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VINTAGE RADIO
By JOHN HILL
The awakening of the Dragon
From a collector's point of view, horn speakers
are valuable items & any receiver from the mid
1920s is only half complete unless it is matched
up with an old horn. While these ancient
loudspeakers all sound much the same, some
are far more desirable than others.
A large proportion of early radio
receivers used headphones as a sound
reproducer. Users of crystal sets and
1-valve and 2-valve receivers had no
other choice; these low powered sets
lacked sufficient output to drive a
loudspeaker. Radios having three or
more valves were a different matter these were capable of loudspeaker
performance.
Loudspeakers were mostly separate
items in the 1920s and the horn
speaker was by far the most common
type. Cone speakers came into vogue
during the latter part of the decade,
after which the old horns quickly fell
from favour. It was at about this stage
of home radio evolution that manufacturers started to tidy up domestic
radios by building them into complete self-contained units. Prior to this,
radio was a fairly untidy affair with
most sets consisting of several bits
and pieces.
Good points & bad points
The old horn speaker had both its
good and bad points - mostly bad!
These two derelict Amplion Dragons were combined into one unit. The water
damaged flare on the left had only two good segments & these were used to
replace two broken segments in the flare on the right.
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Perhaps its only good feature was
sensitivity, while its worst aspect was
a very narrow, peaky, frequency response which resulted in a harsh metallic sound. Horn speakers were also
very fragile and just accidentally
knocking one onto the floor could do
considerable damage. Dangling wires
often resulted in a speaker being
tipped over.
A horn speaker can be described as
a large headphone with a trumpet or
sound horn atta~hed. In the majority
of cases, the driver is constructed in
exactly the same manner as a headphone but with the added refinement
of a variable air gap between the pole
pieces and the diaphragm. This adjustment can increase or decrease the
sensitivity, depending on whether the
pole pieces are brought closer to the
diaphragm or moved further away.
On strong signals, it can be necessary
to move the pole pieces further away
to prevent the diaphragm from rattling against them.
Horn speakers came in a range of
sizes and varied from quite small units
to large floor standing models nearly
one metre high.
Size did not make a great deal of
difference to performance and, generally, one horn speaker sounds much
the same as another. If there were any
notable exceptions, then I have yet to
hear them.
It's also worth noting that not all
horn speakers look like horn speakers. In some instances, manufacturers
built horns into timber or metal cabinets. Never assume that an old speaker
box contains a cone speaker. A close
inspection may reveal that there is a
horn speaker inside the cabinet.
Amplion Dragon
One of the most sort-after horn
speakers is the Amp lion Dragon which
a few Dragons around without their
drivers and I know of one particular
collector who is willing to pay up to
$100 for an Amplion driver to fit his
junior Dragon.
My situation had been the direct
opposite. I have had a Dragon driver
for some years and had been looking
for suitable parts in order to build up
a complete speaker.
The bits and pieces I had been seeking finally materialised recently when
I was lucky enough to obtain two
wrecked junior Dragons without drivers. Unfortunately, both flares were
damaged and the only way a complete speaker could be built was to
combine the undamaged segments of
each flare into one unit.
Soft iron strips hold the flare together. The oak veneer segments slide into slots
in the iron strips & are crimped at each end. An end tab is then folded over for
good measure. The oak segments are extremely difficult to remove without
damaging them.
comes in two sizes: junior and senior.
Naturally, the senior is the larger of
the two.
The appealing aspect of these old
Dragons is their timber flares. Most
horn speaker flares are made of spun
aluminium which, when painted, has
nowhere near the same visual appeal
of the Amplion Dragon, with its segmented oak flare.
Better tone
Old advertisements claimed that the
wooden flare produced a better tone.
Once again, if there is a difference,
then my ears cannot detect it. As far
as I am concerned, Amplions with
oak flares were no better sounding
than any other horn speaker from that
era. However, they were considerably
more expensive than some makes and
no doubt there was a bit of "snob
appeal" attached to owning one because they looked very stylish indeed!
Regrettably, the Amplion Dragons,
with their wooden flares, have not
survived the shipwrecks of time very
well. Although there are still a few
good examples around, the majority
are in poor condition. Whether Dragons or otherwise, most horn speakers
are nearly 70 years old and are showing their age.
Damp storage usually results in the
Dragon's plywood flare separating and
going out of shape. The thin soft iron
strips that hold the oak segments together can also give trouble and severe rust problems are difficult to
solve. What's more, natural rubber was
also used in their construction and
this too can cause problems when it
deteriorates and goes out of shape.
Rebuilding the Dragon
It seemed a simple enough task in
theory - just dismantle the flares,
pretty up all the usable bits and reassemble the pieces. Unfortunately, it's
not that easy in practice!
The oak flare on a Dragon speaker
is not easily dismantled. Each wooden
segment is crimped into position at
The underside of the base was coated
with felt to protect valuable furniture
from scratches - especially receiver
cabinet tops.
Driver attachment
This Amplion Dragon driver had been
in the author's collection of "junk" for
many years. It was still in working
order &, judging by the nameplate,
has had little use. Often, the dragon
emblem is damaged, due to finger
wear as the sensitivity control is
rotated.
The driver on a Dragon speaker is
attached to the horn by a rubber bush.
