Phantom Power Supplies

[Kent King]

I discovered something today that I had never noticed before. Background - I am working on an FM Phantom which has the later Jones plug connector. I just made a crossover cable with a female Jones plug to a standard Scott round plug to test the tuner with a "standard" amp. I was double checking my new connector and saw the 6.3v filament line on the amp I was working with (my working  set in the Stratford cabinet), had the CT grounded. The Jones plug amp with the FM Phantom was grounded on one side, NOT via the CT. The Phantom Deluxe schematic shows one side of the filament to ground.

I happen to have 5 Phantom Deluxe amps here at the moment, so I spot checked. The Jones plug amp is end ground. Two of the round plug amps are center grounded. The other two round plug amps are end grounded, and the CT lead on the transformer has never been soldered.

This implies that Phantom Deluxe amps are not readily interchangeable between sets. Scott always seemed to make things fairly fool-proof, but this would be a difficult to spot issue. Has anyone else noticed this? How are your Phantom Deluxe amps wired?

Kent 

[Bill Liers]

Kent,

I had bought a Phantom FM set from a club member who "could never get it to work right". I discovered the CT ground. (round plugs) I lifted the ground on the PS and all was well. I realize from what you're saying that these pieces were mis-matched by a prior owner. It was a real head scratcher at the time. I no longer have the set for S/N.