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Vintage Radio
By Associate Professor Graham Parslow
The AWA Empire State: the definitive
icon of the Bakelite radio
The view at left shows the R28 radio with its original aged (and yellowed) celluloid window and dial face while at
right is the restored unit with reproduction dial parts.
The beauty of the AWA R28 radio has grown along with the
nostalgia for the period now called “Art Deco”. AWA Empire State
radios epitomise art from the “machine age” and have become the
must-have radios for collectors in Australia (and beyond). Just as
Penfold’s Grange Hermitage has become Australia’s iconic wine
and is now expensive, the Empire State is now a definitive icon
and is also expensive.
T
HE VINTAGE radios featured in
SILICON CHIP are usually discussed
in terms of the underlying technology
of their RF (radio frequency) and audio
sections. However, the Empire State’s
mystique owes little to its technology, although it was a state-of-the-art
superhet radio for its time.
Instead, its mystique derives from its
92 Silicon Chip
perception as a classic of design and in
this context it’s appropriate to diverge
a bit from simply listing the technical
details. What makes a classic? It is
almost always the intent of a designer
to unleash a classic on the world but it
is the fickle nature of public taste that
determines the outcome.
I can illustrate this through my
ownership of a 1965 Ford Mustang
fast-back that I bought back in 1975
when it was merely an old car. These
days, I can hardly stop at a petrol
station without someone coming up
to say what a beautiful car it is and
wanting to have a chat. It is a classic!
AWA produced a series of Bakelite
Empire State radios between 1934 and
siliconchip.com.au
These two photos show the view inside the author’s R28 as purchased (left) and after restoration (right). Someone had
replaced the mains cord at some time in the past but this non-original item was replaced with a cloth-covered mains cord
fitted with a Bakelite plug which is more in keeping with the era. A reproduction ARTS&P label (blue) was also fitted to
the restored receiver. The chassis is best removed from the cabinet by unscrewing the four rubber feet at the bottom rather
than undoing the two screws that attach it to the wooden base (doing the latter makes reassembly difficult).
1937 (Radiolettes R28, R29, R30, R31,
R32 & R37 and Radiola R48). AWA
were the biggest Australian manufacturer of radios in the 1930s and their
most profitable and best-selling lines
were console radios. These were large
floor-standing units for the lounge
room, which were marketed on the
attractiveness of their timber cabinets.
By contrast, there was a stigma at the
time about “plastic” items that were
perceived as cheap and inferior. Plastic
(from the Greek plastikos, meaning
mouldable) became the descriptor for
all man-made polymers, including
Bakelite.
Is the Empire State a truly Australian design? There is an urban myth,
found by a Google search, that the
shape is modelled on the Art Deco
profile of AWA’s Sydney headquarters
tower. This is easily refuted because
the building was not erected until
1939. Borrowing from US radio designs, with inspired adaptation, is a
more credible explanation.
The R28 radio was most likely styled
after the Air King Model 66 designed
by Harold Van Doren and John Gordon Rideout in New York, 1933. It is
now a classic for US collectors. For
Australia’s most iconic radio, there is
no accessible information about the
decisions made by management and
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The component layout under the chassis is rather crowded due to the fact that
the R28’s cabinet has just 240mm of usable width. Even so, the cabinet was
one of the largest moulded Bakelite cabinets at the time. A previous owner
had replaced the capacitors and the mains cord. The new cloth-covered mains
cord fitted by the author was correctly restrained using a cable clamp rather
than using a knot (as shown here) which is now illegal.
the composition of the design team
that led to the Empire State radio.
Bakelite
Bakelite is a thermosetting plastic
which is a condensation product of
phenol and formaldehyde. In 1907, it
was the world’s first synthetic plastic
and marked the introduction of the
‘polymer age’. Pure Bakelite resin is a
pleasant shade of amber.
