capn
Minor Hero
Posts: 44
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Post by capn on Jan 4, 2012 13:48:50 GMT -5
I have two XPA-1(s) and one XPA-5. All three produce an audible hum when powered on. It makes no difference if anything else in the system is connected and/or powered on. In other words, if I were to place the XPA-5 on a bench by itself, plug it in and power it up, I will hear an obvious audible hum emanating from the amplifier itself. The XPA-1(s) exhibit the same behavior although the hum is actually less obvious than it is with the XPA-5. A very small amount of the hum makes its way to the speakers, though much less so when using the balanced inputs. I was astounded to see the all the posts indicating that the amps were dead quiet. I guess I must have just been unlucky and ended up with three noisy amps  |
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Post by House on Jan 4, 2012 13:50:33 GMT -5
I have two XPA-1(s) and one XPA-5. All three produce an audible hum when powered on. It makes no difference if anything else in the system is connected and/or powered on. In other words, if I were to place the XPA-5 on a bench by itself, plug it in and power it up, I will hear an obvious audible hum emanating from the amplifier itself. The XPA-1(s) exhibit the same behavior although the hum is actually less obvious than it is with the XPA-5. A very small amount of the hum makes its way to the speakers, though much less so when using the balanced inputs. I was astounded to see the all the posts indicating that the amps were dead quiet. I guess I must have just been unlucky and ended up with three noisy amps id have to wonder if something in your wiring of the home is causing this.... |
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capn
Minor Hero
Posts: 44
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Post by capn on Jan 4, 2012 14:00:03 GMT -5
I have two XPA-1(s) and one XPA-5. All three produce an audible hum when powered on. It makes no difference if anything else in the system is connected and/or powered on. In other words, if I were to place the XPA-5 on a bench by itself, plug it in and power it up, I will hear an obvious audible hum emanating from the amplifier itself. The XPA-1(s) exhibit the same behavior although the hum is actually less obvious than it is with the XPA-5. A very small amount of the hum makes its way to the speakers, though much less so when using the balanced inputs. I was astounded to see the all the posts indicating that the amps were dead quiet. I guess I must have just been unlucky and ended up with three noisy amps id have to wonder if something in your wiring of the home is causing this.... Interesting thought. Maybe I'll have to extract one of the beasts, lug it over to a friends house, plug it in and see what happens there although I fully expect I'll still hear the hum. |
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Post by House on Jan 4, 2012 14:03:50 GMT -5
worth a try
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capn
Minor Hero
Posts: 44
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Post by capn on Jan 4, 2012 14:07:09 GMT -5
.... and the risk of a hernia  |
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Post by pavowren on Jan 4, 2012 16:10:51 GMT -5
I have two XPA-1(s) and one XPA-5. All three produce an audible hum when powered on. It makes no difference if anything else in the system is connected and/or powered on. In other words, if I were to place the XPA-5 on a bench by itself, plug it in and power it up, I will hear an obvious audible hum emanating from the amplifier itself. The XPA-1(s) exhibit the same behavior although the hum is actually less obvious than it is with the XPA-5. A very small amount of the hum makes its way to the speakers, though much less so when using the balanced inputs. I was astounded to see the all the posts indicating that the amps were dead quiet. I guess I must have just been unlucky and ended up with three noisy amps do you hear the hum standing next to the amp or from listening position at the sofa? with my Parasound amp, i only hear the buzz standing over the amp. yet it bothers me since the other amp (van alstine) is very quiet. so when people say xpa-2 is dead quiet, i'm not certain where they are positioned. still awaiting on my reservation... |
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Post by House on Jan 4, 2012 16:18:29 GMT -5
no matter where i am sitting or laying the xpa-2's are DEAD quiet......
as for the hernia.....MUSCLE UP! ;-)
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capn
Minor Hero
Posts: 44
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Post by capn on Jan 4, 2012 17:15:16 GMT -5
I have two XPA-1(s) and one XPA-5. All three produce an audible hum when powered on. It makes no difference if anything else in the system is connected and/or powered on. In other words, if I were to place the XPA-5 on a bench by itself, plug it in and power it up, I will hear an obvious audible hum emanating from the amplifier itself. The XPA-1(s) exhibit the same behavior although the hum is actually less obvious than it is with the XPA-5. A very small amount of the hum makes its way to the speakers, though much less so when using the balanced inputs. I was astounded to see the all the posts indicating that the amps were dead quiet. I guess I must have just been unlucky and ended up with three noisy amps do you hear the hum standing next to the amp or from listening position at the sofa? with my Parasound amp, i only hear the buzz standing over the amp. yet it bothers me since the other amp (van alstine) is very quiet. so when people say xpa-2 is dead quiet, i'm not certain where they are positioned. still awaiting on my reservation... I can hear the hum from my listening position as soon as I fire up the three amps (powering on one amp triggers the next which triggers the next). Once the audio program fires up, it overcomes the hum, but obviously, it's still present. Like I said before, I was astonished to find this thread and see so many posts claiming no hum whatsoever; I wish that were the case for me. |
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LCSeminole
Global Moderator 
Res firma mitescere nescit.
