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Mohawk
  
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Midgetape 300
Portable tape cartridge audio recorder - this page is a stub

Midgetape 300 was a portable transistorised audio tape cartridge recorder, introduced in 1957 by Mohawk Business Machines in New York (USA) as a solid state 1 successor of the valve-based Midgetape 44. Although initially intended as a dictation machine, it was also used in surveillance as it could easily be hidden on the body. This was further promoted by the availability of a wrist­watch microphone and a shoulder holster. It is known that these devices were used by the CIA.

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In late 1957, the Midgetape 300 was succeeded by the nearly identical Midgetape 400 'Chief', which added Automatic Volume Control (AVC) when recording. At the same time, accessories were released to make the device even more suitable for surveillance and covert recording [G].

  1. In this context, solid-state means that it is built with transistors instead of valves (tubes).

Specifications
  • Device
    Miniature audio recorder
  • Purpose
    Dictation, covert recording
  • Model
    Midgetape 300
  • Manufacturer
    Mohawk Business Machines
  • Year
    1957
  • Predecessor
    Midgetape 44 (BR-1)
  • Successor
    Midgetape 400
  • Medium
    Tape, Dupont Mylar base
  • Width
    6.35 mm (1/4 in)
  • Speed
    4.76 cm/s (1 7/8 in/s)
  • Cartridge
    45 min/side
  • Input
    ≥ 1 mV, 2000Ω
  • Output
    10 mW into 2000Ω
  • Response
    150 - 5000 Hz
  • W&F
    < 0.7%
  • S/N
    42dB
  • Bias
    20 kHz
  • Transistors
    4
  • Dimensions
    220 x 100 x 55 mm
  • Weight
    1.2 kg
  • Price
    US$ 250 (1957)
Transistors
  • 1 x GT81
  • 1 x GT-82
  • 2 x 2N406
Accessories
  • Microphone
  • Earphone
Options
  • 401
    Leather carrying case
  • 402
    Internal Power Amplifier with built-in speaker
  • 403
    Mains power supply unit (for 110V AC only)
  • 404
    Transcribing Control [5]
  • 405
    Cowhide briefcase concealment (with hidden microphone)
  • 406
    Same as 405, but without hidden microphone
  • 407
    Telephone pick-up coil
  • 408
    Wristwatch microphone
  • 409
    Concealable lapel microphone
  • 410
    Throat microphone
  • 411
    Standard microphone/speaker with clip stand
  • 412
    Shoulder holster
  • 420
    Car battery converter (12V)
  • 421
    Stethoscope-style earphones
  • 422
    Combined speaker/microphone with PTT
  • RL-60
    Tape cartridge 2 x 30 min.
  • RL-90
    Tape cartridge 2 x 45 min.
  • T-12
    Motor battery (12-15 hours)
  • T-50
    Motor battery (50+ hours)
Documentation
  1. Midgetape pocket tape recorder - Instruction Manual
    Mohawk Business Machines Corp., undated.

  2. Midgetape 'Chief' (400) Supplementary Instructions
    Mohawk Business Machines Corp., undated.

  3. Midgetape 300/400, Circuit Diagram 1
    Howard W. Sams & Co., Inc. 1960.

  4. Mechanical Parts List with exploded view 1
    Howard W. Sams & Co., Inc. 1959.

  5. Midgetape Transcribing Control 1
    Mohawk Business Machines Corp., undated.

  6. Midgetape Chief (400) Leaflet

  7. Midgetape Chief (400) datasheet and pricelist 1
    25 November 1957.
  1. Obtained from Vintage Technics website [1].

References
  1. Vintage Electronics, Mohawk Midgetape 300
    Retrieved June 2022.
Further information
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Crypto Museum. Created: Thursday 09 June 2022. Last changed: Monday, 12 February 2024 - 15:06 CET.
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