Crossover for 1940-41 optional hi-fi system

[David C. Poland]

Need some input.

Anyone have the optional speaker system in working order for your Scott Philharmonic, Phantom Deluxe or Laureate?    

And did you service the crossover, replacing the pair of caps inside?

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The outboard crossover has the output transformer and sockets for woofer and tweeters.

Seem to be 5 crossover versions that plug into the Amp in place of the standard 38 ohm spkr.

The optional hi-fi speaker system uses an 8 ohm woofer and 16 ohm tweeters.

Overview - crossover type chronology from early 1940 to early 1942:

1st:  large crossover - with 2 K cycle  cut off. No small cable to receiver.

2nd  large crossover - with 6 K cycle cut off. No small cable to receiver.

3rd   large crossovers - with 6 K cycle cut off - and small cable to receiver.

4th  small crossover - with 6 K cycle cut off - no rectifier & small cable to receiver.

5th  small crossover  - with 6 K cycle cut off - rectifier tube for tweeter field coils & small cable to receiver. 

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I followed the Riders diagram (Vol 14 -pg 12) to change a type 3 to a type 2, removing the small cable because my early Phantom Deluxe receiver lacks the small socket that controls tweeter function of later receivers. I have double checked the wiring against the diagram and all components have proper continuity: field coil, output transformer, point to point wiring, woofer voice coil, tweeter voice coils. I replaced the 2.35 MFD caps inside. My early Phantom Deluxe plays fine with the standard 38 ohm speaker. But the optional speaker system fails to produce audio.

I just returned from Kent's. We compare my recapped crossover with another unrestored crossover he has. And tried both mine and his on another working Phantom Deluxe. Neither his crossover nor mine produced audio using the correct 8 ohm woofer.

Kent just finished restoration of an FM Phantom Deluxe. - a late production with Jones plugs. It plays fine on a standard speaker. His crossover is unaltered wiring but for replacement  of the 2.35 MFD caps inside. But his recapped type 5 crossover speaker system fails to produce any audio. 

So we are both perplexed with our respective multi unit hi-fi speaker systems at the moment.

Hence,  a request for comments from anyone with functioning optional multi unit speaker system.

[David C. Poland]

Scott and Karl - you answered one of my questions - that when the tweeters are switched off, the woofer switch increases the frequency range  for non-FM reception for later production - perhaps for 1941 production - for receivers equipped for crossovers equipped with the small cable to the receiver.

Now - to get back to my project Phantom Deluxe and the speaker system. And rethink the impact of converting back to a type 2 crossover.

[David C. Poland]

Success - working crossover. 4 solder joints needed to be re-flowed.

With the crossover opened up, and on low voltage with a dim bulb tester, measured voltages present and to assure the 5 pin woofer plug was correctly inserted and voltages in the right points. Then full power - but no audio although the magic eye registered reception. Rechecking voltages - sudden sound. More prodding.

Found several intermittent solder joints in the crossover. Re-flowed them. 

[Karl Sherwin]

Good to hear David, could this be the same problem with Kent's crossover?

[Kent King]

Well, I finally had time to work on my network and get it working. I wound up making a couple interesting widgets. The black box has a "standard" Scott set plug receptacle that converts it to a Jones plug male to go into a later amp. The cable laying beside it is the opposite - you can plug a Jones plug tuner into a "standard" Scott amp. So with this I was able to use one of my regular earlier Phantom Deluxe chassis and put it on the Jones plug/amp with the 4 speaker system. The amp has a slight hum I need to resolve but the speaker system sounds great and you can really hear the tweeters when they are "in" vs "out". Now to restore the FM Phantom tuner that is with the amp/speaker setup.