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First Silvertone Superhets, 1931

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Forum » Manufacturer's / brands history » MANUFACTURERS and TRADE NAMES (present in the museum) » First Silvertone Superhets, 1931
           
Ernst Erb
Ernst Erb
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18.Aug.12 20:00

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The first Sears Silvertone Superheterodyne found in the season catalogs are the model Silvertone 1320C , a 8-tube radio phonograph console and the 7-tube cathedral Silvertone 1585 with five knobs: Sears catalog #163, Fall & Winter 1931/32 on page 219 - and on page 216 the 6-tube Silvertone console 1401 with two knobs, on page 218 as Gradfather clock masterpiece Silvertone 1391 or 1390. The Sears schematic page 204 show for the same chassis: 1390, 1400 (see 1401), 1402 (see 1403), 1404 (no 1405?), 1406, 1470 and 7009, but due to offers with and without tubes with different numbers, most probably 1401 and 1403 etc. are the same. Rider's 2-14 omits 1406, 1470 and 7009. Schematic page 213 shows the models 1430 and 1510 as 10-tube super with tuning meter.

The 1320C has four knobs, forming a triangle with the escutcheon! See general remarks about Silvertone models 1928 to 1936 in this link.

I found no Superhet in the #162 catalog for Spring & Summer 1931, but there are existing Superheterodynes, which must have reached the market before the one mentioned above, maybe only advertised in ads and/or radio catalogs.
The 1320C features already the forth "generation" of otherwise similar chassis. At least some models before were made by Colonial Radio Corp., Buffalo, NY.

The very first Silvertone superhets
The first Silvertone Superhet chassis is most probably represented with the schematic containing models Silvertone 1320, 1322, 1324, 1326 and (slightly different) model 1450. There was even necessary a revised schematic with an other mixer system, grid mixer instead of a cathode mixer (and some small other details). Both I call here below version "A" and we don't (yet) use separate model pages for this slight schematic differences but show both schematics. There is also the 6-tube superhet family starting with 1390 in this period, but I deal here with the family starting with 1320.

Very fast was made a new chassis with quite a different setting of tubes etc. I call this only here version "B", since some models have the same model designation but an other look for the knobs. In common they are 8 tube Superheterodynes with remote cut-off screen-grid RF amplifier and IF, parallel 2 x UX247 output.

"A" with 3 x 235: 3 knobs in v (triangle, top down) tuning in chassis.
Page 187 of the Sears schematic book 1928 to 1936 lists the following five models for the same schematic and parts etc.:
Silvertone model 1320, 1322, 1324, 1326 and 1450. I call it "A" and believe that it was the first series, which probably caused problems due to poor development of the placement of tubes and other parts and their wiring. This shows quite a bad placement on page 189 for the first 4 models. The model 1450 (page 190) differs mainly in the transformer and it has a filter condenser R6081. All can also have a 25 cycle transformer. Tuning condenser is underneath in the chassis.
"A" has the tubes 235 RF, 227 osc, 235 1st det, 235 IF, 224 2nd det etc., 2 x 247 and 280.
The original schematic (page 186) shows a cathode mixer, a revised schematic (page 188) a grid mixer plus small other differences.

 

Wiring picture scanned by member John Kusching.

Schematic also in Rider's # 2, pages 11, 12 (or 524-19 and 524-20) for the Sears 1320, 1322 and 1324
and Riders #2, pages 25, 26. 27, 28 (or 208F to 208I) for the Colonial model 47 and model 48.

The revised schematic for Colonial model 47 "revised" and model 48 "revised" can not be found in Rider's 2, 3 or 4, but turn up on volume 10 on the Colonial MIsc. Page 10-4 (bottom) as drawn Septbember 22, 1931/Dec. 18, 1931. But this is still for "A"!
The "B" version was made by Sentinel Radio (manufacturer 106).

 

Pictures by courtesy of guest radiomaniac1949, ARF forum. (for "A")
 

"B" with 2 x 235: 3 knobs in a straight line, tuning above chassis:
Probably in the same year we find some of them with a renewed chassis, we call "B".
The models with the same schematics etc. are Silvertone model 1320, 1324, 1326X, 1386, 1454, 1456, Radiogram console 1531 and 7004 (part list 106 on page 185). Tuning condenser is on top of the chassis.

"B" has the tubes 235 RF, 227 osc, 224 1st det, 235 IF, 224 2nd det etc., 2 x 247 and 280.
Schematic 109 (also B109) is made by Sentinel Radio (United Air Cleaner Corp.), not anymore by Colonial!

 

Photos by courtesy of member Gerry O'Hara, Canada. (for "B")

 

This article was edited 08.Sep.12 19:03 by Ernst Erb .

  
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