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Author Topic: Help on JW Miller IF transformer types  (Read 235 times)

W1JTO

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Help on JW Miller IF transformer types
« on: November 13, 2021, 03:51:53 PM »

I have a radio under restoration (EM Sargent WAC-44) that has 4 JW Miller Iron core IF transformers ...

Stated IF is 456kc - but these transformers seem not for 455 - more like 525

XTAL (on or off) ->
CF-612-Q1 (input) ->
CF-612-Q2 (intrastage) ->
6K7G (IF1) ->
612-Q2 (intrastage) ->
6F7G (IF2) ->
612-Q3 (full wave) ->
6H6 (detector)

These Miller IF Transformers are 612-Q series (supposedly 500-550 kc), the 612-C series were the ones rated for 450-470 kc.

The CF-612 Q isn't cataloged.

A F-612 is, which has switchable selectivity, is but only in C series (455kc), NOT in a Q series (500kc)

Anyone know much about these ? Educated guesses even ???

I have almost zero documentation on this radio


73 John W1JTO
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W9GB

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Re: Help on JW Miller IF transformer types
« Reply #1 on: December 01, 2021, 02:06:26 PM »

J.W. Miller Company
Catalog #58 (36 pages)
https://worldradiohistory.com/Archive-Early-Radio-Assorted/CATALOGS/Miller-Coils-Catalog-58.pdf

Catalog #61 (177 pages)
http://www.tubebooks.org/file_downloads/Miller_No-61_.pdf

Page 26 : Iron Core Transformers
612-Q models are 525 kHz, 500-550 kHz Range
Schematic diagrams of cores (#83) found on Page 36

612-Q1 : Input
612-Q2 : Interstate
612-Q3 : Full-Wave* diagram #84
612-Q4 : Half-Wave
===
Radio Museum : E.M. Sargent WAC-44
Single conversion superhet with 2 stages of RF with individual front panel trimmers for the two RF stages and "first detector" (aka mixer) stage.
https://www.radiomuseum.org/r/sargent_wac_44.html

Antique Radio Forum
Restoration of WAC-44 Receiver by Rodger, WQ9E (Central Illinois)
https://www.antiqueradios.com/forums/viewtopic.php?f=5&t=401293

==
E.M. Sargent, an old shipboard radio operator, started the E. M. Sargent Co. in his home in 1924.

In 1926, he designed the Infradyne Circuit as a means to circumvent the Superheterodyne Patent (see forum).

His 1928 Amateur Radio license was W6SC.

A couple of early receivers, the "Long-Distance De Luxe" and the SW201 were produced in 1930/1931 by an affiliate company, the Radio Constructors Co.

Later Sargent built normal superhets, for instance model 11.MA and some others - most often commercial double conversion sets.

In 1934 the company moved to its definitive address, at 212 Ninth St., where they operated until the production of their last receiver in 1940.

In 1948 Sargent sold his stock to L.C. Rayment, who formed with his son the Sargent-Rayment Co., to produce hi-fi equipment.

E.M. Sargent died in 1948 at the age of 56.
« Last Edit: December 01, 2021, 02:23:43 PM by W9GB »
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W9GB

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Re: Help on JW Miller IF transformer types
« Reply #2 on: December 01, 2021, 02:32:50 PM »

Radio News, March 1941
WAC-44 receiver shown in Davega advertisement, 3rd page.
https://worldradiohistory.com/Archive-Radio-News/40s/Radio-News-1941-03-R.pdf
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