Pb-13 Ultra Hum!

[Soundman]

Hey SVS owners,
I noticed just the other day some hum coming from my PB-13 Ultra. It is only noticeable when the gain is turned about halfway up, and of course it becomes louder the higher you turn the gain. I have only just recently noticed this. Has anyone else experienced something similar? I may have to just call SVS. ....but I hope not.

 

[croseiv]

Is the hum there with the sub cable disconnected?

 

[Soundman]

Is the hum there with the sub cable disconnected?

Good question. I haven't tried that. Let me try that first.

 

[Soundman]

Is the hum there with the sub cable disconnected?

The hum is there with the cable connected and disconnected. I hope this is not an issue with amp.

 

[TLS Guy]

The hum is there with the cable connected and disconnected. I hope this is not an issue with amp.

It is an issue with the amp.

 

[Soundman]

It is an issue with the amp.

I thought it might. It is a very soft hum, and the gain must be up at least half way to hear it, but it is there. I wonder if this is affecting SQ. You can't really hear it during a movie or music, but once it is quiet in the room, it can be heard. Again it is very soft and you must be listening for it. The noise level of my TV and PS3 is a bit louder then this hum is. Is the amp in the Ultra going out? That would just be my luck. I haven't heard of SVS having issues with their sub amps.

 

[TLS Guy]

I thought it might. It is a very soft hum, and the gain must be up at least half way to hear it, but it is there. I wonder if this is affecting SQ. You can't really hear it during a movie or music, but once it is quiet in the room, it can be heard. Again it is very soft and you must be listening for it. The noise level of my TV and PS3 is a bit louder then this hum is. Is the amp in the Ultra going out? That would just be my luck. I haven't heard of SVS having issues with their sub amps.

Yours would be the third case recently, and they have started with hum.

 

[croseiv]

Yep, it's definitely the amp. Between here and AVS I've read of several "hummming" issues lately. I'm happy to say mine know there lyrics and don't hum at all.... They'll (SVS) probably send you a replacement amp pretty quickly.

 

[Soundman]

Yours would be the third case recently, and they have started with hum.

Started with a hum? And what did the hum lead too? Does the amp eventually just go out?

 

[TLS Guy]

Started with a hum? And what did the hum lead too? Does the amp eventually just go out?

All they got in the end was a very loud hum. SVS were good at sending new amps though.

 

[Soundman]

All they got in the end was a very loud hum. SVS were good at sending new amps though.

Oh boy. Well, looks like I'll be giving them a call on Monday. Thanks.

 

[Soundman]

Well, I contacted SVS this morning. I got a reply back in a bout 20 minutes.

Here's what Jack from SVS had to say:

Sorry you're having trouble with your PB13-Ultra. We'll take care of it.

It could be a problem with the sub amp (which is an easy switch) , or you also might have a ground loop in the system. Likely culprits are an incoming cable TV or satellite feed, a PS3, or a tactile transducer. Have you added any components lately to the system, or made any other changes to the set-up? The subwoofer is always the component which hums when there is a ground loop present, although it's usually not the cause.

Do me a favor and disconnect ALL audio and video interconnects and cables from your AVR. Plug in the AVR and the subwoofer on the same AC outlet. Turn on the subwoofer with no subwoofer cable attached. Does the subwoofer hum when standing alone?

A little trouble shooting, but Looks like SVS is trying to get this resolved soon. We'll, see what happens.

 

[Soundman]

Well, I contacted SVS this morning. I got a reply back in a bout 20 minutes.

Here's what Jack from SVS had to say:

Sorry you're having trouble with your PB13-Ultra. We'll take care of it.

It could be a problem with the sub amp (which is an easy switch) , or you also might have a ground loop in the system. Likely culprits are an incoming cable TV or satellite feed, a PS3, or a tactile transducer. Have you added any components lately to the system, or made any other changes to the set-up? The subwoofer is always the component which hums when there is a ground loop present, although it's usually not the cause.

Do me a favor and disconnect ALL audio and video interconnects and cables from your AVR. Plug in the AVR and the subwoofer on the same AC outlet. Turn on the subwoofer with no subwoofer cable attached. Does the subwoofer hum when standing alone?

A little trouble shooting, but Looks like SVS is trying to get this resolved soon. We'll, see what happens.

