Axiom Home Page Forums General Discussion Advice from Axiom Owners Yet another amp question - parasound and hum.

Hmm, just came across this thread.
NH, you may be interested to take a gander at my thoughts on the Halo units way back here.

That is odd to say the least. I have never had a Parasound product hum on me at all. My current HALO has been hush hush since day one. I think in total I have had maybe a total of 8 or 9 Parasound amps and they have all been fantastic and quite! My current HALO has been run through an Onkyo receiver and now my Denon 3805 and it's still dead quite.

I honestly have no explanation why some people hear a hum with these. I have owned more of these then most and have yet to hear a thing.

Come to think of it, the only hum I ever had that I can remember was from a Bryston and that was a ground loop hum which was easily corrected. Parasound, Odyssey, Anthem, Marantz, NAD, ROTEL etc etc etc have all been hum free in my house................but I'm the guy who spent more on the wiring, fuses, box etc etc in my house then most people do. In spite of what some think, I'm a true believer with respect to the power coming in does make a difference on what comes out.

NH, the hum was not a ground loop. The hum was also absent on 3 other amps and two receivers plugged into the same outlet. This issue was definitely related directly to the Halo itself. (Note that in my earlier statement i thought i had related it to a Denon source unit but that was actually ruled out since i broke down and brought my big Onkyo upstairs for use as a preamp.)

If the Halo unit was reacting to something from the power supply in the walls, then its design is flawed but i'm not saying all these Halos do this either. In fact, i wouldn't be surprised if some have it and some don't. I've read at least one other report on the hum but quite some time ago so unfortunately i do not recall which forum it was.
In any event, some problems have been reported with other Halo units such as this lengthy thread on the new units over at The Spot. Concentrate on the posts by Paul Carleton and you will see alot of what i came across. I found this thread just shortly after i took the Halo back from auditioning during my search for answers.
Notice how his use of "power conditioners" did very little to affect the ground loop issues he was having. The ground loops seemed to just move around from item to item but in no way did these conditioners do what they are marketed for. Power from the walls is and always should be regulated by the onboard power supply of the unit. I'm not sure that any electronics piece comes without a power supply that doesn't have regulation onboard. Conditioners are useless. Surge and sag protection are different stories. Bren can tell you all about his pro experience with power from the walls and into the machines over beer until you are blue in the face.

If you continue to read further down, Paul believes he has found the problem (after talking with Parasound), not in the amp but rather in the Halo C1 controller. After reading through this, i started to get concerned about the build quality (back to the design word again) of these Halo units. That is when i started this thread and since gave up on buying the A23.
I now own the Anthem MCA.
Paul summed up my own thoughts quite nicely:
It wasn’t bad but it would be nice on a unit with this price point not to have it at all. It can get pretty bad if you don't have the cable tie that Parasound is now installing on later units. Other than redesigning where the balance inputs go or where the power supply is placed, there is not much else you can do about it.
Again he is referring to the controller but i believe something similar is happening in the amp. I never did take off the lid to see as i knew the unit was going back to the store.
Incidentally, many others have reported no hum whatsover with their Halo units and enjoy them tremendously. If you have another amp, put them together and run them through the same preamp w/o anything playing. Turn up the volume and see if the Halo gets 'louder' either in itself or through the speakers. I had not realized the hum was abnormal until i had it compared to another amp and again i must stress that it was not audible during music playback.

chess, I have seen other reports on the Parasound "Hum" to. Perhaps I have just gotten lucky or something. I can't explain it at all. To me at least Parasound builds nice stuff. I have never had a problem with any of Parasound's products. Not only have I had there amps but for a time when I went completely off the wall I was running the AVC-2500U for a pre. Great pre but when my wife found out what I had into it................I had to sell it. lol

NH, i had my heart set on the Halo. It was the perfect amp for me for features and price. It just fell through because of this oddity and if it were not for the Anthem, i would probably still be searching for an amp today.
Do you know how few amps have any kind of trigger onboard? I really enjoy the auto sensing signal-on function of both the Halo and the Anthem but both also had the more standard 12v trigger as well. Many of the amps i've looked through, several thousand dollars a piece, did not have anything more than a manual on switch. If i wanted to turn my equipment on manually all the time, i would not bother owning remotes!
You would think for several grand the amp companies would put such a simple component into their units so you can turn your system completely on and off from the couch or across the room.

We could start a whole new thread on what I'm about to say but...............I'm one of those folks that never shuts there gear off so I don't use the triggers. Everything I own in HT gear stays on 24/7 except my TV. I can't even remember why I do it anymore but I have done it for years. I have a habit of coming home from work and heading downstairs and thumping a tune. I like the fact that everything is charged up, warm etc all the time.

I'm not real up on Anthem. I may have to try something from them just for $hits & giggles. Pricey or not to bad?

Thread hi-jack in progress.....................

Ah NH, i've covered my thoughts on the 'leaving equipment on' routine many times before.
Of course some will say that it changes the sound, etc. etc., but in all reality it just wastes electricity. Sound be damned, the environment should be the more important consideration.

The Anthems are HIGHLY reasonable in price for what they deliver. Much like many of our purchases {ahem axioms ahem ahem}, we try to find a good value, good quality for prices that do not fall into the audiosnob category, unless the item REALLY has something we like or need. Audiogon has proven to be an amazing resource in looking for equipment since local stores still jack up prices.
The Anthem MCA20 amp was going for $1500 plus taxes at a local shop. I could get it for about $850, less than one year old, on Audiogon. You can see the stats sheets here.
It is really quite a boring aesthetic unit although the silver face does help. For its features and specs, as well as the Anthem build quality and reputation, along with the fact that Anthem is another Canadian company, just sold me.
So far the unit has performed flawlessly, is dead quiet, runs barely luke warm and has plenty of power and headroom for what we paid. They power the big Tannoys just fine.

In reply to:

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Ah NH, i've covered my thoughts on the 'leaving equipment on' routine many times before.

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Shhh... Manitoba Hydro probably sells extra power there.

Bren R.

I'm doing my part for the power people!