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Mackie M1400 poweramp problem

Discussion in 'Electronic Repair' started by powerampfreak, Jun 3, 2008.

  1. Eeyore

    Eeyore Guest

    Not at all but the quality varies dramatically. I'm expecting to be going to
    Shanghai / Ningbo quite soon in fact.

    Only because our Indian sub-contractor had bankrupted the company. Those
    transformers were custom made by Toroid International which is a highly respected
    brand. I'm sorry you had that problem but it wasn't a design oversight for sure.

  2. Eeyore

    Eeyore Guest

    The work I've seen come out of Kwan Asia is second to none. Orient Power /
    Oritron is pretty good too.

    As you imply, few Chinese know how to design well though, and if you get a good
    relationship going they will freely admit this. I have met one good Chinese
    designer though, a chap called 'Tim' Lau. He co-developed the QSC RMX series
    with Pat Quilter AIUI.

  3. Eeyore

    Eeyore Guest

    A lot of Korean compnaies are moving their manufacturing to China. I could talk
    volumes about that and the troubles it caused.

  4. Eeyore

    Eeyore Guest

    Aluminium actually.

    Given its age, I would recommend replacing them. NO amplifier PSU electrolytics
    last for ever. Do buy a decent brand. We used Sanwha which are great for the
    price but not widely available. A Panasonic is probably your best bet. Sub-woofers
    will give them more of a hammering than full-range too.

  5. Eeyore

    Eeyore Guest

    I'm glad you appreciate the design considerations I put into it.

    Oh yes they are ! Quite comfortably so in fact. Do you know how to do ripple
    current calculations ? These HE series show a ripple current rating of 2.5A each
    but that's @ 105C and they don't get that hot.

    No, those are the smaller ones nearby.

  6. Arfa Daily

    Arfa Daily Guest

    Seems a bit better now Tim, although there still seems to be periods of time
    when it is not accessible. It wasn't yesterday afternoon for a couple of
    hours. I was beginning to think that something had screwed up on my machine,
    but 'net access was ok, and the mail server was properly accessible. News
    server access just suddenly returned ( I had a news post pending in the
    outbox, and my machine will try to send it every 5 mins until it gets
    success). I can't remember ever having had similar issues with the original
    NTL server, which I had been on for many years since NTL were first cabling
    up the country. The problems only seem to have been occuring since they
    "migrated" I think was the word, to the 'new and better' Virgin Media binary
    news server. Is this the same sort of issues that you have been experiencing

  7. Arfa Daily

    Arfa Daily Guest

    Ah ... Studiomaster. I will remember that Graham, when I next get one in
    that's giving me some grief ...


  8. Tim Phipps

    Tim Phipps Guest

    I appreciate it wasn't a design issue just an unfortunate fault. I was
    impressed to get a direct reply from Toroid Int. who did offer to supply
    the part but the cost was prohibitive as it would have been a one off job.

    I don't know who is making these T.amps for Thomann but they seem to be
    pretty decent. I haven't opened mine to look but I've heard some say
    that they are copies of an old Crest design.
  9. Eeyore

    Eeyore Guest

    Stop for a second to think how many tens of thousands were made and how few you

    I just bought a 700D on ebay btw for a club install that's going 3 way active
    (for the HF drivers). You can see I do have confidence in my own products.

    And you can always email me for repair tips.

  10. Eeyore

    Eeyore Guest

    It's a real shame about that. There was a repair oufit in Liverpool that had a small
    supply of the TXs but they're long gone now.

    I've seen those. Maybe I'll get to find out who it is.

    I doubt that on account of the fact that Crests are massively overengineered as a rule
    (nhence expensive to build). Far more likely another QSC ripoff. If the output
    transistors' collectors are grounded it's almost a dead cert.

  11. Tim Phipps

    Tim Phipps Guest

    FYI it's these ones I'm talking about. I've also seen them branded as
    Audiohead and C-mark.
  12. Eeyore

    Eeyore Guest

    I know very well the ones you mean but from an external visual I can tell nothing.

  13. Arfa Daily

    Arfa Daily Guest

    Yes, I don't see that many. But always useful to have a 'contact' within a
    company ...

  14. neon


    Oct 21, 2006
    it is not ringing but oscillating. tie the input to gnd and see if it is stil there.
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