Newbie questions: 3 prong AC, grounding

[mturnerb]

All:

I'm starting a new build of a G*S*G. Has anyone used 3-prong AC cord? I'm thinking of using IEC C13 style connection. If so, how is the ground connection wired?

Also - is the PCB grounded in any way to chassis?

I noticed discussions of grounding/not grounding transformers - advice here?

Any general advice on grounding appreciated.

[Geek]

Grounded cords are easy to adapt to anything - you just have to seperate chassis and signal ground.

Ground wire to chassis and how I do the noise bleed is a 100R/2W Metal Oxide (or carbon comp) between signal ground and chassis.

There are other methods - another common one is a pair of 6A Si diodes "chasing each other" and bridged with a 100n cap between signal and chassis ground.

Another is a 100n cap in series with a 51 ohm resistor between the grounds.

The point is to make all exposed metal safe and grounded while isolating the signal ground a bit to avoid ground loops while still bleeding off noise.

Cheers!

[mturnerb]

Thanks - of course your reply is leading to some more questions:

1. Where do you tap the signal ground - from the inputs?
2. Looking at PCB, the standoffs appear to be isolated from chassis (no chases to other parts of circuit) - so where in the design is the PCB grounded to chassis, or is it?

I'm still gathering parts so some of my questions may be answered during assembly but input is much appreciated.

TB

[Geek]

Hi,

I don't have the PCB, so I'll just give you general practise:

- A "star" ground where all negative signal/power wires are taken from should be at the lowest impedance point of the circuit. This is usually where the transformer centre tap connects to the filter caps.

- Jump the power to chassis ground with your chosen method at this point.

Cheers!