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MegaWatt S-700-12 switching power supply

Discussion in 'Amateur Radio Gear Swapshop' started by N0NB, Feb 9, 2017.

  1. N0NB

    N0NB Active Member

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    I recently purchased a MegaWatt S-700-12 50 amp switching power supply. As I outlined in this thread, the fan is too loud for my shack. The supply is new in the box as I received it new from MegaWatt on February 3, 2017. I had it powered up long to set the output to 14V and while doing that I learned the fan is too loud for my shack environment. I powered it up the next day to make the sound level measurements listed in the thread above.

    I am asking $110 for the supply shipped to the continental US. Payment details will be agreed upon later.


     
    Sonar likes this.

  2. jon666

    jon666 Sr. Member

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    i have the same issue.
     
  3. BenMara

    BenMara W9WDX Amateur Radio Club Member

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    your linked thread does not work
     
  4. N0NB

    N0NB Active Member

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    BenMara likes this.
  5. N0NB

    N0NB Active Member

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    I wish I wouldn't have missed your post in the linked thread.
     
  6. wavrider

    wavrider W9WDX Amateur Radio Club Member

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    Still for sale?
     
  7. Tallman

    Tallman W9WDX Amateur Radio Member, KW4YJ EXTRA class

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    Some people are sound pitch sensitive. Some can hear the humming in New Mexico and some can't. A friend of mine could hear the horizontal sweep of a color television.
    The sound irritated so badly if someone switched on a television he would leave.
     
    BenMara likes this.
  8. Sonar

    Sonar Well-Known Member

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    I've read many posts complaining about the fan noise on the 50 amp megawatt. I'm assuming there is no issues with the lower amperage megawatt power supply fans. Is there any fix for this as far as the owners of these power supplies go? Any way to slow that fan down just enough to quiet it without causing the PS to overheat? I'm assuming the megawatt company knows that their 50 amp power supply fans are very loud. Not knowing much about power supplies and how much airflow is needed to keep the different amperages that are supplied by each model properly cooled, is there a fix or is it a necessary evil? Would you or anyone suggest one who likes the megawatt brand purchase two of the smaller power supplies? I watched their video and learned that megawatt power supplies can be running series. Running two smaller ones would I'm assuming take care of the large single (loud) fan issue while supplying enough amperage for one's needs. 73.
     
  9. Paul-W5lz

    Paul-W5lz Member

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    I think you meant to say to run them in parallel. Parallel will increase the current, series would increase the voltage.
     
  10. N0NB

    N0NB Active Member

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    For me it is simply the audible noise level that is unacceptable. I recently stopped using a laptop here in the shack to process my weather data in favor of a fanless ARM board as its fan was simply too annoying. When I turn the AF gain down on the K3 I can hear the hum of the RS-50M. I have it off the floor on some supports which got rid of a lot of it, but I find fan noise and hum to be quite irritating. Fortunately, this Lenovo M73 desktop computer is so quiet I can hardly tell its on.
     
  11. N0NB

    N0NB Active Member

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    So far, still available and still unused a year on. :(
     
    Shadetree Mechanic likes this.
  12. wavrider

    wavrider W9WDX Amateur Radio Club Member

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    Guess the question is how low will you go on price?
     
    Shadetree Mechanic likes this.
  13. Shadetree Mechanic

    Shadetree Mechanic 808 On The North Side of Dover

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    I am actually looking for one of these now.
     
    wavrider likes this.
  14. Road Block

    Road Block Member

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    Can't you change the fan out to a more quiet fan?
     
  15. jon666

    jon666 Sr. Member

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    i just bought another 40 amp m.w p.s. the 50 amp one is still in the box. to dam. loud for me.
     

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