rontj
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Post by rontj on Jan 22, 2014 1:23:27 GMT -5
Test to see if it is ground loop problem. Hiss can be normal to an extent. Hum, or hum+hiss may not. Test 1: Take the 3-prong plug from your power amp cable and plug it into a 3 to 2-prong adapter. This removes the ground from the circuit. (These are usually light gray in color and can be purchased for less that a dollar if you don't already have one.) Plug it into the wall. If the buzzing/humming sound stops them you have a ground loop problem and your ground is connected in the outlet in this case. Test 2: If there is no change from doing Test 1, then there may not be a ground wire, or the ground wire may not hooked up, in your outlet. Test to see if the ground is present by using a circuit tester. I used the small yellow type with indicator lights: www.amazon.com/GE-50542-3-Wire-Receptacle-Tester/dp/B002LZTKIA/ref=sr_1_3?ie=UTF8&qid=1390329899&sr=8-3&keywords=circuit+testerIf the tester is not showing the ground as connected therein may be your problem. With an extension cord test in different outlets around your room. This was strange but in testing outlets in my living room I found two ungrounded outlets in my house. Inexplicably, one was dead quiet with my power amp plugged in while the other was noisy. Thanks for this suggestion, though I'm quite certain my outlet is grounded, as I recently had a dedicated 20A circuit installed by a licensed electrician. I have the Emo amp connected to a high-quality passive PS Audio power conditioner, and the PS Audio conditioner of course is connected to the 20A cirucuit. But I do have the 3-2 prong adapter, and will use it, and observe what I hear. Thanks for the idea. I can't recall my speakers making this much noise when the speakers were powered by the receiver. I plan on reconnecting my speakers directly to the receiver, and observing how the speakers sound re: the static/hiss/hum. And, it's not loud, but I can hear it from the primary, and I never noticed hearing static/hiss/hum from the primary in the 7 years before I added the Emo amp.
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rontj
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Post by rontj on Jan 22, 2014 1:26:08 GMT -5
I forgot to mention that I have found that refrigerators, fluorescent tube lights, and anything with a fan in it in particualar, if on the same circuit as your power amp, can generate 60 cycle hum. I don't believe this is effecting my system, but nonetheless, thanks for the tip, islandman.
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rontj
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Post by rontj on Jan 22, 2014 1:31:03 GMT -5
Buzz induced from lighting dimmer switches is Triac or SCR noise leaking into the audio equipment chain. This can occur when the power for both the light and audio gear is drawn from the same circuit or phase of mains electrical power. It can also occur due to induction due to proximity. Some dimmers are better than others. RFI is induced due to sharp spikes of current. Dimmer chokes and filters can help alleviate this issue. Then one of my tests shall be to kill the circuit on which my dimmer resides, and observe if the static/hiss/hum decreases or not. Thanks for this info, hemster.
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hemster
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Post by hemster on Jan 22, 2014 1:43:08 GMT -5
Buzz induced from lighting dimmer switches is Triac or SCR noise leaking into the audio equipment chain. This can occur when the power for both the light and audio gear is drawn from the same circuit or phase of mains electrical power. It can also occur due to induction due to proximity. Some dimmers are better than others. RFI is induced due to sharp spikes of current. Dimmer chokes and filters can help alleviate this issue. Then one of my tests shall be to kill the circuit on which my dimmer resides, and observe if the static/hiss/hum decreases or not. Thanks for this info, hemster. Yes and if you find that to be the cause, the options are to replace the dimmer with a better one (one that includes choke suppression, especially if the existing dimmer is old and the SCR variety) or install a choke/filter.