OK, What do you guys think? I unplugged everything, even surge pro/power cond. so nothing is connected to the wall. Then I turn on the sub, making sure the sub cable was disconnected from the sub. There is still an audible hum. However, once I connect the sub cable back to my processor, the hum is more pronounced. I need to verify that this 100% an amp issue and not a ground loop. What do you guys think?

 

[Chu Gai]

OK, What do you guys think? I unplugged everything, even surge pro/power cond. so nothing is connected to the wall. Then I turn on the sub, making sure the sub cable was disconnected from the sub. There is still an audible hum. However, once I connect the sub cable back to my processor, the hum is more pronounced. I need to verify that this 100% an amp issue and not a ground loop. What do you guys think?

From your description, you've got two things going on. One is the amp by itself introduces a slight hum under specific conditions. The other is some sort of a ground loop that piggy backs on top of the existing amp issue. Keep everything connected, but disconnect the incoming cable from your cable or satellite box that goes to your system. When you do that, does the hum stay the same or decrease?

 

[Soundman]

From your description, you've got two things going on. One is the amp by itself introduces a slight hum under specific conditions. The other is some sort of a ground loop that piggy backs on top of the existing amp issue. Keep everything connected, but disconnect the incoming cable from your cable or satellite box that goes to your system. When you do that, does the hum stay the same or decrease?

I don't have a cable/satellite box connected to the system. I have an antenna for over the air HD channels, but that's it. This system is mainly for movies and games ....and some music from time to time. Main components are the PS3 and the Wii.

 

[Chu Gai]

So, does disconnecting the antenna do anything? If not, it's going to be a process of trying to figure out which component is the culprit.

 

[Soundman]

So, does disconnecting the antenna do anything? If not, it's going to be a process of trying to figure out which component is the culprit.

Not sure. I'll have to play around with it when I get home.

 

[Soundman]

So, does disconnecting the antenna do anything? If not, it's going to be a process of trying to figure out which component is the culprit.

SVS is basically saying it is the amp. From SVS:

It certainly sounds from what you've described like it's the sub, and the amp is the only part of the sub that could cause this. If you had another sub to substitute, that could help confirm. The amp is not very heavy, so figure ~$20 to NC.

 

[armaraas]

This probably won't be much help, but when I had a hum in my sub it was from the svideo connection from the receiver to the tv. Disconnect the svideo, no hum. No idea why, but you might want to check various connections from the receiver if you haven't already.
My solution was simple, upgrade the receiver...(I was only using svideo for OSD).

 

[Buster_Dave]

Armaraas,

Not sure if this will help out in tracking down what is causing the HUM. (It may still be in your PB13's AMP) But I've had some experience with this in the past ( many years ago ) and I tracked it down to bad earthing or more to the point induction or correct term "Ground Loop "( somewhere in the electrical cabling in the house I was living in at the time). It only became evident when I had the sound system up and running. Anyway how did I prove it? (I read an article in an Audio Mag discussing causes of noise in Audio Systems. They discussed many... and how to test and or offered solutions to problems.Cutting to the chase:- I made ( Modified an Extension cord ) by disconnecting the earth at both ends ( I did this to prove if I had an earthing issue in the house ) . So you just have the Active and Natural connected and no Earth. (You’ll probably notice some audio gear and other electrical items don't even have an earth connector on the plug.. just active and neutral.

Below and behold when I tested it out ( Connected modified extension cord to the Stereo AMP )... NONoise/Hum. But of course this did not fix the ground loop issue of the house, but at least I proved it wasn't my audio gear at fault. Anyhow at the end day I had to properly earth my house by putting an additional earth spike ( a long copper rod into the ground ) and then connected a thick multiwired cable and connect it close power point near where I ran my audio and other electricals. This fixed it permanently.

Now I’m defiantly NOT saying you have to go to these lengths to get rid of the hum you only need to prove if it’s the Subs AMP or not !!. Also may I mention if you are not technically inclined don’t even bother.. or you may want to get someone ( An electrican to test your house wiring and they should be able to prove it if it is faulty by simply running and connecting some test gear.).

One more thing you may want to try.. Physically disconnect every electrical appliance in the house including the fridge !. If still there try running a long extension cord to a power point closest to your powerbox. As previously mentioned ( may be earthing loop problem ).

Hope this go’s someway to helping you trouble shoot the problem.

P.S .. I too have a PB13.. Simply Awesome.. Best bit of audio gear on the planet.

Cheers