Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: ernie_jr on November 30, 2011, 04:16:57 pm
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ok, help me out.
I have a stancor a 8054 o/p tranny that measures 128 ohm on one side and 113 on the other side. In the ampeg clone I am building sound is very distorted and low on power, so I hook up another a 8054, it measures 152 and 148. It plays much cleaner and
louder than the first o/p. My guess is the first on has died even though it still measures ok.
Any thoughts?
Thanks,
Ernie
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It plays much cleaner and louder than the first o/p. My guess is the first on has died even though it still measures ok.
Any thoughts?
Thanks,
Ernie
Is "much cleaner and louder" what you expect the amp to sound like, or is there still some unwanted distortion & not quite as loud as it should be?
If the amp is performing as expected, then yes, I suspect the OT has a problem that cannot be measured with the DMM.
If it still lacks the expected clean & volume, then possibly there is another problem that switching the OT's in/out sort-of fixed....maybe there's some oscillation & you moved some wires around that made it a bit better(?)....just throwing out some ideas.
G
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Use the geofex "advanced" method for testing output trannys. Put 2 or so volts ac on the secondary and read each 1/2 of the primary. In my experience they should read very, very close i.e. mA close. I've had slightly damaged OT's that still work a little (low vol., bad sound) but they always read a little off on the primary.
Dead OT's read way off.