ground loop on pot buss 18 watt

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tweedydum
Posts: 16
Joined: Mon Feb 02, 2009 2:45 pm

ground loop on pot buss 18 watt

Post by tweedydum »

hi,
just assembling an 18watt build. I have not insulated the pots, so they are in electrical connection with the chassis. Undaunted, I added a wire buss across the backs of all pots and will use this for pot leg groundings, and grounds for the board.

two questions - Is the pot physical connection to the chassis the only connection to ground this buss should have? Also, might I be getting into ground loop territory?

I had thought this was a standard way of grounding the circuit, but am now not so sure.

thanks,
Dave
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M Fowler
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Location: Walcott ND

Re: ground loop on pot buss 18 watt

Post by M Fowler »

Dave,

I have built amps using many different type of grounding schemes. The best I have found is using a star ground for each stage.

The noninsulated input jack is already grounded as long as there is no paint or powder coating there, bolted directed to bare chassis. With a cliff jack it is not grounded. With the cliff jacks I have run the buss wire along the pots to the jack ground.

On my 59 Bassman using a turretboard instead of the common eyelet board Fender used I ran my buss wire floating off the turret ground points and wired my pot grounding points to this floating buss wire which then terminates to ground on the chassis.

Not sure all this helps, but shows many ways to successfully ground amps.

Mark
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Bob-I
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Location: Hillsborough NJ

Re: ground loop on pot buss 18 watt

Post by Bob-I »

I've used that method many times with no issues. If you question the ground loop, meaning if you get unexplained hum, lift the buss wire off the pots and suspend it, grounding it only on the end by the input jack.
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Structo
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Location: Oregon

Re: ground loop on pot buss 18 watt

Post by Structo »

I like that scheme as well.

Ground the buss wire below the input jack and have the input ground there as well.
Tom

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tweedydum
Posts: 16
Joined: Mon Feb 02, 2009 2:45 pm

ok, thanks

Post by tweedydum »

ok, I will proceed.
thanks!
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