Emerson Model 25A Mantle Radio (1932)
The Emerson model 25A is a small
4-tube radio that was considered quite
an achievement in miniaturization back in
late 1932 when it was first offered for
sale. In no time at all it became a hugely
popular set, with some 46,000 models
sold within the first five months of it being
available. It established the viability of
sub-compacts in the marketplace and
spurred other manufacturers into making
miniatures of their own.
The model 25A weighed in at just 6lbs
and had a list price of $25, complete with
Cunningham tubes. A carrying case
could be purchased for $2.50 extra.
Initially borne out of the need to survive
during the Great Depression, turning out
inexpensive but stylish compacts was to
become an Emerson speciality. Other
makers were known to have scrutinized
the Emersons, looking for any ideas that
would help them lower their own costs.
The radio shown has its original knobs
and an accurate reproduction grille
cloth, from grillecloth.com. The cabinet
was made for Emerson by Ingraham
(patent #89,628 attributed to Ostilio
Ciccarelli), though I have never seen
one bearing the Ingraham sticker.
The chassis is a single band Tuned-
Radio-Frequency (TRF) type with tube
line-up 39 (RF amp), 36 (2nd detector/
af amp), 38 (af power output) and 37
(rectifier). The use of a type 37 triode
as rectifier is unconventional (plate and
grid wired together). However, the B+
current demanded by this set is modest
and within the capabilities of this tube in
its non-amplifying role.
The schematic can be viewed at
Unlike many of the models of the era,
fitted with resistive line cords, this one
employs a resistive element strapped to
the metal chassis to supply the correct
filament voltages. It can be seen along
the rear edge of the chassis (lower
part) in the photo to the right.
When found, this radio did play very
weakly. I restored it electrically by
re-stuffing all the paper capacitors
below the chassis as well as re-packing
the above-chassis capacitor pack.
With the exception of one out of
tolerance resistor, the remaining
components, including tubes, all turned
out to be good.
Variants of the basic model were soon
offered for sale. One such appeared in
January of 1933, just about a month
after the set was first introduced. It
featured a 7-pin "accessory" socket at
the rear (see www.radiophile.com) that
could be hard-wired in different ways to
provide several options for powering
the set. In announcing it Emerson
|"Radio manufacturers report good business with the midget sets because of their size and for the
reason that they operate on either alternating or direct current. These miniature outfits are designed
to supplement the console by use in the kitchen, the recreation room and for students in college as well
as any place a second set may serve a useful purpose.
Several of these models weigh as little as six pounds and can be carried in a specially designed handbag.
Characterising the demand as phenomenal, Emerson Radio reports having sold 46,000 of these radios in
the first five months after the outfits were introduced"
Emerson Universal Compact... a handful of radio that works anywhere. ...the world's biggest selling little radio.
You can read about the use of this
accessory socket on my Emerson 415
There also appear to be at least two
different original knob styles for the set.
Adapted Also for Use on--
|Warning to Imitators!
We will take drastic legal action
against anyone who dares to
imitate, copy and/or offer for
sale a radio set similar in
design and appearance to the
Emerson Universal Compact.
...from an Emerson trade ad seen in
Radio Retailing, Jan 1933.
..1933 newspaper extract.