Firing Up Old Amps

Discussion in 'Let's Talk Vintage' started by Marshall50w, Feb 26, 2021.

  1. Marshall50w

    Marshall50w Well-Known Member

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    Due to lockdown etc. I haven't switched on some of my amps for say 12 months.
    I have a 1987 from 1970, a 1959 from 1975 & a Hiwatt DR103 1974.

    I have read people using variacs presumably to introduce voltage 'gently' so as not to damage components. I don't have a variac whatever that is, any suggestions or do I just hit the on switches ?
     
  2. anitoli

    anitoli Well-Known Member Gold Supporting Member

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    Just turn them on.
     
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  3. neikeel

    neikeel Well-Known Member

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    12 months you are probably ok.
    The 50w is easy to reform with tubes out, a 100k 2w resistor I series with B+ line after rectifier and switch on. Monitor the voltage drop across the resistor until <5vdc and you are done. Switch off and unplug from wall.
    Drain the filter caps as usual (check 0v with meter) and reconnect B+. Tubes back in and you are away. You can do same with 1959 too but you have to lift one leg of the bleeder resistors and the PT yellow wire (centre tap).
    The Hiwatt can also be done. Depends how much of a perfectionist you are!
     
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  4. Georgiatec

    Georgiatec Well-Known Member VIP Member

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    Just go for it. If they were fine 12 months ago they should be fine now.
    PS. If that's you in your avatar you don't look unlike Billy Duffy.
     
    Last edited: Feb 26, 2021
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  5. BatmansMarshall

    BatmansMarshall Well-Known Member

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    Your gentle start is right there on the dials before you. Turn everything on low setting and then dial up after she is on. 12 months is nothing. It depends where it's been more than how long out of commission. If I pulled it out if a barn loft that would different to it sitting on a basement shelf. You dig?

    Note: unless it's neil young's barn of course.
     
  6. Marshall50w

    Marshall50w Well-Known Member

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    Georgiatec - thanks for the advice. The comment re my avatar is a bit harsh ...... on Billy Duffy !!
     
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  7. Seanxk

    Seanxk Well-Known Member

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    Nice set of amps, just make sure each gets a good long jamming and all will be fine.
     
  8. shakti

    shakti Active Member

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    The weak link, so to speak, are the electrolytic capacitors, and they are subjected to full voltage once you turn the standby switch on (or even switch the power on for some of the capacitors). Follow neikeels instructions and you will get it right. But as others have said, 12 months would probably be OK, at least if they were used very regularly before that.
     
  9. ricksdisconnected

    ricksdisconnected Well-Known Member

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    they run around $70
     

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