Grouding question ?

Mitch: Are you talking about simply running an external wire from your outlet to the Hydra? If that is the case, i see nothing wrong with doing that. Just make sure that it can pass a sizeable amount of current. Sean
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What you're describing to me sounds like you've taken two male plugs and connected a 16 gauge wire between the ground tabs with no other wiring between the hot & neutral tabs. You intend to plug this into the Hydra and into your wall outlet, hoping that it will act as a common ground for the entire system.

If that summary is correct, i would suggest doing the following. Unplug your Hydra from the wall and unplug your components from it. Take a multimeter and measure the resistance between the ground tab of the AC plug you'll be using and each individual ground tab on the other outlets. So long as they all measure very low in resistance, this should work fine. Personally, i would have used a heavier gauge wire as that ground will act as a default for all of the components simultaneously, not just one. Given that your ground wire to the outlet is probably 12 gauge at best ( unless you've rewired ), that is what i would use here.

While you've got the Hydra disconnected, measure the resistance from the ground tab to the chassis of the component. This should be as low as from ground to ground on the AC sockets of the Hydra. Then measure the resistance from the chassis to the neutral tab on a couple of the outlets on the Hydra. This should read very high if not infinity. The lower that it reads, the less efficient it will be at shielding the internal connections from incoming RFI. At the same time, the ability to reduce EMI from being radiated out of the chassis will have also been reduced. It would be relatively simple to correct this if you run into this situation, but it would require modifying / rewiring the internals of the Hydra.

Hope this helps to answer your question and gives you the info that you were looking for. Sean
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Mitch: To me, that is a very half-assed attempt at grounding a system. It is not only unsafe, it takes a lot of things for granted. Here are the reasons why i say what i do:

1) Using such an approach, all components are grounded through the chassis of the one chosen component. While one would think that this gets rid of the potential for a ground loop, all of the grounding taking place occurs via the negative conductors of the interconnects. Given the design of some interconnects, how much current do you think that they would pass before the circuit opened up? Once the circuit opened up in a safety situation, the only thing left to absorb the potential voltage & current would be you.

2) If the components are properly designed, the interconnects / RCA jacks are "floating" i.e. not physically connected to the chassis of the component. As such, you could ground the chassis of the preamp ( or any other device ) and still not have a real ground.

3) If the RCA jacks / interconnects aren't electrically tied to the chassis of a defective component, that component would still be "hot" due to the lack of connection to ground.

4) Due to the situation in #3, you could end up with some of the components grounded and some of them not. This now gives you a difference in ground potential, resulting in the potential for a higher noise floor and / or ground loop.

Your best bet is to run an external ground wire from the Hydra to the outlet. Since everything is plugged into the Hydra, you still end up with only one common path to ground and it is a true electrical ground, not that of a chassis which could be "floating". Just make sure that your AC grounding system is up to snuff. Sean
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Mitch: I'm not familiar with the internal design of any of Shunyata's Hydra's. You really do need to contact them and see what they recommend. My guess is that their surge protection claims become null and void when there isn't a ground wire connected. As such, they should be able to tell you how to connect a ground wire between the Hydra and the wall outlet.

Other than that, from what i can tell there should be nothing wrong with connecting the ground connection on the output of the Hydra to the ground connection at the wall outlet. As mentioned before, use two male plugs and simply connect JUST the ground tabs via heavy gauge wire, nothing to the hot or neutral. Ground "should be" ground, regardless of where it is at in the circuit.

Why the power cord that you want to use has no ground is beyond me. The fact that it will sacrifice all of the surge protection and possibly some of the passive filtering that the Hydra achieves would have me looking elsewhere. Sean
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