Amplifiers

avphile
avphile Posts: 38
edited December 2007 in Speakers
Can someone set me straight? The cost of a three channel stereo amplifier (i.e. (GFA 5500) is $1500. The cost of a five channel home theater amplifier (i.e. GFA 7705) is $1700. Is there a difference in the sound quality between the two because the cost per channel does not add up? What am I not accounting for?
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  • F1nut
    F1nut Posts: 50,779
    edited December 2007
    What is your intended purpose?
    Political Correctness'.........defined

    "A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."

    President of Club Polk

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  • DarqueKnight
    DarqueKnight Posts: 6,765
    edited December 2007
    avphile wrote: »
    What am I not accounting for?

    Parts quality for one thing.

    There is a big difference in the sound quality between the 7705/7707 and the 5500, which is why I chose to go with three 5500's in my home theater system (1 each for dual center speakers, front, and surrounds). The 5500 is optimized for 2 channel audio applications whereas the 7705 is strictly a home theater amp. The 7705 is worlds better than the typical home theater receiver, but does not deliver the level of detail and dynamics provided by the 5500.

    When you think about it, you know there are some compromises since the 7705 runs over twice the number of channels off the approximate same size power suppy as the 5500.

    Also, in case you don't know, the 7705 requires a 20 amp outlet. An electrician can convert a typical home 15 amp outlet into a 20 amp outlet.
    Proud and loyal citizen of the Digital Domain and Solid State Country!
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  • avphile
    avphile Posts: 38
    edited December 2007
    F1nut

    I want to do both. I can only afford one amp not multiple 2 channel amps.

    DarqueKnight

    I am I better off with 2 channel if I want better sound quality? Taking your post a step further. Monoblocks are better than 2 channel? I have a Pioneer Elite 84TXSI (7 channels at 140WPC). What improvements can I expect if I go to 200WPC?
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  • halo
    halo Posts: 5,616
    edited December 2007
    avphile wrote: »
    What improvements can I expect if I go to 200WPC?
    Ask cfrizz :rolleyes:

    200wpc from a dedicated amp is much more than 175wpc from a receiver. Receivers usually get their wpc channel rating driving only one channel. It is misleading.
    Audio: Polk S15 * Polk S35 * Polk S10 * SVS SB-1000 Pro
    HT: Samsung QN90B * Marantz NR1510 * Panasonic DMP-BDT220 * Roku Ultra LT * APC H10
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  • Face
    Face Posts: 14,340
    edited December 2007
    Take a look on Audiogon.
    http://cls.audiogon.com/cgi-bin/cls.pl?ampsmult&1201841360
    http://cls.audiogon.com/cgi-bin/cls.pl?ampsmult&1201758155
    http://cls.audiogon.com/cgi-bin/cls.pl?ampsmult&1201396178
    "He who fights with monsters should look to it that he himself does not become a monster. And when you gaze long into an abyss the abyss also gazes into you." Friedrich Nietzsche
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  • DarqueKnight
    DarqueKnight Posts: 6,765
    edited December 2007
    avphile wrote: »
    I am I better off with 2 channel if I want better sound quality?

    Generally. It depends on the amp manufacturer's design goals. Some design their multichannel home theater amps to have comparable sound quality to 2 channel amps.
    avphile wrote: »
    Monoblocks are better than 2 channel?

    Maybe. It depends on the circuit design and component quality of the monoblocks. Splitting a stereo amplifier into two chassis' allows each channel to have a dedicated power supply and there is more physical space for larger, higher quality components and more heat sinking. [/QUOTE]
    avphile wrote: »
    I have a Pioneer Elite 84TXSI (7 channels at 140WPC). What improvements can I expect if I go to 200WPC?

    Let's talk about the 7 channel situation first. If 7 channels are sharing the same power supply and a demanding, bass heavy signal comes through just one of the channels, the power supply will be preoccupied with trying to supply power to just that one channel. The sound quality of the other 6 channels will suffer.

    Also, you have to pay attention to the power specs of multichannel amps. Some of them cannot supply their rated power to all channels simultaneously and continuously.

    All watts are not equal. 50 watts from a high quality amp might sound better thant 150 watts from a low quality amp. Power specifications alone cannot provide the total insight into an amps true performance. Other things like circuit design and component quality also affect performance. Generally, the higher in power you go, the less likelihood there is of stressing the amp. The less stress there is on the amp, the better it sounds. It is analogous to a person working on an assembly line where he is required to remove 50 pound boxes off a conveyor belt all day long. If the man is capable of lifting 60 pound boxes for eight hours, he can get the job done, but he is operating at 83% if his capability. We can expect that he would be very tired at the end of his shift. There might also be some dropped or mishandled packages due to fatigue. If we replace the 60 pound capable man with a man capable of comfortably lifting 200 pound boxes, then he will be operating at only 25% of his capacity. He is never stressed or fatiqued and the probability of error is greatly diminished.
    Proud and loyal citizen of the Digital Domain and Solid State Country!
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  • nms
    nms Posts: 671
    edited December 2007
    It is analogous to a person working on an assembly line where he is required to remove 50 pound boxes off a conveyor belt all day long. If the man is capable of lifting 60 pound boxes for eight hours, he can get the job done, but he is operating at 83% if his capability. We can expect that he would be very tired at the end of his shift. There might also be some dropped or mishandled packages due to fatigue. If we replace the 60 pound capable man with a man capable of comfortably lifting 200 pound boxes, then he will be operating at only 25% of his capacity. He is never stressed or fatiqued and the probability of error is greatly diminished.

    That's a beautiful analogy! Excellent description of why more power is better.
    My system

    "The world is an ever evolving clusterf*ck." --treitz3
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  • cfrizz
    cfrizz Posts: 13,415
    edited December 2007
    +100 on that! Well done DK!
    nms wrote: »
    That's a beautiful analogy! Excellent description of why more power is better.
    Marantz AV-7705 PrePro, Classé 5 channel 200wpc Amp, Oppo 103 BluRay, Rotel RCD-1072 CDP, Sony XBR-49X800E TV, Polk S60 Main Speakers, Polk ES30 Center Channel, Polk S15 Surround Speakers SVS SB12-NSD x2
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  • cfrizz
    cfrizz Posts: 13,415
    edited December 2007
    The more power & the more channels you get in the amplifier is the more money it is going to cost. But once you have it, you are all set for years to come.
    avphile wrote: »
    Can someone set me straight? The cost of a three channel stereo amplifier (i.e. (GFA 5500) is $1500. The cost of a five channel home theater amplifier (i.e. GFA 7705) is $1700. Is there a difference in the sound quality between the two because the cost per channel does not add up? What am I not accounting for?
    Marantz AV-7705 PrePro, Classé 5 channel 200wpc Amp, Oppo 103 BluRay, Rotel RCD-1072 CDP, Sony XBR-49X800E TV, Polk S60 Main Speakers, Polk ES30 Center Channel, Polk S15 Surround Speakers SVS SB12-NSD x2
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