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Northern No. 1 Mahogany Brown

Started by wds, June 23, 2015, 06:37:20 PM

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unbeldi

#30
Quote from: Ktownphoneco on June 26, 2015, 06:14:52 PM
That is very interesting !   I'll send "rdelius" a personal message, and see if he can send me the original pictures he took, and if he still has the set, and imagine he would,  and see if he can take several more pictures of the receiver and transmitter assembly from several different angles.   I agree with your hypothesis.    If there's one, well, maybe that was it, but if there are two, then there are more.  That's just common sense and logic.   
Thanks for bringing this to my attention. 

Jeff Lamb

I believe most if not all of the trial sets in 36 used this receiver. I know I have seen more than one.

unbeldi

Coincidentally, Poplar1 has a another thread going right now about 302 field trial sets, there is also a link to another one of the receivers by rdelius:

http://www.classicrotaryphones.com/forum/index.php?topic=6775.msg77680#msg77680


wds

I completely forgot to mention something about the purchase of this phone.  It was listed for a starting price of $95.  I threw out a bid of $101.01 just for the fun of it thinking someone would end up with the phone for a much higher price.  One other bid was thrown out at the last second for - $101.01.  I had to do a double take to see if I have lost the phone to someone else because the color of the screen changed when the auction ended.  I've won and lost phones by 1¢, or 5¢, but a tie for that odd an amount is a first for me.
Dave

DavePEI

Quote from: wds on June 30, 2015, 03:30:02 PM
I completely forgot to mention something about the purchase of this phone.  It was listed for a starting price of $95.  I threw out a bid of $101.01 just for the fun of it thinking someone would end up with the phone for a much higher price.  One other bid was thrown out at the last second for - $101.01.  I had to do a double take to see if I have lost the phone to someone else because the color of the screen changed when the auction ended.  I've won and lost phones by 1¢, or 5¢, but a tie for that odd an amount is a first for me.
Incredible!
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wds

#34
Another brown No. 1 passed through ebay last week.  It shows on the listing as black, but if you looked at the cracks and breaks, it's definitely brown.  There were many spots where the black paint had worn off and the brown really shows through, so I'm surprised at the lack of interest.  I watched the listing for several days and was the only person who bid on it.  The handset was perfect, and cleaned up real nice.  The inside of the phone is beautiful - too bad it's so badly damaged.  The handset now sits on my good brown phone. 

The base of the phone is different than all my other No. 1's.  It's flat, and the coil and condenser are different.  Would this have been an earlier model, or maybe a Signal Corps phone?

(I'm having trouble uploading pictures - more to follow)
Dave

wds

#35
New Handset on my other brown phone.
Dave

Ktownphoneco

Dave   .....    Nice find.     Is it an "NF" handset, or an "NU" ?     Are you referring to to the "innards" of the set you posted the pictures of ?      If so, that's one of the very early models.      They had a flat steel base, not aluminum.         See if you can find a date on the induction coil.    It should be on the left or right side (depending on which way your looking at it), and is probably 1935, 36 or 37.
A curator with a telecommunications museum in Montreal, told me a retired Northern Electric  engineer who volunteers at the museum, suspects an induction coil of that design, was installed for field testing.    His theory was based on the fact that the coil was held together with machine screws, which are subject loosening from vibrations created through the base by the ringer.     He said if the machine screws loosened, and the iron cores started to move, even a little, it could result in changes in the resistance of the coil's windings.     I'm no engineer, so I have no idea if that is accurate information or not.     I also suspect the coils were purchased directly from Western, but that's only a suspicion on my part.
The ringer is a Northern "NB1A" frequency ringer, probably dated in the late 1930's.    I have no idea what frequency it was wound for.   I would also have assume it was made for an independent telephone company for use in party line exchanges which used frequency ringing.     The cross strap is slightly different, in that there's no bulge with a hole for the clapper shaft to pass through, like the "B1A" ringer.
The condenser, should be a Northern "N3A".     The dial is British type, and one independent telco in particular here in Canada, purchased Uniphones from Northern, and were in the habit of using Siemens dials.     That was the Manitoba Telephone Service (MTS).     
As you say, too bad the case is damaged.     It's a good example of an original Uniphone.

