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  1. #1
    mega-amp's Avatar
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    New project...advice on size of compressor/condenser



    Hello, new to the forum, with a few questions on a cooling project. Not quite a CPU cooler, but the same idea; just need to remove much more heat than the typical cpu cooler. Not sure where this should go, please move to the correct forum as necessary.

    I'm Building a simple class A amplifier. It's the Nelson Pass 'Son of ZEN'. The issue with this amplifier is that it generates a tremendous amount of heat....1200W at idle, for about 50W of music power (for one channel); not efficient, but it sounds amazing. Four of the resistors in each channel develop around 250W of heat, these are the resistors I want to 'supercool'.

    So basically I need to figure out whats needed to properly remove 2000W of heat for stereo operation. These 8 large Dale 250W resistors are mated to a cooling plate with 2 resistors per plate. (http://www1.mscdirect.com/cgi/NNSRIT...-SearchResults)

    The plates will act as the evaporator, not quite sure if they should be connected parallel or in series.

    What combination of compressor and condenser would be needed to keep the cooling plate temperatures in the area of 32C?

    pic attached is showing one channel


    Thanks!!!DSCF0516.jpg



  2. #2
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    Re: New project...advice on size of compressor/condenser

    Hi mega-amp and welcome to the forum.
    There are two options you could go for
    1 A chlled water cooled unit
    2 A small RAC (window rattler) with converted evap coil.
    2kW is a lot of heat in a room - it's like having a small heater on full tit. I would go for a 2.5 - 3 kW RAC & the two loads must be connected in parallel other wise one will cool and the second will be hotter. Then thinking on the other hand a chilled water system would allow a little time capacity. Since it's a constant load the compressor will cycle off and on and it may get too hot too fast on the off cycle before the compressor cuts back in. At least with the chilled water there is a buffer and the amp won't overheat. You will need over temp cutout protection for the amp - just in case. You may be able to buy a chilled water unit and pump to suit off the shelf, just not sure where may be a search on net will give a result.
    Ok I just thought of something that would do it on the cheap. If you could get your hands on an old coke/soda post mix machine. May be from ebay or ?. These are around the right size and all you need to do is hook up a pump and some water hoses. Get a smaller capacity one as they are a little bigger than what you need.
    Last edited by Tesla; 18-09-2012 at 12:17 PM. Reason: Last lines added

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    Re: New project...advice on size of compressor/condenser

    .

    First thing don't drill holes into those plates to mount the resistors

    I agree with Tesla and would go down the chilled water route.
    In the uk you can pick up a used beer chiller for resonable money,
    I'm sure you could find one local to you in us?

    They are self contained water coolers and that is then used to cool
    beer, or other drink related fluid.

    You coud circulate the water through your two plates, the loads would
    be well within most flash coolers.

    Regards

    Rob

    .
    Last edited by Rob White; 18-09-2012 at 05:04 PM. Reason: Spelling

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    Re: New project...advice on size of compressor/condenser

    Quote Originally Posted by mega-amp View Post
    Hello, new to the forum, with a few questions on a cooling project. Not quite a CPU cooler, but the same idea; just need to remove much more heat than the typical cpu cooler. Not sure where this should go, please move to the correct forum as necessary.

    I'm Building a simple class A amplifier. It's the Nelson Pass 'Son of ZEN'. The issue with this amplifier is that it generates a tremendous amount of heat....1200W at idle, for about 50W of music power (for one channel); not efficient, but it sounds amazing. Four of the resistors in each channel develop around 250W of heat, these are the resistors I want to 'supercool'.

    Thanks!!!!



    In the Olympic stadium last month during the opening ceremony,
    it was reported the sound system was a million watts............

    Try cooling that.............

    Regards

    Rob

    .
    Last edited by Rob White; 18-09-2012 at 05:12 PM.

  5. #5
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    Re: New project...advice on size of compressor/condenser

    Just an aside to the above suggestions...

    I would go with the chilled water route as it would enable easier movement of the amplifier if this is required. Flexible, removable, water hoses are easier to move around than refrigerant filled copper tubes.

    Also you can locate the cooler unit somewhere where it's noise won't interfere with your sound output.
    Brian - Newton Abbot, Devon, UK
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  6. #6
    mega-amp's Avatar
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    Re: New project...advice on size of compressor/condenser

    Looks like a chiller is the way to go, for many reasons, some of which I overlooked of course (portability and noise interference being top on the list). Fortunately, I have access to a small warehouse of NOS refrigeration compressors, condensers, and all the other bits. Chillers on ebay here in the us are kind of pricey. I'm sure I'll have a few questions as I proceed with the build. Stay tuned!!

    Thank you!

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