AAARRRGGGHHH! Please make the buzz stop!

[CraigV]

A couple weeks ago, I noticed a “buzz” coming out of my speakers. It’s loud enough to hear when them amp (XPA-5, within about 7 inches) is turned on, and becomes louder upon turning on the pre-amp (B&K reference 50 within 2 feet). It’s more of an electronic buzz than a hum or hiss. My brain is hard-wired to be hyper-critical and hyper-sensitive of such imperfections, and this one is driving me nuts. To try and get rid of it, I have tried the following:

Plugged everything into a power conditioner (Belkin Pure AV 30)

Plugged just the amp into a regular wall socket

Plugged just the pre-amp into a wall socket

Plugged both the amp & pre into a wall socket

Switched from unbalanced to balanced connectors (improvement, but not eliminated)

Swapped out the Belkin PC for an old Adcom (ACE 515)

Tried every combination of plugging amp/pre into a Hum-X hum eliminator device

Checked to ensure there was still a solid ground going from my breaker box to the ground outside (although it is rather oxidized)

Screwed a wire connection into the chassis of the amp & pre via a screw that hold the cover on, and linked it to the “ground” connection of the Belkin PC

Turned off/unplugged al other components linked/plugged into the pre-amp

Short of making a human sacrifice I have tried everything I can think of, and the buzz is still there. Please, are there any other steps/tweaks I should try?

 

[PeterWhite]

The Meaning of Buzz

A couple weeks ago, I noticed a “buzz”

Do you have another amp? Anything, an old receiver you had in high school days? Replace the current amp with that, just connect your main speakers to it, and see what happens.

 

[sawzalot]

I am sorry to hear this Craig I know how much you love this amp, I think you covered all the obvious bases with the trouble shooting, if you remember I had a similiar buzz and it was completely gone as soon as I disconnected the HD digital box so it was prolly the cable signal in my case sorry wish I could help more .

 

[bandphan]

Doesnt emotiva recommend not using power conditioners with their amps?

 

[TLS Guy]

A couple weeks ago, I noticed a “buzz” coming out of my speakers. It’s loud enough to hear when them amp (XPA-5, within about 7 inches) is turned on, and becomes louder upon turning on the pre-amp (B&K reference 50 within 2 feet). It’s more of an electronic buzz than a hum or hiss. My brain is hard-wired to be hyper-critical and hyper-sensitive of such imperfections, and this one is driving me nuts. To try and get rid of it, I have tried the following:

Plugged everything into a power conditioner (Belkin Pure AV 30)

Plugged just the amp into a regular wall socket

Plugged just the pre-amp into a wall socket

Plugged both the amp & pre into a wall socket

Switched from unbalanced to balanced connectors (improvement, but not eliminated)

Swapped out the Belkin PC for an old Adcom (ACE 515)

Tried every combination of plugging amp/pre into a Hum-X hum eliminator device

Checked to ensure there was still a solid ground going from my breaker box to the ground outside (although it is rather oxidized)

Screwed a wire connection into the chassis of the amp & pre via a screw that hold the cover on, and linked it to the “ground” connection of the Belkin PC

Turned off/unplugged al other components linked/plugged into the pre-amp

Short of making a human sacrifice I have tried everything I can think of, and the buzz is still there. Please, are there any other steps/tweaks I should try?

If you get the buzz with just the amp connected to the speakers, and nothing connected to the input, then it is not a ground loop.

Connect the pre amp with no inputs connected. Then add devices to the preamp one by one, that will show you where the ground loop is getting in.

If the amp buzzes with no input, then this is likely RF interference picked up by the speaker leads and fed back to the high gain circuits through the negative feedback of the amp. If this is the case, the usual culprit is silicon controlled rectifiers in light dimmers.

 

[CraigV]

Doesnt emotiva recommend not using power conditioners with their amps?

Yes, but I tried it both ways just to see if it would make a difference

 

[CraigV]

I am sorry to hear this Craig I know how much you love this amp, I think you covered all the obvious bases with the trouble shooting, if you remember I had a similiar buzz and it was completely gone as soon as I disconnected the HD digital box so it was prolly the cable signal in my case sorry wish I could help more .

If you get the buzz with just the amp connected to the speakers, and nothing connected to the input, then it is not a ground loop.

Connect the pre amp with no inputs connected. Then add devices to the preamp one by one, that will show you where the ground loop is getting in.

If the amp buzzes with no input, then this is likely RF interference picked up by the speaker leads and fed back to the high gain circuits through the negative feedback of the amp. If this is the case, the usual culprit is silicon controlled rectifiers in light dimmers.

But if the only connection between the cable box & the pre-amp is an optical cable, would that matter?

I also temporarily disconnected the grounds from the phone line & the cable – still got the buzz. There is one dimmer switch in use, I’ll disconnect that & see what happens. We make generous use of the compact fluorescent light bulbs – does that mean anything?

