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Hoffman Amps Forum image Author Topic: 5f1  (Read 2221 times)

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Offline Medman

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5f1
« on: October 06, 2013, 02:17:47 am »
I am about to assembly my amp and she where you can ground one side of the heater circuit  from transformer and just run 1wire to tubes and I Have seen the heater wires run to pilot light and 100ohm resisters go to ground and run twister pair to tubes. Is one better than other to keep out hum. Thanks JP

Offline TIMBO

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Re: 5f1
« Reply #1 on: October 06, 2013, 02:35:07 am »
If your heaters do not have a centre tap then use two 100ohm resistors to ground and defiantly twist the heater wires together, I use two different coloured wires that way its easier to get the phasing right if there is more that two preamp tubes.  :icon_biggrin:

Just looked at the schem and the phasing is not a problem when there is only one preamp tube. this will give you an idea on the heater wiring   http://www.ceriatone.com/images/layoutPic/fenderLayout/Champ-Ultra-Layout.jpg  :icon_biggrin:
« Last Edit: October 06, 2013, 02:41:03 am by TIMBO »

Offline sluckey

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Re: 5f1
« Reply #2 on: October 06, 2013, 08:29:40 am »
Quote
I Have seen the heater wires run to pilot light and 100ohm resisters go to ground and run twister pair to tubes.
much better
A schematic, layout, and hi-rez pics are very useful for troubleshooting your amp. Don't wait to be asked. JUST DO IT!

Offline tubeswell

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Re: 5f1
« Reply #3 on: October 06, 2013, 10:32:02 am »
'nother vote for twisted pairs. Twisting AC pairs together helps cancel out EMF surrounding the wires, which eliminates a potential source of unwanted coupling and hum.
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