S300 Rear Panel: Ground Binding Post?

There’s a ground binding post in the rear panel that the user manual made no mention of. Can someone tell me what it is for? Will it help with the hum/buzzing problem without having to use a “ground lifter?”

Which binding post is it that you’re asking about? That little guy, with the sideways line going to the pyramid looking picture is a ground. The big one, that looks equal size to the red one, not sure.

Can’t say for certain for the S300, but I have a dedicated ground post on my Pass X250.5 and it is intended for chassis to chassis grounding to deal with hum if necessary. In practice I use it with the speakon cables from my two REL subs for that purpose. Pass provides it knowing that because the amp is fully differential using the black speaker binding post as a ground point isn’t feasible and in fact attempting to use it as a ground reference would be … not good.

The “little guy” is what I’m interested in. Where do you ground it to?

That is indeed intended to be a chassis ground. If you don’t have a hum problem now you don’t need to use it. If you do it is there as an option to deal with hum. Keep it simple. No hum … no worries. If you do have a hum problem connect it to the chassis ground of the component you suspect is causing the ground loop.

Thanks for helping out a newbie, owlsalum! I do have a hum problem. It’s the high pitched 120Hz kind. I use a Marantz SR7012 as the pre-amp, which is causing the hum. SR7012 has a signal ground terminal on the rear panel. It’s for the turntable according the use manual. Can I use it to ground the S300? If not, where should the ground wire go on SR7012?

even if you think there is no Ground Issues, you might be extremely surprised with the results…do it anyway…really, costs a few minutes and pennies…nothing to lose, except the noise…

In hifi, I’ve usually seen those grounds are for the turntable to the amp or preamp. But it’s also true that a ground is a ground is a ground, so I’d get a little cheapo wire and ground the Marantz to the S300 and see if that helps.

Does the Marantz have a three prong plug connector for power (that would be a hot, neutral, and ground)? Does the S300 have three? Or do they have a two wire power plug?

Thanks for the reply, @dkerlee! I’ll get a grounding wire to try it out. Both SR7012 and S300 have the 3-prong plugs.

Hmmm well that should mean that they are both already electrically grounded. Those two ground wires are the same in the plug in the wall, so I don’t suspect using the ground nut will make a difference. But it wouldn’t hurt!

We are now including the grounding post with all of our Stellar amps. I’m very excited about this because it makes grounding REL subs to the stellar gear MUCH easier. This is pretty much the only purpose.


Excellent thinking.

Huge improvement over unscrewing the chassis screw and hoping it isn’t all painted over underneath!

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Thanks for the definitive answer. I guess I’ll try a ground lifter plug to solve the hum issue then.

How I wish I had a honest to goodness TT grounding post on my BHK Pre. Without having to hijack a back panel painted or anodized screw (darned tricky to tighten too with a nut on the inside).

Ok, ok, I’m out of minor, well extremely minor, gripe mode about a component that otherwise is the best of its class I’ve ever used in my system.

You should really consider adding grounding posts to all products, including PowerPlants. They really help.

My S300 does not have the grounding post. In very layman terms, how does one ground the amp without the post?


Your S300 is grounded. The post is there in case your subwoofer needs a chassis ground to hook up through the high level input.

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