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Bi-Amp or Monobloc

Discussion in 'AV Receivers & Amplifiers' started by EvilMudge, Jan 19, 2003.

  1. EvilMudge

    EvilMudge
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    I think I can guess the answer most people are going to give, but which would be more worthwhile in a purely theoretical case.

    If I can get a two channel power amp of say 50W each and a monobloc of 100W for the same price, all things being equal which would make more sense to go for?
     
  2. dts_boy

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    well, you would need 2 monoblocs as it only has amplification for 1 channel. it dedpends on what speakers you are trying to power - personally i would go for the monoblocs, but that would mean spending twice as much
     
  3. Phil_Yeoman

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    Their is no right answer here. The answer depends on impedence of the speakers, power supply withiin the amp, listening volume and type of source.

    You also need to consider the space requirements of the amps. This is not such an issue with stereo but when you use seven in a full ex setup then space does become a real issue.

    As far as the sound quality is concerned a monoblock with tend to exhbit better control and will have a more dynamic signiture (not always a good thing). Channel separation tends to be much better as obiously the power amps are electrically isolated from each other.

    The decison as to what is best will be based on your circumstances. If you require a reference level AV setup that can blow away the local multiplex then blocks are the only way to go. If on the other hand you simply wish to have quality sounding system in your living room then multichannel power amps will be more than adiquate.

    Phil
     
  4. alexs2

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    As Phil says,there is no right answer,but having owned both mono and stereo Krells amongst others,I definitely would say monoblocs are the best,even at that price level.

    The bass goes deeper and more controlled,and the other frequency ranges are also handled better....having said that,many stereo amps,if properly designed,with ideally dual mono construction,can come quite close.

    In my case,I found not only space was an issue,but also heat and electricity consumption,since I use some of the older non-sliding bias Krells....I prefer the bass end of these to the newer ones,although havent had a set of FPB's home...one day!
     
  5. EvilMudge

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    Sorry, I haven't made myself very clear. The idea is either to drive both drive units of a 2-way speaker from one monobloc or bi-amp using a stereo unit with lower power per channel, but similar total power output. My leaning was towards bi-amping, but this may not be as effective as a single more powerful amplifier.

    I'm considering a pair of Cyrus SmartPowers, which can run in either 2 channel or bridged mode, and was trying to decide which way to run them. But if it's not worth bothering with the 2 channel I might as well get an aPA7.5 for each channel instead. Or I might look elsewhere. Don't know at the moment.
     
  6. Phil_Yeoman

    Phil_Yeoman
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    Bi Amping is next logical step on from bi wiring and should in theory produce a more coherent soundfield due the increase in power to each driver.

    I have sucessfully played with this type of setup and can report that the only way I could get any benefit from it was to activly filter the signal before amplification. This ment that the low sinals went to the channel driving the woofer, mid to the the midrange and high to the tweeter channel.

    The effect was that the sound was tighter and the volume would go much louder. The downside was that the oveall effects were only minutly better than tri-wiring from a monoblock and the increase in signal processing added its own flavour to the sound.( the other downside for me was that I would have had to add amother 15 channels of amplification to my system :))

    If I were you I would bi-wire your speaker to a monoblock the system is less complex and has the added benefit of having large reserves of raw power "just in case you need it". ;)

    Phil
     
  7. EvilMudge

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    Thank you Phil.

    TBH I'll probably still go with the SmartPowers just so that I can play around with them (and they will fit quite nicely into the deadspace behind my fronts). That way I can switch between modes to see which suits my speakers best.
     
  8. Spligsey

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    Phil.

    Superb choice of powers you have (Bryston 7BSST)

    That's some serious power your pushing:) :)

    Adzman
     
  9. HotblackDesiato

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    I went with their predecessor biamped, added the PSX-Rs then some more Powers to monoblock, which i preferred.

    spence
     
  10. GaryG

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    I have also trodden the bi-amping stereo vs monobloc path. You state the price is the same so the monobloc is the better bet (but will cost twice as much because you need two).

