AW23 Speaker Question

[Joe Miller]

I am starting a patch job on a spare AW23 Speaker.  Before I start, I decided to wire check the FC, VC, and all the connections to the plugs.  It appears that the speaker wiring has not been modified but it doesn't match the schematic I have of the amp (35 watt amp).  The voice coil measures about 15 ohms (DC) which probably means it is the 19 ohm VC rather than the 38 ohm VC.

Are there variations in the wiring for the various AW23 Speakers?  And if so, which ones went with which version of the AW23?

Thanks,

Joe

[Thomas Day]

Joe: according to the schematic I have, for the 5 pin plug, pins 1 and 7 should be about 19 ohms, so 15 is good. Pins 3 and 4 should be 3700 ohms and pins 4 and 5 should be 1300 ohms. 
The 7 pin plug to the amp has the output transformer and field coil connections. 
What doesn’t match ? 

[Kent King]

What Thomas said tracks what I have seen. I have not identified a difference in the AW23 speaker connections for the tweeters. But I never say never with Scott sets...

Kent

[Joe Miller]

I will recheck everything later today and report back.  Thanks for your help, guys.

[Thomas Day]

Joe and Kent. There are wiring differences in the tweeter and bass speaker wiring, that were pointed out some time ago. I have the schematics for both, and here are the changes. Both are for the 5 pin plugs and sockets. 
First variation for socket 1: pin 1, gray wire to lug G of terminal strip with jumper to lug T2 to center tap  of voice coil side of output transformer. Also jumped to lug 1 of socket 2. White wire to pin 2 of socket 1 and jumped to pin 2 of socket 2 from top of secondary of output transformer and to T1, not used. This is for an extension speaker when jumper is removed and 2nd speaker is connected to T1 and G terminals. Pins 3, 4, and 5 of socket 1 connect tweeter field coils to amp chassis. For socket 2, only pins 1, 2 and 5 are used. 
Second variation for socket 1: pin 1 connected to center tap of output secondary and unused lug T2 of terminal strip. Pin 2 socket 1 jumped to pin 2 socket 2 and T1 of terminal strip and top of voice coil winding. Pins 3, 4 and 5 socket 1 same as above. Pin 5 socket 1 jumped to pin 5 socket 2, pins 1, 3 and 4 socket 2 not used. 

[Joe Miller]

Aha, Tom

I just checked mine again and the wiring matches my schematic except plug 2 and socket 2 pins 1 is used (rather than pin 2 as shown) for the ungrounded side of the voice coil.  Other than that mine matches just fine.  Would you mind sending both schematics that you have. I have another speaker that I want to check and having both schematics would be handy.  Now I need to find an audio output transformer (spec 1-D-216, 16682.)  Do you guys know where I might start my search?  Again, thanks for your help on this.

Joe

[Scott Seickel]

I have never heard of variations in the wiring, but there are 2 different AW23 speakers. 

I think the early ones had a voice coil impedance of 38 ohms, and the later ones were 19 ohms.  The proper output transformer takes care of the difference in VC impedance, so it is not an issue unless you are measuring the VC resistance. 

[David C. Poland]

The primary difference between the early 1935's 38 ohm speaker and the 1936-7 version is the later is wired as a 19 ohm speaker - as I recall.

See Riders Vol 14. - Scott page  27 and also the 1936 circuit diagram showing speaker wiring pg 18

.

The terminal board in the speaker pedestal  - are different for the two speaker versions.

The  respective Q tweeter sets are slightly different as well - have different model numbers.

[Joe Miller]

I wonder if the 38 ohm went with the 5 knob and the 19 went with the 7 knob version?  (or vice verse?)

[Thomas Day]

Joe Miller said:

Aha, Tom

I just checked mine again and the wiring matches my schematic except plug 2 and socket 2 pins 1 is used (rather than pin 2 as shown) for the ungrounded side of the voice coil.  Other than that mine matches just fine.  Would you mind sending both schematics that you have. I have another speaker that I want to check and having both schematics would be handy.  Now I need to find an audio output transformer (spec 1-D-216, 16682.)  Do you guys know where I might start my search?  Again, thanks for your help on this.

Joe

[Thomas Day]

Joe, attached are the diagrams I have. At least 1 is with the service data in the archive. 1 shows 19 ohm voice coil other shows 38 ohm coil.

Thomas Day said:

Joe Miller said:

Aha, Tom

I just checked mine again and the wiring matches my schematic except plug 2 and socket 2 pins 1 is used (rather than pin 2 as shown) for the ungrounded side of the voice coil.  Other than that mine matches just fine.  Would you mind sending both schematics that you have. I have another speaker that I want to check and having both schematics would be handy.  Now I need to find an audio output transformer (spec 1-D-216, 16682.)  Do you guys know where I might start my search?  Again, thanks for your help on this.

Joe

[Joe Miller]

Thank you sir.

Joe