Unfortunately, the pure product is
August 2014 93
This title will be a must for anyone
interested in Australian social history,
design and nostalgia. This handsome
production displays over 400 radios
in colour on 230 pages.”
If you are unable to locate a bookseller with stock, try emailing Peter
Sheridan at peter<at>petersheridan.com
You can also use Amazon to acquire
Peter’s latest book: “Deco Radio: The
Most Beautiful Radios Ever Made”.
Bakelite was cheap per unit in
volume production but it required a
high investment cost to set up moulds
and presses. By contrast, the costs
associated with set-up for modern
thermo-mouldable plastics, such as
PVC, are negligible relative to Bakelite
and production rates are much higher.
It’s no mystery why the production
of Bakelite radio cabinets ended in the
early 1950s.
Celluloid
This view shows the front of the chassis without the dial. Note the geared
drive mechanism for the dial pointer which rotates through almost a full
360°. The 5-inch (125mm) electrodynamic speaker still sounds good.
brittle and it was Leo Hendrick Baekeland (1863-1944) who empirically
modified the properties by strengthening the phenolic polymer with
fillers, initially with asbestos and in
subsequent commercial applications
A rare jade-coloured model features
on the cover of this book titled “Radio
Days: Australian Bakelite Radios”.
94 Silicon Chip
with cellulose (sawdust) or starch
from flour. Moulding Bakelite to useful shapes requires high temperature
and pressure. A pressure of 350 tons
was used for the moulds that made the
Empire State cases.
The R28 radio featured here is
the first of the series and was only
released in black. An alternative polymer (formaldehyde-urea, trade name
‘Radelec’) with added colourants was
subsequently used to create a remarkable range of finishes. You can see the
colourful results by making a Google
image search for “Empire State radio”.
An even better way to see the colour variants is to acquire the impressive coffee-table book “Radio Days:
Australian Bakelite Radios”, by Peter
Sheridan and Ritchie Singer. The
promotion for this book from Angus
and Robertson reads: “A unique and
beautiful publication charting the history of the Bakelite radio in Australia.
For the first time, a photographic
history from the ’30s, ’40s, and ’50s,
highlighting art deco design in radio
and the extraordinary range of colours.
The most plentiful natural polymer
in the world is cellulose, the structural
material of trees and other plants. Cellulose (as its nitrate derivative) was
the basis for an early polymer that was
transparent and mouldable, most notably as the base of photographic film.
The use of celluloid dates from 1870
but it’s basically a natural product
rather than a synthetic formulation.
Unfortunately, cellulose nitrate undergoes slow oxidation and changes
colour to yellow and becomes more
brittle with age (similar to the way its
parent polymer, cellulose, contributes
to changing wood colour and properties with age). The dial window used
for the Empire State radio is celluloid
and the example featured here was
appropriately aged.
The importance of originality can be
argued vociferously but for this radio
I purchased reproduction plastic versions of both the transparent window
and the celluloid station-calibrated
dial. The “as new” result is my preference in this case but the original celluloid dial parts have been put away
for safe keeping.
ARTS&P
The Empire State is a superhet design and sets of this type were only
just beginning to become widely
available at the time of its release. The
superhet design was desirable because
of its ability to discriminate between
stations with small frequency differences. This was becoming increasingly
siliconchip.com.au
Fig.1: the circuit of the AWA R28. It has a fairly conventional RF amplifier (6D6) stage followed by a 6A7 converter
and then a 6B7 IF amplifier/detector/AVC rectifier/audio amplifier. The latter then drives a type 42 pentode output
valve, while a type 80 provides full-wave rectification of the transformer secondary to produce the HT voltage. The
“D-L” switch across resistor R2 alters the gain of the 6D6 for distant and local reception and was necessary to avoid
overload on strong signals.
important as more and more stations
began crowding onto the airwaves
during the 1930s.
