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Hoffman Amps Forum image Author Topic: AC wiring inside the chassis  (Read 2564 times)

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Offline labb

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AC wiring inside the chassis
« on: September 16, 2024, 05:16:30 pm »
Most AC wiring run parallel and the heater wires run over head. What say ye. Will it be a hummer or not with this wiring

Offline shooter

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Re: AC wiring inside the chassis
« Reply #1 on: September 16, 2024, 05:23:51 pm »
if you run the output of "V1" parallel to them, ya, she'll hum
filaments are noisy wires, with "relative" high voltage, so treat them like a poisonous snake, keep sensitive things away, you'll have a quiet amp
Went Class C for efficiency

Offline Latole

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Re: AC wiring inside the chassis
« Reply #2 on: September 17, 2024, 03:49:15 am »
The heater operate on AC and 69 cycles, wich generates noise. If you twist them, the noise will be eliminated

Offline pdf64

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Re: AC wiring inside the chassis
« Reply #3 on: September 17, 2024, 10:31:29 am »
I think that if heater wiring is tucked in the corner, tweed style, then it's normal / most practical to do it first.
Whereas with up and over style 60s and onwards, it's normal / most practical for the heaters to be done last, once everything else is wired.
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Offline acheld

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Re: AC wiring inside the chassis
« Reply #4 on: September 17, 2024, 10:38:12 am »
I prefer the "tucked in the corner" style, but either will work fine.   

See: https://www.valvewizard.co.uk/heater.html about half way down the page.

My heater wires are twisted fairly tight using the "drill method." 
« Last Edit: September 17, 2024, 10:40:54 am by acheld »

Offline HotBluePlates

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Re: AC wiring inside the chassis
« Reply #5 on: September 18, 2024, 06:45:51 pm »
... if heater wiring is tucked in the corner, tweed style, then it's normal / most practical to do it first.
Whereas with up and over style 60s and onwards, it's normal / most practical for the heaters to be done last, once everything else is wired.

That is exactly how I wire heaters when building amps.

Offline shooter

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Re: AC wiring inside the chassis
« Reply #6 on: September 19, 2024, 04:59:31 am »
stole this from Steve.  I've wired them "railroad tracks" over the top, tucked in the corner, the key is sensitive signals in close proximity, heed that "rule of thumb" n there's seldom ever a "hum issue"
Went Class C for efficiency

Offline Brownie

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Re: AC wiring inside the chassis
« Reply #7 on: September 23, 2024, 02:43:19 pm »
If I do a "tweed build", I'll stick the heater wiring down into the floor and the corner of the chassis and then I'll "fly" the other leads to the other socket tabs. I'll do the opposite on the "black panel" type amps. On the Repurposed (hacked) Garnet, the heater wiring was just pressed to the floor and far away from each other leading to the miniature tubes

Offline labb

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Re: AC wiring inside the chassis
« Reply #8 on: September 23, 2024, 03:11:33 pm »
JFI: just finished the amp. It does not hum. Has some white noise when the two gain stages and the master volume are about max but I expected that. Thanks for the discussion. I tried to have this discussion on another board and was about called a heretic by the moderator. If you want to twist then twist. Probably the safest for most builders but you don’t have to. Last three amps I built were done this way. Next one I wai do like Steve’s. His looks a lot better than mine.

Offline HotBluePlates

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Re: AC wiring inside the chassis
« Reply #9 on: September 23, 2024, 07:47:48 pm »
... I tried to have this discussion on another board and was about called a heretic by the moderator. If you want to twist then twist. Probably the safest for most builders but you don’t have to. ...

For whatever reason, guitarists getting into electronics can be overly dogmatic.

I guess McIntosh is dumb for not-twisting their heaters. Tektronix must be dumb for not twisting their heaters.  It's not like those knuckle-heads know much about electronics anyway...

 


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