Moniblock Amplifier Series 7R

Croft Acoustics Ltd.; Birmingham

Data
Forum
Pictures
Collections

  • Year
  • 2016 ?
  • Category
  • Audio Amplifier or -mixer
  • Radiomuseum.org ID
  • 362009

 Technical Specifications

  • Number of Tubes
  • 3
  • Number of Transistors
  • 2
  • Main principle
  • Audio-Amplification; Hi-Fi-High End products
  • Wave bands
  • - without
  • Power type and voltage
  • Alternating Current supply (AC) / 115 / 230 Volt
  • Loudspeaker
  • - This model requires external speaker(s).
  • Power out
  • 100 W (undistorted)
  • Material
  • Metal case
  • from Radiomuseum.org
  • Model: Moniblock Amplifier Series 7R - Croft Acoustics Ltd.;
  • Shape
  • Tablemodel, low profile (big size).
  • Notes

  • Croft Acoustics Series 7R (Monoblock/Regulated Version)

    • Type: Monoblock (single-channel) hybrid power amplifier, regulated version.
    • Input Stage:
      • Typically uses ECC83 (12AX7) tube, sometimes with additional tubes for regulation (e.g., Tesla 0G3, ECC99).
    • Output Stage:
      • High-quality MOSFETs, as in the Series.
    • Topology:
      • Hybrid: tube input, MOSFET output.
      • Monoblock configuration: each unit drives one channel, with an independent power supply.
    • Power Output:
      • 50–55 watts RMS into 8 ohms per monoblock; higher output into lower impedances.
    • Power Supply:
      • Features a regulated high-tension (HT) supply for the tube stage.
      • Larger 300VA toroidal transformer for increased current capability and stability.
      • Additional regulation tubes (e.g., 0G3) may be present for voltage regulation.
    • Construction:
      • Hand-wired, point-to-point, no PCBs.
      • Metal chassis for shielding and durability.
    • Sound/Performance:
      • Improved channel separation, control, and dynamic headroom due to monoblock design and regulated supply.
      • Greater refinement, grip, and stability across the frequency range relative to the standard Series.
    • Physical Characteristics:
      • Each amplifier is dedicated to a single channel, requiring a pair for stereo use.

    Technical Comparison Table

    Feature Series 7 (Stereo) Series 7R (Monoblock/Regulated)
    Channels 2 (stereo) 1 per unit (monoblock)
    Input Stage ECC83 (12AX7) ECC83 (12AX7) (+ regulation)
    Output Stage MOSFET MOSFET
    Power Output 45–50W per channel (8Ω) 50–55W per unit (8Ω)
    Power Supply Standard Regulated HT, larger transformer
    Construction Hand-wired, no PCBs Hand-wired, no PCBs
    Chassis Shared with other Croft models Metal, monoblock configuration
    Sound/Performance Musical, detailed, best with 90dB+ speakers Improved control, separation, and refinement

    Summary:
    The Series 7 is a minimalist stereo hybrid amplifier with a tube input and MOSFET output, designed for high musicality and value. The Series 7R is a monoblock, regulated version with a larger power supply and additional voltage regulation, offering enhanced channel separation, control, and sonic refinement.

  • Mentioned in
  • -- Original prospect or advert
  • Author
  • Model page created by Gary Cowans. See "Data change" for further contributors.

 Collections | Museums | Literature

 Forum