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Post by aud on Jan 22, 2014 10:05:04 GMT -5
Hi rontj, just read your last post above. Things have become much worse I think I can safely say. This has led me to respond with a whole new approach which I know can sometimes be more deleterious than helpful but I've decided to ask you this because you are now hearing uneven noise from the listening chair and you sound very frustrated and rightfully so. The surround sound receiver you talk about, what mode was it set at when the above occurred. Pro Logic IIx, DTS, no mode, etc. and I apologize before hand, but I forgot what sources you are using. Computer based, Blu Ray player, CD player etc. ? Hopefully this line of questioning is all mute because Emo Support got the problems resolved already. Hi Aud. Well, I wouldn't say they've become worse, it's just that I'm paying more attention than I have in the past, and getting a proper and accurate description of the problem. Frustration level is minor, as I've not yet begun trying to find the cause, but am confident I'll find it when I put aside the time needed to devote to this problem. The static/hiss/hum has likely always been uneven, I'm just not been aware of it. Re: the listening mode, I'd say Dolby Digital. I don't use PLII, as I prefer to listen to two-channel sources in stereo. But this is a good question. Sources are PS3 (older, fat), TiVo, OPPO Blu-ray, Roku and Sonos. I've not yet identified whether there's any difference in static/hiss/hum in the 5 difference sources. I'm glad to hear it's not as bad as it sounded. The reason I asked the questions was because I had an experience about four years ago with my Pre/Pro and a high end Source (hooked up via coax digital) that was producing the same conditions you described. I did a complete hum/buzz/ground loop trouble shooting routine for a couple of weeks with no resolution to the problem. The Pre/Pro company kept telling me it was a ground loop problem even though I kept telling them it was a static noise type of sound (like you were describing) only coming out of certain channels of a 7- channel system. Trust me I now know what a true ground loop problem sounds like. I've had to deal with too many of them over the years. For now I'll spare everybody the details as to how it finally got fixed unless you get to that point.
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Post by garbulky on Jan 22, 2014 10:16:36 GMT -5
I guess at this point it should be asked of the OP if they use a power conditioner of sorts as that may cause interference with the amp.
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KeithL
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Post by KeithL on Jan 22, 2014 11:28:07 GMT -5
Just a few interesting tid-bits.....
ALL analog audio electronic components make some noise.
"Hiss" is made by every component and circuit; even a passive resistor, just sitting there, will "create" some tiny amount of hiss if you connect it to an amplifier. The amount of hiss will depend on the gain of the amplifier, the value of the resistor, and the amount of current flowing through it - if any.
"Hum" is actually the sound of the AC power in your neighborhood. It is loudest near power lines and big transformers, but pretty well saturates the entire civilized world. You may hear mechanical hum from a transformer (because the magnetic field actually makes the wires that comprise the transformer vibrate), and it may find its way into the electronics.
My point here is that, with sensitive enough speakers, and a quiet enough room, there is no such thing as an amplifier that makes no noise when its on. ALL amplifiers produce some hiss. The only two questions are whether you will hear (or notice) it under normal conditions, and whether there is hum (and, if so, if it is louder than the hiss). Human ears are amazingly sensitive. In a dead quiet room you can actually hear a pin drop - and hear the hiss of a quiet amplifier at ten paces. (There were studies where certain rooms were found to be TOO quiet; because the room was so quiet, people were distracted by the sounds of papers and clothes rustling, other people breathing, and the humming of the ceiling lights. The solution was found to be to REMOVE padding from the ventilators so the soft "whooshing" of the air would raise the background noise level high enough to cover up the other distracting microscopic noises.)
Also, just FYI, most amplifiers make slightly more noise when the input is open (unconnected) than when it is shorted. This is why, sometimes, you actually will hear more noise with nothing connected than, for example, a preamp connected but turned off (when it's off it shorts the input). Contrariwise, the outputs of many pre/pros are shorted when they are on, but muted, but not fully shorted when the power is off (the mute function sometimes actually requires power to "actuate").
