SCOTT NAPIER ALLWAVE 12

[Lance Hughes]

Good morning everyone,

           This is my first time posting so please forgive me if I mess something up. I have recently purchased the radio stated in the subject line above and please see the attached pictures. Single tuner, Serial M-99, single speaker, and AVC with the Wunderlich tube. Before powering up the radio on a dim bulb tester, I notice the 80 rectifier tube was in one of the 45s' socket and the 45 was in the 80 socket. I decided I better start checking underneath the power supply before applying power. I noticed filter caps have been changed out in the past and some soldering on wires in different locations. I pulled the tubes out in the power supply and began tracing wiring and taking resistance measurements. The biggest GOTCHA so far is what I understand to be the audio interstage transformer. Please correct me if this is not the correct terminology. My Fluke meter shows an open circuit on all connections. I have never seen a transformer open like this. Anyway, I need a replacement. Performing research by looking at the grid and plate characteristics of the 45 and 56 tubes. I believe this transformer from Antique Electronic Supply could possibly work.

 https://www.tubesandmore.com/products/transformer-audio-interstage-...

P-T156

Any advice will be greatly appreciated letting me know if this part would work or I'm totally out in left field. I'm in and out of the house today so it may take time for me to respond. 

Thanks!

[David C. Poland]

For most Scott cabinets, the Tauscher sound board if used was hidden behind the speaker cloth. But the Regent cabinet of 1940-41 did display the Tauscher sound board. And some custom installations might display the sound board instead of speaker cloth.

The Scott Tauscher sound board was introduced mid 1940 and available for 15, 12 and about 8 (or 9?) inch diameter speakers. Scott News, Vol 12 No #3 feature article. They do turn up retrofitted on earlier Scotts as was yours. 

The Tauscher sound board can be handy on the work bench to protect the speaker cone and improve the bass response a bit. I may harken to a violin in looks, but it is no violin-like sound enhancement despite the fancy curved cut outs.

[Lance Hughes]

Good morning David,

 

           Thank you for the great information. I believe my speaker baffle is two to three boards glued together. I'm away from home at this time but will return this weekend and will check. I will also attempt to slide the baffle back into the cabinet to see if there are any hints of where screw holes might have been, such as pin holes in the wood, etc.. Your description of the baffle sounds exactly what I have but again I will verify this information.  On the subject of the speaker, electronically I understand the difference. Was there ever a model number printed on these Jensen speakers or some type of identification? Also, you stated two field coils. From my schematic, I show a field coil, voice coil, and a antibucking coil. My voice call was open and I had it rewound.  Just guessing and not knowing what I'm talking about, I would assume that the only way to tell the difference between the Jenson speakers is to perform a resistance test on the impedance matching transformer, field, and antibucking coil. 

[David C. Poland]

I differentiate the AW-12 and AW-15 speakers by the basket casting. You have the AW-12 speaker.

And different 4 diget part numbers stamped on the pedestal.

Two field coils. One is in the B+ circuit. The other is in the negative Bias circuit for the output tubes.

The field coils are wound side by side on a common tubular form.

[Norman S Braithwaite]

Dave, there were three types of speakers employed in the AW-15.  One was physically identical to the AW-12 Deluxe speaker, another was a cast speaker with oval openings in the basket, and the third was s stamped frame version.  Visual differences cannot be relied upon for differentiating the AW-15 speaker from the AW-12 Deluxe speaker.

Norman

[Lance Hughes]

Thank you gentleman for the prompt replies. I will look for the 4 digit part numbers stamped on the pedestal. If I find these numbers, is there anyone who would be interested in these numbers in order to keep up with what speakers go with what radio?

[David C. Poland]

Norman - thanks. Good to know.

For the AW-15, I have seen only the casting with oval openings for the several I have had and the 4 in my possession now.

Presents an issue if we improve the AW-15 speaker info page in the 2nd edition of the Scott Collectors guide.

[Thomas Day]

Lance: Check the back side of the outer rim of the speaker.  There may be a series of numbers printed there. Jensen and other makers identified them with these numbers.  The first two are the makers code, I think Jensen is #52. The next set of numbers will be a date code. Last number of the year and week of production.  Any other numbers may indicate the model and type.  I found all this information when I needed to have several Jensen and Magnavox field coil speakers re-coned for several Leslie speaker cabinets I rebuilt.  There is a list of makers and their code numbers on the web. 

Thom

Lance Hughes said:

Good morning David,

 

           Thank you for the great information. I believe my speaker baffle is two to three boards glued together. I'm away from home at this time but will return this weekend and will check. I will also attempt to slide the baffle back into the cabinet to see if there are any hints of where screw holes might have been, such as pin holes in the wood, etc.. Your description of the baffle sounds exactly what I have but again I will verify this information.  On the subject of the speaker, electronically I understand the difference. Was there ever a model number printed on these Jensen speakers or some type of identification? Also, you stated two field coils. From my schematic, I show a field coil, voice coil, and a antibucking coil. My voice call was open and I had it rewound.  Just guessing and not knowing what I'm talking about, I would assume that the only way to tell the difference between the Jenson speakers is to perform a resistance test on the impedance matching transformer, field, and antibucking coil.