EH Scott Radio Enthusiasts

The Fine Things are Always Hand Made

I am in the process of restoring a Phantom Deluxe remote control chassis. It uses the later, long amp. For testing, I pulled the 15 inch speaker out of my other Phantom Deluxe in the Stratford, and the set plays great. Power supply voltages, set B+ and bias are all where they should be.

Now: I have two other speakers with the 7 pin plug here, a 12 and a 15. They could be from a Philly or a Phantom. I check all the DC resistances for the field connections - they are identical to the one I tested with. The DC resistance of the output transformer is a bit higher (total DC resistance of the test speaker was about 165 ohms across the outside. These two speakers read about 220 ohms. When I use either of these speakers, the neg bias voltage goes much higher than the 27v - with the Variac at 90VAC, I'm already seeing -35v. And the B+ is low, doesn't come up like it does on the test speaker.

The only thing I can think is that the output transformers are for P-P parallel 6L6s as in the Philly, creating a different load/bias than the single P-P 6L6 Phantom. As I mentioned, the field windings read exactly the same. Both the 12 and 15 in speakers behave the same. And yes, the numbers on the output transformers are different...

Thoughts and suggestions are most welcome!

Kent

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OK...so I just patched everything together and tried to operate the 12 inch speaker with the toroidal filament transformer. Guess what...it worked well! Sound isn't great but the speaker is unmounted and was face down. Tone controls worked well. Since the ning site doesn't do videos, I uploaded a video into a new folder "Videos" in the Scott Info Archive. Go check it out. 

Now I need to figure out how to mount this and make it look decent. I may have to put it into a box type of thing like a crossover. Thanks to everyone for the hints, tips and idea. 

Kent

One advantage of the power handling capacity of the toroidal is suitablity for the standard 38 ohm speakers for the higher power 40 watt Philly and 30 watt Phantom Deluxe amps using 6L6's. (Also the 1941 Scott Laureate with two 6L6's in PP).

But what of the Scott offered optional high fidelity multi unit speaker system using an 8 ohm main speaker?  From above comments, would Phantom Deluxe and Philly need different output transformers on the crossover? Or would the closeness of higher transformer turns ratio make lesser percentage difference, thus making different output transformers unnecessary?  That is, are the outboard crossovers universal for both amps? 

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