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Discussion Starter · #1 ·
I've just added a Carver amp to my Yamaha reciever. As soon as I turn on the tv (Sony-34xbr800), my speakers start to buzz/hum. I've checked with every components that connected to the system, and it's the tv that causes the buzz.


I never had this problem before I added the amp. So, is it the amp or the tv? Is there anything i can do to solve this?


Thank you for reading
 

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Hmmm. You didnt' have this problem until you added the Carver amp? Certainly could be a ground loop issue. Here are some questions I have:


* How is the TV connected to your receiver?

* Does your TV have a cable TV RF cable connected to it?

* If so, what happens if you disconnect your cable TV cable from the TV and leave everything else connected?

* Did you change any wiring when you added the Carver amp?

* How is the receiver connected to the amp?

* Providing your model numbers and equipment age might help, too.

* Also, let us know what your AC wiring is like -- is this an older home?


These kind of problems can be a pain in the *ss to troubleshoot. They key is really isolate which component and/or cable is causing the problem.
 

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I got rid of my ground loop problems (loud hum) of my two independent power amps (crown and alesis) which were part of my 5.1 setup. I simply added those adapters sold in hardware stores on the end of each amp's wall plug to transform the three pins to two pins thereby isolating the grounds of each amp.


I live in Canada and I don't know if these adapters (cost a dollar each) are legal and sell in the U.S.A.
 

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Discussion Starter · #4 ·
Thanks for the reply,


Here is the connection before adding the amp (no buzz/hum):


My TV (Sony 34XBR800) is not connected directly to the receiver (Yamaha RXV630) nor the outdoor antenna. For audio, I have my dvd player (Panny RP82) via optical and HD tuner (Zenith 420) via digital coax, connected to the receiver. For video, they both are connected to TV via component cables. All of these equipments are connected to a new dedicated circuit.



Then just last weekend I added the amp (Carver AV806X). I didn't make any changes to the connection except connecting it to the receiver via digital coax cables and moving the speaker cables from the receiver to the amp.


Here is the problem:


When I turn on the HD tuner and/or playing dvd, my speakers buzz/hum if my TV is on. If I turn off just the TV and leave the dvd player and/or the HD tuner on, the buzz/hum stops. When I disconnect my outdoor antenna (which is grounded) from the HD tuner and TV, the speakers (Infinity RS) still buzz if the TV is on. I've tried connecting my TV to a different circuit, and it still causes the buzz.


I house is an older home but again, all my equipments are connected to a new dedicated circuit which I think is connected to the same ground.


BTW, my amp and TV (and the rest) are 2-plonge plug, connected to a surge protector.


Thank you for reading
 

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Couple of things to check.


First, is the surge suppressor good quality. You may be getting interference passed through that. Especially if its not really a surge suppressor but just a normal power strip.


Second, does the amp sit right next to the tv? Maybe the amp is picking up some interference from the tv.
 

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I also wondered if maybe your new amp is picking up some interference from the TV. How close together are they? Do you get the buzz if you remove all the cables connected to the TV?


The challenge here is to figure *how* the buzz is coupling into your amp -- is it radiated or conducted via cable -- and which device is the root cause. I would suggest disconnecting all of the devices from the TV and Receiver, and just leave the Receiver connected to your new amp. Turn everything on and see what happens. If things are quiet, then try reconnecting each device one-at-a-time until the buzz returns.


Post back with what you find.
 

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Discussion Starter · #7 ·
Thank you for the reply,


The amp is now sitting about 12 inches right above the TV.


I'll try to do what you guys have suggested, and I'll post the result tomorrow.


Thanks again
 

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Discussion Starter · #8 ·
Well guys,


I've disconnected everything from the receiver except for the amp, and the buzzing is still there (when the TV is on). Then I've disconnected everything from the TV, and guess what? the buzzing is there. I've even tried the 2-pronged plug on the surge protector, and the buzzing is still there. It just keeps on buzzing, and buzzing...and buzzing like energizer bunny. I haven't tried moving the amp away from the TV yet, my cables are not long enough. Any other suggestions?


Thank you for reading


A. Dejkorn
 

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So even with ALL cables disconnected from the TV and receiver -- except for the receiver-to-amp cables -- the buzzing still remains. We're getting close:


* What happens if you disconnect the cables between the receiver and amp? Leave the speaker cables connected first.

* If the buzzing remains with ALL cables disconnected (except speaker cables), then you know something is getting in either through the air (RF), or perhaps AC line (although your 2-prong adapter would remove the ground as a factor -- which device(s) have you tried the 2-prong adapter on?)

- now try moving the amp farther away from the TV. If the buzz gets quieter you can be pretty sure it's coupling somewhere via radiated RF

- if distance makes no difference, it's certainly coupling via the AC line


* If the buzzing is gone with the cables between receiver and amp disconnected, I would try a couple of things:

- try different cables [to rule out a bad cable shield]

- try connecting cables to JUST the amp (leave the connections to the receiver disconnected) [to see if RF is coupling into this cable]


Another thought ....

With all the cables disconnected, try using your headphone jack. Do you hear the buzz? Not sure if your receiver and amp both have headphone jacks, but if so, try them both.


And to be complete it might be worth moving the speaker connections back to the receiver just to verify that the problem is gone there.


We'll solve this one yet.
 

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Discussion Starter · #10 ·
Thanks litzdog,


I'll try that tonight.


Meanwhile, I'm beginning to think, it's the radiated RF and not the AC line. I've tried connecting the surge protector with the 2-prong plug and plugged into the wall outlet, it's still buzzing.


Thank you for reading


A. Dejkorn
 

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Let us know what you find tonight. If it does turn out to be radiated RF interference, hopefully you can solve it by moving the amp away from the TV. It's certainly unusual for a high-end TV and amplifier to exhibit this sort of problem. You might want to see if the dealer would let you try a similar setup at their showroom, or take your amp back to them and try it there, or perhaps swap it just to try a different amp in your system.
 

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Discussion Starter · #12 ·
litzdog,


I got home very late last night, so didn't have time to move the amp. Though I did try disconnecting the cables from the receiver with the speaker cables still connected to the amp, the buzzing was still there.


This weekend I'll try moving the amp away from the TV. If the buzzing is still there, I'll swap out the Sony with my bedroom TV.


I bought the amp used from Audiogon, and doubted I could return it.


Thank you for reading


A. Dejkorn
 

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Try grounding out the inputs to the amp. Do this by taking a RCA male to RCA male patch cord and with the free end, short the center pin to the sleeve with a screwdriver. Also try moving slightly the volume control(s) on the amp if they exist. Sometimes the input circuit of an amp (or volume control wiper) can end up floating and this causes EMF to be picked up and amplified. Good luck.
 
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