• Country
• Great Britain (UK)

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

• Year
• 1958

• Category
• Audio Amplifier or -mixer

• Radiomuseum.org ID
• 126865

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

• Number of Tubes
• 2

• Valves / Tubes
• EF86 EF86

• Main principle
• Audio-Amplification

• Wave bands
• - without

• Power type and voltage
• Powered by external power supply or a main unit.

• Loudspeaker
• - For headphones or amp.

• Material
• Metal case

• from Radiomuseum.org
• Model: Varislope II - Leak, H.J.; London

• Shape
• Chassis only or for «building in»

• Notes

• A Mono Pre-Amplifier to use with a Leak TL/10, TL/12 or TL/25 Power Amplifier where a microphone input, tape facilities and a variable steep-cut filter are required .

  Description
  Input Selector: A ten-position switch for choice of inputs from:—
    Microphone: Sensitivity, 3 mV. r.m.s. Input impedance 200kΩ.
    Tuner: Response, level. Sensitivity, 50 mV. r.m.s. Input resistance varies from
     100kΩ-250kΩ *
    Records: Input resistance varies from 50kΩ-100kΩ *
    Six separate characteristics are available:
      (a) NARTB.
      (b) AES.
      (c) RCA ORTHO, RCA New Ortho.
      (d) COL. LP. (U.S.A.).
      (e) BRITISH LP.
      (f) BRITISH 78.
    Aux.: Response, level.  Sensitivity, 50 mV. r.m.s. Input, 100-250kΩ *
    Tape: Response, level. Sensitivity, 50 mV. r.m.s. Input resistance 100kΩ.
        * Dependent on the position of the pre-set level control.
  Treble Control: Seven positions providing both treble lift and cut.
  Slope Control: Continuously variable from 50db to 5db per octave.
  Bass Control: Seven positions providing both bass lift and cut.
  Volume Control: The switch controls the amplifier.
  "From Tape Replay Amp.": Input jack for tape replay amplifier
      (of any output impedance up to 50kΩ) embodying playback equalisation.
  "To Tape Record Amp.": This jack permits the user to record on to tape from radio or
      records when using a recorder embodying a low level recording amplifier.
  The following components are mounted on the rear of the preamplifier:
      (1) Co-axial plugs and sockets for tuner, pick-up and auxiliary
         input connections.
      (2) Pre-set controls for adjustment of inputs from tuner and
         pick-ups.
      (3) Octal socket from which H.T. and L.T. supplies may be
         drawn for a tuner unit (or tape oscillator, etc.).
      (4) Octal male socket for connecting to the power amplifier.
  Dimensions: Front panel, 11 5/8" x 4 7/16"
              Chassis, 10 1/2" x 3 9/16" x 4 3/4" deep.

  Price in 1955 £16 16s 0d plus purchase tax.

  See also the similar Leak Vari-Scope Pre-Amplifier which does not have tape facilities.

• Source of data
• -- Collector info (Sammler)

• Literature/Schematics (1)
• Photofact Folder, Howard W. SAMS (Date 12-58, Set 425, Folder 9)

• Literature/Schematics (2)
• -- Original prospect or advert (Brown Brothers Ltd 1955 Catalog No. 520 Page 125)

• Author
• Model page created by a member from A. 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