 

[TLS Guy]

But if the only connection between the cable box & the pre-amp is an optical cable, would that matter?

I also temporarily disconnected the grounds from the phone line & the cable – still got the buzz. There is one dimmer switch in use, I’ll disconnect that & see what happens. We make generous use of the compact fluorescent light bulbs – does that mean anything?

If your cable box is connected via optical, it can not contribute to a ground loop.

A lot of fluorescent lighting can easily be a source of RF, especially if the neutrals in your home are inadequate. Fluorescent lights present a discontinuous load and stress neutrals. In many homes the neutrals are not adequate for this form of lighting and neutral gauging results, which can certainly add to RF interference.

You are starting to build a persuasive case that your problem is in fact RF penetration.

Disconnect or switch off the dimmer as a first step. The turn off all fluorescent lights and see what happens.

 

[CraigV]

If your cable box is connected via optical, it can not contribute to a ground loop.

A lot of fluorescent lighting can easily be a source of RF, especially if the neutrals in your home are inadequate. Fluorescent lights present a discontinuous load and stress neutrals. In many homes the neutrals are not adequate for this form of lighting and neutral gauging results, which can certainly add to RF interference.

You are starting to build a persuasive case that your problem is in fact RF penetration.

Disconnect or switch off the dimmer as a first step. The turn off all fluorescent lights and see what happens.

Forgive my ignorance, but does it make a difference if the lights are on or off? If I’m not mistaken, they are all off when the system is turned on.

 

[TLS Guy]

Forgive my ignorance, but does it make a difference if the lights are on or off? If I’m not mistaken, they are all off when the system is turned on.

The SCR has to be off, or disconnected if it has no on/off switch. The fluorescent lights can not emit RF if they are all off.

The next problem is that the RF may not be arising in your home, it can be from any home, that shares the same street transformer with you.

 

[Adam]

Craig, best of luck with that. That also drives me nuts. I had a hum that was related to my external TV antenna, but I was lucky in that my Belkin conditioner removed the hum.

 

[CraigV]

SCR .

SCR

 

[CraigV]

Craig, best of luck with that. That also drives me nuts. I had a hum that was related to my external TV antenna, but I was lucky in that my Belkin conditioner removed the hum.

Just so I can say I’ve tried everything I’m going to route my cable TV cable through the Belkin

 

[Adam]

Just so I can say I’ve tried everything I’m going to route my cable TV cable through the Belkin

I already knew that was the problem, though, because the hum went away when I disconnected the cable running from the TV to the wall jack. If I read your other posts correctly, you tried disconnecting everything from the pre-amp (except for the amp).

I'll read through here again, but have you disconnected everything from the amp except for the speakers?

 

[TLS Guy]

SCR

Silicon controlled rectifier. It is the device in dimmers that creates RF noise. You can not bias them to the zero crossing point, or you have a poor dimmer, so they all make some RF noise, it is a matter of degree.

I think you live in White Bear Lake or somewhere near there, right. Next time I'm down at our Eagan residence I can make a house call and try and make sense of it, if we can't get you sorted through this thread.

 

[CraigV]

Silicon controlled rectifier. It is the device in dimmers that creates RF noise. You can not bias them to the zero crossing point, or you have a poor dimmer, so they all make some RF noise, it is a matter of degree.

I think you live in White Bear Lake or somewhere near there, right. Next time I'm down at our Eagan residence I can make a house call and try and make sense of it, if we can't get you sorted through this thread.

Wow, that’s a very generous offer, but motivating my kids to clean up the house for visitors is another “buzzing annoyance” which no matter of RFI elimination will cure. I’ll give these other things a try and post the results. I hope other people can gain some insight/knowledge from my demise.

 

[croseiv]

Just came across this thread. I hope it's NOT the amp.

 

[CraigV]

Well drats, I got the wrong kind of switch. The light is controlled from two different places and therefore needs a 3 way switch. But the bad news is - even with the dimmer switch completely out of the picture (circuit) I still have the buzz. This is getting really frustrating. I think next I’m going to have to physically separate power cords from inter-connects from speaker cable. One thing I did notice - with no power going to the pre-amp, and with just the amp on, the buzz is 99% gone.

 

[Adam]

Did you ever completely disconnect everything from the amp except the speakers, or did you just run it with the pre-amp unpowered? More of a curiousity, as your test appears to have proven out that it's not the amp.

The remaining buzz from the amp - does it sound like the hiss that's present with a lot of amps?

 

[croseiv]

Well drats, I got the wrong kind of switch. The light is controlled from two different places and therefore needs a 3 way switch. But the bad news is - even with the dimmer switch completely out of the picture (circuit) I still have the buzz. This is getting really frustrating. I think next I’m going to have to physically separate power cords from inter-connects from speaker cable. One thing I did notice - with no power going to the pre-amp, and with just the amp on, the buzz is 99% gone.

Yeah this is good news as it seems to rule out the amplifier!