The Zenith S-829 (S829) is one of three magnificent chrome-front sets in
the line of small-white-dial radios that Zenith offered for the 1935 model
year. The cabinets for all three were designed by the Chicago industrial
designers Rosenow and Company*.
The small-white-dial sets bridge the gap between the earlier window dial
types and the soon-to-appear models featuring big "black magnavision"
dials. They represent a highly collectible segment of Zenith radios in their
own right, with some collectors striving to find examples of each model.
The S-829 is a rare variant on the model 829, having extended shortwave
coverage. It was offered at a time when the popularity of shortwave
listening had reached an all-time high. So confident was Zenith in the
ability of its sets to provide reliable shortwave reception that beginning
with this and other 1935 models, they offered a money back guarantee:
Zenith Model S-829 Chrome-Front Tombstone Radio (1935)
Zenith... guaranteed to give you shortwave reception. Or your money refunded.
"Now for the first time you can buy a radio with perfect confidence. A
Zenith...guaranteed to give you shortwave reception! At the time of your
purchase you receive a Guarantee Bond from your dealer. If at the end of ten
days you have not received short wave programs direct from one or more of
the following: Europe, South America or the Orient every day...the money
you paid for your set will be refunded"
"Zenith is best fitted to offer you this unusual guarantee. Since 1923, when
Zenith shortwave equipment was used aboard the Schooner Bowdoin on the
MacMillen Expedition to the Arctic, the leadership of Zenith in shortwave
has definitely been established"
|Zenith Model 829 Triple Filtering
Seven Tube superheterodyne. Tunes American, foreign, police, amateur and aviation
broadcasts. 8" dynamic speaker. 18.5" high.
Advertising for the model 829 reveals its original purchase price to have
been between $69.95 and $76.95, complete to the aerial. I've found no
pricing for the S-829, though it was perhaps just a few dollars more.
The S-829 is a 7-tube three-band superheterodyne covering the standard
broadcast band from 550-1500kc, shortwave band 1 from 1500-4600kc
and shortwave 2 from 5.8-16mc (approximately). The tube line-up is 6D6
(RF amp), 6D6 (mixer), 76 (LO), 6D6 (IF amp), 75 (2nd detector/AVC/1st
AF), 42 (power amp) and 80 (rectifier). Automatic Volume Control (AVC) is
applied to the RF, mixer and IF tubes. The schematic can be found here.
Note that the circuit of the S-829 differs significantly from that of the 829 -
aside from expanded frequency coverage the IF is lower and the tube
complement is modified.
Starting with the 1935 models, Zenith promotional material made much
play about "triple filtering", embodied within their entire model line. Here's
some of what they had to say about it in their newspaper advertising:-
"Triple filtering is a new method of sifting out
imperfection in both short-wave and standard
reception - reception that makes Europe more real
than it has ever been before. Triple filtering works in
exactly the same manner as if you had looked through
an unfocused field-glass, then had the focus adjusted
until the figure stands out sharp and clear. That's
what Zenith has done in triple filtering - brought the
world famous personalities of Europe to listeners in
new clarity - in living breathing reality."
Copy such as this is no more than advertising hyperbole and reveals
precious little about the heart of the "invention". To be sure, Zenith used
the term in connection with numerous models over a period of several
years, ranging from basic entry level models all the way through to the
top-of-the-line 1000Z Stratosphere. These models had such a diversity
of circuit characteristics - including no, one or two RF stages and either single or dual IF amplifiers, that it is difficult to conceive of any single facet
of the circuitry that "triple filtering" might refer to. My guess is that it actually alludes to the three domains of filtering, RF, IF and AF, inherent in any
competently designed superhet. Each domain plays a key role in taking an off-air electromagnetic babble and progressively refining it to the point
where a single, desired station is intelligible to the listener. In this respect, the Zenith sets offered no more than any other superhets of the day.
* Cones & Bryant, "Zenith Radio, The Early Years 1919-1935", Schiffer Books, Atglen, PA, 1997, p 201.
Zenith "small white dial" series