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KeithL
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Post by KeithL on Jan 22, 2014 11:49:16 GMT -5
The thing that worries me about "ground isolators" is that, if they really do provide isolation, they basically have to use a transformer... and transformers produce all sorts of non-linearities and distortions (some more than others, of course). However, since even the best and most expensive transformers are still quite far from perfect, I would avoid these if at all possible. Note that transformers generally do NOT produce hiss, and they should remove any ground related hum, it's just that they add THD and frequency response anomalies (which can be very nasty, and which can vary depending on what source and destination components you connect to them.) To phrase that differently: transformers are one of those components that definitely DO alter the sound, and each type has a "sound" of its own.... which can change dramatically depending on what you hook it up to... I would say trying one of these is a great DIAGNOSTIC step, since, if the problem magically goes away when you insert it, you have pretty much confirmed that it was a ground problem, but I would listen to it very carefully before even considering leaving it connected for normal listening. The AT speaker position hiss is something the manufacturer will state is within specification. My Parasound stuff, and other brand equipment I have had that same noise. At 4-5 feet from the speaker, it's an issue. First step is to check for ground loops. If at all possible, power everything from the same circuit. Make sure no dimmers, or refrigerators/motors share the same circuit. Go to radio shack and buy one of these: www.radioshack.com/product/index.jsp?productId=2062214Try to cleanup your wiring/cabling and it may prove wise to replace your cables with a spare(s) one by one. It's a long shot, but a good place to start if the above doesn't work. Thanks for this suggestion. I'll keep it in mind. I've not yet had a chance to thoroughly review and attempt to identify the cause of my static/hiss/hum, but am confident I'll find the cause. I'll keep this product in mind. It connects in-line between receiver and amp? What does AT stand for? I do have all equipment powered on a dedicated 20A circuit, with no dimmers on that one circuit. I do have a dimmer in the room, though it's on a separate 15A circuit. Cabling is 80% clean. I could tighten it up a bit, but not much. No power cables are running parallel to any signal cables, certainly. Seems that the most revealing first test to perform is to reconnect the speakers to the receiver, and listen to the speakers. If they are much quieter, then the cause of the current static/hiss/hum must be either the 5 RCA interconnects, or the amp.
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Post by jmasterj on Jan 22, 2014 11:56:23 GMT -5
Thanks Keith,
That's good information. When I responded to the op's post I mentioned how I wasn't as concerned with the little noise I could hear from my equipment. I do however have a question. What is causing the hiss several members say they are experiencing on start up? I have a pair of XPA-100's I have not heard this on my set up but was wondering what it is that might be causing this phenomena any idea?
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rontj
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Post by rontj on Jan 27, 2014 16:21:10 GMT -5
Then one of my tests shall be to kill the circuit on which my dimmer resides, and observe if the static/hiss/hum decreases or not. Thanks for this info, hemster. Yes and if you find that to be the cause, the options are to replace the dimmer with a better one (one that includes choke suppression, especially if the existing dimmer is old and the SCR variety) or install a choke/filter. I still haven't had the time to properly test and try to isolate the cause, but I did shut power to my room's dimmer from the main circuit breaker, and observed no change in the static/hissing from the main left speaker. All my A/V equipment are on 2 dedicated 20A circuits and 1 dedicated 15A circuit.
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rontj
Minor Hero
Posts: 95
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Post by rontj on Jan 27, 2014 16:23:10 GMT -5
Just a few interesting tid-bits..... ALL analog audio electronic components make some noise. "Hiss" is made by every component and circuit; even a passive resistor, just sitting there, will "create" some tiny amount of hiss if you connect it to an amplifier. The amount of hiss will depend on the gain of the amplifier, the value of the resistor, and the amount of current flowing through it - if any. "Hum" is actually the sound of the AC power in your neighborhood. It is loudest near power lines and big transformers, but pretty well saturates the entire civilized world. You may hear mechanical hum from a transformer (because the magnetic field actually makes the wires that comprise the transformer vibrate), and it may find its way into the electronics. My point here is that, with sensitive enough speakers, and a quiet enough room, there is no such thing as an amplifier that makes no noise when its on. ALL amplifiers produce some hiss. The only two questions are whether you will hear (or notice) it under normal conditions, and whether there is hum (and, if so, if it is louder than the hiss). Human ears are amazingly sensitive. In a dead quiet room you can actually hear a pin drop - and hear the hiss of a quiet amplifier at ten paces. (There were studies where certain rooms were found to be TOO quiet; because the room was so quiet, people were distracted by the sounds of papers and clothes rustling, other people breathing, and the humming of the ceiling lights. The solution was found to be to REMOVE padding from the ventilators so the soft "whooshing" of the air would raise the background noise level high enough to cover up the other distracting microscopic noises.) Also, just FYI, most amplifiers make slightly more noise when the input is open (unconnected) than when it is shorted. This is why, sometimes, you actually will hear more noise with nothing connected than, for example, a preamp connected but turned off (when it's off it shorts the input). Contrariwise, the outputs of many pre/pros are shorted when they are on, but muted, but not fully shorted when the power is off (the mute function sometimes actually requires power to "actuate"). This is very enlightening, Keith, and does reduce my concern quite a bit. Thanks for this post. I'll continue to put some effort into trying to isolate the cause, which seems to be isolated to my main left speaker, but I'll have less worry over the issue should I be unable to identify the cause.
