Five and seven knob Allwave 23 power supply differences?

[Robert Jackson]

Fellas,
I have a simple question for you. I have started scouting for a couple of power supplies for my Allwave 23's. I have one power supply in very poor shape, due to mouse damage, for a five knob and I have no power supply for a seven knob. Can anyone tell me if there is a difference in power supplies between the two models or are they interchangeable? I appreciate your assistance.
Regards,
Bob

[Norman S Braithwaite]

They should be interchangeable.  There were two versions of the AW-23 power amplifier but the changes were not related to the version of receiver chassis.

Norman 

[Robert Jackson]

Thank you Norman. By the way, both AM and FM are now working on the 800B we had discussed earlier and will be finishing the electronic updates to the power amp/supply shortly. Then on to updating the caps etc for the receiver chassis and figure out why the tweeter (high end) isn't working. There is bass and mid but missing most high end. I have also completely stripped and refinished the cabinetry. Stained it in Phyfe red mahogany and filled the the pores with a very dark paste wood filler. (Highly recommend W.D. Lockwood & Co. stain. It is excellent.) Gave it a rubbed lacquer finish. Very true to the original cabinet. I am extremely pleased with the results and will post photos after all is complete. Thank you again for your reply.

Bob

Norman S Braithwaite said:

They should be interchangeable.  There were two versions of the AW-23 power amplifier but the changes were not related to the version of receiver chassis.

Norman 

[David C. Poland]

[David C. Poland]

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BOB - good to meet you at Estes Auction today.

Re the 800B we discussion points: - the AC power is routed through the speaker plug and on to the receiver and then to the on/off relay. So you need the amp, receiver and speaker to power it up. The tweeter is switched "off" in AM and SW mode, so if it fails to operate in FM mode look for a bad connection. The later Jensen coax speaker is the same blue color but has a plastic bell cover and a power resistor inside in lieu of the field coil, and is backwards compatible to earlier production sets. There are a series of modification improvements after serial number 2000. In order for the radio to switch between AM and FM, the band and selectivity controls must be in specific positions.

[Robert Jackson]

David,

I was also happy to meet you yesterday. I thoroughly enjoyed being able to spend some time with you at the auction. It made my trip all the more worthwhile. I will look to use your insights as I continue progressing with the 800B. Now having the two extra 800B's from the the auction I will be able to assemble a fairly respectable looking radio. The auction AW23 is much better than what I have so I will use it as the primary and the old one for parts if needed. The AW23 power supply from yesterdays auction will be used on a seven knob tuner in my Stamford cabinet. One question, the Stamford came with the large speaker only. If I remove the tweeters from my Tasman and securely mount them to the side panels in the Stamford, would there be any more involved other than plugging them in? 

Take good care

Bob

[David C. Poland]

Bob,

The Stamford has a fairly small speaker grill and lacks room to mount the tweeters facing forward above the pedestal speaker.  Go to page 4 of one of the Owner Manuals for the Full Range High Fidelity model for an illustration of mounting the tweeters on the side grills. The owners manuals are available in the set folders on the Scott document site.   Note that Scott provided a mounting bracket for mounting on the side "tone truth" grill. The illustration suggests how to fashion your own bracket.   With side mounted tweeters, Scott suggests placing the cabinet in a corner of the room.

Note also the same illustration shows tweeter cable plug arrangement.  Read the instructions for speaker connection on page 4 and 5.   The tweeter pair was an option.   Tweeters plug into the left socket #1 (viewed from the back)  and the short cable plugs into the right #2 socket.    However, if no tweeter is used, then the short cable plugs into the left #1 socket.     The speaker has a big ceramic power resistor  in addition to the field coil. The field coils in the tweeters substitute for that big power resistor, hence the bit about rearranging the use of socket 1 and 2.

Speakers - the 12 inch Magnavox pedestal with 925 ohm field - 2 versions supplied:  

The early 5 knob version radio speaker  uses a 38 ohm Voice Coil. The Jensen tweeters Q4-7077A and Q4-7078A are intended for this speaker.

The later  7 knob radio version speaker has a 19 ohm VC. The Jensen tweeters Q4-8685A and Q4-8686A are intended for this speaker.  

The 12 inch pedestal speakers seem interchangeable as to early or late version radio.  But using the  correct tweeter set seems necessary for optimal tweeter performance. Both tweeters sets have the same field coil specs, but the voice coils match the respective pedestal speaker at 38 or 19 ohms.

There is a terminal board behind the removable panel low on the base of the speaker pedestal. Study the technical data and diagrams to see the difference between the two version speakers as to that terminal board.

-Dave

[Robert Jackson]

Dave,

Just read the owners manual on speaker installation for Full Range Fidelity sets. Fantastic stuff. Discovery of all the nuances of Scott radios is exciting and enjoyable. I read the whole manual. Thanks for the info.

Bob

David C. Poland said:

Bob,

The Stamford has a fairly small speaker grill and lacks room to mount the tweeters facing forward above the pedestal speaker.  Go to page 4 of one of the Owner Manuals for the Full Range High Fidelity model for an illustration of mounting the tweeters on the side grills. The owners manuals are available in the set folders on the Scott document site.   Note that Scott provided a mounting bracket for mounting on the side "tone truth" grill. The illustration suggests how to fashion your own bracket.   With side mounted tweeters, Scott suggests placing the cabinet in a corner of the room.

