The Type 'Z' Receiver
|This is what A.J.S. had to say about the receiver. It
shows how people's ideas about, and use of radios, have
changed since the early days. Bear in mind that this is a
very simple type of receiver, consisting of an aerial tuned
circuit, with reaction from the first stage to give better
selectivity and sensitivity. Most people would not accept
this type of performance today, when compared with the
performance that we get from modern receivers.
|"The A.J.S. 2-Valve Cabinet receiver is a self-contained
instrument with a wave-length range from 60 metres upwards,
depending on the coils used. When used on a standard
100-foot aerial, and under normal conditions, it will give
loudspeaker reception over a distance of 20-25 miles from a
normal Broadcast Station, and 100 miles when receiving from
the High Power Station. In quoting these figures we have
taken great care not to exaggerate, and it is highly
probable that in most cases loudspeaker reception will be
heard over much greater distances. When headphones are being
used it will come as a surprise to most purchasers to learn
how far broadcast programmes can be heard.
||This receiver is built into an upright cabinet of solid
mahogany and of handsome design. We would like to emphasize
the fact that the workmanship is equal to, and in keeping
with, the cabinet work of our most expensive models.
An ebonite panel, on which is mounted three knobs, is let
into the front of the cabinet. Two of these are used in
operating the receiver, the third one being used for
switching off and on. All valves and coils are contained
within the cabinet, but may be brought to view by merely
raising the deep hinged top. This protects the valves from
damage, and preserves the neat appearance, which would
otherwise be spoilt if the coils etc., were exposed.
|This receiver is not built from cheap components made to
make a cheap set, and put in a handsome container in order
to deceive the public. The variable condenser, for example,
is the identical model used in our most expensive sets, and
is probably one of the most efficient low-loss,
straight-line wavelength condensers procurable.
that a more open scale reading is obtained on low
wavelengths than is used on an ordinary condenser. This
condenser has an extremely low minimum. It is mounted with a
metal shield which eliminates all possibility of
hand-capacity effects. The condenser dial is provided with a
neat and simple means of obtaining a vernier adjustment.
The two valve receiver and Junior horn
loudspeaker, from the Symphony catalogue. Courtesy of John
|We have gone to some length in describing this
condenser, as the condenser is probably the most important
component and one of the factors which make short-wave
reception possible on this receiver.
The A.J.S. accumulator carrying case.
||Two plug-in coils, which cover the whole broadcast range
(except the high power), are supplied; other coils can be
purchased separately. One of these coils acts as the aerial
coil, the other as a reaction coil. Owing to a unique
feature in the design of the circuit, reaction is not
fierce, but is very smooth and even; this, and the fact that
the moveable coil is operated through a smooth-acting
vernier movement equivalent to a gear ratio of 40:1, ensures
ease of manipulation and perfect control. The circuit is
choke coupled, as we firmly believe that this is the most
practicable method of procuring distortionless amplification
of speech and music over the whole range of the audible
scale. A further advantage of choke coupling is that it
tends to minimise many forms of low frequency disturbance.
Dull emitter valves are supplied with this set. They are of
the A.J.S. Mullard type. When used with the accumulator
supplied they should enable the set to be run for 100 hours
before the accumulator requires recharging.
|Plug-in resistors are fitted in front of each valve, and
should the purchaser at any time desire to use other valves,
theses resistors may be changed. The accumulator is supplied
in a compact case, complete with close fitting lid and
carrying handle. It will be to your advantage to read the
instruction label attached to the accumulator when it comes
to you. An A.J.S. Junior loudspeaker is supplied with the
set. This is not a baby model, but stands 19 inches high,
and produces full, round tones.
This receiver is supplied by itself, or as a complete
receiving installation. By a complete installation we mean
that not a single extra component or accessory need be
purchased. A length of wire will be required to connect the
aerial to the receiver and the receiver to earth. This is
not included, as the length varies in nearly every case."
Specification of complete 2 valve loudspeaker installation
Cabinet receiver, 2-valve, Type 'Z' as illustrated.
1 - A.J.S. Junior loudspeaker.
1 - accumulator, A.J.S. Lucas 'Milam', 2 Volt, 50 Amp.
2 - valves, A.J.S. Mullard 2 volt dull emitter.
2 - 50 volt H.T. batteries.
1 - set of A.J.S. coils, 45 and 50, to cover 255 to 55 metres.
1 - set of connecting wire.
1 - coil (100 feet) of aerial wire, copper 7/22 gauge.
2 - shell insulators.
1 - 9" Lead-in tube.
Price of receiver only _ _ _ _ _ _
Price Complete _ _ _ _ _ _ _ _ _ _ £13.18s.6d.
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