Jeff Lamb

Doug Rose

Dave....is your set Mahogany Brown or Burled Walnut. Looks like Burled Walnut to me....Doug
Kidphone

wds

Sorry about that - it's Burled Walnut.  Brown is just easier to say.
Dave

wds

#39
Handset is NJ, coil is II 37, transmitter is 12/37.  The ringer seems to be straight line, and rings nice.  The bells have a nicer tone to them than the usual w.e. ringer.  The condenser seems to be riveted down, even though it has screws. 

I notice that NJ was not one of the options, so I will take another look and post a picture of the handset after while.
Dave

Ktownphoneco

If the handset has an HA1 receiver, it's an "NU".     Most likely one leg of the "U" has been rubbed off.       I'm not aware of any other "N" series handsets, other than the "NF" and "NU".   
The reason I stated that the ringer is a frequency ringer, is because the top of the clapper shaft has a striker typical of frequency ringers, and if you look directly between the coils, at the pivot point of the clapper assembly, you'll notice a flat metal spring, which is also typical of a frequency ringer.     Most, if not all telephone ringers in older telephones are wound to produce optimum performance at a specific frequency, so technically, all old phone ringers are really frequency ringers.
However, it is possible that it was designed and manufactured to operate at 20Hz, which is approximately the frequency of the ring signal on a private line.     There may have been an issue surrounding the manufacture of the ringer in the standard B1A configuration.        Uniphones went into general production in September of 1935, however to the best of my knowledge, Western didn't start general production of the B1A ringers until 1937, and I'm quite sure Western wouldn't have licensed Northern to make their own version of the B1A, prior to that date.
This is pure conjecture on my part, but it makes sense, that Northern required a ringer for their Uniphones in 1935, so they designed one with subtle differences to the B1A, in order not to violate their agreements and close relationship with Western.       The N1B1A has a number of different characteristics to the B1A.     The resistance of the B1A is around 4500 - 4600 ohms, while the NB1A ringer is approximately 6000 ohms.       The clapper assembly is as previously described, physically different.       The rear notch in the gong mounting frame of the NB1A, where the ringer cradle tab would normally clamp a B1A in place, on a 302 set, is only half the width of that on the frame of a B1A ringer.        On the NB1A, there's also no front protrusion on the ringer frame cross bar, through which the clapper shaft travels on a B1A ringer.

Unbeldi would know the answer to this, but it would be interesting to know the ring frequency that the NB1A ringer is wound, or tuned to.      But I'm not sure it can be achieved without specialized equipment such as an oscilloscope or similar piece of equipment.

Jeff Lamb


unbeldi

#41
The clapper of that ringer does seem odd, but I have seen at least two other types too.
This ringer seems to have the normal yoke of the time.  Why would a frequency ringer have a bias spring?
Just tapping?

I have also seen unbiased Northern B-type ringers which seem more appropriate for frequency-selective ringing.

The induction coil looks like a typical early Western Electric 101A as they were made from ca. 1932 (maybe 1931) to 1937.   See another example in my first picture (I-37).

The condenser looks just like a 194A,  1 µF ringing & 2 µF audio, as was used in 684-type subsets of the time.

