Power Amplifier Model 9

Marantz (Sound United LLC); Vista, CA

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  • Year
  • 1960–1968
  • Category
  • Audio Amplifier or -mixer
  • Radiomuseum.org ID
  • 219390

Click on the schematic thumbnail to request the schematic as a free document.

 Technical Specifications

  • Number of Tubes
  • 7
  • Main principle
  • Audio-Amplification
  • Wave bands
  • - without
  • Details
  • Hi-Fi equipment
  • Power type and voltage
  • Alternating Current supply (AC) / 117 Volt
  • Loudspeaker
  • - This model requires external speaker(s).
  • Power out
  • 70 W (undistorted)
  • Material
  • Metal case
  • from Radiomuseum.org
  • Model: Power Amplifier Model 9 - Marantz Sound United LLC;
  • Shape
  • Tablemodel, low profile (big size).
  • Dimensions (WHD)
  • 15.375 x 8.25 x 10.5 inch / 391 x 210 x 267 mm
  • Notes

  • A massive hi-fi mono power amplifier with power output of 70 watts RMS into 8 ohms. A pair are required for stereo.

    SPECIFICATION  
    POWER 70 watts continuous
    140 watts peak
    Switch for nearly 40 watt triode operation
    RESPONSE  
     At full rated power within 0.1dB, 20Hz-20kHz
    within 1dB, 12Hz-40kHz
     At ½ watt within 1dB, 3Hz-40kHz
    HARMONIC DISTORTION  
     At full rated power less than 0.1% at mid-frequencies
    less than 0.33% at 20Hz-20kHz
    I.M. DISTORTION less than 0.5% at full rated power
    HUM & NOISE Better than 90dB below 70 watts
    DAMPING FACTOR 17
    Damping Factor can be changed
    internally by adding current feedback
    OUTPUT IMPEDANCES 4Ω, 8Ω and 16Ω, plus 1Ω tap
    for center-speaker connection

    TEST SECTION
    Complete built-in instrument for self-testing and balancing of output and driver tubes. Adjustments for balance of driving signal. The circuit includes five screwdriver adjustments, a seven-position test switch, and an accurately calibrated d'Arsonval meter. These simple adjustments eliminate the need for matched output tubes and assure optimum performance despite normal tube aging.

    CONTROLS
    All controls, adjustments and connections, with the exception of the Triode switch, are accessible from the front.
    Gain Control: isolated by cathode-follower, phase circuit.
    Phase Switch: for securing correct phase relation (A + B)  of phantom center-channel  speaker fed by two amplifiers.
    Low Filter: Subsonic cutoff filter, less than 0.25dB at 20Hz, 20dB at 3Hz.
    Test Switch: for bias (plate current) readings for each tube. Built-in test signal for dynamic balance adjustment.

    Five bias and balance adjustments, as well as input and output connections, are located under snap-out access panel.

    The Model 9R has rack fittings.

    The Model 9 was reissued in 1996, one of the Marantz Classic Series.

    Power requirements
    117V (105-125V) 50/60Hz

    Power consumption:  190-250 watts

  • Net weight (2.2 lb = 1 kg)
  • 23 kg / 50 lb 10.6 oz (50.661 lb)
  • Price in first year of sale
  • 324.00 $
  • Mentioned in
  • -- Original prospect or advert (Marantz Model 9 Seventy Watt Amplifier brochure)
  • Literature/Schematics (1)
  • - - Manufacturers Literature (Service manual Marantz 9 Power Amplifier)
  • Literature/Schematics (2)
  • - - Manufacturers Literature (Instruction manual Marantz Model 9 Power Amplifier)

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