Previous Thread
Next Thread
Print Thread
Rate Thread
Page 1 of 5 1 2 3 4 5
Subwoofer and receiver both humming
#441532 03/05/21 08:57 PM
Joined: Sep 2020
Posts: 29
J
Jumbo Offline OP
hobbyist
OP Offline
hobbyist
J
Joined: Sep 2020
Posts: 29
I'm pretty sure my receiver has always had a hum but it seems like it got louder for a brief period and now it's back to being "quieter". Maybe three or four weeks ago my kids were watching antenna tv, after I put them to bed I went to turn the tv off and noticed the picture on the tv was frozen. I turned the receiver off and the picture started moving and the "loud" humming was first heard. It was at this point that I realized that my receiver was affecting my antenna signal. I turned the receiver back on and the picture froze again. I turned it off and the picture returned to normal.
Just moments ago, I had the signal meter up on the tv and turning the receiver on/off had no impact on the signal whereas a few weeks ago it made the signal drop significantly. The past week or so, it seems like the "loud" humming has stopped and it's back to "normal".

If my memory is correct, it was at this same time that I noticed my sub was humming as well. I don't recall it always humming, if it did it was a very low hum that I never noticed.

I did some googling in regards to the sub, I haven't searched regarding the receiver yet. I found several possible causes it could be and grounding comes up often. I just now attempted to ground the sub by putting a wire in the ground hole in my wall outlet and put the other end against the rca connector on the back of the sub. I also tried touching it against the screws on the back of the sub but they all appear to be wood screws so I don't expect them to ground anything. I would think the rca connector would provide a ground but maybe in wrong? Nothing I did worked, the hum was still there. If I unplug my sub cable while it's powered up the hum persists after it's unplugged. If I power the sub off then turn it back on with no cables connected there is no hum.

I'm a novice when it comes to this stuff so I would appreciate any guidance.

Anyone have any suggestions for me to get rid of the humming?

I have my receiver enclosed by baby gates and all of my cables are managed neatly so troubleshooting is going to be a major pain, so ideally I'm trying to get this corrected the first time so I don't have to get to the back of my receiver multiple times.

I honestly can't remember if my speaker and sub wires are in the same bundle as my power cables, and I can't tell without a lot of work to get back there. I am aware that is one of the things to check for and separate them if they are in fact together.

I have the speaker wire for my rears and the sub cable in the same cable management channel. My sub is plugged into a different outlet from the rest of my devices. Everything else is plugged into a "clean power" power bar.

I appreciate any and all suggestions, thanks in advance

Re: Subwoofer and receiver both humming
Jumbo #441533 03/05/21 09:26 PM
Joined: Jan 2007
Posts: 10,490
Likes: 116
M
shareholder in the making
Offline
shareholder in the making
M
Joined: Jan 2007
Posts: 10,490
Likes: 116
Jumbo, if you have an Axiom sub, did you try loosening the ground screw that is on the amp plate?


House of the Rising Sone
Out in the mid or far field
Dedicated mid-woofers are over-rated
Re: Subwoofer and receiver both humming
Jumbo #441534 03/05/21 10:17 PM
Joined: Sep 2020
Posts: 29
J
Jumbo Offline OP
hobbyist
OP Offline
hobbyist
J
Joined: Sep 2020
Posts: 29
[img]https://ibb.co/2PL3t2w[/img]

this is the back of my axiom sub. its an older sub so maybe it doesnt have a dedicated ground? i dont think any of those are a ground

Re: Subwoofer and receiver both humming
Jumbo #441535 03/05/21 10:31 PM
Joined: Jan 2007
Posts: 10,490
Likes: 116
M
shareholder in the making
Offline
shareholder in the making
M
Joined: Jan 2007
Posts: 10,490
Likes: 116
No ground screw on that old sub.

If you have cable connected up to the receiver, try disconnecting it.

