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Connecting the ground to my enclosure? Answered

I'm building gmoon's Valvelitzer inside a utility box. I've just realized that the entire enclosure is going to be grounded, meaning it's going to be directly connected to the negative pole of the power supply, which seems to run at 14V 2.2A (It'll be regulated at 12v before it gets to the tube). Is this dangerous? If it isn't, should I just solder all the ground points to the enclosure? If I run the power along the enclosure, is that going to cause some extra capacitance? Is that bad?

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Re-design (author)2011-04-18

This should be built in a metal box to prevent noise from florescent lights etc. getting into the system.

In this circuit the ground IS the negative pole of the power supply and that should be connected to the case.

There should be no extra ground connection to earth ground.

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lemonie (author)2011-04-18


Grounded means connected to ground / earth / 0V, not directly connected to the negative pole of the power supply. If the negative pole of the power supply is grounded it's the same, but it needs an earth / ground connection. Electrical sockets usually have one.

L

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flagrantfouler (author)lemonie2011-04-18

Well, the supply is a wall wart, and it doesn't have a ground connection. Also I forgot to mention that the box is conductive. How could I create an earth ground, if I can't use the electrical socket's?

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lemonie (author)flagrantfouler2011-04-18

At 12-14V you'll be OK (andy') but in principle you could ground to cold-water pipework if you like.

L

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AndyGadget (author)lemonie2011-04-18

 
If the amp is earthed too, that's asking for hum loop problems.

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AndyGadget (author)2011-04-18

 
If you're running off a wall-wart you don't need to worry about connecting to a mains earth. The outputs of the wart are isolated with respect to mains, so all you need to do is to connect the box to the ground (0V) line of the supply, but do this at one point only to prevent possible earth loops.
The valvelitzer ground and the case will then be at the same potential as your amp ground when you connect the output lead.

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