|
|
Post by Talley on Feb 4, 2016 8:57:09 GMT -5
First off.. I'm a Texas Master Electrician... I'm well aware about transformers. Second... my 18 day old XPA-7 I just realized has it's toriodal transformer humming. It's not loud... it's faint... but audible within a few feet from the amplifier.... much more noticeable when you turn the amplifier off and hear the quiet.
Defect or normal? and if normal then why have I never experienced this with any other amplifier before?
|
|
kazoo
Emo VIPs 
Posts: 359
|
Post by kazoo on Feb 4, 2016 9:03:57 GMT -5
First question to you, did you install any new components in the house lately. Not audio related but house stuff. Like dimmer switches, microwave, fridge?
I had a massive hum on my Adcom also. Was never there and then one day I noticed it. It was pretty loud. Found out I had DC voltage on my AC lines, I measured it with my meter. I could not find what was causing it so I had to order the Emotiva power strip that has the DC blocker built in. It worked like a charm. See if you have DC on your AC lines that is causing your amp to hum. I think mine was caused by a fan controller that was going bad.
|
|
|
|
Post by Talley on Feb 4, 2016 11:55:17 GMT -5
hadn't checked the DC yet but no there was nothing new added....
..remember though if your being fed from a transformer that is feeding your neighbors house it could be their house that is causing the problem as well. I've seen this done.
This is the reason I'm going to switch my feeder circuit to 240v tonight to see if this elmininates this because my 240v is a balanced supply. Shouldn't be any dc on it at all and should quiet everything down. Will try this out first before contacting Emotiva about the noise.
|
|
|
|
Post by vneal on Feb 4, 2016 11:56:48 GMT -5
DEFECT
SHOULD BE DEAD QUIET
|
|
|
|
Post by Talley on Feb 4, 2016 12:40:27 GMT -5
DEFECT SHOULD BE DEAD QUIET Really just like that?... My experience as an electrician and installing transformers are the ones who hum right off the bat always do and the ones that are quiet are always quiet until stressed. I was thinking defect too originally. |
|
|
|
Post by jmilton on Feb 4, 2016 13:00:45 GMT -5
hadn't checked the DC yet but no there was nothing new added.... ..remember though if your being fed from a transformer that is feeding your neighbors house it could be their house that is causing the problem as well. I've seen this done. This is the reason I'm going to switch my feeder circuit to 240v tonight to see if this elmininates this because my 240v is a balanced supply. Shouldn't be any dc on it at all and should quiet everything down. Will try this out first before contacting Emotiva about the noise. One could always move to a quieter neighborhood...  |
|
|
|
Post by Talley on Feb 4, 2016 13:19:38 GMT -5
hadn't checked the DC yet but no there was nothing new added.... ..remember though if your being fed from a transformer that is feeding your neighbors house it could be their house that is causing the problem as well. I've seen this done. This is the reason I'm going to switch my feeder circuit to 240v tonight to see if this elmininates this because my 240v is a balanced supply. Shouldn't be any dc on it at all and should quiet everything down. Will try this out first before contacting Emotiva about the noise. One could always move to a quieter neighborhood... Isolation transformer... done. |
|
|
|
Post by 509Paul on Feb 10, 2016 0:06:57 GMT -5
My XPA-7 was quiet in the beginning but developed a loud buzz in both the transformer and the speakers after a couple months of use. I was unable to change anything in my setup to remove the noise including buying a CMX-2 for DC noise. It was unbearable to listen to so I sent it back for service. They called me and said it had no abnormal noise with all the full load tests. My XPA-2 is dead quiet so I am unsure what the problem is with the XPA-7. Emotiva agreed to refund the XPA-7 and I am going to try the XPA-5 instead once they get a new shipment in. One point they suggested is that Panasonic plasma TVs cause a lot of line noise if you have one.
|
|
|
|
Post by Talley on Feb 10, 2016 6:23:46 GMT -5
My XPA-7 was quiet in the beginning but developed a loud buzz in both the transformer and the speakers after a couple months of use. I was unable to change anything in my setup to remove the noise including buying a CMX-2 for DC noise. It was unbearable to listen to so I sent it back for service. They called me and said it had no abnormal noise with all the full load tests. My XPA-2 is dead quiet so I am unsure what the problem is with the XPA-7. Emotiva agreed to refund the XPA-7 and I am going to try the XPA-5 instead once they get a new shipment in. One point they suggested is that Panasonic plasma TVs cause a lot of line noise if you have one. Nope... no plasmas. Just a few LCDs. |
|
|
|
Post by NotTheHerbie on Feb 10, 2016 8:56:24 GMT -5
When I received my XPA-7, I was in the middle of a home theater makeover that included an XMC-1. I found I had two sources of hum in my system. One was courtesy the cable company. I inserted an isolation transformer before the coax touched any piece of gear and it eliminated the 60 Hz hum heard through the speakers, but I still had a mechanical transformer hum I could hear coming from the XPA-7. There was also a more faint hum I could still hear through the speakers. Taking a chance on it being a DC offset on the AC lines I added a CMX-2, and that eliminated the rest of hum, both mechanical and electrical. FYI, I had an XPA-3 previously installed in about the same location and had no transformer hum. I'm guessing the XPA-7 (or my copy of the XPA-7) is more susceptible to DC induced hum.
