Moderators Youthman Posted January 13, 2013 Moderators Share Posted January 13, 2013 I have always had a buzz coming through mainly my back right surround. If you get close to the Parasound amp, you can hear a low buzz sound coming from the amp so I figure it is being amplified and sent to the speaker. Tonight, I decided to do some troubleshooting and I unhooked the Monoprice RCA on the amp for the Right Surround and the room was totally quiet. No buzz whatsoever coming through any of the 4 speakers that were being amplified. I assumed it was the amp that was causing the problem and thought if it was, when I unhooked the "source" from that channel, the buzz would remain but that is not the case. So I decided to hook up a non-monoprice RCA for the Right Surround from the UMC-1 to the Parasound amp and what do you know, the hum is there but very faint, unlike the huge hum when using the Monoprice cable. When I use the non-monoprice RCA, I hear a faint humm in all 5 speakers. When I unhook the RCA from the Right Surround channel on the amp, I hear No humm in any of the 4 remaining speakers that are hooked up. The amp is 10 years old. I'm wondering if the caps are going bad and may need to be serviced? Someone once told me caps usually last around 10 - 15 years. Still not sure what it is about the Monoprice RCA that magnifies the humm so much. Any thoughts? Quote Link to comment Share on other sites More sharing options...
babadono Posted January 14, 2013 Share Posted January 14, 2013 Youthman, From the look of your equipment list I suspect you have had to track down problems like this before. If not you are blessed. Please do yourself a favor and go to the Jensen Tranformer website and search their app. notes and white papers. They explain how to systematically go through your system and determine the cause of the problem. Of course they want to sell things also but the amount and quality of the knowledge they dispense for free is awesome. Usually with unbalanced gear it is bad cables and dirty connections or somehow unbeknownst to you a ground loop has been introduced in your system. Happy troubleshooting no affliation with Jensen Transformer babadono Quote Link to comment Share on other sites More sharing options...
Moderators Youthman Posted January 14, 2013 Author Moderators Share Posted January 14, 2013 From the look of your equipment list I suspect you have had to track down problems like this before. No not really. I'm descent at troubleshooting through process of elimination but this one confuses me. Not sure what is the actual cause of the hum. Seems like it's generated from the amp. I'll check out the Jensen Transformer website. Usually with unbalanced gear it is bad cables and dirty connections UMC-1 was purchased brand new in Oct 2011, Cables purchased new from Monoprice in April 2010 when I purchased the Parasound Amp from a forum member. or somehow unbeknownst to you a ground loop has been introduced in your system. I always assumed it was a ground loop. But if it is a ground loop, wouldn't that feed throughout all the other speakers when I unhook the RCA cable for the surround back channel? Quote Link to comment Share on other sites More sharing options...
Moderators dtel Posted January 15, 2013 Moderators Share Posted January 15, 2013 Step away from the energy drink, that buzz is bad for your health. [] Quote Link to comment Share on other sites More sharing options...
K5SS Posted January 15, 2013 Share Posted January 15, 2013 Maybe I should have read this a little earlier... Now I am questioning your advise Quote Link to comment Share on other sites More sharing options...
Moderators dtel Posted January 15, 2013 Moderators Share Posted January 15, 2013 Sorry Youthman, you know I am not normal..... But really have you tried any other RCA cable, I say this because I had a brand new Monoprice cable completely dead out of the box, it was XLR to XLR compleatly dead. I think Monoprice is really nice quality for the price and well made but they are only human, I can't hold one problem against them, I didn't even send it back I had got an extra by accident anyway. One thing I found when I had a buzz show up once overnight for no reason was to play something and move some cables and hope to hear something that would lead to maby a lose connection. In that case when I moved a cable the buzz stopped, I separated one cable from others and it stopped, none were power cables I never had that happen before, a few inches solved the problem ? It was a surprise but it shouldn't have been, I do nothing to manage all the wires back there, it's a birdnest of wires, but you can't see any of it. Good luck Quote Link to comment Share on other sites More sharing options...
Moderators dtel Posted January 15, 2013 Moderators Share Posted January 15, 2013 Maybe I should have read this a little earlier... Now I am questioning your advise It's never a bad thing to compare all opinions, there are always a few oddballs in every bunch. [][] Quote Link to comment Share on other sites More sharing options...
wuzzzer Posted January 15, 2013 Share Posted January 15, 2013 Is it a shielded cable? Have you tried unplugging the cable and reversing its connection? Quote Link to comment Share on other sites More sharing options...
