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Is there an idiot's guide to all this?

Discussion in 'AV Pre-Amp/Processors & Power Amps' started by theo cupier, Jan 17, 2005.

  1. theo cupier

    theo cupier
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    Hello, I am an idiot. I've been reading the threads on this forum with interest but too little understanding so thought I'd put my head above the parapet and ask for some help. Hope you don't mind. Can someone give me - and like minded souls, no doubt - a quick guide to matters such as power amps, pre-amps, mono blocks and bi-amping?

    I'm comfortable with the basic concept of:

    1. Source (eg CD) -> Amp -> Speakers

    and even:

    2. Source (DVD) -> Processor -> Power amp -> speakers

    and even my own setup which is:

    3. Source (DVD) -> Processor (E800) 1-> Centre & rear speakers
    ..................................................2-> Power amp (B1) -> Front speakers

    I guess that bi-amping is simply splitting the signal at a certain point to two individual amps and then re-combining it at the speakers. But I'm happy to be proven wrong.

    I also guess that mono blocks split the signal left and right and amplify each channel separately. Does this mean that the ultimate for a 5.1 setup is to have a mono block per speaker? Can one (does one) mono block AND bi-amp? What does bi-amping do that mono blocking doesn't?

    Is a a pre-amp the same thing as a processor?

    I'm not necessarily looking to understand what things to buy to upgrade my setup, but more to understand how I think about piecing together a quality modular system when I next get uncontrollable upgraditis...

    Any knowledge gratefully received

    Thanks

    Theo
     
  2. MarkE19

    MarkE19
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    To bi-amp you have an amp for the bass/mid speaker(s) and a separate amp for the tweeter. Feed the signal out of the processor etc to each individual amp and then wire from amp to the speakers individual binding posts. Your speakers need 2 sets of binding posts or you will damage the amps & speakers, just make sure you removew the metal bars that connect the 2 sets together.

    A mono block is a single (mono) amp in a box. The advantage being that each amp has its own power supply and therefore gets all the power it requires. The ultimate would be each speaker being biamped (or triamped if speakers have 3 sets of binding posts). If you have the space & money then yes you can biamp with mono blocks as a few on these forums do.

    A preamp is basically the volume, bass, treble & source selection controls. This can be part of an integrated amp or separate and fed into power amps.

    Hope this helps,
    Mark.
     
  3. Knightshade

    Knightshade
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    A pre amp is the stage where balance, tone, bass, volume etc are handled. You have some control over this stage.
    A pre amp can be either a single box unit requiring a seperate power amp or combined with a power amp in an 'Integrated' amp (1 box solution)

    Bi amping is when you use 1 stereo power amplifier to drive the hi frequency and one to drive the low frequency in a standard stereo set up. You can use either the power amp stage of an integrated amp and a power amp or a Pre amp and 2 power amps. It's generally considered that 2 power amps will give the better sound. More power, individual power supplies etc.

    The same goes for monoblocks. In order to bi amp with monoblocks you would need a pre amp and 4 monoblocks. This would in theory give you an improvement again. (Believe me it does!) Again the basis for this is you have a single power supply driving a single channel.

    As a general rule for the best possible sound it's best to have a pre amp and monoblocks and then go active. But that's for another day....

    Seems Mark was faster on the keyboard than me....:)
     
  4. theo cupier

    theo cupier
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    Thank you, chaps. Every day is, indeed, a school day.

    To clarify, in my current setup (not thinking about upgrading yet, just want to translate this info in to a context I can understand, honest! :blush: ):

    With a DVD player as the source, the E800 is effectively a pre-amp for the front speakers (as well as being the power amp for the centre and rears). My B1 is power amp-ing the front speakers (the fact that this is also an integrated amp which has my audio sources connected directly is irrelevant for the purposes of this exposition).

    So I could use the pre-outs from the E800 to other power-amps for the centre and rears, yes?

    Do all these things connect via RCA interconnects?

    Is the number of power amps I can use limited by the number of outputs on the back of the pre-amp? ie, since the E800 only has a single L/R pair of outputs for the rears I can only put 1 stereo power amp (or pair of mono blocks) between the pre-amp and rear speakers?

    If one is using mono blocks, does that mean a single interconnect goes from the 'left' output of the pre-amp to the 'mono' input of one power amp and likewise with the right interconnect going to the mono input of the other?

    Presumably each mono block has the usual pair of outputs for the + & - ve speaker cable to its speaker.

    Since all my current speakers have a single pair of posts each, there is no point in my thinking about bi-amping, but mono blocking is possible, yes?

    Thanks again...
     
  5. MarkE19

    MarkE19
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    Go on - you know you want to upgrade :devil: :devil:

    Yes, the preouts can be used for all channels (as long as the processor has preouts for all channels of course) and the E800 would then not be useing its built in amps and would in effect just be a processor rather than an AV amp.

    Depends on the equipment. If the preouts are RCA then yes, but some high end equipment with have XLR connections as well or instead of (For example my MC8B has both).

    Not really. The power amp may also have preouts to feed into another power amp. Or you could use a splitter cable to fed into 2 amps, but this is not such a good way to do it.
    In the past I had an Arcam 8r integrated amp (stereo) that had preouts that I fed to an Arcam 8p power amp (stereo). I then fed the 8r to the tweeters on my B&W 603's and the 8p to the bass speaker - these speakers had the required 2 sets of binding posts to do this. As with your setup the CD player etc was connected to the preamp stage of the 8r.