- Mike
|
|
|
|
Post by 509Paul on Feb 10, 2016 10:19:30 GMT -5
I am ulso unsure why the XPA-7 has a ground pin on the amp plug when none of the other XPA series amps appear to have one.
|
|
|
|
Post by Talley on Feb 10, 2016 15:52:36 GMT -5
I prefer the ground pin. I have an CMX-2 arriving tomorrow. Hope it works  |
|
|
|
Post by Talley on Feb 12, 2016 22:41:14 GMT -5
CMX-2 didn't change anything but I did resolve most of the issue. Changed the feed from my main panel to my dedicated AV panel from 240V to 120V only and unplugged everything from the entire system to leave just a xpa-7 by itself and my speakers hooked up and the transformer is quiet to the point there is only a faint hiss from within 6" of the toriodal. I find this to be acceptable. No way it was like it was before.
Now to continue finding the audible issues coming out of the speakers. Soon as I plug in the RCA from the XMC-1 I get an audible buzz. seems like XLR connectors are the first option to see if this noise gets removed.
|
|
|
|
Post by 509Paul on Feb 12, 2016 23:32:38 GMT -5
I tried XLR cables and EVERY possible troubleshooting step with the XPA-7. I think that amp was flawed from the start and it is strangely no longer available after its short lifespan. I swapped the very noisy XPA-7 out and put a XPA-2 in its identical place without changing anything except not being able to connect the remaining 5 XLR cables and everything is dead silent. I refused the XPA-7 from service and hope the XPA-5 I ordered is as quiet as the XPA-2.
|
|
|
|
Post by Talley on Feb 12, 2016 23:36:19 GMT -5
I tried XLR cables and EVERY possible troubleshooting step with the XPA-7. I think that amp was flawed from the start and it is strangely no longer available after its short lifespan. In the end you got rid of it? |
|
|
|
Post by 509Paul on Feb 12, 2016 23:39:46 GMT -5
Yeah, I refused the XPA-7 from service and they are sending me a XPA-5 instead.
|
|
|
|
Post by Talley on Feb 13, 2016 8:24:58 GMT -5
Yeah, I refused the XPA-7 from service and they are sending me a XPA-5 instead. Could just be a sensitive machine. I'm going to guitar center today to pick me up just one xlr cable for cheap to see if that fixes the noise. if it doesn't then i'll try an input isolator transformer on the interconnect to see if that works. |
|
|
|
Post by 509Paul on Feb 14, 2016 11:48:00 GMT -5
Did you find the issue an track down the buzz source with the cable swap?
|
|
|
|
Post by Talley on Feb 14, 2016 12:56:47 GMT -5
Did you find the issue an track down the buzz source with the cable swap? I'll post what I made on another site: Something I did made a huge.... massive improvement in my sound. I've been troubleshooting some speaker noise that appeared from the new xpa-7 and also having to deal with the transformer noise from the unit too. Unfortunately I did too much to isolate where this improvement came from but I will clue on on what I did: 1. The transformer noise was 90% eliminated when I changed my dedicated AV breaker panel from 240/120v to a straight 120v from the same phase off my main panel. It took me removing everything from the amp and unplugging everything from the wall except for the amp before I could see the improvement. Once I removed one leg off my 60a 240v breaker in my main panel and installed a jumper in my AV breaker panel to make both legs in that panel the same phase... the transformer now just barely makes a noise and have to be within 3" of the unit to hear anything and it's really really faint. SOLVED 2. I've had issues with the high frequency buzzing noise from the midrange/tweeter and I was able to isolate this to the RCA cables. I picked up two CHEAP 5' long XLR cables from guitar center and that noise is essentially removed when using those to the point there is nothing audible I'm looking into some inexpensive XLR interconnects now so if anyone has any recommendations please let me know. I cannot move forward until I have my amp/xmc connected with balanced cables to see if any of the other equipment increases the noise. I also have the CMX-2 installed on the amplifier and pre-amp right now as well so not sure if it made any "audible" improvements however it did not eliminate any transformer hum or noise from the speakers. Only the XLR interconnects did that. Using two of the XLR cables I picked up I can listen to musice and the difference was astonishing. I'm not good at explaining it but the cymbals were so lifelike and the pinpointing of instruments were extremely precise but the biggest difference was some kind of spacious sound that made you feel like you were in the room. It's obvious that having noisy speakers cripples critical listening. The krell I got pretty quiet but unfortunately the XPA-7 seems to be very sensitive... fixing it's woes really improves the sound. |
|
selkec
Emo VIPs
SCREW YOU GUYS, IM GOING HOME!!!
Posts: 3,779
|
Post by selkec on Feb 15, 2016 15:38:45 GMT -5
My XPA-7 was quiet in the beginning but developed a loud buzz in both the transformer and the speakers after a couple months of use. I was unable to change anything in my setup to remove the noise including buying a CMX-2 for DC noise. It was unbearable to listen to so I sent it back for service. They called me and said it had no abnormal noise with all the full load tests. My XPA-2 is dead quiet so I am unsure what the problem is with the XPA-7. Emotiva agreed to refund the XPA-7 and I am going to try the XPA-5 instead once they get a new shipment in. One point they suggested is that Panasonic plasma TVs cause a lot of line noise if you have one. Yeah. I had a panny plasma a while back and it made some of my emotiva Amps humm! Sold the panny... a year later got a samsung plasma and thought I woild give the amp a try again... this plasma also causes hum... im now selling off all plasmas I own. I need amps that do not hum. I returned both the amps also |
|
