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Mohawk
  
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Midgetape 44   BR-1
Portable tape cartridge audio recorder - wanted item

Midgetape 44, also known as Midgetape BR-1, was a portable valve-based audio tape cartridge recorder, introduced in 1955 by Mohawk Business Machines in New York (USA). Although initially intended as a dictating machine, it was soon discovered by intelligence services like the Central Intelligence Agency (CIA) for making covert recordings, as it could easily be hidden on the body.

The device measures 220 x 100 x 55 mm and weights 1.3 kg with batteries and tape cartridge. It is powered by two batteries: a large one that provides 1.5V for the filaments and 9V for the motor, and a small one that provides the 30V anode voltage for the miniature valves (tubes).

All controls and connections are at the front. There are sockets for a microphone and an earpiece. An external amplifier was available separately. Audio is recorded on a 6.35 mm (¼") wide reversible tape that runs at 4.76 cm/s. The cartridge can hold 30 minutes at either side. 1
  

The device can only record and playback. For rewinding, the crank – integrated in the hinged lid – must be used. Development of the Midgetape 44 started in 1954, with a projected sales price of US$ 197.50, but when the device was released in 1955, the sales price had meanwhile been increased to US$ 249.50 [2]. It was succeeded in 1957 by the fully transistorised Midgetape 300.

  1. Later versions of the tape cartridge could hold 2 x 45 min.

Midgeetape 44 - front
With open covers
Tape section with combined record/playback head
Controls
Battery compartment
1.5V/9V battery
A
×
A
1 / 6
Midgeetape 44 - front
A
2 / 6
With open covers
A
3 / 6
Tape section with combined record/playback head
A
4 / 6
Controls
A
5 / 6
Battery compartment
A
6 / 6
1.5V/9V battery

Specifications
  • Device
    Miniature audio recorder
  • Purpose
    Dictation, covert recording
  • Model
    Midgetape 44 (BR-1)
  • Manufacturer
    Mohawk Business Machines
  • Year
    1955
  • Medium
    Tape
  • Width
    6.35 mm (1/4 in)
  • Speed
    4.76 cm/s (1 7/8 in/s)
  • Cartridge
    30 min/side
  • Output
    3 mW into 2000Ω
  • Response
    200 - 4000 Hz
  • W&F
    < 0.7%
  • Valves
    3 (see below)
  • Power
    LT: 1.5V/9V (45 hours)
  • HT: 30V (100 hours)
  • Dimensions
    220 x 100 x 55 mm
  • Weight
    900 grams (1.3 kg with batteries and tape cartridge)
  • Price
    US$ 249.50 (1955) 1
Valves   tubes
  • 2 x CKS49DX or XFW50
  • 1 x CKS42DX or XFY54
Accessories
  • Tape cartridge (2 x 30 min)
  • Battery set
  • Clip-on lapel microphone
  • Earphone
Options
  • External amplifier (US$ 35)
  • Tape cartridge 2 x 45 min.
  • Audio cable (for connection to external amplifier)
  • Leather carrying case
  1. Initially announced in 1954 for US$229.50 [2].

Connections
Earpiece
At the front panel is a 2-pin socket for connection of a miniature earpiece, such as the ones that were used with hearing aids at the time. This socket is not suitable for connection of a loud­speaker. If a higher audio volume is required, an external amplifier could be added, which was available for ~ US$ 35 (1955) [2].

Microphone
Also at the front panel is a circular socket for connection of a high-impedance microphone, such as a crystal microphone. This connector is different from the 6-pin one used on later Midgetape recorders.


Documentation
  1. Midgetape Model BR-1, Service Manual 1
    Mohawk Business Machines Corp., 29 November 1954.

  2. Midgetape Model BR-1, Circuit Diagram 1
    Mohawk Business Machines Corp., 29 November 1954.

  3. Mechanical Parts List with exploded view 1
    Howard W. Sams & Co., Inc. 1959.
  1. Obtained from Vintage Technics website [2].

References
  1. Günter Hütter Collection, Mohawk Midgetape 44
    Austria, October 2019.

  2. Vintage Technics, Mohawk Midgetape 44
    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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