Monoblock MA15 Mk 2 Late

Radford Electronics Ltd.; Bristol

Daten
Forum
Bilder
Sammlungen

  • Jahr
  • 1962 ?
  • Kategorie
  • NF-(Niederfrequenz-) Verstärker oder -Mixer
  • Radiomuseum.org ID
  • 360484

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 Technische Daten

  • Anzahl Röhren
  • 5
  • Hauptprinzip
  • NF-Verstärkung
  • Wellenbereiche
  • - ohne
  • Betriebsart / Volt
  • Wechselstromspeisung / 50 Hz, 200/240 Volt
  • Lautsprecher
  • - Dieses Modell benötigt externe(n) Lautsprecher.
  • Belastbarkeit / Leistung
  • 15 W (sinus/unverzerrt)
  • Material
  • Metall, SICHTBARE RÖHREN
  • von Radiomuseum.org
  • Modell: Monoblock MA15 Mk 2 [Late] - Radford Electronics Ltd.;
  • Form
  • Tischgerät, Truhenform, meist mit Deckel (NICHT Schrägpult).
  • Bemerkung

  • The Radford MA15 series of amplifiers was a well-regarded line of vacuum tube audio amplifiers produced in the 1960s.

    There were four versions:

    1. MA15 Mk1: This was the original version of the amplifier.
    2. MA15 Mk2 Early: An updated version of the original design.
    3. MA15 Mk2 Late: A further refinement of the Mk2 design.
    4. CMA15: This was a kit version of the MA15 amplifier.

    The Radford MA15 Mk2 Late Monoblock

    • Further refinement of the Mk2 design
    • Similar specifications to the Mk2 Early version
    • Possibly included minor component value changes or circuit tweaks

    Maintained the improved high-frequency performance and stability of the Mk2 design

    • Output power: 15 watts (maintained)
    • Circuit design: Revised for better performance
    • Phase inverter: Changed to pentode-triode configuration
    • Feedback: Increased to 27dB of negative feedback
    • Output transformer: Improved design with first resonance at 150kHz
    • Input stage: Added step network for high-frequency stability
    • Feedback network: More complex R/C step network across the feedback resistor
    • Performance: Significantly lower distortion, especially at high frequencies
    • Power delivery: Able to deliver rated power up to 20kHz
    • Phase shifts: Reduced at high frequencies
    • Stability: Carefully tuned for stability with higher feedback

    The Mk2 version demonstrated substantial performance improvements, particularly in distortion reduction and power delivery across a wider frequency range.

    Output Transformers
    The key difference between the output transformers of the Radford MA15 Mk1 and Mk2 models lies in their design and performance characteristics:

    Radford MA15 Mk2 Late Output Transformer (T2063G)

    • Resonance Frequency: The Mk2 output transformer was significantly improved, pushing its first resonance to approximately 150kHz.
    • Performance: This allowed for reduced phase shifts, better high-frequency stability, and lower distortion across the frequency range. It also enabled the amplifier to deliver its rated power up to 20kHz.
    • Design Complexity: The improved design contributed to a more refined sound and greater technical performance, addressing the limitations of the Mk1.

    These enhancements in the Mk2's output transformer were a critical factor in its superior performance compared to the Mk1

  • Literaturnachweis
  • -- Original prospect or advert (HiFi News (UK) Sep 1962)
  • Autor
  • Modellseite von Gary Cowans angelegt. Siehe bei "Änderungsvorschlag" für weitere Mitarbeit.

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