Any ideas what would cause both of my M200s to start buzzing tonight? I was just walking through the room and head a low buzzzzzz that was coming from the two amps in standby mode. When I turn them off it stops (duh!). Speakers aren;t making any strange noises. Nothing bad coming from the speakers when this is happening.
Hmm?
Rob

It could be something harmless like the metal cover vibrating from interaction with the power transformer.

What turn-on mode do you use? Mine do that too at times. I have them on the music sensing. I wonder if a trigger would eliminate it.

I use music sense, as well. It was loud enough to make me wonder if the clothes dryer was on in the next room.
I have to figure out how to use the trigger out on my RX-V1500... Maybe that has something to do with it.

Wow, I don't remember mine being that loud. It's been awhile since I've heard it. I could just hear it, but it annoyed others a bit. It wasn't getting confused with drier level volumes though. I'm pretty sure the noise comes out of the speakers, but I'd have to double check.

it's the transformer that makes that noise.and the trigger setup doesn't get rid of the problem.It's a pretty normal situation that transformers sometimes creat a huming noise.And it's not through the speakers...I have 7 m-200.When i power them up, no humming, but if i let them into standby for a long period, some humming can occur.I also own a avr8000 and the toroidal transformer sometimes hum too when on standby mode for an extended period.The situation occurs with both toroidal and E transformers...Sometimes, when i power up my 2 pa2000, they produce a small transformer hum.If i power them off and on again, it can make the hum go away.

anyway, i read somewhere that thighting the both that holds the toroidal transformer can reduce vibration causing the humming.I know i wouldn't tough a thing.If you can ear that kind of hum while listening to your system, just crank the volume louder.

I just broke down and called Outlaw and talked to Steve. He said that it is most likely a low voltage or low current situation that's causing the transformer to vibrate intermittently.

Seems that if there is something on the same electrical circuit that pulls a lot of amps, the M200 is sensitive enough to react this way. This could be anything from a space heter to a powerful subwoofer...

He also pointed to a powerstrip that could be 'constricting' the flow of power to the units. Over time, each time the strip takes a surge, it slowly wears out. Since the M200s are electrically and thermally protected, he said there isn't a need for the surge protector anyway. A power conditioner or a regulator, perhaps.

My first course of action will be to look at all the items on that branch curcuit and see if turning any devices on causes the hummm. Second, if that fails, is to isolate the amp on a different circuit with an extension cord and see if that stops it.

Wish me luck.
Rob

Wierd Question- Is this transformer humm creating a magnetic field? I noticed this morning that my TV looks like it had a magnet up on it!

Wierd- Thanks
Rob

every peice of metal inducted with current will produce a magnetic field.It's how electric motors work...
I neer had any problem with the magnetism of amps near ts, but it should be considered a probability.

Okay-
The whole saga as I have finnaly figured it all out:

We got a new shed out in the yard that I am going to use as my workshop. I have been working to finish the interior, so I have an electric space heater in there on an extension cord from the house. I didn't know it, but the exterior outlet that the thing is plugged into happened to be on the same circuit as the AV gear.

So, I noticed my M200 amps humming a couple of days later. I called Outlaw and Scott suggested it was a voltage or current drop in the line from something else pulling a large load. I figured out it was the space heater. Scott said it did no harm to have the amps hum, so seeing as how the space heater was only temporary, I didn't want to run an extension cord from another circuit as I could live with the hum for a few more days.

So with the amps humming every once in a while. I started to notice a color bloom in the corners of my TV. I had an old set of speakers that I thought were shielded next to the TV for a little while and thought they might have done it. The TVs self-degauss wasn't doing anything for days, so I figured the speakers had screwed up the shadowmask bad enough to need a manual degauss.

Well, the lightbulb went off in my head and I woke up at 3am and checked for Santa, then the TV. Colors still there, I turned off the humming amps, ran the extension cord and waited a few minutes to let the field dissapate.

I Turned the TV on and -magic-. The degauss actually worked and the picture is perfect again. So, yes, the transformers were putting out a huge magnetic field while they were humming.

So, to recap: Space heater on same circuit as M200 amps caused voltage drop, making amp transformers hum. Humming caused magnetic field that screwed up the TV. Fixed by putting amps on another circuit while space heater is in use. Permanant fix will be to run a dedicated line for the AV gear. Phew!
I need an Egg Nog.

Frankly, I find it difficult to believe that the power transformer started buzzing because of a low voltage situation. A properly designed transformer shouldn't care one bit what the input voltage is.

Perhaps a more likely explanation was that the heater was causing distortion of the AC waveform, which certainly could cause a transformer to buzz. Alternately, the DC regulation stages (if any), could have dropped out of regulation from a voltage sag, causing the buzz.

Whatever the cause, your issue is solved.

All I'm saying is this is what Scott said. I also went and put the Fluke on the circuit and found 118v present w/o the space heater and no buzzing amps. I switched on the space heater and watched the voltage drop to 112 and heard the amps starting to buzz.
Call it whatever you like. Bottom line- low line voltage caused the amp transformer to buzz. Strange but true.
Thanks for all the advice. I hope this doesn't happen to anyone else! But, if it does, now you know.
Rob

Hmm- magnetic field ain't coming from tha amps. The buzzing is long gone since they are on a new circuit, but the magnetic distortion is back after a few days. Fixed one problems, though!