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Post by alucard on Jul 7, 2017 19:49:10 GMT -5
Hello,
I bought my first external amp (class a/b) maybe 5 years ago. Sold it because it made my speakers buzz and continued using my Anthem MRX receiver. The MRX did not cause my speakers to buzz at all - dead quiet.
I moved to another house a couple years later and wanted to give amp+pre/pro a try. Sure enough the speakers buzzed again. And I dont mean putting my ear to the speaker - I mean sitting at the listening position. I even noticed my sub's amp had a slight buzz and the amps (3ch+2ch) had minor buzz. I was about to give up, but found jensen iso max eliminated the buzz from the speakers. I tolerated the minor buzz from the amps.
Recently, I sold the 3ch and 2ch amps because they would not fit in a new TV stand. Tired of listening to TV speakers I used my emo A-100 to power the front speakers while I waited for a 5ch class D amp to be delivered. I did not use the iso max with the A-100 and the amp and speakers were dead quiet. Why was this? Excited to get the 5ch amp I hooked it all up just a couple hours ago (no iso max) and the speakers buzz again. And to top it off, the map hisses quite loudly. Too distracting to leave it in. So it's sitting in the box to decide what to do next.
Both of these homes are over 30 years old. I have confidence that there must be some ground fault or other electrical issue. I'm going to ask an electrician to come out and test, but can they really find the exact cause and fix it. I'm almost at the point to give up and go back to an AVR.
I do wonder why the A-100 did not have this issue and wonder if any of Emos 5ch amps would, such as the A-5175 or A-500.
Onward and upward, I hope.
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Post by socketman on Jul 7, 2017 20:29:10 GMT -5
If the new amp has a 3 prong plug try lifting the ground by using a 3 prong to 2 prong converter. I use a 2 prong extension cord and cut the knob off that blocks the 3rd prong. I lived in an old house before this house which is newer and the old house was a nightmare. I had to lift the grounds and power part of my system with an extension cord running down my hallway from the kitchen to prevent ground loops. Cable tv can cause ground loops as well and you may need to add a baluns to filter the noise. Try running with only minimal amount of connections to the pre keep unplugging stuff till the noise goes away.
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Post by lehighvalleyjeff on Jul 7, 2017 21:05:44 GMT -5
From personal experience it sounds like a ground loop. Very simply disconnect the cable or sat connection coming in from the wall. If the buzz disappears that's the culprit.
Also try a cheater plug (if you have a three prong plug on the amp try a two prong converter).
Hope this helps.
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Post by alucard on Jul 7, 2017 21:21:17 GMT -5
Thanks for the responses. While I don't have cable or satellite box connected to anything, the house is wired (sat attached to house). Could be a hidden box connected to the power? The amp does have 3 prongs and I tried a cheater plug already. No luck.
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Post by socketman on Jul 7, 2017 21:30:31 GMT -5
if you just have the speakers connected to the amp but not to the pre/pro do you still have a noise. also is the noise noticeable in all five speakers. If you have a piece of extra speaker wire you could try connecting between the amp and pre pro cases to create a ground between the 2 . I have been through this with a phono preamp and turntable and it can be a nightmare to clear up. Emotiva has a device that aparently works really well in this situation . emotiva.com/products/emotiva/accessories-0 |
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Post by alucard on Jul 7, 2017 22:01:39 GMT -5
if you just have the speakers connected to the amp but not to the pre/pro do you still have a noise. also is the noise noticeable in all five speakers. If you have a piece of extra speaker wire you could try connecting between the amp and pre pro cases to create a ground between the 2 . I have been through this with a phono preamp and turntable and it can be a nightmare to clear up. Emotiva has a device that aparently works really well in this situation . emotiva.com/products/emotiva/accessories-0Speakers and amp still made noise when only speaker cable and power cable to amp was connected. I put the amp in another room and only connected the power and the amp made noise. I can mitigate the speaker noise with the iso max - just prefer not to have all that clutter. That'll hold me over till I move next summer. I just need to find a solution for the amp noise. I have tried AVA Hifi humdinger and the Emo CMX-2 on the previous amp (class a/ab) and my sub and it did not help with those. I returned those and now hesitant to try those particular ones again with this new amp. |
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Post by socketman on Jul 7, 2017 22:16:41 GMT -5
well i understand your trepidation but i read good things on the forum here. Can i ask what brand the new amp is. I bought a $500 phono preamp from a reputable place and i tried everything to make it quiet i finally sent it back and bought a Project tube box($750) and all was quiet,perhaps something happened in shipping. Can you take it to a freinds house and try it plugged in there or maybe go to the neighbors house and plug into their outside plug LOL> Sorry i missed that you tried the cmx2 , so thats definitely not worth trying again , the 6 just has more outlets.
