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Grounding 101

cubby01

cubby01

aka Buck
Anyone got a min to answer a question about tube amp grounding?

Chassis is just an aluminum top plate. I'm going to use a 3 prong IEC plug socket for wall power. PT secondary HT has center tap. For 6.3 secondaries do not have CT and I will use artificial CT (couple of 100ohm resistors).

What should the IEC socket ground be connect to? Just the chassis? Or just to the secondary CT, or both?

Is there a best place to ground the 6.3 artifical center taps? (I have two pair of 6.3 secondaries, I'll use one for rectifier and one for the other tubes I think.)

The input jacks I have are not insulated. Should the jacks be isolated from the chassis?

Thx.
 
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On homebrew stuff I keep all the components isolated from the chassis metal and connect the ground lug from the wall socket to it. I take all the grounds from the amp components and stack them on one central ground lug (star grounding). Tom Bavis can explain commercial grounding very well, so hopefully he will chime in.
 
Thanks Jay, That answered my main question. I'll isolate the input jacks as well by mounting on a piece of G10 or something to keep everything floating.
 
You'll probably wind up going back and grounding the input jacks, I left mine float and wound up with a hum. I grounded them to the common ground and all was quiet.
 
Dave, right my plan was to still ground the input sleeves on the input jacks to the common ground for the circuit, ... but not to the chassis top plate which will only be connected to the IEC (C13/C14) socket ground, ie mains earth ground.

If I should be doing something different I'd like to hear it.
 
cubby01 said:
Dave, right my plan was to still ground the input sleeves on the input jacks to the common ground for the circuit, ... but not to the chassis top plate which will only be connected to the IEC (C13/C14) socket ground, ie mains earth ground.

If I should be doing something different I'd like to hear it.
Click to expand...

You got it right. The ground should only attach to the chassis metal, and everything else should be isolated from that, and run to a single tie point.:yes:
 
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