    Bi-amping really only comes into it's own when using active filters and discarding the speaker cross-over. That's not to say you wont get a benefit from bi-amping with standard cross-overs, just that the improvement is outweighed by the cost. If you had two stereo amps then bi-amping would be worth doing but if you are buying another amp specifically for bi-amping it would be better to sell your existing amp and spend the money on a better monobloc.

    BTW, I see the Smartpower is approx £600. Before you commit to buying them I would strongly recommend you contact Shaun Williams at Williams-Hart and arrange to have a home dem of his monoblocs which are a similar price. They are in the same league as top end Naim kit and are an absolute steal at the price. If you're anywhere near the Midlands you can have a listen to mine if you like, I replaced Audiolab 8000MX monoblocs with them. In addition, you can upgrade them as funds permit, I dived straight in and bought the 'SE' versions, fantastic value for money, not far off my Krell monoblocs.

    http://users.classicfm.net/williamshart/jlhampli.htm
     
  11. Phil_Yeoman

    Phil_Yeoman
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    Adzman / Spligsy

    They do perform :D and the volume level is shall we say interesting! The only problems I have had was the amount of heat they produced.

    These are the pro versions and for some unknowen reason they seem to run even hotter than the standards. They are mounted in a adapted 19inch rack and I have to build a system that passes refirgerated air into the enclosure.

    The only problem I had was that they were a bitch to match with the MC12 and it took over two weeks of tweeking the input senitivites to make them truly sing.

    Phil
     
  12. EvilMudge

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    Spence,

    What speakers were you running with the powers? Also, in what way did going to bridged mode improve the sound over bi-amping?

    Also for those who keep reminding me that I will need two monoblocs to drive two speakers, I'm going to need at least three to drive my front soundstage. I am aware of the problem ;)

    To my mind there are pros and cons for each method. A single amplifier with greater power reserves will give me more headroom and capacity for dynamics. But going with two channels driving the low and high sections will give more control (grip?) over the drive units, and should minimise the interaction between low and high frequencies.
    Opinions on the above please.
     
  13. sounddog

    sounddog
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    I can't talk for others, nor can I speak from experience only knowledge ... but maybe part of the reason people get an improvement running their amps in bridged mono, rather than bi-amping their speaker, is that a bridged amp usually produces 2.5 - 3x the power of each channel when the amp is run in 2ch mode. (i.e. Rotel's RMB-1066 is 6x 60w ... or each pair of amps can be bridged to provide 3x150w and their RB-1070 is 2x 130w or 1x 360w )


    Victoria
     
  14. Phil_Yeoman

    Phil_Yeoman
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    Victoria

    You are right to say that bridge mode tends to produce more power than the sum of the single channels. The problem here is that this power ouput is a measure across the whole reproducable spectrum.

    In truth most off the increase power is at the expense off signal distortion. The limiting factor here is the amount of instananious power that can be reproduced by the power supply. Bridged mode power tends to lack the punch at levels below 80hz. You will find that "in general :rolleyes: " a 100watt monoblock will have much more control and authority than a bridged amp producing 150watts.

    Phil
     
  15. HotblackDesiato

    HotblackDesiato
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    I'm using Missions...753/1/C series speakers...well actually a recent house move means i'm not using them at the minute...hence the Gallos/CHT upgrade to the family room set up.

    Anyway...hopefully this will not sound too "What Hi-Fi"...
    The improvement from biamping to monoblock was primarily that of control, detail and accuracy.
    Bass showed the biggest improvement...became much more defined, starting and stoping with much greater accuracy....a flat E started to sound "right". The sound stage gained a little in depth and became more "life like"...for example female vocals just sound that much more transparent, high notes on a piano are very precise and easily located, while lower octaves spread well and are more diffuse. I could go on but this is starting to sound way too "What Hi-Fi". ;)

    It's the metaphorical equivalent of having your windows cleaned....see i told you i should have stopped while the going was good.;)

    spence
     

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