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Post by Gary Cook on Jul 8, 2017 0:19:43 GMT -5
Hummmmmm (as it sounds, is low frequency) around 50 Hz is most commonly earth loop issues with one or more pieces of gear. Buzzzzzz (as it sounds, is mid range) is not earth loop, it's commonly noise introduced by one or more of the pieces of gear. It may also be introduced via cables, interconnects or speaker cables with the source most likely being some other piece of electrical equipment, light dimmers are a common cause. Hissssss (as it sounds, is high frequency) usually comes from within the equipment itself a,though it can come from speakers acting as antennas.
With the above in mind the first step is to identify the approximate frequency, is it a hummmmm, a buzzzzz or a hissss. There are apps for phones that can display the frequencies they hear, that's more accurate than listening with ones ears.
Cheers
Gary
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Post by bluemeanies on Jul 8, 2017 6:47:42 GMT -5
 Having your electrician in is not a bad a idea and will give you peace of mind. I have been in similar situations more than once especially after introducing a new piece of equipment into the system. What I recommend and this takes time and patience but I believe will solve the problem. First, let me say the those 3prong plugs are there for a purpose. I would disconnect EVERYTHING. Set all components aside...clean everything, especially the terminal areas. Start your setup once piece at a time and starting with your receiver or processor. Turn them on. If there is no noise make the connections to your speakers turning off your power source first. If still no noise introduce each additional piece of equipment one at a time turning them on. I would also recommend a manual ground fault protector. Home Depot sells them and they are reasonably priced. They have single units and also units where you can plug up to 3units into the the protector. Try plugging your amplifier or amplifiers into the same circuit. Hope this helps. |
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Post by garbulky on Jul 8, 2017 7:25:20 GMT -5
You've probably tried this already but you have to figure out which thing is the source of the buzz or at least backtrack it as much as you can. Like does it start at the pre pro or does it start at a cable box.
Then once you've determined which one, change out all your cables. It could be a faulty cable if it's that loud. This includes interconnects or even power cables.
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Deleted
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Post by Deleted on Jul 8, 2017 8:18:57 GMT -5
Wall warts (I hate them) somewhere in the house- they're cheaply made & induce noise on the line. Look at telephones, routers, DVD players, computers, cellphone chargers, electric toothbrush, etc.
My A/V systems all have dedicated/isolated AC lines- separate circuit breaker, hot, neutral & ground from breaker box to wall plug and I still get noise sometimes due to wall warts.
Tighten all breakerbox connections and wall plugs & switches.
Another possibility is rheostats (dimmers) on lights. I have also seen working wall switches that have dirty contacts cause noise, even loose lightbulbs.
Two wires running parallel- one carrying high current inducing noise into the other.
Last but not least- aluminum wiring that was copper pigtailed. Aluminum wiring is now illegal (fire hazard) and to make code, they pigtail 18" of copper to plugs & switches. Copper & aluminum create oxidation if not treated with special chemical & specially made connectors to join them.
If that doesn't get to the most likely cause, then you may have to O'scope the noise & trace it to the source- good luck with that.
Hope these most common causes helps you find the culprit.
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Deleted
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Post by Deleted on Jul 8, 2017 8:56:47 GMT -5
This may be a stupid question, but have you made sure the circuit breaker box has a good earth ground going to a 8 foot copper rod in the ground, outside your house?
Has there been an additional service breaker box added? maybe in garage, outside or AC compressor kill switch?
If those are not physically ground connected either by medal conduit or ground wire, you have an issue.
Forgot to mention a simple test- get a digital VOM (rms preferably) and measure ground to neutral at the ac plug to your amp. Ideally it should be 0 volts. If you read anything above .5 to .75 volts ac, you have a wiring problem, especially if you read 2vac or more.
Incorrect grounding or undersize wire gauge.
