Hello all. My father has an ADCOM GFA545 that has a problem with a buzzing transformer. The sound does not come from the speakers and is only prevalent when plugged into sockets in a certain room. I am certain that the electrical line/circuit is responsible for this. How can I tell what the problem is short of using an oscilloscope? Could it be as simple as the breaker half popped and needs to be reset or it broke and needs replacing? Thanks guys
Start with an outlet tester which you can pick up at any home improvement/hardware store for under ten bucks. It plugs into the outlet and checks for correct wiring and lack of a proper ground.
Thanks Jan. I checked and the circuit seems to check out. The problem has also become intermittent, or maybe it always was and I just didn't notice. What kind of appliance could contribute to this? It is not the fridge as that was running continuously when the humming went off. AC was not on, neither washer nor dryer was on and I don't think the dishwasher was on either. The gap between hum and no hum was about 5 minutes and since then I have not noticed any hum.
What other stuff is plugged into the same circuit? I have an outdoor light that apparently is wired to the same circuit as one of my living room sockets. When I turn the outdoor light on, I get a hum in the living room.
You checked the outlet with the tester I suggested? And you're positive it is wired correctly?
If the noise returns ...
The next step would be using a cheater plug. This is the $0.79 devide that lifts the ground from any appliance. I assume this is a two conductor power cable coming from this component. You'll need to remove the ears of the polarized side of the plug by either filing or cutting them away. This will allow you to reverse the orientation of the plug in the wall outlet. One direction should have less transformer noise than the other.
Is this component plugged directly into a wall outlet or through an AC strip or surge protector?
If this doesn't at least lower the hum, then you can try placing a weight on the top cover of the amp to see if damping is any help. There's a possibility the transformer has loosened or broken a mounting and might need repair.
I will check to see what else is on that circuit. My dad used to have his preamp and cd player ontop of the amp so it could be the extra weight helped damp the hum. I used the kind of tester that basically lights up when the prongs are put into the socket. The cheater plug you speak of, is that the one that converts a three prong device to use a two prong plug? The amp is a two prong cord. I had the amp plugged into the wall directly, through the original surge and a newer one that I know works all with intermittent hum but only in the one room.
The "kind of tester that basically lights up when the prongs are put into the socket" only indicates there is voltage present. Go buy the tester I suggested.
It actually was an incandescent which makes even less sense. The lamp wasn't going to be in that room for long anyway so it is no big loss to move it elsewhere. I think my dad was concerned because he didn't want to have to fix yet another part of his stereo system. First it was his preamp; the right channel was outputting full volume noise in the right channel which blew the woofer of his ML Clarity. Got them both fixed but I think he was ready to get pissed off with another part of his stereo system breaking. Luckily I fixed it before he is getting his new Vincent integrated.
I gotta look into this when a get to my new place and see if my 3B-ST still hums. Like yours, mine is a mechanical hum but I tried plugging it directly into the main power panels utility plug...no other switches/plugs on that line as it's direct to the box, and it still had the mechanical hum. That mind you is even with nothing hooked up and just the amp plugged in. I've gotta get it open one of these days and try tightening up the torroidal power supplies retaining bolts. Either that or send it into Bryston for a warranty service. Just gotta get me a suitable box to ship it.
George, the mechanical hum is not unusual for Bryston, as I understand it, just one of those things. But noticable and intrusive are different matters, all I have heard of is minimal.
"Like yours, mine is a mechanical hum but I tried plugging it directly into the main power panels utility plug...no other switches/plugs on that line as it's direct to the box, and it still had the mechanical hum."
Unless you have a dedicated circuit with a separate ground outside it does not matter what you have on that line as anything in the house can and will affect it, the refrigerator for example, as it shares a common ground.