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Amp channels kick in at slightly different times

Discussion in 'Home Cinema & Hi-Fi' started by Participant, 16 Jan 2014.

  1. Participant

    Caporegime

    Joined: 13 May 2003

    Posts: 32,307

    Location: Warwickshire

    Hi all

    My old NAD3040 sounds great and works pretty much perfectly. There's one very minor niggle, which is that the L+R channels kick in at slightly different times when I switch the amp on (the gap is about two seconds).

    Is this a sign that I need to open it up and give it a service? Any ideas what might be causing this? If it's something that will develop into something more serious, I'd like to catch it early.

    Cheers.
     
  2. lucid

    Soldato

    Joined: 29 May 2010

    Posts: 5,845

    Location: Cheshire

    Are you sure this has only just started happening? If so then the most likely culprit is the big power reserve capacitors are drying out and so taking longer to charge.

    Replacing these isn't a highly technical task but does involve stripping the amp and then doing some soldering work. The caps are also one of the most expensive components. Like-for-like replacements could be as much as £20~£40 each and you might be replacing 4. On that basis you might decide to live with it until a channel dies, then replace the amp.
     
  3. Participant

    Caporegime

    Joined: 13 May 2003

    Posts: 32,307

    Location: Warwickshire

    It's happened since I bought it about 5 months ago and I noticed it straight away. The price was low so I might just live with it until it dies like you say.

    Wouldn't know where to begin soldering caps etc.

    Cheers.
     
  4. lucid

    Soldato

    Joined: 29 May 2010

    Posts: 5,845

    Location: Cheshire

    Right, so you're saying you bought it "as is" and you don't know if it did this from new because you weren't the original owner.

    None of the NAD reviews I've ever read have mentioned the amps coming on one channel at a time. But since most of us turn the volume down before powering on then it's possible (though very unlikely) that this could have been missed. However, it's more likely that this is a fault. The only other issue that was common in dual channel amps was that on increasing volume one channel would sound a little sooner than the other, but that was an issue of channel balance at the lowest part of the volume dial where the percentage error is at its highest.

    NAD amps - good amps - but when so many are available for very little money then it's hard to argue the economy of recapping.
     
  5. Sinopa

    Gangster

    Joined: 23 Nov 2004

    Posts: 301

    I would not worry about it too much. I very much doubt it will develop into anything more serious.

    I'll have a look at the circuit in my service manual and see if anything come to mind.

    One small correction: a dried out capacitor won't take longer to charge. Its capacitance would have reduced so it will in fact charge quicker.