[Boatanchors] What Are the Differences Between Input, Interstage, Output IF Transformers?

[Al Klase]

Scott,

 From J.W. Miller Catalog 38:

Intermediate frequency transformers
require different degrees of coupling for
various circuit applications, and these
are coded as follows:

No.1 Input Stage - Has coupling adjusted
for maximum selectivity and
is for use between the mixer and the
first l.F. amplifier tube when two or
more stages are used.

No. 2 "Interstage - Designed to be used
as the interstage transformer' in a
two stage amplifier or as the input
stage for a single stage amplifier.
Coupling is adjusted to the optimum
degree. May also be used as the
output transformer in an amplifier
in which the second detector is a
non-current consuming load, such as
a bias detector of any type.

No.3 Diode Transformer - For use as
the output transformer to feed any
full-wave diode · detector circuit.
The secondary is center tapped 10
provide equal voltage to both dbde
plates. Adjusted to provide overcoupling
in order l'::> prevent excess
ive selectivity, which would result
in poor audio quality.

No. 4 Diode Transformer - This trans~
ormer is similar to the No. 3 type
except that no center tap is provided.
No.5 Beat Frequency Oscillator-An efficient
electron-coupled type beat
frequency osci"llator transformer for
CW use and for simplifying the logging
of DX stations.

No. "CF" Crystal Filter Transformers These
transformers are sold in pairs
for use in crystal filter circuits of
amateur and commercial receiveTs.
They replace the regular input transformer
and are of the low impedance
link coupled type.

RE:  Tweet Filter from 
https://www.sciencedirect.com/topics/engineering/passbands 
<https://www.sciencedirect.com/topics/engineering/passbands>

"Some receivers use audio filters rather than IF filters to help reduce 
the heterodyne squeal. In the AM broadcast band, channel spacing is 
typically 8 to 10 kHz (depending on the part of the world), and the 
transmitted audio bandwidth (hence the sidebands) are 5 kHz. Designers 
of AM BCB receivers usually insert an R-C low-pass filter with a −3 dB 
point just above 4 or 5 kHz right after the detector in order to 
suppress the audio heterodyne. This R-C filter is called a “tweet 
filter” in the slang of the electronic service/repair trade."

Regards,
Al

On 10/11/2021 2:26 PM, whitebear1122 at comcast.net wrote:
> Hi, What are the differences between input, output, and interstage IF
> transformers?  Then what the heck is a 455 KC Tweet Filter?  Thanks. 73
> Scott WA9WFA
>
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-- 
Al Klase - N3FRQ
Jersey City, NJ
http://www.skywaves.ar88.net