    In a word, YES!

    again, YES!

    Yet again, YES. You are getting the hang of this :thumbsup:

    Mark.
     
  6. theo cupier

    theo cupier
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    Getting the hang of this now, I think. A more focussed question!

    Does that mean that power amping works in series as well as parallel?

    Well, inherently, yes. :blush: However, I've only just gone from 2-channel to 5.1 - by buying the Dynaudio, XLS200 and E800 so want some time to get to know my 'new' setup.

    The problem I would then have is knowing where to start with the next round of upgrades. My initial thoughts, looking at my current kit:

    1. B1 - 12 years of solid performance but always mid-range and wearing out now. Perhaps in need of retirement? Replace with a single surround power amp in the first instance, then get clever with mono blocks etc later. NAD CI9060? Or are there 5 channels of mono block to consider from the get-go?! or do I aim somewhere in between - surround power amp for the centre & rears and mono blocks for the fronts?
    2. LS4a - same vintage as the B1, showing wear & tear now. Spendor 6e? (Yes, some Kef 20x would be lovely but Spendors are a good direct replacement for the Rogers which I have loved and are a slightly more reasonable price!)
    3. 7.1 rears - my spare speakers, previously a zone 2 pair for listening to the radio and certainly not up to the job in the long term. Spendor SR5?
    4. E800 - new to me and if I use the pre-outs on all channels could perhaps prolong its life.
    5. CD50 - old but working fine, seems no point in replacing in a hurry (yet)
    6. SD220 - If you're replacing the processor, you might as well update the source! (get some new codecs etc) but it has digital audio out and component video out, so needn't rush to upgrade, I guess.
    7. 42C - new to me and so far so good, not a priority to replace (yet).
    8. XLS200 - only arrived today! Ultimately will make way for a big SVS, I'm sure (but don't let the XLS hear me say that!)...

    The running order above feels about right; 1-3 being top priority, 4-6 being 'nice to do' and 7-8 being long range.

    Saying that, I have a concern that even the bits of my kit I've not prioritised in the list, above, are a bit old/weary/budget so I'd be concerned that ploughing money into a new power amp and fronts would leave me unbalanced... is that just the early sign of terminal upgraditis??

    And don't get me started on the issue of replacing the old TV with a big, shiny new plasma!
     
  7. MarkE19

    MarkE19
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    No! You feed a line level signal into the first power amp and the preout from that is also line level into the second. Each amp is then connected at speaker level to an individual set of binding posts.

    source > processor > amp 1 speaker terminals > bass speaker binding posts
    amp1 preout > amp2 speaker terminals > tweeter binding posts

    Mark.
     
  8. TimDeLAY

    TimDeLAY
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    Guyes can I ask something more general? Is it the power amp or the pre-amp that define mostly the "character" of the set? I mean if it's going to be musical, dry, bright etc. For instance let's say that we need a musical result from an av amplifier. If we were talking about integrated ones we'd say that Yamaha is not as musical as Marantz. Let's say though that we're connecting Yamaha to a power amp that is considered "musical" (assuming that a power amp can affect the result). Would we have a "musical" output or is the pre-amp contribution to the whole result crucial so we wouldn't change its character? I hope I'm being comprehensive, all I'm asking is how much contribution does the pre-amp and how much contribution does the power amp have to the whole output? Or does it depend on the combination? For instance, I asked some sales person (not that I necessarily trust that person's opinion) and she said that the power amp doesn't practically alter the character of the signal. If you combine a Yamaha AV with any power amp you will still have Yamaha character, only with more driving capabilities. Onother told me that the power amp is the most crucial... opinions?
     
  9. eviljohn2

    eviljohn2
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    Mark (and Theo), a "bridged" stereo amp could be considered amplifiers in series. The amplifier circuits need to specifically designed for this though. That does complicate things a bit I'm afraid.

    As a quick aside, the reason we have a seperate preamp and power amp is to reduce noise. If you do the maths, you'll find that it's beneficial to have a very low noise preamplifier as then the noise in the noisier power amplifier stage is sort of reduced.

    TimDelay, each part of the audio chain can invoke it's own character on it's signal. There's no definitive answer there I'm afraid, otherwise we'd all have the same equipment! :)
     
  10. MarkE19

    MarkE19
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    Agreed, but my post was in answer to a question about useing preouts on a processor/AV receiver to drive 2 monoblocks in a biamped system. In this case you would not have the amps connected in series.

    Mark.
     
  11. Pat Marcus

    Pat Marcus
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    Tim Delay - I recently persuaded my housemate to buy a cyrus smartpower to run his two front speakers, using the pre-outs on a Yahama DSPE800. The upgrade from a cheaper power amp was massive, as the Mordaunt Short fronts were finally being given the clean current suppply they needed to sound good. Power amps make a big difference. Even in my own system, a change from a multichannel power amp driving my fronts to a dedicated 2 channel amp from the same manufacturer brought a leap in clarity, even though the processor stayed the same.
     
  12. diablo

    diablo
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    I'm thinking of doing some bi-amping myself. Have 8 channels of 70+ watts and four speakers, so it seems a waste not to. :D

    I found this What HiFi guide which explains it sufficiently well for me to understand it. ;) I was having problems comprehending why you didn't need to have a crossover between the pre-amp stage and the power amps. I now understand that bi-amp-able speakers take this into account and filter the inputs appropriately. Smart-ass stuff, if you ask me. :)
     

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