Live sound: 4x 5KW amplifier from Linea Research

Discussion in 'General Discussion' started by Boswell, Aug 4, 2017.

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  1. Boswell

    Boswell Moderator Well-Known Member

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    Linea Research have released the latest and most powerful member of their 44M family: the 44M20. This has the mind-boggling specs of four 5KW power amplifiers in one 2U 13Kg chassis, designed for touring companies where subs have to be powered and fed independently from the mids/tops. Its main input is rated to work from 85V to 250V, although by my quick calculations the mains current draw at 85V would have be around 250A for all channels at maximum output.

    Here is the Linea page on the 44M family.

    Here is a PSW report of road-testing the unit.
     
  2. pcrecord

    pcrecord Quality recording seeker ! Well-Known Member

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    5KW in a 2U is impressive. Does it use an external powersupply ?

    I don't have much knowledge of live PAs. The shows I work on are all ordered stageline.
    Last one was a Crest line-array which sounded very good.
     
  3. dvdhawk

    dvdhawk Well-Known Member

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    Impressive, and even 10 pounds lighter than the Lab Gruppen PLM series that Clair Brothers use so much.

    One does have to wonder how those types of mega-power amps get those kind of specs from a 32A Powercon for the mains. Best case scenario (250v) it's still 80A if it were 100% efficient, and "around 250A" in the worst case scenario. I'm sure the connector itself is under-rated and has a safety factor built in, but I guess I'm surprised the regulatory bodies approve of such a huge discrepancy.
     
  4. Boswell

    Boswell Moderator Well-Known Member

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    The 2U rack chassis inludes the four power amps and the power supplies.

    I agree it's a bit hard to see how they can major on the amp delivering 5KW into 2 Ohms continuous rating with all four channels running. In my experience, especially when working with 2 Ohm passive subs, you need to put the power amp for that sub right behind it with something resembling car starter cable connecting the two so you don't lose half the power in the cable. Maybe if you were running a big rig that really has 4 subs stacked together each side you could use one of these 20KW amps to power the block of 4 with acceptably short cable lengths.

    I had a look at the operating manual, expecting to see, towards the back, a set of de-rating curves for real-world operation when using the sort of mains supplies one actually encounters at gigs (usually shared with the lighting crew). But no, there is nothing in there that squares the 20KW output power with a 32A mains inlet connector. Even in the UK, where we locally have areas of 250V mains, 32A would still only be 8KW total. I know of clay potters who have 10KW furnaces, and they are obliged to install 440V 3-phase supplies for those.
     
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  5. dvdhawk

    dvdhawk Well-Known Member

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    I know some of the other major amplifier manufacturers (Crest, Crown, QSC) spec (and advertise) the theoretical limit, but them publish electrical requirements in the manual based on 1/8th and 1/3rd power, which would be more typical in a real world application.
     
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