80 Watt Stereo Amplifier AA-40

Heathkit (Brand), Heath Co.; Benton Harbor (MI)

Data
Forum
Pictures
Collections

  • Year
  • 1961
  • Category
  • Kit (Parts plus instruction) or building instructions only
  • Radiomuseum.org ID
  • 367640
    • alternative name: Heath Company

 Technical Specifications

  • Number of Tubes
  • 6
  • Main principle
  • Audio-Amplification
  • Wave bands
  • - without
  • Power type and voltage
  • Alternating Current supply (AC) / 117 Volt
  • Loudspeaker
  • - This model requires external speaker(s).
  • Power out
  • 80 W (undistorted)
  • Material
  • Metal case
  • from Radiomuseum.org
  • Model: 80 Watt Stereo Amplifier AA-40 - Heathkit Brand, Heath Co.;
  • Shape
  • Book-shelf unit.
  • Dimensions (WHD)
  • 15 x 7.25 x 11 inch / 381 x 184 x 279 mm
  • Notes

  • The Heathkit AA-40 is a vintage high-fidelity vacuum tube stereo power amplifier originally released as a kit in 1962. It is highly regarded by collectors for its "massive iron" transformers and clean, classic analog sound.

    Technical Specifications:
    The amplifier is designed with a common power supply that provides voltages to both channels, featuring separate input levels and bias adjustments for each. 
    Power Output: 40 watts per channel into 8Ω in stereo mode, or 80 watts into 8Ω when switched to mono operation.
    Frequency Response: 20Hz to 20kHz.
    Total Harmonic Distortion (THD): 1.5%.
    Signal to Noise Ratio: 85dB.
    Dimensions: 15 inches wide, 11 inches deep, and 7.25 inches high.
    Weight: 35.75 lbs (approximately 16.2 kg).

    Tube Complement and Internal Components: 
    The AA-40 uses a specific "valve complement" to achieve its output power and sound characteristics. 
    Output Tubes: 4 x EL34 (two per channel).
    Driver/Input Tubes: 2 x 6AN8.
    Semiconductors: Includes 4 silicon diodes and 1 selenium diode rectifier for bias voltage.
    Rectifier Circuit: Uses a voltage-doubling circuit for the main power supply.

    Performance and Maintenance:
    Expert reviewers and enthusiasts often compare the AA-40 to having two Heathkit W-7 amplifiers on a single chassis. 
    Restoration: Due to its age, many units found today require restoration, including replacing coupling and electrolytic capacitors. Restoration kits are still available from specialist sellers like those on eBay.
    Adjustments: The unit includes built-in bias voltage and balancing adjustments, though an external voltmeter is required to set them accurately.
    Reliability: According to users on diyAudio, these amplifiers are "keepers" that can rival modern high-end gear when properly reconditioned. 

  • Net weight (2.2 lb = 1 kg)
  • 35.75 lb (35 lb 12 oz) / 16.231 kg
  • Price in first year of sale
  • 79.95 USD
  • Mentioned in
  • -- Original prospect or advert (Heathkit 1961 July cat page 24)
  • Author
  • Model page created by Glen Orriss. See "Data change" for further contributors.

 Collections | Museums | Literature

 Forum