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AE 34A3A with the carry handle

Started by wds, May 13, 2015, 06:58:17 PM

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unbeldi

#15
The difference between the L-250-A0  and the L-253-A0 is the type of ringing that the unit was configured for from the factory.

L-250-A0  is for  metallic ringing, bridged across tip and ring. This model was delivered with a 2-conductor mounting cord and just a single 1 µF capacitor that was shared for ringing and audio.

L-253-A0 was for divided ringing, using a ground connection as ringing return. This model was equipped with a 3-conductor mounting cord. In this mode of ringing the circuit required a separate ringing capacitor to prevent audio from shunting to ground.  This is the reason you found two condensers on that phone.

So, these numbers are in effect different ordering numbers for a type 34 Monophone.  These were stamped on the bottom of the phone as well as on the wiring diagram label often glued in the inside.  The first catalogs after the introduction of the model still listed these but by the end of the 30s the catalog numbers had changed to shorter codes.

wds

I always wondered why some of my 34's had 2 condensors, and some had 1.  I have had 4 AE 35's - two of them had two condensors, 2 of them had one.  The two I still have are marked L370 - one condensor.  The other two that I no longer have had two condensors, but had no markings on the phone bottom or on the inside.  Can I assume they would have been marked L373?
Dave

unbeldi

Quote from: wds on August 17, 2015, 10:58:35 AM
I always wondered why some of my 34's had 2 condensors, and some had 1.  I have had 4 AE 35's - two of them had two condensors, 2 of them had one.  The two I still have are marked L370 - one condensor.  The other two that I no longer have had two condensors, but had no markings on the phone bottom or on the inside.  Can I assume they would have been marked L373?

I don't know.  Probably not.

It would be nice to have more early catalogs (1935-1939).

When you look at the 1934 catalog, I think that is the first No. 4055 catalog, they list the following order numbers:

==Discrete induction coil sets==
L-220-AO  Metallic
L-221-AO  Ground

==Induction coil RECEIVER sets==
L-224-AO Metallic
L-225-AO Ground




unbeldi

#18
Automatic Electric designed this anti-sidetone circuit in a way that placed the third induction coil winding and its balancing network, in form of a non-inductive resistance inherent in the winding, across both the receiver AND the transmitter.  Therefore they had to place the DC-blocking capacitor in front of the balancing network, where it was shared with a ringer for metallic ringing.   But this wouldn't work for grounded ringing, and a second cap was needed.

Western Electric only placed the anti-sidetone winding across the receiver and the capacitor blocked DC from entering the receiver in the secondary coil path, and this always required two capacitors in the unit.

I would have to go and draw some more circuit studies to decide which way is more efficient in the balance between material cost and circuit performance, but I would think that WECo's is more consistent in terms of maintenance. But since AE changed the circuit for the AE40, I guess that answers the question.

unbeldi

#19
Quote from: wds on May 29, 2015, 08:49:29 AM
Here's one for sale on Ebay. 

AE34 with carry handle

This example that you quote, which (not-)sold on eBay recently, was manufactured as a L-250-B0 (as stamped on the bottom), which is the manual version of the model.  So someone added the dial later, it does look period-correct though.  The ringer  however is a later version; whoever restored this, probably swapped in this straight-line high-impedance type 45 ringer, to replace a frequency ringer; what a shame.

AE_Collector

And the proper ringer with the specially angled bracket for the AE34 likely went in the trash.

Terry


Jack Ryan

Quote from: AE_Collector on August 21, 2015, 12:17:04 AM
And the proper ringer with the specially angled bracket for the AE34 likely went in the trash.

The "easy-lift" version didn't have an angled bracket.

Jack

AE_Collector

#22
Oh...yeah...You must be right. See, I need one of these 34B 34A sets of my own. I have only seen pictures.

Terry