Input caps for P400 preamp(tone) board

Discussion in 'Marantz Audio' started by sherod, Mar 10, 2018.

  1. sherod

    sherod Active Member

    Messages:
    104
    I have seen that most of the Marantz 2270 refurbs include upgrading the input caps (C401,C402) on the P400 board. My question is which point should the inner foil and outer foil lead be connected to for each cap.
     

     

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  2. Steven Tate

    Steven Tate AK Subscriber Subscriber

    Messages:
    2,624
    Location:
    N. Richland Hills, TX
    Pretty sure it doesn’t matter. If you use polypropylene caps, they are non-polar.
     
  3. sherod

    sherod Active Member

    Messages:
    104
    Yes, it is a film and foil polypropylene. I understand that it has no polarity so it can be put in either way, but the concern here is reducing noise. As I understand it, a film and foil has an inner foil for one lead and an outer foil for the other lead. The inner foil should be connected to the output or the direction of the signal. I think this is right. Now as to if one can hear a difference that's another thing. Here is an answer to an email quote a few years ago from a tech at Hovland when asked what is the proper direction to install their capacitors:


    "On the Coupling series caps, the red lead is the foil inner edge and should
    be connected as the output side of the cap, towards the the next stage in
    the circuit. If output side of circuit is not obvious (or if used in
    parallel, say in a crossover or as a power supply bypass), then connect the
    red lead to the lower potential side. On the Speaker MusiCap series, the
    lead with the blue stripe is equivalent to the the red lead, so the same
    above guidlines apply.
    The caps will of course work fine in either direction, but we think you
    will find that or suggestions will yield a more natural, less fatiguing
    presentation--though not quite as initially "exciting" as going the other
    way.

    Thank you for choosing Hovland MusiCaps. We hope you find that they enable
    greater connection to and enjoyment of Music."
     
    Last edited: Mar 11, 2018
  4. MBuras

    MBuras Restoration is an Addiction Subscriber

    Messages:
    532
    Location:
    Champaign, IL
    IMHO you’ll be hard pressed to find someone that can honestly tell the difference on foil orientation (maybe the golden ears of @patfont :biggrin:). The primary concern, especially when using large films that don’t fit flat on the board, is reducing noise from microphone effect. I’ve had to reform leads on big films in that position because I had them mounted too high off the board and they were picking up noise. Only happened once and I learned my lesson.
     
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