Mohawk Midgetape 44 (BR-1).
The very first of a
series of recorders Mohawk Midgetape company "Mohawk
business machines corp. Brooklyn 33. N.Y. ", USA.
and was worth
announced, and promised
to sell at $
in 1955 it
advertised with a price of
In the photo
from left to
announce in the
"Tape Recording" №8
advertising in the same
in the August
issue of "High Fidelity
advertised with a price of
and 500 Midgetape "Professional". Model Midgetape 44
originally sold under the name Midgetape BR-1, and on my
copies made in 1956, there are both markings and
Midgetape 44 and BR-1. Structure and kinematics of all
models are nearly identical. Read more about this in the
The main feature of Midgetape
44 is that its wiring diagram is made on radio tubes. In
this amplifier uses three subminiature radio tubes XFY54 (1
pc.), And XFW40 (2 pcs.). They are inserted into the
five-contact socket, mounted on a ceramic
measuring 25 x 24 x 1 mm, which is in turn soldered to
the window textolite board amplifier. On the ceramic
plate are also planar capacitors and resistors amplifier
circuit. In fact, the whole amplifier is built
on this ceramic plate, and textolite board placed only a
few minor details. For 1956
all performed very technologically.
All ceramic capacitors amplifier, and the circuit
no electrolytic capacitor. Since the recorder tube, it
requires three voltages, 9 v - for motor, 1,5 v - for a
filament of radio tubes, and 30 v - anode voltage. In
fact, these radio tubes designed for the anode voltage
15 - 22 v, and to have enough battery 24 v. Homemade
battery, which I have made instead of the original is
made of two batteries of 12 v, type MN.
Also in the recorders
could be used in radio tubes - type counterparts CK542DX
Kinematics of the recorder is very simple, but provides
a stable speed of the tape. Fast forward is absent, and
rewind by using flip handles, located on the upper lid.
Versatile and erase heads are united in molded monoblock.
To connect a microphone uses a round connector and
headphone jack and output cable - simple two-contact
connector without a key. Built-in speaker in the
recorder there. As an accessory to the
recorder sold to the external amplifier - the speakers.
Mohawk Midgetape 44 (BR-1)
with an external amplifier - speaker (photo from
The device was
bought in a faulty state. The sound was, but
very weak, and amid loud crackling. Repair was quite
difficult, but I managed to find the faulty capacitor on
a ceramic board amplifier. In the process of repair, I
checked the radio tubes, and tried to pick up their
analogues. It turned out that the scheme works fine with
the Russian radio tubes 06P2B (analogue
(analogue XFY54). In this case the frequency
characteristics of the amplifier to improve. Kinematics
was almost a working, required only lubrication of
bearings, and replace the rubber belt unit rolling. The main belt,
made of coiled steel spring, I do not have to. Currently,
the recorder works perfectly, as new. Externally, the apparatus is preserved
very well, and mechanics was also a little worn.
Apparently they are not used for a long time, most
likely he quickly broke down, and forgot about it.
recorder came with the original batteries. One of them -
b-battery 30 v, such as Eveready № 506, the other - the
battery of the engine and glow of tubes, such as 2X62X
Burgess. This battery has three contacts, one medium -
common (-), and two side with voltages + 9 v, and + 1,5
v. New same battery, I gathered from six batteries AAA,
and one AA.
Also included with the recorder I got the original
cassette (cartridge), the original crystal microphone,
unfortunately failed, and the connecting cable to
connect to an external amplifier. The tape has an
unusual design with the coils located one above the
Her body and all the
details in full metal. Tape, 1 / 4 inches short
of 1 hour of recording (2 x 30 min.). At
a speed of 1, 7/8 inches per second.
Dimensions recorder 220 x 100 x 55 mm. Weight complete
with batteries and tape - 1,3 kg. Net weight 0,9 kg.
Photos can be enlarged
The photo on the left of
the apparatus with the original batteries. In the photo
on the right improvised.
On the left picture view of the apparatus
below. One can see the two screws fixing the kinematics
to the shell. In the larger picture right is marking the
date of manufacture - NOV 23 1956 OK
Dimensions without motor centrifugal
regulator - 49 x 28
Electric motor speed regulator on the
lamp with filter.
It is located in a metal box near the
XFY 54 (32
x 8 mm.).
- XFW40 (27 x 8.5 x
1P3B and 06P2B
38 x 10.2
mm and 32
mm. The actual
10 x 6.7
mm and 30
x 10 x
from different manufacturers
vary in size.