The components look typical of ca. 1937 (pre-302) parts.


unbeldi

#42
Quote from: Ktownphoneco on August 25, 2015, 09:51:57 AM
If the handset has an HA1 receiver, it's an "NU".     Most likely one leg of the "U" has been rubbed off.       I'm not aware of any other "N" series handsets, other than the "NF" and "NU".   
The reason I stated that the ringer is a frequency ringer, is because the top of the clapper shaft has a striker typical of frequency ringers, and if you look directly between the coils, at the pivot point of the clapper assembly, you'll notice a flat metal spring, which is also typical of a frequency ringer.     Most, if not all telephone ringers in older telephones are wound to produce optimum performance at a specific frequency, so technically, all old phone ringers are really frequency ringers.
However, it is possible that it was designed and manufactured to operate at 20Hz, which is approximately the frequency of the ring signal on a private line.     There may have been an issue surrounding the manufacture of the ringer in the standard B1A configuration.        Uniphones went into general production in September of 1935, however to the best of my knowledge, Western didn't start general production of the B1A ringers until 1937, and I'm quite sure Western wouldn't have licensed Northern to make their own version of the B1A, prior to that date.
This is pure conjecture on my part, but it makes sense, that Northern required a ringer for their Uniphones in 1935, so they designed one with subtle differences to the B1A, in order not to violate their agreements and close relationship with Western.       The N1B1A has a number of different characteristics to the B1A.     The resistance of the B1A is around 4500 - 4600 ohms, while the NB1A ringer is approximately 6000 ohms.       The clapper assembly is as previously described, physically different.       The rear notch in the gong mounting frame of the NB1A, where the ringer cradle tab would normally clamp a B1A in place, on a 302 set, is only half the width of that on the frame of a B1A ringer.        On the NB1A, there's also no front protrusion on the ringer frame cross bar, through which the clapper shaft travels on a B1A ringer.

Unbeldi would know the answer to this, but it would be interesting to know the ring frequency that the NB1A ringer is wound, or tuned to.      But I'm not sure it can be achieved without specialized equipment such as an oscilloscope or similar piece of equipment.

Jeff Lamb

Well, I don't have an (early) NB1A, otherwise I would have included it in my measurements.  I did measure a 1951 sample of a NECo B1A without noticeable difference in my last update recently.

The frequency response of the B-type ringers is pretty wide, from at least 16 to over 40 Hz when running on 96VAC, and probably till 50 Hz when using a higher ringing voltage.  However, primary resonance is just above 20 Hz, as my graphs show. At higher frequencies, the efficiency drops off considerably as the impedance increases.

I don't know exactly when the B-type ringer was completed, but I do think it was before 1937. It had to be used in the trials of 1936.  In any case, Western Electric also had the A-type ringer, which looked pretty much identical to the B, since 1932 at least. It was used in all the development versions of the combined desk set.

I am unsure that I can agree with the statement that all old ringers were frequency ringer. Of course they responded to frequency, and better to some than others, but most commonly the frequency selectivity was originally achieved by mechanical means, not by electrical resonance.  I haven't found any of the early Western Electric harmonic ringers.  The frequency selective ringers I have plenty of are Kellogg, S-C, and some AE and their main feature is the stiff spring-type clapper instead of a yoke-type pivot clapper.

The straight-line ringers were actually optimized originally to below 20 Hz, because when a human cranks a magneto the resulting frequency is centered somewhere around 16 Hz or so.   IIRC, human muscle fibers have a maximum operating frequency of 25 Hz.

Measurement of the electrical response of a ringer is simply to measure the AC current through the ringer as a function of ringing frequency.  Electrical resonance is achieved at the point where the current is at a maximum; off-resonance operation has always lower current draw.

wds

#43
The handset is NU - my eye's don't work so well early in the morning!

Here's some pictures of the ringer - I see that metal piece now.

(I'm having the worst time getting pictures to upload.  It might take a while to get these pictures attached)
Dave

unbeldi

#44
Thanks.  I see now.  The yoke is clamped on a metal blade, rather than having a pivot axle.

The ringing frequency is a function of the thickness of that blade (stiffness) and the weight of the clapper hammer.

This would position the clapper in the middle of the gongs.   Still what is the bias spring for?
Clearly the clapper is not in the center.