How I got rid of SW amp hum

[wsd]

I have read postings regarding SW amp hum and thought I would post how I cleared mine up.

I recently added a CS10.2 (Great SUB - BTW) to my HT setup and noticed a hum with the sub on.

I used a cheater plug on the sub's amp and the hum went away (telling me I had a ground loop issue).

I verified it was not my COAX cable (unplugged at the wall - hum still present)

I disconnected all of the HDMI cables from the PRE/PRO and hum went away.

When I connected HDMI cables for either the STB (Verizon FIOS) and BR player, the hum returned.

I bought some 12 AWG wire and lugs at Home Depot and grounded the STB and BR player chassis's to the common ground post on my Belkin PF60 and all hum is gone.

[tjcarst]

Thanks for shaing that info. :applause:

[cburbs]

I was hoping with our recent move that my sub hum would go away and it didn't. I wonder if I may have the same issue.

It does seem to go away once I power on the Receiver.

[tesseract]

I bought some 12 AWG wire and lugs at Home Depot and grounded the STB and BR player chassis's to the common ground post on my Belkin PF60 and all hum is gone.

+1.

I've done this in the past and it works very well. I think this countermeasure works best because it addresses the root cause. Completely kills the hum dead, and costs around $2 or less. :applause:

I am not getting any hum with the Dayton amp, though. I am using a power strip plugged into a cheater plug to facilitate plugging in my 3 pronged gear into an old 2 prong 1950's house wiring. But the ground tab is screwed into the wall plate, so I think that everything is safely grounded.

[Travlinlght]

I've done essentially the same thing by connecting the subwoofer amp (in our case it would be the Dayton chassis) to the ground post on the receiver. It's worked the few times I've had a hum issue.

[Lurkerage]

Forgive this question if its stupid but what do you guys mean by ground post exactly? I have spare speaker wire and would love to eliminate the hum I am getting as well. I have 2 18.1's one downfiring with the amp and one plate amp, and the plate amp version seems to be getting more hum, but both have some humming happening. It must be one of the devices in my setup but would have to test them all independently to find the culprit.

If getting a cheater plug is in no way a potentially dangerous thing to do (for people around the equipment or the equipment itself) then that sounds like a better solution.

Let me know what you guys think.

[tesseract]

Forgive this question if its stupid but what do you guys mean by ground post exactly? I have spare speaker wire and would love to eliminate the hum I am getting as well. I have 2 18.1's one downfiring with the amp and one plate amp, and the plate amp version seems to be getting more hum, but both have some humming happening. It must be one of the devices in my setup but would have to test them all independently to find the culprit.

If getting a cheater plug is in no way a potentially dangerous thing to do (for people around the equipment or the equipment itself) then that sounds like a better solution.

Let me know what you guys think.

Turntables have a ground drain wire, this makes the ground potential the same for the TT and the preamp. On the back of some receivers and preamps, there is a ground post for TT's and antennas.

The chassis ground posts below are outlined in red. In the absence of a ground post you can simply use a chassis screw such as the one outlined in blue. Click the picture three times to enlarge.

[Fatcat]

Turntables have a ground drain wire, this makes the ground potential the same for the TT and the preamp. On the back of some receivers and preamps, there is a ground post for TT's and antennas.

The chassis ground posts below are outlined in red. In the absence of a ground post you can simply use a chassis screw such as the one outlined in blue. Click the picture three times to enlarge.

[ATTACH]2654[/ATTACH]

Yeah, I attached a wire (22 AWG) from a chassis screw of my old RDES unit (when I used it) to the ground screw terminal that was on my APC surge protector. The RDES unit would flip out whenever it would catch some static electricity from a finger touch. This little procedure cured it of that.

Best....Carlo.

[chashint]

+1.

I've done this in the past and it works very well. I think this countermeasure works best because it addresses the root cause. Completely kills the hum dead, and costs around $2 or less. :applause:

I am not getting any hum with the Dayton amp, though. I am using a power strip plugged into a cheater plug to facilitate plugging in my 3 pronged gear into an old 2 prong 1950's house wiring. But the ground tab is screwed into the wall plate, so I think that everything is safely grounded.

If you are really concerned about safety ground you need to take the outlet out of the wall and see if there are three wires there (probably won't be though) if there are three wires and the ground wire is attached to the outlet then you need to crack open your circuit breaker / fuse box and see if the ground wires are attached to the ground bus there. If the answers are still yes you need to check to see if the ground bus is attached to a copper rod that is driven into the ground (typically very close to where the electrical service enters the house).

[Lurkerage]

Thanks for the responses guys I will see if I can do this soon :)

[tesseract]

If you are really concerned about safety ground you need to take the outlet out of the wall and see if there are three wires there (probably won't be though) if there are three wires and the ground wire is attached to the outlet then you need to crack open your circuit breaker / fuse box and see if the ground wires are attached to the ground bus there. If the answers are still yes you need to check to see if the ground bus is attached to a copper rod that is driven into the ground (typically very close to where the electrical service enters the house).

I rent my house, so I would have to ask the landlord. I bet you are correct. He is a pretty cool guy, I wonder how he would feel about making my living room 20 amp? :biglaugh:

So how does a guy get a safe ground in the likely event that the tab isn't grounded? I think I will ask the landlord to consider upgrading my living room to three prong outlets.

[wsd]

A word of caution about changing to a 20 amp breaker - you can not just change the breaker at the panel you must make sure the circuit can support it.

According to NEC a 20 amp breaker requires 12AWG wire for the entire circuit.

[Kevin_Wadsworth]

A word of caution about changing to a 20 amp breaker - you can not just change the breaker at the panel you must make sure the circuit can support it.

According to NEC a 20 amp breaker requires 12AWG wire for the entire circuit.

Yes! Please don't just replace the breaker and/or outlet. You'd have to replace the 14-gauge wire in the walls, which is probably not worth the effort.

Thanks for the thread! I have a subwoofer hum in my daughter's bedrom and I hadn't thought if trying to ground the pre-pro chassis.

[cburbs]

OK so my hum sound in my sub goes away when I turn the receiver on. How do I figure out what items I need to ground to each other?

Off the top of my head I tried the receiver to the sub amp and that didn't fix it.

I also tested the following...hooked the sub out from receiver into subamp. Unplugged power from receiver and hum still exists.

[persisting1]

If you are really concerned about safety ground you need to take the outlet out of the wall and see if there are three wires there (probably won't be though) if there are three wires and the ground wire is attached to the outlet then you need to crack open your circuit breaker / fuse box and see if the ground wires are attached to the ground bus there. If the answers are still yes you need to check to see if the ground bus is attached to a copper rod that is driven into the ground (typically very close to where the electrical service enters the house).

Good point. This is something that has to be done.