• Country
• Great Britain (UK)

• Manufacturer / Brand
• Leak, H.J.; London

• Year
• 1963 ?

• Category
• Audio Amplifier or -mixer

• Radiomuseum.org ID
• 122439

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

• Number of Transistors
• 18

• Semiconductors
• AC107 or. BC154 GET113 or. BC153 GET113 or. BC153 OC44 or. BC153 AF118 GET538 AC127 AD140 AD140

• Main principle
• Audio-Amplification

• Wave bands
• - without

• Details
• Hi-Fi equipment

• Power type and voltage
• Alternating Current supply (AC) / 110; 117; 130; 210; 230; 250 Volt

• Loudspeaker
• - This model requires external speaker(s).

• Material
• Metal case

• from Radiomuseum.org
• Model: Stereo 30 - Leak, H.J.; London

• Shape
• Book-shelf unit.

• Dimensions (WHD)
• 330 x 110 x 225 mm / 13 x 4.3 x 8.9 inch

• Notes

• The Leak Stereo 30 was introduced in 1963 as Leak's first transistor amplifier. It came at a time when the audio industry was transitioning from vacuum tubes to solid-state technology. 

  Technical Specifications

  • The Stereo 30 was rated at 15 watts per channel, for a total of 30 watts (hence the name).
  • It utilized germanium transistors, the only type available at the time.
  • The amplifier featured a quasi-complementary germanium transistor output stage.

  Design and Performance

  The Stereo 30 was designed to maintain the high-fidelity stereo performance that Leak was known for, despite the switch to transistor technology. Harold Leak reportedly conducted AB tests comparing the Stereo 30 against his own valve amplifiers, with claims of "near identical results".

  Challenges and Innovations

  • Germanium transistors presented challenges, being noisy and prone to thermal runaway.
  • Leak had to source pre-matched transistors from manufacturers, grouped by gain and leakage characteristics, to ensure consistent performance.
  • The amplifier's design was so well-regarded that it was adopted by many radio and TV stations worldwide for broadcast monitoring.

  Impact and Legacy

  The Stereo 30 was a commercial success and helped make Leak's products more accessible to a wider audience. Transistors were significantly cheaper to manufacture than vacuum tubes, allowing for more competitive pricing.

  Successor: Stereo 30 Plus

  In 1969, Leak introduced the Stereo 30 Plus, which replaced the germanium transistors with silicon devices. This update took advantage of improved transistor technology, offering better performance and reliability

  “Semiconductors present”, only one channel complement listed.

• Net weight (2.2 lb = 1 kg)
• 5 kg / 11 lb 0.2 oz (11.013 lb)

• Mentioned in
• - - Manufacturers Literature (Company Website)

• Literature/Schematics (1)
• -- Original prospect or advert (HiFi News Oct 2023, review Tim Jarman.)

• Author
• Model page created by J. Virgilio Santos. See "Data change" for further contributors.

• Other Models

• Here you find 46 models, 45 with images and 23 with schematics for wireless sets etc. In French: TSF for Télégraphie sans fil.
  All listed radios etc. from Leak, H.J.; London