Western Electric 20AL to 584A Subset

[unbeldi]

You do have an authentic option to use your 51AL with an anti-sidetone subset.

In 1946, the New York Telephone company, for Manhattan, released a one-page addendum to the same BSP, that shows a 51AL connected to a 684A subset, despite only using a three-conductor mounting cord.
A 684A is equivalent to a 302 base, so that could be used also.

I once drew a circuit diagram (attached) for this method to make sense of the wiring.

I think this was also covered in another thread a few month ago.
Here is the link:  http://www.classicrotaryphones.com/forum/index.php?topic=8785.0

[Logan1]

Thanks very much,  You helped me a lot.  learned a lot.

[poplar1]

The NYT diagram has the following restriction: You can have only one telephone connected to the line--no extension phones and no extension ringers. Therefore, if you plan to have more than one phone, it should never be used, because the black condenser wire is permanently connected to the line. This modified subset was sometimes used with pay phones, where extensions were not needed.

The diagram in WR-C63.373, on the other hand, allows you to have other phones on the line. This is the diagram with a blue background shown in the linked topic.

You do have an authentic option to use your 51AL with an anti-sidetone subset.

In 1946, the New York Telephone company, for Manhattan, released a one-page addendum to the same BSP, that shows a 51AL connected to a 684A subset, despite only using a three-conductor mounting cord.
A 684A is equivalent to a 302 base, so that could be used also.

I once drew a circuit diagram (attached) for this method to make sense of the wiring.

I think this was also covered in another thread a few month ago.
Here is the link:  http://www.classicrotaryphones.com/forum/index.php?topic=8785.0

[BDM]

Great info! Logan1 I'm curious, is your 51AL still sporting the original solid-back transmitter (marked #323 or #337)?

[Logan1]

It has a 635A transmitter.  Thanks

[BDM]

Ahh ok. I was going to warn you that the sound quality from solid-back's is so-so with their narrow frequency response.

-Brian

[unbeldi]

The NYT diagram has the following restriction: You can have only one telephone connected to the line--no extension phones and no extension ringers.

The explanation for this is that the circuit presents a very low impedance path for low-frequency alternating ringing current through the telephone.  The three windings of the induction coil are all connected in series with the audio capacitor across the line, permanently. At DC (zero frequency) the coil resistances add up to only a little over 100 ohms, while the ringer's resistance is an order of magnitude or more larger. Therefore the set draws too much current while ringing to drive more than one telephone.

[poplar1]

Bell tap (when going off-hook or dialing on another phone) can sometimes be eliminated as follows:
(1) Try reversing the incoming line wires (on L1 and L2Y)
(2) Make sure that there is a visible gap (at least 1/16 inch) between the clapper and each gong when the ringer is at rest.

Also, did you verify all the wiring including the connections on the hookswitch? Often, someone has modified the wiring when attempting to hotwire the phone to work without a subset.

[Logan1]

Seems to be working ok now, I adjusted the spring screw and make sure there was 1/16 between clapper and bells. Thanks

[unbeldi]

Each circuit has its pros and cons.

The 1946 NYT addendum produces an anti-sidetone circuit, at the cost of line loading.

The 1942 wartime option that Poplar1 presented, only produces a sidetone service, at the benefit of not loading the line and not requiring an old hard-to-find original sidetone subset.  It was likely practiced because of the wartime shortage of telephones, so they revamped sidetone instruments, but had to install them with AST subsets, because they didn't have enough 584s anymore.

Your solution with the 584A subset is the correct solution for the early 1930s.
But, since your desk stand already has a newer F1 transmitter (date > or = 1934), it may have been used another way. However, just using an F1 in a 635 assembly certainly improved voice quality alone.  And in a way, it probably increased the sidetone problem too.
Any clues from the dates when it was converted?

[Logan1]

No clue It just says on it 6-45   635 A  M

[buddy]

I need a schematic to wire my W/E 20Al Candle stick phone to a 534 subset. There is a cut off piece of (2 strand) wire coming out of the phone & there should be a 3 wire coming out. Some one had tried to hot wire it with 2 wires which would have damaged the magnet.

[unbeldi]

A 534A is essentially identically to a 584A.  It is just a little different in shape.

Here is another topic that should help as well: http://www.classicrotaryphones.com/forum/index.php?topic=13894.0

[poplar1]

Green wire from GN in subset to green receiver.
Yellow wire from L2-Y in subset to transmitter.
Red wire from R in subset to hookswitch.

[buddy]

Thanks guys. You were a great help. Now all I need is a schematic for a 534A suset. HELP