5-10 Amplifier

Mullard Wireless, London (see also Mullard Radio Valve)

Data
Forum
Pictures
Collections

  • Year
  • 1954
  • Category
  • Kit (Parts plus instruction) or building instructions only
  • Radiomuseum.org ID
  • 367467

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

 Technical Specifications

  • Number of Tubes
  • 5
  • Main principle
  • Audio-Amplification
  • Wave bands
  • - without
  • Power type and voltage
  • Alternating Current supply (AC)
  • Loudspeaker
  • - This model requires external speaker(s).
  • Material
  • Metal case
  • from Radiomuseum.org
  • Model: 5-10 Amplifier - Mullard Wireless, London see
  • Shape
  • Chassis only or for «building in»
  • Notes

  • The Mullard 5‑10 is a three‑stage, 10‑watt high‑fidelity audio amplifier circuit published by Mullard in 1954 to demonstrate the performance of their EF86, ECC83 and EL84 valves. Intended as a constructional design rather than a factory‑built product, it was first released through Practical Wireless and Mullard technical booklets. The design became widely adopted by kit suppliers and hobby constructors.

    The amplifier uses an EF86 low‑noise pentode as the input stage, followed by an ECC83 long‑tailed‑pair phase splitter driving a push‑pull pair of EL84 output pentodes. A full‑wave rectifier (GZ30 or EZ80) provides HT supply. Under normal loading the circuit delivers approximately 10 W with low distortion, and Mullard offered three output‑stage configurations: normal loading, low loading, and distributed loading (ultra linear).

    Technical Specifications

    • Number of valves: 5
    • EF86 (input)
    • ECC83 (phase splitter)
    • EL84 ×2 (push‑pull output)
    • GZ30 or EZ80 (rectifier)
    • Power output: approx. 10 W
    • Frequency response: 40 Hz–20 kHz,
    • Power supply: AC mains, typically 200–250 V (varies by kit implementation)
    • Loudspeaker: external speaker required (not included in design)
    • Construction: chassis‑mounted components; versions with or without tone/volume controls were supported by Mullard documentation.

    Notes
    The 5‑10 was not sold as a finished amplifier by Mullard; instead, companies such as Stern Radio Ltd. and Stern‑Clyne Ltd. offered kits based on the Mullard design.

    The circuit became one of the most influential British valve amplifier designs of the 1950s, forming the basis for many commercial and DIY builds.

    This was followed in 1955 by the Mullard 5‑20, a higher‑power EL34 design that succeeded the earlier EL84‑based 5‑10

    Some examples of commercial amplifiers:

    UK Stern

    UK Spectone

    Australian Aegis

  • Mentioned in
  • -- Original prospect or advert (Practical Wireless World Oct 1954, p.586-589)
  • Author
  • Model page created by Gary Cowans. See "Data change" for further contributors.

 Collections | Museums | Literature

 Forum