Buzzing from External Speakers

[Y-Guy]

I have a 24" iMac, today picked up a of Bose Companion 2 speakers to replace my old Boston Acoustic speakers which I thought were faulty with the same buzzing sounds.

The problem is that after the computer sits idle with no sound for about 30 seconds the speakers begin to make a humm/buzz noise. I can move the wires and nothing changes. I've spread the speakers as far as I can, and it continues. I moved the Bose adapter to an extension cord and ran it about 25' to an outlet on another circuit from the iMac, still humming.

I've timed the time it takes from no humm to humm and its 30 seconds. My gut is telling me that the iMac is shutting down an internal amp to save power or something.

Is there something I can change to eliminate this, or is this a fault that needs Apple's attention?

 

[Sun Baked]

Like a ground loop hum?

Macintosh: Solutions for noise in the audio signal

Might be others from Apple or some people that have other solutions.

 

[Y-Guy]

Thanks Sun Baked, I see they recommend a Radio Schmuck park I'll go pick one up and see if it solves the problem.

 

[Y-Guy]

Problem solved! I picked up the Radio Shack Ground-Loop Isolator and I have no more buzz.

 

[Sun Baked]

No problem, a lot of people complain about it ... which is why Apple started posting these a long time ago.

 

[Y-Guy]

Update for those with the problem in the future:

After having the Bose speakers for less then a week I returned them. Even with the ground loop I was getting feed back, though much less. However when it was quiet here the subtle humming was very annoying. I figured for $99 and the Bose name I shouldn't have that type of humming. Since there was no way to turn them off other then unplugging them I was constantly turning the volume up and down, not a set it and forget it setup at all.

I picked up a set of the Logitech Z-2300 speakers since Circuit City had them on sale. I wasn't really looking for a large sub, but that's life. I can say even without the ground loop I am getting no feedback what-so-ever.

After 30 seconds when I guess the internal amp shuts down there is still no humm, I do get some white noise if I turn the speakers to max - but that won't happen.

So the problem is once again solved, just with a different ending.

 

[greggwon]

It's the power supply on the Bose Companion II

The low level humm on the Bose Companion II appears to be the power supply. Even with the speakers disconnected from any source of audio, they humm at a low level which becomes quite annoying at mid to high volume levels. Try to find a different 2A or so 12VDC supply and see if that quiets them.

 

[mumdb1]

The low level humm on the Bose Companion II appears to be the power supply. Even with the speakers disconnected from any source of audio, they humm at a low level which becomes quite annoying at mid to high volume levels. Try to find a different 2A or so 12VDC supply and see if that quiets them.

Just bought these speakers today and noticed this exact problem. Can't believe that $99 speakers would hum like this because of a POS power supply, but it's true. Guess I'll try a different supply as suggested and report back.