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Post by vneal on Jul 8, 2017 9:21:48 GMT -5
From personal experience it sounds like a ground loop. Very simply disconnect the cable or sat connection coming in from the wall. If the buzz disappears that's the culprit. Also try a cheater plug (if you have a three prong plug on the amp try a two prong converter). Hope this helps. I agree that this is where you start. If no solution start unplugging any sources one by one. I have had two ground loops in 35 years of audio and one was involved with a cable connection the other was from a wall wort from a phono pre amp. No cheap wall wort supplies for me of any kind. Happy unplugging! All suggestions above are good ones. With properly designed modern equipment it should be dead silence |
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Post by Axis on Jul 8, 2017 9:25:50 GMT -5
Hello, I bought my first external amp (class a/b) maybe 5 years ago. Sold it because it made my speakers buzz and continued using my Anthem MRX receiver. The MRX did not cause my speakers to buzz at all - dead quiet. I moved to another house a couple years later and wanted to give amp+pre/pro a try. Sure enough the speakers buzzed again. And I dont mean putting my ear to the speaker - I mean sitting at the listening position. I even noticed my sub's amp had a slight buzz and the amps (3ch+2ch) had minor buzz. I was about to give up, but found jensen iso max eliminated the buzz from the speakers. I tolerated the minor buzz from the amps. Recently, I sold the 3ch and 2ch amps because they would not fit in a new TV stand. Tired of listening to TV speakers I used my emo A-100 to power the front speakers while I waited for a 5ch class D amp to be delivered. I did not use the iso max with the A-100 and the amp and speakers were dead quiet. Why was this? Excited to get the 5ch amp I hooked it all up just a couple hours ago (no iso max) and the speakers buzz again. And to top it off, the map hisses quite loudly. Too distracting to leave it in. So it's sitting in the box to decide what to do next. Both of these homes are over 30 years old. I have confidence that there must be some ground fault or other electrical issue. I'm going to ask an electrician to come out and test, but can they really find the exact cause and fix it. I'm almost at the point to give up and go back to an AVR. I do wonder why the A-100 did not have this issue and wonder if any of Emos 5ch amps would, such as the A-5175 or A-500. Onward and upward, I hope. Send whatever amp you bought back as soon as you can to get a refund. Buy the Emotiva amp of your choice. Call a qualified Electrician if you still have a ground hum. Have a nice day !  |
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Post by alucard on Jul 8, 2017 9:46:09 GMT -5
Thanks for all the replies. I will start with having the electrician check for earth ground, etc. I'll also test using a ground fault protector.
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DYohn
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Posts: 18,489
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Post by DYohn on Jul 8, 2017 10:04:23 GMT -5
The most common name for the problem you appear to have is DC offset on the ground line. This is usually caused by something plugged in or wired to your house although a bad house main ground might cause it too. Look for things like a coax-fed cable TV box (satellite might be able to cause it too), an old refrigerator or freezer in the house, a dimmer on a lamp or wired into a wall light circuit, or a cheap wall-wart power supply. It can also be caused by other houses on your block that happen to be on the same power feed, but since it moved with you I suspect it is something you own. The best way to track it down is painful and time consuming as it means unplugging everything in your house except the sound system to see if it stops, and if it does then to plug things back in and turn them on one at a time to identify when the humm returns. Then eliminate that item. The Emotiva CM2 can help if only the amp is plugged into it (it did in my case) but if the problem is severe enough perhaps not. There are other power devices that can help, but the best solution is to identify and get rid of the actual cause.
Another issue could be your preamp. What are you using?
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Post by alucard on Jul 8, 2017 10:44:07 GMT -5
Another issue could be your preamp. What are you using? Thanks for the response. I'm using the Emo XMC-1. |
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Post by alucard on Jul 8, 2017 10:46:50 GMT -5
I left the amp on overnight and no longer hear the amp noise from the listening position. Up very close, the amp sounds like a quite laptop. Still have speaker buzz but will resolve that with an isomax. I will still have an electrician conduct a check out.
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DYohn
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Post by DYohn on Jul 8, 2017 10:59:03 GMT -5
Another issue could be your preamp. What are you using? Thanks for the response. I'm using the Emo XMC-1. OK so this is home theater we are talking about and not 2-channel, yes? Does the XMC-1 use a three-prong power cable or two-prong? First try disconnecting all interconnects from pre/pro to amp and see if the hum is in the amp by itself. You can then try unplugging all inputs to the XMC-1 (especially HDMI) and see if the issue changes. And lastly if none of those things change the issue, try taking a piece of speaker wire and touch one end to the metal case of the pre/pro and the other end to the metal case of the amp. If none of those things has any effect then the issue is coming from the power system in your house and we are back to probable DC offset. |
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Deleted
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Post by Deleted on Jul 8, 2017 11:01:27 GMT -5
I can almost guarantee, your problem is one of my suggestions- barring bad equipment.
I was an Electronics Field Service Specialist in my previous life and these are the types of problems I was called in to solve.
I don't mean to disparage the average electrician, but many will not find electrical noise issues (other than loose connections), a master electrician may.
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