Perpetual motion machines don't exist.
http://www.hulu.com/watch/21710/the-simpsons-stir-crazy-kidsIf you will it, dude, it is no dream. -
well , my normal amp the Cambridge 540r has specs for all channels driven but the L/R power is higher if only L/R are driven. (limitation of continual psu output ?)
"80W per channel @ 8 Ohms all channels driven/100W per channel @ 8 Ohms 2 channel ".
and the power consumption is higher than the output. at 850w .
Should have qualified my post by saying "generally". There are a small hand full of receivers out there actually rated for all channels driven simultaneously, but the common four (Onkyo, Denon, Pioneer, and Yamaha) don't rate all channels simultaneously, only two at a time.