Some of the
For example, the lamp
has dimensions of
5.6 mm and
commensurate with the
had to unplug the
On the left he is
in his place,
he pictured right
and you can see
an empty window
the amplifier board
On the ceramic plate
located lamp socket, planar capacitors and resistors
Such modules for hearing aids began to be produced in
same in PDF) and during the war, this technology
produced modules for military use.
Look at the report on the symposium on printed circuits,
which was held in 1947 in the United States.
producing in 1955,
started producing commercially in
in a magazine
"Radio & Television News"
August 1950. In
addition to these
modules, they are
to assemble the radio
on a ceramic substrate
in a miniature
version, such as
Manufacturing technology is described in the
magazine "Radio & Television News" №12 for 1949. Conductive tracks on the ceramic substrate made
by photo printing emulsion with silver powder
and fusing in a furnace. The resistors were
formed by applying to a substrate through a
stencil graphite resistive paint, followed by
firing in a furnace.
As can be seen,
is very similar to
"Radio & Television News"
August 1950, but
there are some differences.
there were several
Model 2" and
recorder module is used
have the same
of the amplifier
"Ampec" from the catalog
1952. There is also a
by this technology.
"Centralab Catalog №
shows the prices for
all models of these
PC-202 and PC-204,
without the vacuum
tubes and the
PC-203 and PC-205
I must say that
at that time
For comparison, for
example a stationary
of the recorder
at the time
I did not have, but
did not need, since
was only a faulty
now brought them to
make a normal
The values of
are approximate, but
it is not critical,
since such schemes
with a large
presented in the
"Centralab Catalog №
is slightly different
from the one I
Also in the catalog
indicates the use of
the lamp module
CK512AX, CK547AX, CK548AX,
CK549AX, DX, but
are not mentioned
CK525AX, CK542AX, DX, XFY54
XFW40, which are also
in them. This could
mean that in addition
in the directory.
service manual, which I
recently managed to acquire.
placed at the bottom of
Another version of
but with the volume control and
the magazine "Radio &
Television News" №12 for 1949.
Actually, it turns out
that such a portable tape recorders could appear much
earlier, back in the 40s. Technology tape recording time
has already been, and everything else, mechanical parts,
engine and compact batteries is not a problem in the
manufacture and sub-miniature radio tubes began
producing commercially in 1940. This example CK501X,
CK502X, CK503X, CK504X production of Raytheon. The truth
is the first such lamps were somewhat larger than it is
now - 39.7 x 14 mm and in the version with base, they
became even greater. The marking lamp base absent index
X, - CK501 ... CK504.
The first mention of
these lamps I
have found in the catalog
I found in the
"Radio Chack Catalog"
that for five
has not changed
at the same
time it is made
smaller radio tubes index
Familiar sizes today have lamps "Raytheon" with
the AX index, which began to be produced during
It is in this version like radio tubes have
become very popular and widely used in the
future of diverse radio equipment, even in
aviation and space.
Subsequently, similar lamps made even smaller
sizes, such as radio tubes
CK538DX is measured only
25.4 x 7.2 x 5.6 mm.
should add that the use of such lamps in the
portable equipment first mastered in Germany.
In 1951 we began to produce the
first "pocket" wire recorder
assembled in three subminiature lamps type DF67
Original battery type
2X62X. Dimensions 60 x 55 43 mm. Weight 210 g.
The battery is assembled with 14
elements, covered with resin.
Homemade battery made of six AAA
batteries, and one AA batteries. For the manufacture of
cardboard boxes used a scanned image of the original.
The original battery 30 v such as
Eveready ¹ 506. The sizes 35 х 29 х 15 mm. Weight of 25
g. The battery is inserted into the steel container, and
squeezed it flat shaped spring.
Homemade battery 24 v is made of two
batteries of 12 v type MN. To supply anodes 24 v enough,
since they are calculated on the anode voltage 15 - 22
The original tape unassembled. The body
and all parts of iron, and coils located one above the
other. The width of the film 1 / 4 inches. Hours 1 hour
(2 x 30 min).
Connection cable for
connection to an external amplifier. Has a shunt
resistance of 2.2 kom.
Crystal microphone and the original packaging.
Unfortunately, it turned out to be defective. Capsule
microphone consists of an iron shell with aluminum
membrane, under which the crystal. After opening of the
membrane revealed that the crystal was destroyed.
Crystal Repair I used from another microphone. Now the
microphone is in working condition.
Mohawk Midgetape BR-1
The construction of all
types of recorders Mohawk Midgetape same.