Hum and pop

[edshull]

I think I'm getting some serious electric noise through my XPA-2. When I play something and stop, after about 20 minutes I'll notice a loud pop from my speakers, and then silence. Kinda like when your fridge cuts out and that noise you didn't really notice stops. When someone came in the other day, the noticed the humming from the speakers as well. 

I had the amp plugged into a power strip, but I read that it's better to go directly into the wall, so I did that. And it still hums and pops. I ordered up the Emotiva power conditioner, but I'm not sure that will do the job. 

I tried calling for support, but I'm not able to reach anyone and no one has called back. So I figured I'd ask here if anyone else has experienced that problem, and if so how you stopped it? 

Thanks!

[teaman]

Hi Ed, I have a home theater set up with a Sherbourn PT-7020C4 as pre/pro and XPA-2 and XPA-5 Emotiva amps and I have buzz too. I bought a power conditioner from Emotiva and it cut down on it but did not eliminate it completely. I also tried the ground adapters on my power amps and the buzz is still there. These a a couple of inexpensive options to try. As far as the pop after turning off the amp I had a little noise and pop when the balanced cables were in use. When I switched to RCA it went away. I spoke with someone in Emotiva's tech dept and they told me if it bothered me and i was set on using the balanced inputs it is a quick and easy fix for the,....outside of the fact that it cost a ton to ship the amp back for this repair. I ended up passing and just continued to use the RCA-s. Maybe swith them up and see if the pop goes away.


Tim

[edshull]

Jan 20, 2017 15:09:23 GMT -5 teaman said:

Hi Ed, I have a home theater set up with a Sherbourn PT-7020C4 as pre/pro and XPA-2 and XPA-5 Emotiva amps and I have buzz too. I bought a power conditioner from Emotiva and it cut down on it but did not eliminate it completely. I also tried the ground adapters on my power amps and the buzz is still there. These a a couple of inexpensive options to try. As far as the pop after turning off the amp I had a little noise and pop when the balanced cables were in use. When I switched to RCA it went away. I spoke with someone in Emotiva's tech dept and they told me if it bothered me and i was set on using the balanced inputs it is a quick and easy fix for the,....outside of the fact that it cost a ton to ship the amp back for this repair. I ended up passing and just continued to use the RCA-s. Maybe swith them up and see if the pop goes away.


Tim

Thanks, Tim. I am using balanced cables. And now that you mention it, I remember someone mentioning this issue in the past, but that was back in like 2010. They said it was a "known issue", so I assumed they would have taken care of it 7 years later.

So you're saying the pop went away with the RCA's, but you're still getting the hum?

[teaman]

Yes, pop went away completely but my hum is still present. I think part of my problem is that I have it inside a built in cabinet and all of the cables behind the units are intertwined. If I take the time someday I am going to separate the HDMI's from the XLR's. I am sure the fact that everything is balled up in a cavern together it is bringing on more problems than it is worth. Maybe try switching to RCA's and see if that does the trick with the pop. It may even help with the hum!

[edshull]

Thanks, Tim.

It sounds like we're having similar issues. I may try switching to RCA's, but I'm concerned about the constant humming. Since I can't get anyone to return my calls, I'm thinking I may have to take advantage of the 30 day policy. Maybe try a Bryston.

[teaman]

Jan 20, 2017 16:07:13 GMT -5 edshull said:

Thanks, Tim.

It sounds like we're having similar issues. I may try switching to RCA's, but I'm concerned about the constant humming. Since I can't get anyone to return my calls, I'm thinking I may have to take advantage of the 30 day policy. Maybe try a Bryston.

I would think if you call Emotiva directly and ask for tech support they will take care of you. The Bryston amps are beautiful but three times the price so that is a decision you will have to weigh for yourself. I have a ton of Emotiva amps and only that one set up has a buzz. This might work as a cheap option to see whether the buzz is a ground loop or not.

www.frys.com/product/8172945?site=sr:SEARCH:MAIN_RSLT_PG

Can pretty much find them at any big box store.

