Case grounded or earthed

[akunec]

Im in the process of building my gainclone amp and I was wondering if i should connect the power ground to the case? I was hoping to connect the earth wire to the case, but my rca plugs are mounted on the case and are not insulated. Is it alright to connect the ground to the case?

Thanks
Alex

[pinkmouse]

You should always ground the case for the sake of safety.

If you have to improvise insulation for your existing phonos,or buy some new insulated ones, that is a small price to pay for your, or someone else's life.

[akunec]

So should i ground the case to earth (the bottom prong) or just to the power ground. If its to the power ground, then why would i need insolation on the rcas? The signal ground is connected to the power ground anyways.

Thanks
Alex

[wigginjs]

Shouldn't your earth ground and power ground be connected?

[scone]

Originally posted by akunec
So should i ground the case to earth (the bottom prong) or just to the power ground. If its to the power ground, then why would i need insolation on the rcas? The signal ground is connected to the power ground anyways.

The case should definitely be connected to the ground from your wall, this is for safety. The power ground will also be connected to this ground, but you can make that connection via a jumper wire to any point on the chassis you choose.

The audio input grounds should also be connected to power ground at some point, but I would not trust the connection you have right now between the uninsulated rca jack and the chassis. You may have contact issues with it later on if the rca jack shifts around in the hole you drilled for it (i am assuming the case is anodized or painted, so the only contact you have right now is where the rca jack touches the inside of the hole you drilled in the chassis.... correct me if i'm wrong.) I guess typically people get insulated rca jacks and run a wire from the ground connection jumper on the jack to the point where they wish to connect audio input ground to power ground. I'm not sure what the reasoning is for using insulated jacks, so perhaps someone could explain it to me? I used uninsulated jacks in my gainclone but I still ran a wire connecting the ground jumper on the input jack to the power ground. Technically I have audio in grounded to two slightly different points along the chassis... I have not heard any detrimental side effects of this.

[mpmarino]

Technically I have audio in grounded to two slightly different points along the chassis... I have not heard any detrimental side effects of this.

That would be a 'potential' ground loop, if I'm not mistaken...

Marc

[zBuff]

So why do some people believe in seperating grounding for power and grounding for signal? Can u use diodes to stop ground loops?

On the Brian GT kits there isn't a ground on the power rectifier boards is there? And assumedly if there isn't a ground on your transformer there is nothing to be connected either? I'm using torodials with dual secondaries. No ground connection.

[chrish]

I have the early version of Brian's boards, and it certainly does have a power ground on the rectifier board: PG+ for the positive rail and PG- for the negative rail. The torroid wires will be 25v, 0v, 0v, 25v (or whatever voltage transformer you have). The two power grounds then get tied on the amp circuit board.

[zBuff]

oh yes they do.

Stupid me

[scone]

That would be a 'potential' ground loop, if I'm not mistaken...

I think so yes. I believe it only becomes a problem when there are voltage differences between the ground points and you get stray currents in your chassis. Perhaps this has something to do with the 'quality' of earth ground? In any case, I didn't like the idea of running a bunch of wires into a star ground node because it would make the inside of my chassis even messier than it is...