Any advantages to using a 2 and 3 channel amp over a 5 channel?

Discussion in 'Archived Threads 2001-2004' started by scott cerv, Apr 9, 2002.

  1. scott cerv

    scott cerv Stunt Coordinator

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    Looking into what to power my future system (DM604S3, LCR600S3, 602S3). Was thinking of getting the RMB-1075, but wondering if the 200W will kill the rears (don't think they would ever see peak wattage). I'll listen to 70% music 30% HT. Would like to have the RMB1095 for the fronts. Should I go w/ a 3 channel 200W and 120W 2 channel or 200W 5 channel??

    SC
     
  2. Aslam Imran

    Aslam Imran Second Unit

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    Speakers can see a lot more than they are rated for, for short amounts of time. In movies or music you are only listening to a few watts (depending on your speaker sensitivity) most of the time. Only when an explosion or a musical cresendo (spelling?) comes along do your speakers see more than hundred watts for that short duration. So even if you were running speakers rated at 100W you could hook them up to a 200W amplifier and be perfectly fine.

    Also 2+3 channel combo instead of a five channel amp gives better flexibility as you can place 2 channel amp near the rear speakers minimizing speaker cable length. Interconnects can be run to longer lengths as they are shielded while its better to minimize speaker cable length as they are non-shielded and more prone to EMI. Theoritically 2+3 channel amps must also be better sonically as the power supplies are separate plus most stereo amplifiers are better designed than a multi channel amp with separate power supplies for both channels etc, etc. So funds permitting you might want to go with 2+3 channel combo.
     
  3. John Kotches

    John Kotches Cinematographer

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    Aslam,

    I'm troubled by your theory. Here's what you said that I'm troubed by:

     
  4. Aslam Imran

    Aslam Imran Second Unit

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    Well I have compared a few stereo/5 channel amplifiers like the Rotel 1080 vs the 1095, the B&K 2220 vs the 7250 and the Parasound 1500 vs the 2205. In all the cases I found the stereo amplifier to sound marginally better, esp. in the area of imaging, than the similarly powered 5 channel counterpart. I just attribute this to the dual monoblock design of the stereo counterparts. However newer designs like the sherbourn and some of the more expensive amps invalidate my argument as they implement separate power supplies (including the transformer) for all the channels. So I might not entirely be right here.

     
  5. MatthewJ S

    MatthewJ S Supporting Actor

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    In many cases I believe you would wind up with more current on demand ,but I would hope everyone would used matched amps so the sonic characteristics would be the same....
     
  6. Doug_B

    Doug_B Screenwriter

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    Wrt interconnects vs speaker cables, the key differentiator driving construction of each is the fact that ICs carry low level signals versus high level for speaker cables. A low level signal is thus much more susceptible to noise of a given level than the high level signal. Thus, ICs need to be shielded better, and thus typically cost more per unit length. You need a relatively strong signal near a speaker cable to make a noticeable impact on the signal it carries. Of course, what gets noticed by an individual has a lot to do with the entire system quality as well as the individual, so I speak in generalities here (and I exclude balanced connections from this discussion).

    To make a long story short, I wouldn't want to pay for multiple unbalanced ICs of reasonable quality spanning the length of a room, nor would I want to compromise on the quality of such lengths.

    Doug
     
  7. Larry B

    Larry B Screenwriter

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    Is there also an economical advantage in that, if one has separate amps, three channels of amplification would be idle when listening to stereo?

    Larry
     
  8. John Kotches

    John Kotches Cinematographer

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    Aslam,
    I've compared the Aragon 8008BB vs. the 8008x3B and 8008x5 and have not heard any discernible differences.
    Now granted the Aragons are a bit pricier than the B&Ks, but from my point of view, the assertion that the power supply is "better" isn't necessarily valid.
    Others have pointed out that the speaker cable requires less shielding, as it carries a high level vs. a low level signal in an IC, which ties back to the balanced cable comment I made.
    Nothing wrong with healthy disagreement, since we aren't lobbing around "what are you, stupid or something?" [​IMG]
    Regards,
     
  9. John Kotches

    John Kotches Cinematographer

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    Larry,

    In either case, you have 3 channels of idle amplification.

    The two box solution would permit you to turn off the surround amplifer via a remote trigger, if that was what you chose to do... I think this is what you were trying to say.

    Regards,
     
  10. Doug_B

    Doug_B Screenwriter

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  11. Kurt Kelson

    Kurt Kelson Extra

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  12. Kurt Kelson

    Kurt Kelson Extra

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    bump
     
  13. Doug_B

    Doug_B Screenwriter

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    Kurt,

    See the "Doug" review of the 2ch Stratos at audioreview. I use this for my mains. I do mostly music on my system, so I don't have anything of value to add concerning the HT3. If I get into multichannel music (I may be auditioning SACD and/or DVD-A within the next month), that will likely change.

    Doug
     
  14. John Carrigan

    John Carrigan Auditioning

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    Just a quick question on some of the comments above
    I may soon be purchasing M&K powered S-150P’s for the L, C & R, with the unpowered SS-250's for the side rears and unpowered S-150's for the back rears, with either the RMB-1075 or 1095 to power the rears and RSP-1066 as my pre/pro (may instead opt for the Pioneer TX49 as my receiver for all channels and amps for the rears, still very undecided, some advice may help).
    As the L, C & R are powered I would be going with IC's, and speaker cable to the rears. As the 150P's accept balanced should I go with balanced with the 1095's, remembering that the 1095 is not true balanced (and that balanced cost a lot more than standard IC's, with my maximum run 7m) and do I have to keep both fronts the same length of balanced cable. Also what speaker cable would you suggest for the rears (maximum length of run is 7m) and should I keep all speaker runs the same length.
    [​IMG]
     

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