Minifon Protona Special.
This is one of the
later models in the series of wire recorders Minifon.
They were produced from 1960 to 1965. From 1960 to 1962,
their company produced "Protona GmbH"; Hamburg, and from
1962 to 1965, after the merger - "Telefunken", Germany.
In the first 50 years also produced models
P55
and Mi51,
and their electronics was still a tube. Both these
models are collected on 3-miniature vacuum tube, and for
their work required 3 batteries. 12 v to power the
motor, 30 v - the anode voltage, and the 1,5 v - glow
lamp. Minifon Protona Special, which I represent, made
in 1962, has 6 transistors, and is powered by a battery.
It makes me wonder. Precision mechanics performed a
technically flawless, and after the repair works like a
clock. Block heads during the move up - down uniformly
laying wire on the coil. See how it works, have fun.
Dimensions recorder 177 x 102 x 42 mm. Weight
800 g.
Coil diameter 44 mm accommodate the volume of a special
wire with a diameter 0,038 mm, sufficient to work for 5
hours at a speed of 23 cm / sec (model L). Also used the
wire diameter 0,05 mm. For these recorders and the other
was a standard rate - 34 cm / sec (model S). Nutrition
12 v. Batteries required size, as I understand, made
specifically for this series recorders. In the
kinematics used engine with electronic speed
stabilization. The active elements of the stabilizer are
the transistor and the light bulbs. Movement of the
engine is transmitted through belt a cylindrical
flywheel axis of rotation which is horizontal. Further
work shaft rollers and a system of gears. Unlike other
portable recorders that time, there is hitchhiking. When
the coil wire ends, she pressed the lever is released.
This lever, in turn, presses the power circuit breaker,
located under the coil. The solution is simple and
original works flawlessly. As an indicator of hitch is
used, the red light bulbs, located above the miniature
needle indicator of the supply voltage. Block heads made
in the nonseparable case with a guide groove for the
wire, and has special springs to prevent her jumping
down. During the head moves up - down uniformly laying
wire on the coil. This motion is realized through a
system of gears. Four keys, - "stop",
"rewind", "play back", and "record" are made from high
quality plastic and are arranged in a row. Above them is
counter flow wire. To the left of them, jack for
external power supply, and the right connector for
microphone and headphones. No built-in speaker. On the
flip lid case recorder glued brief instruction manual in
English. Housing cast, made of durable magnesium alloy.
For recorders in this series were issued special spy
accessories, such as a microphone, under the camouflage
watches, a device for recording telephone conversations,
a miniature microphone with a clip, and others.
Know that in Germany, these recorders are sold for 925
DM (model S), and 985 DM (model L), which was at that
time large sums. All models Minifon were very popular,
used by special services, and successfully sold in 80
countries. The device has got me in the hands of a very long time,
and I repaired it then improvised means. Therefore, the
photographs can be seen on the modern, including
domestic radio components. For example, instead of the
visible LED indicator lamp. Also replaced belt and
tires on one of the rollers. Now the recorder is in
working condition, but I plan to find a family details,
and put everything in their original condition.
Video
review
After 1962, in the United States on the label in the box
between "minifon"
and "special"
could be
placed logo
"ITT".
Photos can be enlarged
Photographs taken during the repair
On the left the original batteries 12 v.
On the right hand-made battery 12 v.
Microphone to the recorder Minifon
Protona Special, Minifon Attache, and Minifon Hi-Fi.
Power supply 12 v to type recorders
Minifon.
Coils of wire
Block
heads to the wire recorders Minifon Protona Special and
Minifon P55
Electrical circuit and technical parameters Minifon
Special.
Photo from the book by Roland Shellin "Minifon
Spy in the
pocket", (Roland Schellin, "Minifon
Der spion in der tasche").
It is seen that in the scheme may be 4 or 5 types of
transistors, OC304, OC307, depending on the
modification.
However, in my recorder to 6, with a different type
(OC75). The
amplifier is built on four transistors, one used in the
stabilizer speed motor, and another as a protection
diode on power supply.
Description of the Minifon Special in the
Telefunken catalog
Microphone, clock-clad "Minifon", and
advertising similar watches "Lafayette"
There is no
such recorder in my collection, but since this model is
outstanding, I decided to post here the information I
know about it.
In 1958 - 1959, a prototype of the Minifon Liliput
recorder, even smaller than the previous Minifon models,
was designed. It weighs 500 grams,
dimensions 136 x 87 x 43 mm, food, 8 - 10,5 v battery
from a compact Mini-accu. There were options for wiring
3 and 4 transistors. In a series of model unfortunately
did not go, and at auctions, I have not seen it yet.
A total of about 10 copies were produced.
Now it is known that
two of them are in private collections, and two more are
in the museum storage.
A photo of the recorder is placed on the cover of the book by
Roland Shellin "Minifon The Spy in Your Pocket", (Roland
Schellin, "Minifon Der spion in der
tasche"). In this book of 200 pages
of detailed history and construction of all models
Minifon with plenty of photos.
Also Roland Schellin shared with me
several photos of Minifon Liliput, which show details of
his design
The kinematics of the recorder are largely borrowed from
previous Minifon models.
It is interesting that in this small
design even the meter of wire consumption has been
placed