BTW, not sure you are aware but you can trade that old sub in for a new one. I'd bet even the least expensive Axiom sub (EP125) is better than that one. I have two EP125s and like them very much. I also have four EP500s, two EP600s and an 800. I really like them all! smile


House of the Rising Sone
Out in the mid or far field
Dedicated mid-woofers are over-rated
Re: Subwoofer and receiver both humming
Jumbo #441536 03/05/21 10:47 PM
Joined: Sep 2020
Posts: 29
J
Jumbo Offline OP
hobbyist
OP Offline
hobbyist
J
Joined: Sep 2020
Posts: 29
I do not have cable (if you mean cable tv) hooked up to the receiver. The tv antenna that i mentioned in my original post is connected to the tv, not the receiver.
I have an old Xbox, a playstation 3, a DVD player and the tv hooked up to the receiver. And naturally, my speakers, an am and fm antenna are hooked up to the receiver. Off the top of my head that's everything that is plugged into it, and everything is connected via hdmi.

I was not aware of the trade up, thanks for pointing that out. I will look into it but it's not likely in the budget at the moment.

Re: Subwoofer and receiver both humming
Jumbo #441537 03/05/21 10:49 PM
Joined: Sep 2020
Posts: 29
J
Jumbo Offline OP
hobbyist
OP Offline
hobbyist
J
Joined: Sep 2020
Posts: 29
Am I correct in assuming the rca connector would provide a ground?
I have no issue opening it up and making a ground connection if necessary, but don't want to waste my time doing that if it's not going to make a difference

Re: Subwoofer and receiver both humming
Jumbo #441538 03/05/21 11:26 PM
Joined: Jan 2007
Posts: 10,490
Likes: 116
M
shareholder in the making
Offline
shareholder in the making
M
Joined: Jan 2007
Posts: 10,490
Likes: 116
I can't advise you to connect the safety ground from your AC receptacle to the RCA jack. I'd expect the RCA jack is not connected to safety ground internally but rather what is called "raised ground". Raised ground usually has a resistor or capacitors or MOVs or even all three connected to ground.

It's a pain, but you may want to try disconnecting everything from the receiver and then sequentially plugging everything back in while you listen for the hum.


House of the Rising Sone
Out in the mid or far field
Dedicated mid-woofers are over-rated
Re: Subwoofer and receiver both humming
Jumbo #441539 03/06/21 12:30 AM
Joined: Sep 2020
Posts: 29
J
Jumbo Offline OP
hobbyist
OP Offline
hobbyist
J
Joined: Sep 2020
Posts: 29
If it is a grounding issue I was going to put a proper ground inside the sub, I was just using the rca jack for testing purposes.

When I unplug the sub cable from the sub and its still humming, would that indicate the issue is the sub's ground?
I would expect that if it's humming, once I ground it the humming should stop. Is that a fair assumption?

I'm really trying to avoid disconnecting everything if I can

Re: Subwoofer and receiver both humming
Jumbo #441540 03/06/21 01:34 AM
Joined: Jan 2007
Posts: 10,490
Likes: 116
M
shareholder in the making
Offline
shareholder in the making
M
Joined: Jan 2007
Posts: 10,490
Likes: 116
Could be a leaky filter capacitor in the power supply. You could be more sure of that by cutting open a spare RCA cable, shorting the wires together and connecting the mess to the sub jack. That eliminates any possibility of airborne noise getting in via the sub's RCA jack. It is a high impedance input after all.


House of the Rising Sone
Out in the mid or far field
Dedicated mid-woofers are over-rated
Re: Subwoofer and receiver both humming
Jumbo #441541 03/06/21 02:10 AM
Joined: Mar 2002
Posts: 3,749
Likes: 37
connoisseur
Offline
connoisseur
Joined: Mar 2002
Posts: 3,749
Likes: 37
Are you using a shielded sub cable?


Enjoy the Music. Trust your ears. Laugh at Folks Who Claim to Know it All.
Page 1 of 5 1 2 3 4 5

Moderated by  alan, Amie, Andrew, axiomadmin, Brent, Debbie, Ian, Jc 

Link Copied to Clipboard

Need Help Graphic

Forum Statistics
Forums16
Topics24,940
Posts442,457
Members15,616
Most Online2,082
Jan 22nd, 2020
Top Posters
Ken.C 18,044
pmbuko 16,441
SirQuack 13,840
CV 12,077
MarkSJohnson 11,458
Who's Online Now
0 members (), 563 guests, and 1 robot.
Key: Admin, Global Mod, Mod
Newsletter Signup
Powered by UBB.threads™ PHP Forum Software 7.7.4