Note also the same illustration shows tweeter cable plug arrangement.  Read the instructions for speaker connection on page 4 and 5.   The tweeter pair was an option.   Tweeters plug into the left socket #1 (viewed from the back)  and the short cable plugs into the right #2 socket.    However, if no tweeter is used, then the short cable plugs into the left #1 socket.     The speaker has a big ceramic power resistor  in addition to the field coil. The field coils in the tweeters substitute for that big power resistor, hence the bit about rearranging the use of socket 1 and 2.

Speakers - the 12 inch Magnavox pedestal with 925 ohm field - 2 versions supplied:  

The early 5 knob version radio speaker  uses a 38 ohm Voice Coil. The Jensen tweeters Q4-7077A and Q4-7078A are intended for this speaker.

The later  7 knob radio version speaker has a 19 ohm VC. The Jensen tweeters Q4-8685A and Q4-8686A are intended for this speaker.  

The 12 inch pedestal speakers seem interchangeable as to early or late version radio.  But using the  correct tweeter set seems necessary for optimal tweeter performance. Both tweeters sets have the same field coil specs, but the voice coils match the respective pedestal speaker at 38 or 19 ohms.

There is a terminal board behind the removable panel low on the base of the speaker pedestal. Study the technical data and diagrams to see the difference between the two version speakers as to that terminal board.

-Dave

[David C. Poland]

Bob,

Note that there are 2 manuals, for the early 5 knob and for the later 7 knob. There are a few differences, so you may benefit by reading through the other.

And there is a 3rd owners manual (actually the first) occasionally seen, when Scott initially introduced the AW-23 naming it the IMPERIAL, before he learned another radio already used that name. Some folks still refer to this 23 tube model as the Imperial.

[Robert Jackson]

Thanks David. Even though I won't be getting to the AW23 until later this year, I am filing away as much reference material as I can now. As usual my strategy will evolve up until I begin so thanks for pointing me to any reference sources. Planning the restoration is almost as fun as doing it. 

David C. Poland said:

Bob,

Note that there are 2 manuals, for the early 5 knob and for the later 7 knob. There are a few differences, so you may benefit by reading through the other.

And there is a 3rd owners manual (actually the first) occasionally seen, when Scott initially introduced the AW-23 naming it the IMPERIAL, before he learned another radio already used that name. Some folks still refer to this 23 tube model as the Imperial.

[Jeff M]

Hi David,

Old thread and thought to chime in. Is there an easy way to visually tell the difference between the Magnavox 12" speaker for Q4-7077A and Q4-7078A versus the 12" speaker designed for the Q4-8685A and Q4-8686A?

Also you stated that the 12 speaker is interchangeable to the early or late version chassis but the speaker needs to be matched correctly to Q4 speaker pair? Does this mean that a later version magnavox 12 can be used with the Q4-8685A and Q4-8686A set on an early 5 knob imperial? 

Trying to make sure before getting too far into this project, thank you.

David C. Poland said:

Bob,

The Stamford has a fairly small speaker grill and lacks room to mount the tweeters facing forward above the pedestal speaker.  Go to page 4 of one of the Owner Manuals for the Full Range High Fidelity model for an illustration of mounting the tweeters on the side grills. The owners manuals are available in the set folders on the Scott document site.   Note that Scott provided a mounting bracket for mounting on the side "tone truth" grill. The illustration suggests how to fashion your own bracket.   With side mounted tweeters, Scott suggests placing the cabinet in a corner of the room.

Note also the same illustration shows tweeter cable plug arrangement.  Read the instructions for speaker connection on page 4 and 5.   The tweeter pair was an option.   Tweeters plug into the left socket #1 (viewed from the back)  and the short cable plugs into the right #2 socket.    However, if no tweeter is used, then the short cable plugs into the left #1 socket.     The speaker has a big ceramic power resistor  in addition to the field coil. The field coils in the tweeters substitute for that big power resistor, hence the bit about rearranging the use of socket 1 and 2.

Speakers - the 12 inch Magnavox pedestal with 925 ohm field - 2 versions supplied:  

The early 5 knob version radio speaker  uses a 38 ohm Voice Coil. The Jensen tweeters Q4-7077A and Q4-7078A are intended for this speaker.

The later  7 knob radio version speaker has a 19 ohm VC. The Jensen tweeters Q4-8685A and Q4-8686A are intended for this speaker.  

The 12 inch pedestal speakers seem interchangeable as to early or late version radio.  But using the  correct tweeter set seems necessary for optimal tweeter performance. Both tweeters sets have the same field coil specs, but the voice coils match the respective pedestal speaker at 38 or 19 ohms.

There is a terminal board behind the removable panel low on the base of the speaker pedestal. Study the technical data and diagrams to see the difference between the two version speakers as to that terminal board.

-Dave

[David C. Poland]

Scott changed the Voice coil ratings and the way an auxiliary speaker would be hooked up.

The early speaker has a terminal strip inside the little back cover. There is a wire protruding from a little hole and with a spade lug which you move from T1 to T2 when using a remote speaker. See Riders info for illustration on the page for hooking up an auxiliary speaker. The original speaker cone is black.

The later speaker original cone is gray. Behind the back cover over the terminal cover, there is no little wire with a spade lug. 

Early version 5 knob radio Magnavox speaker  - 38 ohm (30 ohm DC resistance).  

                      use tweeters Q 7077A  &  7078A  

Late version  7 knob radio Magnavox speaker  - 19 ohm. (15 ohm DC resistance)

                      use tweeters Q 8685A  & 8686A

Either main speaker can be used with either amp. Both sets of tweeters have the same field coils. But the correct tweeters should be paired  with the proper main speaker due to the output transformer design inside the speaker pedestal. You are dealing with a high powered amp and the difference on VC ratings would be important in obtaining good audio and presenting the proper load to those expensive 2A3 output tubes.