RD Junior Amplifier

Rogers, Catford (see also Rogers Birmingham)

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  • Year
  • 1949 ?
  • Category
  • Audio Amplifier or -mixer
  • Radiomuseum.org ID
  • 360583

 Technical Specifications

  • Number of Tubes
  • 4
  • Main principle
  • Audio-Amplification
  • Wave bands
  • - without
  • Power type and voltage
  • Alternating Current supply (AC) / 50 - 60 Hz, 110-115-125/200-230-250 Volt
  • Loudspeaker
  • - This model requires external speaker(s).
  • Power out
  • 8 W (14 W max.)
  • Material
  • Metal case
  • from Radiomuseum.org
  • Model: RD Junior Amplifier - Rogers, Catford see also
  • Shape
  • Chassis only or for «building in»
  • Dimensions (WHD)
  • 11 x 5.5 x 6 inch / 279 x 140 x 152 mm
  • Notes

  • The Rogers RD Junior Amplifier is a compact, high-fidelity mono amplifier designed for versatile performance and reliability. Its thoughtful design emphasises stability, low distortion, and efficient use of components, making it one of the most respected amplifiers in the British market during its time.

    Key Features:

    • Frequency Response: ±0.25 dB from 20 Hz to 30,000 Hz. With the presence plug inserted, the response rises to +5 dB at approximately 3 kHz to 30 kHz.
    • Negative Feedback (NFB): 20 dB ±1 dB over 30 Hz to 20,000 Hz.
    • Input Sensitivity: 600 mV RMS for 8 watts output.
    • Total Harmonic Distortion:
      • At 8 watts: 0.12% at 1 kHz.
      • At 10 watts: 0.2% at 1 kHz.
      • At 12 watts: 0.5% at 1 kHz.
    • Hum and Noise: -80 dB below an output of 8 watts.
    • Output Impedance: Configurable for 2–3 ohms, 6–8 ohms, or 12–16 ohms via plug-in units.
    • Damping Factor: 20.
    • Power Outputs:
      • High tension (HT): 270V at 40 mA.
      • Low tension (LT): 6.3V at 2A.
    • Valves: ECC83 (double triode), two EL84 (output tetrodes in ultra-linear push-pull configuration), and EZ81 (rectifier).
    • Output Transformer Specification: Rated for up to 25 watts with a frequency response of ±1 dB from 20 Hz to 50,000 Hz.
    • Power Consumption: Approximately 60 watts.
    • Operating Voltage: Configurable for mains supply of either:
      • AC: 200–230–250V at a frequency of 50 Hz.
      • AC: 110–115–125V at frequencies of either 50 or 60 Hz.

    Note: The Earlier version, c1949 - 1954, used two PX4s.

  • Net weight (2.2 lb = 1 kg)
  • 15 lb 0 oz (15 lb) / 6.810 kg
  • Mentioned in
  • -- Original prospect or advert (The Gramophone July 1956, page 68)
  • Literature/Schematics (1)
  • -- Original prospect or advert (The Gramophone Jan 1950, Page XV.)

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