The superhet design goes back to
1918, when it was invented by Edwin
Armstrong as a means of obtaining
better amplification of RF (radio
frequency) signals. This was done
by converting the received signal frequency to a lower frequency (the IF
or intermediate frequency) that could
then be better amplified by the inefficient valves of the time.
Ongoing arguments about who
owned the patents and rights to royalties kept the superhet out of general
commercial production in Australia
until a compromise was eventually
reached. This involved manufacturers
paying a set royalty to a single agency
that would distribute the money. AWA
overcame these patent problems to
make superhets in the 1920s but these
did not perform to modern standards.
A label on the back of the Empire
State R28 lists the various patents
embodied in the radio and these date
from 1919-1932. Also affixed to the
siliconchip.com.au
back was an Australian Radio Technical Services and Patents (ARTS&P)
label that certified that royalties had
been paid.
Each label was uniquely identified
by a serial number and the first year
of issue was 1934, the year the R28
set featured here was made. Unfortunately, only some miniscule white
residue of the original label remained
when the radio was purchased. I now
know that 1934 ARTS&P labels were
white but the R28 was also sold during
1935 when the labels changed to blue.
The other R28s I initially looked at
all had blue ARTS&P labels and this
caused some confusion. After looking
at those labels, I made a reproduction
for this radio and unfortunately it is
erroneously blue and carries a ‘B’ prefix. A future project to create a white
ARTS&P with the correct ‘A’ prefix for
1934 is planned.
Circuit details
Fig.1 shows the circuit details of
the Empire State R28. As shown, it’s
a 5-valve set with three tuned circuits.
The album cover of this double record
set produced in 1982 by Telmak
(Balmain, NSW) lists artists and
recordings of the heyday of radio
from the 1930s to the 1950s. The dial
indicates that this is an R48 model but
it is fitted with non-genuine knobs.
The speaker grille fabric is also nongenuine.
The five valves are as follows: (1) a
6D6 (or type 78) RF amplifier, (2) a
6A7 mixer-oscillator producing an
IF of 175kHz, (3) a 6B7 IF amplifier/
August 2014 95
detector/AVC rectifier/audio amplifier,
(4) a type 42 output pentode and (5) a
type 80 HT rectifier.
The three tuned circuits are adjusted
by a triple-gang tuning capacitor, the
various sections being associated with
the aerial coil, the inter-stage RF transformer and the local oscillator. Note
that the 6B7 reflexes the output of the
detector diode back to the grid so that
the valve simultaneously amplifies
both IF and audio signals.
The power supply uses a conventional transformer. Its secondary output is full-wave rectified by the type
80 and the resulting HT line is then
filtered by C22, the loudspeaker field
coil and C23. The filtered HT voltage
is then fed to the plates of the valves.
The R48 uses asbestos to line one side of a metal can holding the two HT filter
electrolytics, to protect them from heat generated by the type 80 rectifier. This
asbestos was painted with high-temperature blue paint to stabilise it (see text).
The left photo shows the asbestos before painting, while the right photo shows
the asbestos after painting (rectifier valve removed).
The 6D6 RF valve, the 6A7 converter valve and the 6B7 IF amplifier/detector/
audio amplifier valve are all shielded by a divided metal screen at one end of
the chassis (the later R29 model is easily recognised because it has separate
shields around the individual valves). The two IF transformers are located
under the chassis, immediately below the converter and IF valves. The warning
label reads “This instrument has been designed for the use of Radiotrons. To
ensure consistent good results and to safeguard against possible damage use
only genuine Radiotrons of the correct type as replacements”.
96 Silicon Chip
Restoration
This unit was in quite good condition when received but there’s one
critical aspect to watch out for in this
set. A priority in dealing with an R28
(and other old radios) is to assess the
state of any asbestos, if present. Many
radios of the 1930s and 1940s incorporated small asbestos sheets to provide
heat shielding and these sheets were
generally attached to structures adjacent to the hottest valves (rectifier and
output pentode).
