The Zenith S-829 (S829) is one of three magnificent chrome-
front sets in the line of small-white "airplane" 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*, an organization that in 1933 had
done the industrial design for some of Grigsby-Grunow's
Majestic smart set" radios (based on the patent record).

The 800-series of small-white-dial sets bridges the gap bet-
ween the earlier window dial types and the soon-to-appear
models featuring big "black magnavision" dials. They repre-
sent a highly collectible segment of Zenith radios in their own
right, with many collectors striving to find examples of each

The S-829 is a revision to the model 829. When it appeared
in the "New Set Specifications" edition of Radio Retailing in
September of 1934 (pg. 42), the 829 was listed as providing
shortwave coverage to 12.0mcs and as using a type 37 tube
for its Local Oscillator (LO). However, the S-829 extended
coverage to ~16.0 mcs (printed on its dial scale) and switch-
ed to using a type 76 tube for LO. The IF was lowered too.
Just when the switch was made is however unclear.

The 829 was ostensibly upgraded to improve sales at a time
when the popularity of shortwave listening was at an all-time
high. So confident was Zenith in the ability of its all-wave sets
to provide reliable world-wide reception that beginning with
this and other 1935 models, they offered a money back gua-
rantee (see ads & ad extracts on this page). Interestingly, by
1937, Zenith had amended the terms of this guarantee so as
to apply only to sets installed by a Zenith dealer and outfitted
with a Zenith doublet antenna. They had introduced these
antenna attachments in 1934 and at first priced them separ-
ately from the radio, but in August 1937, after much public
confusion, they increased the price of all receivers having
three wave-bands or more to include the doublet.

Advertising for the model 829 reveals its introductory purch-
ase price in the East to have been $69.95, "complete to the
aerial". I've found no pricing for the S-829, though it's likely
that once introduced Zenith would have continued to refer to
it simply as the model 829 in their advertising. The 829 was
introduced in the summer of 1934.

Starting with the 1935 models, one of the big themes in Zen-
ith's promotional material was "triple filtering", a feature that
they claimed was embodied in their entire model line. Below
are some typical newspaper ads and extracts therefrom illus-
trating what they had to say about it. See my other 1935
model pages for yet more.

The copy in these ads appears to be no more than advert-
ising hyperbole and reveals precious little about the heart of
the invention". To be sure, Zenith used the term in connect-
ion 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's difficult to conceive of any single facet of the circuitry that
"triple filtering" might refer to. My guess is that it actually all-
udes to the three domains of filtering, RF, IF and AF, inher-
ent 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, despite their claims of triple filtering's exclusivity
to their particular offerings.

The S-829 is a 7-tube three-band superheterodyne covering
the standard broadcast band from 550-1500kcs, shortwave
band 1 from 1500-4600kcs and shortwave 2 from 5.8-16mcs
(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.

* Cones & Bryant, "Zenith Radio, The Early Years 1919-
1935", Schiffer Books, Atglen, PA, 1997, p 201.
Zenith S-829 Chrome-Front Tombstone Radio (1935)
...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.
"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."
Zenith "small white dial" series
Zenith S-829 Chrome-Front Tombstone Radio (1935)
Zenith S-829 Chrome-Front Tombstone Radio Rear View  (1935)
Dec 2nd 1934, West Virginia
Oct 1934
July 1934, Radio retailing, inside front cover
181/2" (H) * 15" (W) * 8" (D)