Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: RobBozic on September 08, 2018, 04:38:58 am
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Hi,
Ive got a 5E3 PT with 384-0-384 ac on the secondary. As Im in Australia we use 240V.
Now on the PT primary I ground the 0 and use the 240, what if I ground the 110 and still use the 240, would I get a secondary voltage of 274-0-274? (384 - 110)
Thanks
Rob
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You'll get about 700-0-700 until the primary winding burns open. Shouldn't take too long.
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...Now on the PT primary I ground the 0 ...
Yikes, no!
One end of the primary connects to the mains 'neutral', the other connects to mains 'live / hot', the latter via fuse and 'power' switch.
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Yes, I meant wiring the 0 to the Neutral :smiley:
Its for an existing amp which does work.
Rob
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What Sluckey said. You would be putting 240V into 240V-110V or 130V worth of primary winding.
First thing: it sucks BIG current because the over-voltage saturates the core and current gets to 10X to 1000X normal.
Next thing: the secondary *rises* to like 709-0-709. Opposite of what you are thinking. Far too much for any g-amp.
Third thing: room fills with smoke as the over-current primary catches fire. You have turned a working PT into a stinky paperweight. (In an extreme case the cellar fuse *may* blow first; actually you should have a proper chassis-fuse which may die faster than the PT.)
You also mess with the 6.3V winding (11.6V) but I don't think it will live long enough to matter.
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Noted, and Thanks for the reply.
Rob