In the R48, the type 80 rectifier valve
dissipates about 8W of the 48W total
and asbestos lines the side of the can
housing the two HT filter electrolytics.
This asbestos was painted blue using
high-temperature paint (eg, from Stove
Bright or White Knight), to stabilise it
against shedding airborne spicules.
It’s essential to wear the correct
protective equipment when working
with asbestos. Miniscule amounts of
asbestos can cause deadly long-term
health problems if inhaled. Ordinary
dust masks are not effective and protection requires a filter respirator fitted
with a class P1 or P2 filter cartridge.
Any clothing must also be protected
from contamination and you should
not use compressed air to blow away
dust if asbestos is present. Guidelines
for dealing with asbestos are available
at http://www.health.gov.au/
In this case, the R48’s chassis was
cleaned with turpentine to remove the
dust and grime. Matching blue paint
was then applied to some areas of
corroded metal work. The grille fabric
was thin with some small holes, so a
dark brown backing fabric was added
behind the original material. This ensiliconchip.com.au
The yellow inset section here is the
original R28 dial from 1934 but more
stations had joined the airwaves by
1936 when the R29 was marketed.
The outer section is the reproduction
R29 dial installed on the R28 radio
featured here.
This view shows the author’s fully-restored 1934 AWA Radiolette R28 with its
reproduction R29 dial. Along with restoring the electronics, considerable effort
was also put into restoring the cabinet, so that it now looks almost like new.
Ernest Fisk was the General Manger of
Amalgamated Wireless of Australasia
at the time the R28 was made and was
a familiar public figure in the 1930s.
He made various royalty agreements
with both Marconi UK and RCA
America, the latter also giving him
the rights to use the badge names
“Radiola” and “Radiolette” (as used
on the front of the AWA R28).
hanced its appearance while showing
no evidence of the added fabric.
Unfortunately, heat from the diallight (a 6.3V 2W globe) had resulted
in a small burn mark on the celluloid
dial-scale. This, along with yellowing
of the dial-scale, led to the decision to
replace it with a reproduction.
Finally, considerable effort went
into carefully polishing the cabinet.
The result can be seen in the accompanying photo.
The price of an icon
At the time of its release in 1934,
siliconchip.com.au
the basic AWA Empire State Radiolette
R28 was considered an “entry-level”
set and sold for £15/15/– (ie, 15 pounds
and 15 shillings). This was subsequently increased to £16/16/– (or 16
guineas as it was then quaintly called)
for the R39 in 1936. A tradesman at
that time earned about £4 a week, so
even entry-level sets weren’t cheap
considering they cost around four
weeks’ wages.
These sets were advertised as the
“second set in the home for the kitchen
or sunporch.” And in keeping with this
theme, later models were promoted as
having “a sparkling array of beautifully
coloured cabinets which harmonise
perfectly with modern interiors”.
The basic black and brown units
have survived in reasonable numbers
but that does not make them cheap
today. The unit featured here was purchased on eBay for $1600 in January
2010. The highest price known to be
paid at auction is $16,800 in March
2010 for a jade-green example. A jadegreen example has also changed hands
privately for around $20,000.
These high values have sometimes
led to flagrant misrepresentations of
kindred radios (and reproductions) as
Empire State models. As ever, when
purchasing such sets, it is caveat emptor; let the buyer beware. The luckiest
acquisition I know of is by a fellow collector who found one at his local tip.
Despite the high prices paid for
some models, they’re far from being
the most valuable vintage radios on
the world stage. That honour goes
to a rare art-deco Sparton Nocturne
which fetched US$120,000 in Los
Angeles, USA.
So where do you display an Empire State radio? Easy – taking a cue
from the movie “The Castle”, it went
straight to the pool room.
Acknowledgement
Peter Sheridan and several members of the Historical Radio Society
of Australia (HTSA) provided helpful
information during the preparation of
SC
this article.
August 2014 97
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