Posts: 20,850
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Post by LCSeminole on Jan 4, 2012 17:53:33 GMT -5
The only noise coming from my XPA-2 & XPA-5 are the after market cooling fans that I'm using, otherwise mine are dead quiet at idle even with my Klipsch speakers. Makes me wonder if this could be an electrical grounding problem in your house.
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Post by roadster on Jan 4, 2012 18:02:27 GMT -5
I have two XPA-1(s) and one XPA-5. All three produce an audible hum when powered on. It makes no difference if anything else in the system is connected and/or powered on. In other words, if I were to place the XPA-5 on a bench by itself, plug it in and power it up, I will hear an obvious audible hum emanating from the amplifier itself. The XPA-1(s) exhibit the same behavior although the hum is actually less obvious than it is with the XPA-5. A very small amount of the hum makes its way to the speakers, though much less so when using the balanced inputs. I was astounded to see the all the posts indicating that the amps were dead quiet. I guess I must have just been unlucky and ended up with three noisy amps I have the same trio as you, all three dead quiet. |
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Post by roadrunner on Jan 4, 2012 19:13:02 GMT -5
Hum coming from the amp is usually one of two things. First, "dirty electrical service" can make the transformers buzz pretty well. Often this is a result of DC components in the AC service. Second, resonance causes the shelf/amp to emit a buzzing sound. The cure is to decouple the Amp from the shelving. Anti-vibration material usually does the job. You can also try moving the amp to another shelf.
Both of these can cause an audible noise from your sweet spot even though the speakers don't emit any noise at all. Well, any noise except the music. ;D
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Post by pavowren on Jan 5, 2012 9:02:02 GMT -5
... First, "dirty electrical service" can make the transformers buzz pretty well. Often this is a result of DC components in the AC service. ... please explain more about this dirty ac service. by dc components, do you mean those small black box ac/dc transformers used for routers and such? should i move these to separate outlets? what are some solutions? |
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Post by hikinokie on Jan 5, 2012 9:35:29 GMT -5
Hum coming from the amp is usually one of two things. First, "dirty electrical service" can make the transformers buzz pretty well. Often this is a result of DC components in the AC service. Second, resonance causes the shelf/amp to emit a buzzing sound. The cure is to decouple the Amp from the shelving. Anti-vibration material usually does the job. You can also try moving the amp to another shelf. Both of these can cause an audible noise from your sweet spot even though the speakers don't emit any noise at all. Well, any noise except the music. ;D RR... I just got a XPA-5 to replace my IPS-1 that was stolen (along with everything else) when I was burglerized. Plugging it in it makes a LOUD buzzing noise heard across the room like the IPS before it. The IPS was sent back under warranty and I was told that the noise was "normal". With no other choice I unbolted the power switching (110-220) transformer and installed a grommit betreen it and the metal. *poof*, no more hum. So you can imagine my disappointment when I turned on the XPA yesterday. You can place your hand lightly on top of the chassis and feel the vibration. Do I break my back and send it back to Emo only to be told this is "normal". What BS!! Something so simple as mechanically isolating the transformer from the chassis when it was designed would cure much of it. I thought long and hard wether to get another Emo amp or buy a Pioneer Elite receiver. I must be an idiot or a fool. |
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capn
Minor Hero
Posts: 44
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Post by capn on Jan 5, 2012 10:56:51 GMT -5
I feel your pain. I'm sure if I sent my own XPA-5 back I'd be told there is nothing wrong with it.
