EH Scott Radio Enthusiasts

The Fine Things are Always Hand Made

I thought this was a Masterpiece Speaker.  It has the 8 pin plug and it is wired like the Masterpiece schematic shows except for pin 7 which is connected to ground rather than to the 4th terminal point.  The schematic shows a field coil with 2 separate windings (4 wires).  My field coil measures 925 ohms with a tap at 532 ohms (3 wires).

Anyone know what I have here?

Thanks,

Joe

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I believe that is a Phantom speaker rewired for an octal plug.

Norman

Agree that is a new cable. My early Phantom (uses 6V6's) has an octal speaker socket, as does my Sixteen and Masterpiece..

Can't match the numbers on your speaker to any examples I have of the 12 inch flange mount Magnavox.

Scott used that style speaker for the Sixteen, Masterpiece and Phantom (interchangeable) - featured 2 separate field coils. On the coil bells of 2 of my of my Phantom/Masterpiece speaker- model is 302 and part # 645  171.

The Super 12 used same style speaker, but it had only one field coil but same output transform (also 6V6s) and a 5 pin plug and socket. Cant read the part number on the damaged Scott label.

I suggest a little detective work on your  speaker to assure it has 2 field coils (the B+ field is tapped) and that the cable is correctly wired. 

I think Norman may have it.  I think it is for the Phantom Deluxe but wired using an octal plug for some reason. This speaker definitely does NOT have the two separate Field Coil windings with 4 leads.  Mine is a 3 wire field coil with one roughly center-tapped winding.

Where might I find a 7 pin plug so I can make this fit a Phantom Deluxe?

The 20 tube AM  Phantom Deluxe without logging scale uses the 6V6 amp which has an octal speaker socket.

The 20 tube AM Phantom Deluxe WITH logging scale uses the 6L6 amp (as does the 28 tube FM Phantom) with 7 pin socket, (except the last of production using a 10 pin Jones socket).

So - which Phantom Deluxe amp do you have?

The 6V6 amp uses the 12 inch (or 15 inch) speaker with 2 field coils - one for the B+ circuit and the other is part of the negative circuit providing bias for the output tubes. However, is strange your speaker has both the red and black wire to the ground post terminal on the speaker terminal board. 

The 6L6 Phantom amp uses a speaker with a single 925 ohm field tapped at 515 ohm (same field coil as the the Philharmonic and Laureate standard speaker). The standard single Phantom speaker for the 6L6 amp has 38 ohms VC. The 4 unit optional high fidelity speaker system with tweeters still has the main speaker with the same tapped field 925 ohm field coil, but all 3 speaker are 8 ohm. plus the outboard crossover (per Riders info). 

If your speaker truly has only one tapped field coil, then the "Masterpiece" tag in incorrect because the Masterpiece needs the second field coil.  And neither  Masterterpiece field coil speaker measurers anywhere near 925 ohms.

The 7 pin plug is very tough to find ... and it has different spacing than a 7 pin tube base. Probably limited to finding a trashed Scott speaker with intact table with that plug.

I have the following Phantom tuner chasses:

1. AM Phantom Deluxe with red dial and no logging scale.  Has a 7 pin plug

2. AM Phantom Deluxe with black dial and logging scale.  Has a 7 pin plug

3. AM/FM Phantom Deluxe.  Has a Jones plug.

I have three amps that I think belong to these tuners:

1. 6L6 tubes with 7 pin set and speaker sockets

2. 6L6 tubes with 7 pin set and speaker sockets

3. 6L6 tubes with jones plug set and speaker sockets.  This one has a black power transformer.

The Jones plug variant is late production - appropriate for the late FM Phantom (or late AM Phantom)  with logging scale - so pair the Jones plug equipped items.

The other two amps with the 6L6 pair would have adjacent 6J5 drivers in the middle of the amp chassis. 

I believe the AM Phantom with logging scale would go with either of these other two 6L6 tube amps. 

As for the AM Phantom without the logging scale, the amp originally supplied used a pair of 6V6 output tubes and the pair 6J5  drivers were at the far end of the chassis opposite end of the power transformer. However I expect one of the 6L6 amps could be used with it - but explore both amp diagrams for any variations in set socket wiring just to be sure of compatablity. 

I believe all 3 of your amps used the standard 12 or 15 inch Scott speaker of 1940-41 having the single field coil of 925 ohms tapped at 525 ohms ...  or the optional 4 unit speaker system recommended for the FM Phantom (and FM Philharmonic).

Good luck finding the 7 pin plug for the speaker in question.   As a last resort, replace the amp's speaker socket with a 7 pin tube socket that fits some 7 pin plug (or tube base) you can locate. (Keep the socket you remove with the amp.). Even better, some sockets (as seen on some tube testers) have enlarged pin holes that fit both type 7 pin tubes and such a socket should  fit the proper 7 pin Scott speaker plug  as well when you find one.

Great info, thank you Dave.  I will soon be restoring all three of these and will be careful to make sure I follow your guidance when matching components up.

Joe

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