[Gary Cook]

Jan 20, 2017 15:02:55 GMT -5 edshull said:

I think I'm getting some serious electric noise through my XPA-2. When I play something and stop, after about 20 minutes I'll notice a loud pop from my speakers, and then silence. Kinda like when your fridge cuts out and that noise you didn't really notice stops. When someone came in the other day, the noticed the humming from the speakers as well. 
I had the amp plugged into a power strip, but I read that it's better to go directly into the wall, so I did that. And it still hums and pops. I ordered up the Emotiva power conditioner, but I'm not sure that will do the job. 
I tried calling for support, but I'm not able to reach anyone and no one has called back. So I figured I'd ask here if anyone else has experienced that problem, and if so how you stopped it? 
Thanks!

Hum is almost always induced, I have not heard of an Emotiva power amp generating hum internally. So you need to do a bit of fault finding. The first task is to separate the interconnects from the power cables, that's the most common cause of hum. especially RCA's. Then move the speaker cables away from any power cables.

You haven't included a list of your gear, so without being specific, next I would disconnect the source (pre amp) to the power amp and if the noise disappears then it's coming from the source. Same process next, disconnect all of the sources from the pre amp and if it still hums then it's the pre amp. If not, then it's a process of eliminating each source to the pre amp, connecting them one by one, until the hum starts, then that's the source.

I know the immediate response is that "it didn't hum before I added the Emotiva power amp, so that must be the problem". I would be amazed if you installed a power amp without moving the cables, interconnects, power cords, speaker cables etc, even the smallest amount can be the issue.

The Emotiva tech guys have just spent a bunch of time getting ready, going to and getting home from the CES show, working weekends etc. So cut them a bit of slack, they probably have a back log of calls to get through.


Cheers
Gary

[edshull]

Thanks, Gary. Here's what I'm running right now, and also what I found the problem to be, at least some of it.

Audio Technica LP120 (modified)
Sonos Connect
Bluesound Node 2
Parasound Halo P5
Emotiva XPA-2 Gen 3
Magnepan MMC2's with dual DWM's
Hsu Research VTF-2 Subwoofer
Signal Cable Silver Reference speaker cables, balanced cables, coax and optical

An Emotiva tech did call me back and was very helpful.

After doing some research after the call I found it was the HSU doing the humming. As soon as I unplugged in, it lessened significantly. I think I'll still benefit from the power conditioner. I'm hoping things will clear up more when that gets here.

As for the popping, I'm still investigating. It's a difficult one to track down. It may have been the Hsu as well, but I did notice it only seemed to happen when I stopped playing the Bluesound after 20 - 30 minutes. It didn't seem like it was doing it after the Sonos. So that makes me wonder if it's the Bluesound going to "sleep" or something like that.

I'm keeping an open mind that it may not be the Emotiva. They have an excellent reputation. I am doing an amp comparison with Bryston to see if it's better (at least 4x better, which will be a challenge), and a Crown 1500 and 2500. I'm hopping the Emotiva wins out.

[leonski]

Any way to run a dedicated outlet for at least some of your stuff?

Also, glad you DID find one of the Hummers. Now? are there other things on the circuit which could also induce noise? Dimmers? FishTank Pumps? CFL or LED lighting?
Lots of stuff can cause problems. Heating blanket? Plasma TV?

I have a VTF-2 MK3 or so and it is dead quiet. And thru a Panamax power conditioner. Formerly, it was thru a dedicated outlet w/main amp and Also dead quiet.
Maybe get on the phone to Dr Hsu and ask about possible sources of hum in his sub?

Don't buy Monster.

[Gary Cook]

I have never experienced a power conditioner eliminating hum, in fact it I've never experienced a power conditioner doing anything good for a sound system. One exception, an external concert using multiple diesel generators for power, one of which was rogue. So personally I'd give the power conditioner a miss unless you have detailed data on your power supply that indicates that there is an issue. Even then it depends on what the specific issue is.

