Western electric candlestick phone question

[Andy Cuffe]

Excuse the slightly off topic post, but I'm willing to bet there are
at least a few people here who might be able to answer my question
about a Western Electric model 51 candlestick phone I'm restoring.

It has a 323 transmitter with a bakelite cup. The sound it picks up
is about the right volume, but very tinny compared to even a 40's
carbon mic (not much high, or low end). Someone on the other end I
tested it with compared it to the sound of an acoustic phonograph.
Does this sound about right for this mic, or is there something wrong
with it?

If I can't make it sound any better, I'm considering replacing it with
a more modern carbon mic I could install in an empty transmitter shell
I have.
Andy Cuffe
***@psu.edu

[Hagstar]

Post by Andy Cuffe
It has a 323 transmitter with a bakelite cup. The sound it picks up
is about the right volume, but very tinny

The frequency response curve of the 323 features peaks at 1000 and 1600
hz, and lower ones at about 3200 and 3800. The 1000 hz peak is right in
the middle of the typical range for voice. But I have one of these solid
back transmitters here in a candlestick, and it does sound super tinny.
The carbon does settle- I assume you've tried tapping it. Note the small
hole in the mouthpiece, intended to prevent an infant from drawing
vacuum on the carbon and shorting them out across the line entirely, and
possibly starting a fire.

Please don't bother "debunking" this- you can't make this stuff up :)

John H.

References: "Old Time Telephones" by Ralph Meyer, "The History of the
Bell System"

[Bruce Mercer]

Since we're on the subject, what was the purpose of the
capacitor in the base of those candlestick phones? It
was a W.E. phone but I don't recall the model of it right
now. No dial, and the cap. was dated Oct. 1914.

Bruce

[Brian Hope]

The cap is a blocking cap. It prevented line current from flowing through
the ringer box which would give a false off-hook signal. Also prevents dc
from passing through the receiver which could weaken the permanent magnet.
An excellent resource for these old phones is "Old Time Telephones" by Ralph
Meyer. You should be able to get it at your library.

[Paul Dietenberger]

Post by Bruce Mercer
Since we're on the subject, what was the purpose of the
capacitor in the base of those candlestick phones? It
was a W.E. phone but I don't recall the model of it right
now. No dial, and the cap. was dated Oct. 1914.
Bruce

In the base? I've only ever seen caps in the bases of dial stick phones;
they used a #61 filter to eliminate contact arc RF interference while
dialing (apparently, if people had problems with interference on their
radios while dialing their phones, this filter could be installed to
eliminate it.). But that seems unlikely way back in 1914.

Usually the caps in a phone are found in the ringer box because they're too
big to fit in the base of a stick phone. One low-voltage paper unit about
1-2uF to block DC from the receiver, and a high-voltage .47-1uF paper to
block DC from the ringer. In newer phones like the 302 these two caps are
installed together in a single metal case about 5" X 1/2" X 1".

[Bruce Mercer]

Yes, the cap was in the base and there was no dial. The cap was rectangular.
The metal part of the phone looked like it had been nickel
plated under the black paint, where the paint had worn away. I no
longer have the phone but may be able to dig up a picture of it. I think
Brian may have had the answer. Seems like I remember dial phones
didn't appear until 1927 (?) when RF interference would have been a problem.


B.

Post by Paul Dietenberger
In the base? I've only ever seen caps in the bases of dial stick phones;
they used a #61 filter to eliminate contact arc RF interference while
dialing (apparently, if people had problems with interference on their
radios while dialing their phones, this filter could be installed to
eliminate it.). But that seems unlikely way back in 1914.
Usually the caps in a phone are found in the ringer box because they're too
big to fit in the base of a stick phone. One low-voltage paper unit about
1-2uF to block DC from the receiver, and a high-voltage .47-1uF paper to
block DC from the ringer. In newer phones like the 302 these two caps are
installed together in a single metal case about 5" X 1/2" X 1".

[Andy Cuffe]

Post by Hagstar
The frequency response curve of the 323 features peaks at 1000 and 1600
hz, and lower ones at about 3200 and 3800. The 1000 hz peak is right in
the middle of the typical range for voice. But I have one of these solid
back transmitters here in a candlestick, and it does sound super tinny.
The carbon does settle- I assume you've tried tapping it. Note the small
hole in the mouthpiece, intended to prevent an infant from drawing
vacuum on the carbon and shorting them out across the line entirely, and
possibly starting a fire.

Thanks for the interesting information. The frequency response of my
mic is similar to that. I've been able to improve the sound quality
noticeably by stuffing the transmitter case with sound absorbing
material and putting a couple of large blobs of RTV silicone on the
back of the diaphragm. This has helped damp some of the odd echoing
resonances.

It's almost usable as is it, but it would be nice if I could boost the
sensitivity of transmitter a little. I'm using an induction coil from
a WE 302 desk phone for testing. Would a newer induction coil help?
What about an electronic solution? My ringer box is missing the
induction coil anyway, so I wouldn't have a problem with installing a
much more modern ciruit if it would improve the sound quality. I'd
like to leave the original transmitter in if possible. I don't expect
the same sound quality as a modern phone, but I'd rather not have to
yell!

Andy Cuffe
***@psu.edu

[Paul Dietenberger]

Post by Andy Cuffe
It's almost usable as is it, but it would be nice if I could boost the
sensitivity of transmitter a little. I'm using an induction coil from
a WE 302 desk phone for testing. Would a newer induction coil help?
What about an electronic solution? My ringer box is missing the
induction coil anyway, so I wouldn't have a problem with installing a
much more modern ciruit if it would improve the sound quality. I'd
like to leave the original transmitter in if possible. I don't expect
the same sound quality as a modern phone, but I'd rather not have to
yell!

Well, a newer induction coil would actually make things worse rather than
better because they were designed to be used with more sensitive
transducers. The 101A coil out of a 302 is the right choice for this setup.

Starting around 1940, 20AL (nondial) and 51AL (dial) sticks were upgraded by
the phone company with a "bulldog" style transmitter and the 706 receiver.
These contained the F1 transmitter and HA1 receiver capsules respectively,
as created for the 302 phone in 1937 and offered *far* superior transmission
quality to all the older units. Such upgraded phones were called 120AL and
151AL respectively. I have a 151AL, dated 1940, which is as usable as any
new phone.

Also you just have to double-check your wiring to ensure you have it
correct. I presume you have the schematics; if not they can be found at
atcaonline.com.

Good luck
Regards, Paul

[Hagstar]

Post by Andy Cuffe
My ringer box is missing the
induction coil anyway, so I wouldn't have a problem with installing a
much more modern ciruit if it would improve the sound quality.

Sure, I'd pop in one of those little network cards made for the purpose-

http://www.phonecoinc.com

Or you could just adapt something from a junk phone, which might be more
fun :) The network from a junk Trimline phone might well fit. The
Trimline was a really important and much labored over design easily
taken for granted now. But the first baby step from clunky desk and wall
phones that made you come to them toward today's Phone-in-Pocket world
was- the Trimline.

John H.