It is not uncommon for the bush to
perish away to almost nothing, leaving the driver separate from the rest of
the speaker. It is for this reason that
complete speakers in working order
are comparatively rare. There are quite
Any "back from the grave" restoration
of this nature requires a visit to an
electroplater. Re-nickelling helps to
bring back that as-new appearance
and is often an essential part of the
restoration.
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1993
97
individual segments of the horn.
This was the case with my rebuild
and some of the lighter toned segments were touched up with oak wood
stain, making the overall appearance
of the flare a little more uniform.
I might add at this stage that working on the flare is a delicate operation
and one must be careful not to lift the
veneer at the .ends of the segments.
Old oak veneer is very brittle and
splintery and any loose ends need to
be glued down before working on the
flare. Each flare segment is made of
3-ply and this consists of two outside
layers of oak veneer, with another slither of timber in between. The overall thickness of the ply is only about
2.5mm.
A tedious task
The driver fits onto the end of the horn with nothing to hold it in place but the
friction of a rubber bush. As the rubber perishes, it loses its grip & the two
sections separate - one reason why so many Amplion Dragons now have no
driver attached.
.
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Stripping the flare back to bare
wood and metal proved to be a long
and laborious task. While some would
argue that the speaker's originality has
been ruined by doing this, one must
remember that I have combined parts
from three separate speakers in differing stages of disrepair. If the finished article is to have any appeal
whatsoever, then it must be refurbished so that it will look as though it
is a single unit.
Regrettably there are not enough
Amplion Dragons in good original
condition to go around and combining various bits and pieces was the
only way out of my dilemma.
Painting the metal strips that hold
the oak segments in place was also a
tedious job and calls for a steady hand.
The inside of the flare was particularly difficult to work on.
Semi-gloss finish
The electroplating included all nuts, bolts & washers. Attention to such details
enhance the overall appearance of the finished restoration.
the ends, which makes their removal
quite difficult. Great care is required
if the segments are to be removed
without damaging them.
Reassembling the flare also has its
problems because once the segments
have been removed they do not go
back tight enough to hold together.
They really need to be glued into place,
otherwise the reconstructed flare
keeps falling apart.
With my particular flare rebuild,
one flare had two segments replaced
with p1.eces from another flare. I would
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SILICON CHIP
have preferred to completely strip the
flare but I didn't want to risk damaging the various pieces and have to go
through all the reassembly hassles.
Matching the segments
One particular problem when combining the flare segments of two or
more speakers is that they may not
match visually as well as they did
originally. The oak veneer doesn't all
come from the same oak tree. As a
result, there can be significant tonal
and wood grain differences between
When restoring an antique such as
a horn speaker, a much better effect is
obtained with semi-gloss finishes.
Painting it up so that it is all bright
and shiny really does spoil the illusion. A dull lustre is far more appropriate for antiques and a horn speaker
is no exception to this rule.
The timber flare was not the only
part of the speaker that required attention. The pressed steel horn was in
need of painting and all the nickel
fittings such as the base and various
nuts and bolts were packed off to an
electroplater to be "re-nickelled".
These metallic items looked particularly shabby and really needed the
full treatment.
Eventually, all the bits and pieces
were reassembled and I was rewarded
with an excellent example of an Amplion Dragon in working order. It was
well worth the effort!
A true collector's item
'
.
The finished loudspeaker, circa 1926. Many hours of work went into restoring
the oak flare and painting the metal strips that hold it together. Although horn
speakers are terrible things to listen to, this one is a true collectors's item.
It was fortunate that the driver I
have had for so long was in working
order and only required a coat of paint
to tidy it up. Some Amplion drivers
are not easy to dismantle as there are
no convenient screw heads to undo.
They seem to be sealed units that
were not meant to be tampered with.
Listening to the old Amplion confirmed my previous remarks. It sounded no better or worse than most other
horn speakers. However, its looks and
general appearance are far more appealing to the eye than most and that
is what the old Dragon is all about. It
is a collector's item in the true sense
of the term!
An interesting aspect of collecting
horn speakers is that although they
are primitive by modern standards,
they were the pinnacle of technological development at the time they were
made. Every invention has to start
somewhere and from that point on it
is gradually modified and improved
until technical excellence is finally
obtained.
For example, consider how much
sound recording and reproduction
equipment has improved since the
early days of the Edison cylindrical
gramophone. Likewise, the loudspeaker has gone through many stages
of development during the past 70
years.
One does not have to listen to a
horn speaker for very long to fully
appreciate just how much time and
effort has gone into loudspeaker development since the 1920s - a time
when the Amplion Dragon reigned
supreme.
SC
TETIA/MITSUBISHI ELECTRIC AWA
TECHNICAL LECTURES
13th and 14th March 1993
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WMM,i ►iidW
Enjoy a weekend of informative technical lectures and exciting afterhours fun at the
luxurious WREST POINT Hotel/Casino. Subjects include VCRs, TVs, CDs, Fax,
microwaves & cellular telephones. Fares, accommodation, meals etc. are a legitimate
business deduction so why not take a tax free_Q~~ak aw8:_y from the routine?
Go on! Be a Devil!
- - , :::F= -- Contact Cliff Townsend, 27 Alma Road, Orford, Tasmania 7190
or phone him on (002) 57 1266.
FEBRUARY
1993
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