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rontj
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Post by rontj on Jan 27, 2014 16:24:49 GMT -5
I guess at this point it should be asked of the OP if they use a power conditioner of sorts as that may cause interference with the amp. Yes, I do use a PS Audio passive power conditioner, and will test plugging the amp straight into the my dedicated 20A wall out, and also a shared 15A wall outlet, to see if there's a difference.
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Post by dean70 on Apr 29, 2014 18:23:06 GMT -5
I have the XPA-5 and XPA-2 & they both have a brief startup "hiss" (the XPA-2 is much shorter in duration). There is also a low level hum which is noticeable when the XPA-5 is on from all speakers (4 x rears & center), which is not present from the front mains connected to the XPA-2 (it is virtully silent - you have to put your ear in the ribbon tweeter horn to hear any hiss). They both run from the same source (PC soundcard) & difference is the XPA-2 is connected to the same double power outlet as the PC, the XPA-5 is connected further away. The speaker cable runs are short from the XPA-2 to the mains, where the rears connected to the '5 are run along the roof space.
Can only put it down to a ground loop or picking up noise from the long speaker cable runs.
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Post by Gary Cook on Apr 29, 2014 19:03:37 GMT -5
I have the XPA-5 and XPA-2 & they both have a brief startup "hiss" (the XPA-2 is much shorter in duration). There is also a low level hum which is noticeable when the XPA-5 is on from all speakers (4 x rears & center), which is not present from the front mains connected to the XPA-2 (it is virtully silent - you have to put your ear in the ribbon tweeter horn to hear any hiss). They both run from the same source (PC soundcard) & difference is the XPA-2 is connected to the same double power outlet as the PC, the XPA-5 is connected further away. The speaker cable runs are short from the XPA-2 to the mains, where the rears connected to the '5 are run along the roof space. Can only put it down to a ground loop or picking up noise from the long speaker cable runs. "Low level hum" usually = ground loop issue. Cheers Gary
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Post by Bmac on Sept 29, 2014 17:37:02 GMT -5
has anyone tried running their xpa-5 through a power conditioner/surge protector like a panamax to solve the hissing problem?
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Post by Gary Cook on Sept 29, 2014 19:02:23 GMT -5
has anyone tried running their xpa-5 through a power conditioner/surge protector like a panamax to solve the hissing problem? I've never encountered "hiss" (high frequency noise) in a power amplifier that came through the power supply. "buzz" (mid frequency noise) I have heard through a power supply but it's very rare. "hum" (low frequency noise) is more likely entering through the power supply ,although vary rarely caused by the power supply itself. In general I have found power conditioners / surge protectors create many times more problems than they solve. I never ever use them with power amplifiers and I avoid (like the plague) using them with any other quality hifi gear. Cheers Gary
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Post by AudioHTIT on Sept 29, 2014 23:33:35 GMT -5
has anyone tried running their xpa-5 through a power conditioner/surge protector like a panamax to solve the hissing problem? I agree with Gary, it would be very unusual for 'hiss' to be affected by a power conditioner. Normally it's either the preamp or power amp, sometimes a source. Have you narrowed it down the the XPA-5? Is it the same in all channels?
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