Moderators Youthman Posted January 15, 2013 Author Moderators Share Posted January 15, 2013 Sorry Youthman, you know I am not normal..... I thought it was great. [] I love humor that is in good "taste". Step away from the energy drink, that buzz is bad for your health. Too funny dtel. Surprisingly, I have never had an energy drink. I've taken a sip of my son's but never drank one myself. I have never felt the need for one. I'm pretty high energy without them. Growing up, I was probably ADHD......but we just always called it hyper active back then. I bet my parents wished they had medicine for it. [] But really have you tried any other RCA cable, Yes, take a look at the third paragraph in my original post. I unhooked the monoprice and hooked up a non-monoprice RCA and the hum is WAY less, barely noticable where the Monoprice cable is actually very loud and very noticable. What I don't understand is if I unhook the RCA for the Surround Back completely, I do not get ANY hum from the other 4 speakers. If I plug in the Monoprice Cable, I get a BIG hum. If I switch the Monoprice cable out with a different non-monoprice RCA, I get a very low volume hum. When I bought the UMC-1, I took about 45 minutes to manage all of my cables with zip ties making sure signal cables were away from power cables. The good news is I know I can use a different cable to almost get rid of the hum but the hum is there nonetheless. When I put my ear to my parasound amp, I hear the same hum coming from the amp (pretty faint). That is why I'm thinking it is the amp that is generating this hum and then amplifying it to the speaker. And there must be something wrong with the one Monoprice RCA that is causing it to amplify that sound. there are always a few oddballs in every bunch. They just all seem to collect here in the forum. [] Is it a shielded cable? Have you tried unplugging the cable and reversing its connection? These are the RCA cables I am using from the UMC-1 to the Parasound amp. I'm assuming it's shielded? I have it zip tied to the other RCA cables so I have not tried reversing it to see if I get the same hum. It's pretty difficult to get to them back there. Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted January 15, 2013 Share Posted January 15, 2013 Buzz and ground loop hum. I normally don't group them together. The only time I experienced a true ground loop, it was definitely a hummmmmm, not a higher pitched buzz. I believe ground loops hum at 60Hz. Quote Link to comment Share on other sites More sharing options...
Moderators Youthman Posted January 15, 2013 Author Moderators Share Posted January 15, 2013 The only time I experienced a true groung loop, it was definitely a hummmmmm, not a higher pitched buzz. I believe groung loops hum at 60Hz. The "buzz" is a lower frequency pitch. I went into our music pastor's office to his keyboard and as best as I can tell, on his 71 key keyboard, the sound is very close to the second to the left white key on the keyboard. I sing but I'm not a musician but I know that is definitely not a high pitch sound, nothing like a hiss for sure. I'll record a video with my iPhone and upload it later tonight. Maybe that will help. Quote Link to comment Share on other sites More sharing options...
babadono Posted January 15, 2013 Share Posted January 15, 2013 Youthman, So how is it going? From the way you describe the piano keys it sounds like it is 'hum' you are hearing. As far as the acoustic hum that you hear from the amplifier itself, is it louder than it used to be? Or are you just focusing more on it now? I did a search on that model and found some pictures with the lid off. That baby has a large toroidial power transformer it, it is going to make some noise. It is up to you whether you can live with it or need to seek out a 'quieter' amp. That being said, it is possible that the capacitors are aging but I think 10 years is a little premature. I know it has only been overnight but have you checked out Jensen's website? Do you have some RCA shorting plugs or cables? Your going to need 5 for your 5 input amp. Basically to start and eliminate the Parasound amp from being the problem you need to: 1. Turn off the amp. 2. Disconnect all the inputs from the Emotiva Pre and install the 5 shorting plugs on the inputs.3. Leave your speakers hooked up. 4. Turn the gain controls fully clockwise if they aren't already. 5.Turn on the amp. You now have all the inputs of the amp directly tied to the amp's ground. This is the best it is going to get. You should only hear gaussian noise eminating from your speakers or if there is some hum it should be very low level. Is the level acceptable to you? If 1 channel is noticeably less quiet then maybe you do in fact have an amp problem. Parasound's website says each channel has its own power supply and therefore it could just that 1 supply. If the noise level is acceptable you must work your way back towards the inputs one tedious step at a time. babadono Quote Link to comment Share on other sites More sharing options...
Moderators dtel Posted January 15, 2013 Moderators Share Posted January 15, 2013 When I put my ear to my parasound amp, I hear the same hum coming from the amp (pretty faint). I have the same problem with the 2 little Crown D-75's, they have a little hum in the amp itself, the speakers a quiet to my ears ? Sounds about like the hum from a computer but the Crown's do not have a fan, you can't hear it with music playing even at the lowest levels. Quote Link to comment Share on other sites More sharing options...
babadono Posted January 18, 2013 Share Posted January 18, 2013 Youthman, I use those Monoprice RCA cables to go from my AVR to my powered subs. Mine are OK. Perhaps you got one bad/marginal one. I talked to Monoprice Tech Support and they said they use RG-6 quad shieled to build those cables. I took the back shell off of 1 of mine and found out they 'pot' the connections so they cannot be reworked. The shield connection resistance should be extremely low with quad shielded cable but perhaps they did not do a good soldering job on 1 of your cables. Do you have an extra? or is your problem fixed? babadono Quote Link to comment Share on other sites More sharing options...
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