Parasound Halo Integrated Buzz/Hum


Hi all. I bought a Parasound Halo Integrated last week and discovered there is a faint low frequency buzz coming from my speakers from all inputs except the home theater bypass (more on that below). In a completely silent room I can hear it from my listening position about 8ft away from the speakers, but it's not very loud at all. After a quick Google search and some reading, the most likely cause seems to be a ground loop issue.

Unfortunately, I am not sure if it is as simple as that. I disconnected all inputs and plugged it in an outlet with no other devices connected. I also moved it to a different outlet in my apartment, again with only speakers connected, and it still buzzes. Different model speakers have been tested as well.

The buzz only comes from the speakers, not from the amp itself or if headphones are plugged in. This integrated amp has home theater bypass inputs and there is no buzz when this input is selected. However, if I connect my AVR to these inputs, there is a buzz. This buzz can also be heard through headphones connected to the Parasound. Unlike the buzz from other inputs, this buzz does not increase when I increase the volume.

My apartment is in an old building, which in all likelihood had its wiring redone over the past decade or so. I used a 3 wire receptacle tester on some of the outlets. It indicates there is an open ground in my living room (something I should probably bring to my landlord's attention!), but other outlets appear to be wired correctly. The buzz is there regardless of what outlet I use, however.

The amp was bought from an authorized dealer and I am still under warranty, so I can certainly get it replaced or repaired. Before I do that, however, I would like to make sure I have exhausted all of my options. Do any of you knowledgeable folks have any idea if I am missing something? 
tod_
Tod you might need Harrison filters...I have the same problem. They are cheap..they don’t alter the sound....
I had the Halo Integrated for 1 1/2 years and it was dead quiet, never heard any hiss from my 94db sensitive speakers.  If the dealer is close, I would bring the amp into the store and try it out in their show room.
stereo5:
I wish that was an option, but I bought it online. That is also why I am trying to find out if it’s the amp or maybe the AC lines in my building. I would rather not deal with the return process. I certainly appreciate your input, however, and it is good to know it’s supposed to be dead quiet even with sensitive speakers.

jayctoy:
Would you please let me know what filters you mean? I looked up some Harrison filter and the unit was about the same price as the integrated amp! Are these filters for the AC line or for RCA inputs? The reason I’m asking is because the buzz is also present on the digital inputs.

The buzz sounds just like the 60Hz Cycle Hum in the example below:
http://blog.shure.com/whats-that-noise-and-how-to-fix-it/
Post removed 
It appears 20 years later that Parasound is still having the buzz humming problem with their amps.. Having owned two Parasound amps and three Parasound Preamps since 1992, here is what is more than likely the problem. Noise coming from the transformer due to faulty grounding during assembly at the plant in Taiwan. This was a very severe problem
with their biggest stereo amp ever, the HCA-3500, which had dual transformers. Two of my audio friends owned the 3500 back in the early nineties, at the time I owned the HCA-1200 which didn't have that problem. Both my friends amps had the buzz, humming problem from their transformers and had to be sent back to Parsound to properly ground the transformers. The same problem was also experienced with audio reviewers at the time with the 3500, the amp was eventually put out of production.

I have owned 3 separate pieces of Halo gear and never had a hum/buzz issue.

One thing to try, disconnect any Cable TV/Antennas. They are the most common source of ground issues. There's good cheap fixes if that turns out to be the case.

Best,

E
Cable is the number cause for sure....  but i also had a weird buzz /hum I could not put my finger on.   It turned out to be one of those scent warmers that my wife plugs in all over the place....
I would borrow another amp from a friend or store, plug it in to the same outlet, if theres no buzz or humming coming from your speakers, than its probably a ground defect in the integrated. 
I had a Halo Integrated and experienced the same issue. I used 6 different pairs of speakers with the amp, in addition to different outlets, cables and source components. I also checked the ground points inside the amp. The noise always remained at the same level, however, it was low enough that it was rarely noticeable during playback.

 The only other amps I’ve had in my system that produced similar noise were all 3 Rogue Audio integrateds. My experience led me to believe that it’s in the nature of the H-Int’s design, not a QC issue.
Thank you all for the responses.

@erik_squires , @oddiofyl
I do not have cable TV, so I am afraid that can’t be the cause. I do have cable internet and an antenna, but I have tried the integrated with those unplugged. In fact, I have literally unplugged everything in the same room and the issue persists.

@audiozen
I do have AVRs in my apartment (both Denon). One of them is on the same outlet and is completely quiet. So it likely is the integrated, or as @helomech mentions, it could be the design of the amp.

That said, I’m not sure if I want to accept that a $500 Denon AVR performs better than a $2,500 Parasound in that regard. Also, @stereo5 above says his Parasound Halo Integrated was dead silent. It could be that the Parasound is just more sensitive to some sort of interference, I suppose.

In an effort to take the wiring in my apartment out of the equation entirely, I will see if I can test the integrated at a friend’s house sometime this week.

In the meantime I have also emailed Parasound. I have had some communication with the CEO(!), who is asking me the usual ground loop related questions.
I also have a Halo Int, I've had it for a few weeks.  It does not have any hum, and is dead silent.  I do have it plugged into a Furman power conditioner though.