I'd also not waste my time on the Crowns, they are OK for subwoofer amps, but not in the same league as an XPA-2.

Just because you can hear the hum from the subwoofer doesn't mean that the sub woofer is actually the source. Hum is commonly caused by a grounding issue, either a piece of gear with a bad ground/shield or 2 pieces of gear that "talk" to each other through the ground/shield. That can be a missing shield on a cable, either damaged or deliberately missing ie; designed that way. It can take a while fault finding, patience and changing only one thing at a time is the best method. As I mentioned above, remove everything and then reconnect them one at a time.

Cheers
Gary

[vneal]

Amps should be dead silent

You have a ground loop hum

do a search on it

start by unplugging sources
if it goes away that is your issue

wall worts are notorious for this

[Percussionista]

The only time I've experienced a loud "pop" after turning off an amp, was back in the Phase Linear days, with a 400 amp. It was more of multiple sizzling electrical cackles and pops than just a single pop. I had it into the shop a few times over the years. There were bad output-transistors at least. I'm thinking an internal capacitor was discharging out the amp after the juice was pulled. Scary nasty sounding. (Sorry I have to ask, but you didn't pour any Rice Krispies into the amp, did you? nevermind)

[hemster]

Jan 21, 2017 19:01:28 GMT -5 Percussionista said:

The only time I've experienced a loud "pop" after turning off an amp, was back in the Phase Linear days, with a 400 amp. It was more of multiple sizzling electrical cackles and pops than just a single pop. I had it into the shop a few times over the years. There were bad output-transistors at least. I'm thinking an internal capacitor was discharging out the amp after the juice was pulled. Scary nasty sounding. (Sorry I have to ask, but you didn't pour any Rice Krispies into the amp, did you? nevermind)

At first glance I read "The only time I've experienced a loud "poop" after turning off an amp...". A quick double-take confirmed I read wrong (thankfully!). 

[leonski]

Jan 21, 2017 17:12:30 GMT -5 Gary Cook said:

I have never experienced a power conditioner eliminating hum, in fact it I've never experienced a power conditioner doing anything good for a sound system. One exception, an external concert using multiple diesel generators for power, one of which was rogue. So personally I'd give the power conditioner a miss unless you have detailed data on your power supply that indicates that there is an issue. Even then it depends on what the specific issue is.

I'd also not waste my time on the Crowns, they are OK for subwoofer amps, but not in the same league as an XPA-2.

Just because you can hear the hum from the subwoofer doesn't mean that the sub woofer is actually the source. Hum is commonly caused by a grounding issue, either a piece of gear with a bad ground/shield or 2 pieces of gear that "talk" to each other through the ground/shield. That can be a missing shield on a cable, either damaged or deliberately missing ie; designed that way. It can take a while fault finding, patience and changing only one thing at a time is the best method. As I mentioned above, remove everything and then reconnect them one at a time.

Cheers
Gary

My experience w/a PC was just the opposite.   A profound change for the better.   Blacker between notes.  Even the TV (this was in CRT days) now had NO SNOW.  Turning the source off, the screen went dead black.
The audio was so much better that I had to re-align my speakers.   Just a better version of itself.      

But, to be fair, I had NO hum or noise problem to begin with.

Also, to be fair,  you CAN or should be able to eliminate some noise using a simple Isolation Transformer.   My Panamax has a 'balanced' and 'isolated' position switch for the Iso Transformer.  I think it lifts the ground on the 2ndary, but I'm not certain.  

And I'll agree w/Gary in that you must now go thru a troubleshooting procedure.   You might have something as simple as a shielding problem on an RCA cable from being pulled out by the wire.    Something May be causing the hum.   If you disconnect the RCAs to the sub and it stops, try connecting with speaker wire to those terminals.   Stuff like that.   A process of elimination until you figure it out.