slight amp buzz

[scarpi]

I just noticed my B&K Reference 200.5 series two amp puts out a low volume buzz from all five of my speakers. You have to be within about three feet of the speakers to hear it. It is independant of the volume control on my preamp and is still present if all my gear is off except the amp (so it is coming from the amp). When you put your ear on the amp itself there is no noise. It only comes out of my speakers. Anybody else have the same issue with this amp? Is it normal? Of course when you play movies or music at a normal level the buzz is not audible. The amp is on a dedicated 20 amp circuit.

[Glen B]

Unplug all input connections from the amp [make sure the power is off], power it up and see if you're still getting the buzz. Don't forget to turn the power off before you reconnect everything. Are your ICs routed away from power cords ? If not, they can pickup hum. How sensitive are your speakers ? Very sensitive speakers can make modest levels of system noise more audible than ones of average sensitivity.

[scarpi]

Unplug all input connections from the amp [make sure the power is off], power it up and see if you're still getting the buzz. Don't forget to turn the power off before you reconnect everything. Are your ICs routed away from power cords ? If not, they can pickup hum. How sensitive are your speakers ? Very sensitive speakers can make modest levels of system noise more audible than ones of average sensitivity.

Thanks for the reply Glen. I will try your suggestions. My system is a nice system but the wires behind it look like piles of spaghetti all over the place. And to make matters worse it is very hard to get back there. But I will try. Not only do I have all the av gear but also there is a 350 lb CRT Mitsubishi tv in the middle of it! To answer your questions, my ICs are not totally separated from my power cords, and my front three speakers are Paradigm studio 100s v2 (about 88 - 90 db sensitivity). The interesting thing is that the left front speaker has the loudest buzz, the right front speaker is a little quieter, and the center speaker has almost no buzz - you have to put your ear a few inches from that speaker to hear it there. My surround speakers are Kilpsch on walls and I really don't hear any buzz from them. Of course they are about 7 feet up on the side walls. Well, this will make a nice project for today. I hope nothing is wrong with my amp because recently I've had alot of equipment in and out of this system (repairs, replacements etc) and I'm getting tired of crawling behind it (I'm not as young as I was in 1975). My wife is beginning to think I'm nuts. It truely is a wire mess. I actually think that I need a better rack. My amp is on the bottom shelf about 2 inches off the floor and all the cables and power cords are near it. It's almost like the whole system needs to be taken apart and put back together by a professional who knows how to really organize the cables and has young knees and back. Sorry for the long answer Glen, (you can tell I'm alittle frustrated) but I will try your suggestions and again I appreaciated it. ;x(

[John Holmes]

Dmantis, can probably give you some advice on this. From what I recall, this was not uncommon with the B&K amps.

[John Holmes]

scarpi,

Since you've begun to get answers here, I deleted the other thread.

[scarpi]

Thanks John. Well I spent the better part of today rerouting electric cords and bundling signal cords away from power cords. I also was able to remove two extension cords that I did not need after organizing the gear better. Then I spent some time checking my interconnects and for some reason two of them had loose end plugs that I screwed tight. I don't know the correct term for them (they are the male plugs on the end of the cord ). Then I rerouted my left and right interconnects to try and give them more space from other cables. I then turned only my amp on and the buzz is basically gone. To hear it you have to put your ear a few inches from the left or right speaker now whearas before it was audible from a few feet away. So here is the topper of the story. After doing all of this, I go to turn on my amp to listen to some music. I just recently had a dedicated 20 amp line installed for this amp. So I turn on the amp and after about two seconds it turns off and I notice my 20 amp Panamax suppresor that is on that line shut off the power. So I go out to the electrical box and I see the breaker is red and needs to be reset. Well I thought no big deal but it did seem kindof strange. So I go to reset the breaker and the breaker comes out of the electrical box. Gee I guess the electrician didn't do too good of a job installing the breaker in the box. Thank goodness I had my Panamax on line or maybe the improperly installed breaker might have sent some kind of surge to my amp. So now I have to wait for the master electrician to call me and set up a time to come back to install the breaker properly (you know so it doesn't fall out of the panel). :M Thanks guys for your input, I think this problem is solved.

[scarpi]

To end this story, the electrician came back out and put in a new beaker and all is well. The first one had a bad clip so it did not stay on the connector in the house electricial box thereby shutting off the power. Weird but all is ok that ends well. :B

[John Holmes]

Glad it is all worked out.

[Glen B]

To end this story, the electrician came back out and put in a new beaker and all is well. The first one had a bad clip so it did not stay on the connector in the house electricial box thereby shutting off the power. Weird but all is ok that ends well. :B

Was it an arc fault breaker (should have test buttons on it) ? That may explain why it tripped from a loose connection. That's a good thing. A standard breaker would likely have kept arcing repeatedly at the contact point, causing burning and pitting, or worse, a fire.

[scarpi]

No it did not have any test buttons on it. Basically the contact clips did not hold it tight in the box so it actually sprung off the house box connection causing the power to go off to my amp. The electrician told me later that he used a "restored" breaker (read used). He replaced it with a new one that grabs tight when snapped in place and no problems anymore. Gee you'd think for $300 he would have used a new one in the first place. I didn't know he put in a used breaker at first.