The long and the short of this is that there are several variables here, and methodologically it's really hard to pin down exactly what is happening.

1. AC quality coming into house varies.

2. Design of particular brand/model will have more or less hum.

3. Individual example of model will vary, according to quality of particular parts used to build it and the care with which it was built.

Although hum/no hum can be something of a predictor of performance of the piece of equipment in your hands in your house, it's never a guarantee that it will perform in the same way.

I am also having a hum buzz problem with my 2.1 in the phono section. The amp is integrated is about 14 months old with problem starting approximately 5 months ago.Like you I unplugged everything except the speakers problem still present, moved the amp to another area and outlet still hum. The noise seems to get louder and softer at different times, it is also much louder in the mc position(my cartridge is mc)Every other section is dead silent.
.
AC power quality is not the issue. I’ve worked in mitigating ground loop and EMI noise in avionics for years, and I’m sorry to say the problem is in the amp. The AC coming into my home is as clean as any. I checked the internals of my Halo Integrated thoroughly and I could only conclude that the amp has a less-than-ideal circuit layout or connection issue that would require extensive disassembly to find.

If you Google some internal pics of the H-Int, you’ll notice there’s some variation to the wire routing. I know they also had a rash of bad volume pots in some of these amps (though that’s not the culprit in this case). So I’ll retract my prior statement and say that it is potentially a QC issue, but I think it’s far more likely that they simply revised portions of the design/layout at some point.




@helomech
I fully expect it to be the amp as well. I will still test it at a friend's house, just to be sure. If it also hums there, which I expect, I will contact the dealer. Thanks for your input. 
Quick update:
The Parasound CEO actually had someone from the dealer cc'd on our correspondence. He asked the dealer to have it shipped back. They are mailing me a label and I will return it at some point next week. Everyone involved seems really pleasant, thankfully. I am hopeful I will end up with a dead silent unit.
Post removed 
^ Did they fix the problem?
Not yet. I returned the unit on Sunday, 1/28 and it was delivered at Audio Advisor the afternoon of Tuesday, 1/30. I was hoping I would be contacted a day or two after but that did not happen. 

I decided to call them on Monday, 2/5, and ultimately spoke with their technician. He is the person responsible for checking returned units. He said they received the unit without a note stating what was wrong with it. I was never instructed to provide such a note. The only instructions I received were to pack all contents and ship it with the provided shipping label. 

Regardless, he asked me to describe the problem. He said he'd look into it and give me a call back - and he did. He returned the call and told me it performed normally, in his opinion. He said he could hear a hum if he places his ear right next to a speaker but otherwise it was inaudible. He did say he was in a somewhat noisy environment, however. I told him that it sounds about right. I can't hear it if it is noisy in my room either and would have to put my ear next to a driver as well. However, in a dead silent room I can hear it from 9ft away. My speakers may also be more sensitive than the ones he used. I also told him I would expect the unit to be silent, especially if my relatively cheap Denon AVRs are. He agreed and said he would talk to the manager about a potential replacement.

The good thing is that he was able to hear the hum if close enough to a speaker. So I asked him, before sending any replacement back to me, to listen and make sure it is silent. He told me he has some units over there (including some on the repair bench) and would take a listen and call me "tomorrow" after speaking with his manager. 

Several days have passed and I have not received his return call yet. I think I will give them a call sometime today or tomorrow if I don't hear back. I am little disappointed I have to be the one following up on this, and I am also disappointed they think that kind of hum is acceptable. I realize in the audiophile world the Parasound Halo Integrated is an affordable product, but I would still expect it to be silent. Am I being too picky?

Thankfully, I am well within my 30-day satisfaction period. They will refund me if they can't provide a unit performing to my expectations.
If your Denon AVR has a two prong cord, that’s likely why it’s silent compared to the Halo.

I think there’s a few manufacturers that expect customers to accept hum since of it’s not audible during playback. I’m not surprised by the tech’s initial response. That was basically his way of saying it’s acceptable within their normal QC parameters. Some claimed to have gotten similar responses from Rogue. I’ve had 3 of their integrateds in my system, and all hummed to some extent.
This was one of the factors that led me back to Yamaha.

Good luck. I hope they can sort it out.
Even if you were not within the return period, Parasound’s warranty is one of the best I have ever seen. They are extremely pleasant to deal with and will go out of their way to make things right. I would just ask AudioAdvisor for a new unit. I’m really a fan of the Halo Integrated.
I had some more contact with the folks at Audio Advisor. I had to follow up, but they are actually really nice folks to work with. They were willing to get a new unit and listen to it themselves before shipping anything out. They claimed the unit they listened to still had some noise, but was (according to their technician) slightly less bad. I ended up agreeing to having the new unit sent over, figuring it was within spec.

It turns out this new unit is much better than the one I returned. In a quiet room, if I literally put my ear within an inch or two of the driver I can still pick up a very faint hum but much less than it was before. If I remove my ear more than a few inches, however, it becomes inaudible. 

So it appears this hum does vary from unit to unit and what I have picked up on is probably within spec. That said, I would never have heard it on this new unit and I am happy with what I got.

It was nice of Audio Advisor to send me a new unit to replace my refurbished unit. Customer service from Parasound and Audio Advisor has been outstanding.
Glad they took care of you. Thanks for the update.