Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: dpm309 on April 01, 2015, 11:15:37 am
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I am replacing a PT on a B-52 AT100 and have a question on the primary hook ups. The original had a red and white wire and I am assuming the red is line and the white is neutral. The replacement (from B-52) has a blue and brown wire for the primaries. Does it make any difference which way these are connected? The primaries are connected directly to the power switch. I am guessing that it does not make any difference but want to make sure.
Thanks,
Dan
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Should not make any difference.
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Thanks Sluckey, that's what I thought.
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Finally finished installing the new PT and everything sounds good. I do have a question about the built-in thermal fuse that B52 uses for their PTs. The old PT showed shorted windings in the primary but I am wondering if it was the thermal fuse that caused this. Did some research and found that thermal fuses are also used in some high-end audio equipment PTs and while it is possible to replace the fuse in some cases, it is not worth the effort. What is the advantage of these thermal fuses since once they blow, the PT is virtually useless?
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> old PT showed shorted windings
> wondering if it was the thermal fuse
The fuse goes open, not short.
> What is the advantage of these thermal fuses since once they blow, the PT is virtually useless?
The idea is the fuse won't open until the PT is about to catch FIRE. Without the fuse, in another minute you could have had a hot stinking smokey mess in your hands, possibly setting the curtains or stage-sets on fire, panicking your customers, and in the end a useless transformer. The fuse just avoids the excitement. The problem happened before the fuse cut-out.
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Sounds to me like the big fire & smoke thing will just make the audience think it's just part of the show :icon_biggrin: