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Power Transformer for Gibson GA-5T


 
2/12/2004 2:13 PM
Doug
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Power Transformer for Gibson GA-5T
I need a power supply for a Gibson GA-5T guitar amp with a 6X4 rectifer, two - 6BQ5 power tubes, a 6C4 and a 6EU7 preamp tubes. The original power transformer was a horizantal type power transformer and the schematic calls out a 255-0-255V power supply to provide 90 ma with no signal and 102 ma at 12-1/2 watts output. I like the Hammond tranformers and have used many but the closest I can get to the original is the 270DAX 75VA, sec. 260-0-260 @ DC ma 90, 6.3V @ 3.5A. Will this unit provide enough millamps to power the Gibson at close to full output? Can I do something to keep the peak demand down? Or are the Hammonds underrated enough that another 12 ma above the specified 90 ma won't matter too much? My line voltage at home runs 122-125V AC and I sure would like to keep from putting in a transformer with too high of a step-up and/or one that weights a lot more. You guys are great and I thank you for help.
 
4/4/2004 5:31 AM
AngelBoy
From what I recall, the Skylark runs the single EL-84 at a voltage over the max recommended by the tube manufacturer. EL-84s in general should not run hotter than 300 volts on their plate. Because of this I'd go lower than 255-0-255 rather than higher.  
 
 
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