I find myself now just following my father's advice from years ago whenever I complained about some noise I was hearing in my car, which was "Just turn the radio up loud so you don't hear it"
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Post by roadrunner on Jan 5, 2012 20:47:24 GMT -5
... First, "dirty electrical service" can make the transformers buzz pretty well. Often this is a result of DC components in the AC service. ... please explain more about this dirty ac service. by dc components, do you mean those small black box ac/dc transformers used for routers and such? should i move these to separate outlets? what are some solutions? I am sorry I was just too lazy to give a fuller explanation of what "dirty electrical service" is. I assumed everyone already knew what it was and had just not realized that it was responsible for a goodly percentage of the noise emitted by an amplifier's transformer. DC component was just my lazy way of saying that DC electricity had managed to contaminate the AC service in your home's electrical service. The presence of DC going thru the transformer causes it to vibrate; and this vibration is the hum/buzz that you hear coming directly from the amp rather than from the speakers. There is nothing wrong with the amp and sending it in for service won't help because the problem is the DC hitching a ride with your Home's electrical service. Often, decoupling the amp from the shelf will prevent the resonance from becoming audible. Hikinokie "decoupled" the transformer and the noise disappeared. I would have tried to decouple the amp by placing anti-vibration devices between the amp and the shelf -- a lot less work than Hikinokie's solution. Sometimes, just moving the amp to another shelf will change the resonant frequency and the noise will go away. In a thread from a year or so ago, there was a thorough discussion of this very issue. Lonnie participated in that discussion; an electrician chimed in about the ramifications of DC on the electrical service; and a lot of Lounge members also contributed to a very informative thread. If one of you wants more information you can go back and find that thread. If you find it, you might want to post a link to that old discussion for others who also wanted a more detailed discussion. |
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Post by Viktor on Jan 6, 2012 12:28:53 GMT -5
My 3 UPA-1s all buzz when placed on the bed and with no other connections than the power cord. The level of the noise varies a little between each unit, but they're all what I would call quiet, unless you're sitting right in front of them on the floor. When switched on, the buzz quickly ramps up to a clearly audible level and then fades down to very quiet, though still audible because you notice the difference when they're switched off again. The UPA-2 exhibits the same thing but my unit seems slightly less audible than the UPA-1s.
I wonder if this has anything to do with the 220 volts they're fed here.
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Post by pavowren on Jan 7, 2012 15:13:35 GMT -5
i understand that it is specifically the transformer (that big toroidal monster) which buzzes. is this similar to the buzz you hear when you walk under one of those tall electrical transmission towers?
well as far as xpa-2 is concerned, i'm hoping it is 'dead quiet' as some claim 'cause my order is finally in!
[UPDATE - Jan 11]
xpa-2 arrived, unpacked, connected the power cord, turned it on. No buzz/hum. No sound. Then, i pushed the front power button. Still absolutely no sound with my ear laying on the grill. now, i have switched out the old parasound with this HEAVY monster, and all i hear is sweet music!
do i have to register this amp? where is the serial #?
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Post by Viktor on Jan 7, 2012 17:24:49 GMT -5
Yes, for me it's a typical 50 Hz hum.
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Post by kong73 on Jan 7, 2012 18:12:17 GMT -5
Have you tried a 3 prong female to 2 prong male cheater plug? This might help eliminate that if it is a grounding issue. My PE 1000 watt amp produces a hum IF I don't use the cheater plug.
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NorthStar
Seeker Of Truth
"And it stoned me to my soul" - Van Morrison
Posts: 0
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Post by NorthStar on Jan 7, 2012 18:27:11 GMT -5
please explain more about this dirty ac service. by dc components, do you mean those small black box ac/dc transformers used for routers and such? should i move these to separate outlets? what are some solutions? I am sorry I was just too lazy to give a fuller explanation of what "dirty electrical service" is. I assumed everyone already knew what it was and had just not realized that it was responsible for a goodly percentage of the noise emitted by an amplifier's transformer. DC component was just my lazy way of saying that DC electricity had managed to contaminate the AC service in your home's electrical service. The presence of DC going thru the transformer causes it to vibrate; and this vibration is the hum/buzz that you hear coming directly from the amp rather than from the speakers.There is nothing wrong with the amp and sending it in for service won't help because the problem is the DC hitching a ride with your Home's electrical service. Often, decoupling the amp from the shelf will prevent the resonance from becoming audible. Hikinokie "decoupled" the transformer and the noise disappeared. I would have tried to decouple the amp by placing anti-vibration devices between the amp and the shelf -- a lot less work than Hikinokie's solution. Sometimes, just moving the amp to another shelf will change the resonant frequency and the noise will go away. In a thread from a year or so ago, there was a thorough discussion of this very issue. Lonnie participated in that discussion; an electrician chimed in about the ramifications of DC on the electrical service; and a lot of Lounge members also contributed to a very informative thread. If one of you wants more information you can go back and find that thread. If you find it, you might want to post a link to that old discussion for others who also wanted a more detailed discussion.Hi Ronnie, I tried to locate that ditto thread but without success (I'll keep trying)...___________ * Look at the new Yamaha Aventage A/V receivers Series with their 5th foot near the center right under the main transformer. - There is a very specific reason for that... => People can do the very same at home with their amps or receivers, by improvising and positioning their own custom 5th foot also directly under their unit's transformer. It's worth trying.{You can even take one of the feet from one of your other component that is out of service, and adjust it so that it perfectly fits under your new desired component.}Reason for edit: {...} |
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