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Message |
    
Clark514
Member
Username: Clark514
Post Number: 54
Registered: 6-2003
| | Posted on Wednesday, April 27, 2005 - 8:29 am: | 
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I HAVE AQUIRED A SHELL OF A PHANTOM AMP AND I AM GOING TO RESTORE IT AS A KEEP ME BUSY PROJECT...PROBLEM IS THE 3 TRANSFORMERS ARE MISSING OUT OF IT.....DOES ANYONE HAVE AN IDEA WHAT TRANSFORMER THAT WE CAN GET NOW DAYS I CAN GET TO PUT IN IT.....ALL THE ELECTRONICS UNDER THE BOTTOM ARE STILL THERE AND I HAVE CHECKED EVERY PART SO FAR THE ONLY THING I SEE I NEED IS THE 3 TRANSFORMERS.....THANKS IN ADVANCE.....CLARK CEF122 |
2600
Advanced Member
Username: 2600
Post Number: 557
Registered: 7-2002
| | Posted on Friday, April 29, 2005 - 5:34 pm: |
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Uh Clark, if the eight 100 uf 350 Volt electrolytic filter capacitors are all still original, it doesn't matter that they check okay with the power turned off. Those parts are too old to trust if they are original. Once you install transformers, those filters will "remember" how old they are and begin to fail. That kind of part isn't supposed to last 20 years let alone 30-plus.
It's a good idea to put a resistor in parallel with each replacement filter, all the same value. Not only do they serve as bleeder resistors, but they keep the 900 Volts DC split evenly three ways. The factory left them off, but every legit "ham" amplifier you'll see has these "equalizing" resistors, one across each filter in a series string. The value is not critical. The higher the resistance, the less heat they will produce. A 470K resistor can be as small as 1 Watt and be okay. We use 220k 2 Watt. They just need to be all the SAME resistance value.
The one place I know to get the transformers is out of junk units. That transformer was a pretty reliable part, and didn't fail very often.
You won't find a stock "catalog" part off the shelf to replace it. I used to have a "Stancor" brand catalog number for that one.
The first D&A amplifiers used that stock catalog part. Once he started making enough of his amplifiers, they hired a contractor to make a copy of the 'catalog' part, buying them in bulk. Had to be cheaper that way.
The original Stancor part was discontinued over 20 years ago, so it won't be easy to find, even with the old discontinued catalog number.
The amplifiers, working with tubes are worth less than the tubes, removed and sold alone. Should make a junk "organ donor" not too expensive, once you track one down.
Best I can recall, the specs showed 12.6 Volts AC at 5 Amps, and 680 Volts AC center-tapped at one half Amp, more or less.
To have them made, custom would probably cost over $100 each.
73
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Crackerjack
Intermediate Member
Username: Crackerjack
Post Number: 391
Registered: 7-2004
| | Posted on Friday, April 29, 2005 - 7:18 pm: |
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11 tubes? I bet it hums when the power comes on. LOL |
Clark514
Member
Username: Clark514
Post Number: 55
Registered: 6-2003
| | Posted on Saturday, May 07, 2005 - 6:30 pm: |
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2600 you are right ...the 100uf 350volt caps are the only thing i have replaced in it....i do remember about the caps in tube equiptment......well i see i sr237 on ebay and it is being sold by someone i have bought from before so maybe i will have one after this week.....and you are right the tubes are worth more than the linear itself whole......and crackerjack i hope it doesnt humm once i get it together or all is lost LOL....... |
Pogo12
Junior Member
Username: Pogo12
Post Number: 19
Registered: 3-2005
| | Posted on Sunday, June 04, 2006 - 4:32 pm: |
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You could have them made by the peter dahl cpmpany but they would be expensive |
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