Harman Kardon A-700 information needed

Discussion in 'Tube Audio' started by RS Steve, Sep 13, 2018 at 3:01 PM.

  1. RS Steve

    RS Steve Tube Junkie Subscriber

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    I have had this amp lingering around here not being used for some time, don't see much information on it available. Seems like it is a bit rare, anyone here on AK own one? Curious to see how well regarded it is.

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  2. RWood

    RWood Brakes just like a little girl. Subscriber

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    @robnec was restoring one last month.

    I’ve never laid hands nor ears on that one but having redone several A500s and 300s I liked what I saw in terms of upgrades on the A700 circuit.
     
  3. RS Steve

    RS Steve Tube Junkie Subscriber

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    Thanks for the response, I downloaded the service manual yesterday, found a couple U-tube videos on the A-700, but not much else. Someone has already replaced most of the capacitors in it, looks like I will have to do dome testing and see how it performs.
     
  4. Patrice B

    Patrice B AK Subscriber Subscriber

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    The only thing I know of it is here but you probably already know: http://shermanr.web.prw.net/Page_02.htm

    Being in Award lineage (A300, A500), it must definitely be good with more oomph than the 300 and 500 (love my A500!).
     
    Last edited: Sep 16, 2018 at 8:43 AM
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  5. buickguy62

    buickguy62 Active Member

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    I recapped one a couple years back, I had Hamseed Hamfest make four can caps, exact drop in units, not cheap, but it's what the customer wanted, and it greatly simplified the restoration. I would expect they kept specs on the units. Jim McShane was very helpful in leading me through the power and bias supply updating and tube selection. Customer very satisfied. Check PM from me.
    Tom

    IMG_7231.JPG IMG_7244.JPG IMG_7245.JPG IMG_7247.JPG A700-02 Schematic power section as built 12-2-16.jpg
     
  6. RWood

    RWood Brakes just like a little girl. Subscriber

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    That schematic shows one of the improvements over the 500: a separate winding to provide DC to the phono and preamp tubes. On the lesser models they take the DC from the power tube cathodes, which does work, but it makes those two circuits interdependent, and bias can’t be dialed in.

    Thanks for posting, Tom; you helped me a lot with Award series amps.
     

     

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