I just purchased a pair of B&W 803Ds over the weekend. Once they were hooked up to my system I listened to a few CDs playing on a Sony CD player. Everything is good, speakers sound wonderful.

I then turned on my Dell laptop which is always hooked up to my 990 via USB cable but didn't start playing any music yet. I walked away from the laptop to another part of the room and I noticed a high pitched tone in the room but couldn't figure out where it was coming from. I finally tracked it down to the tweeter in the 803. I turned off the laptop and the high-pitched tone disappeared. I turned the laptop back on and it appeared again. I then unplugged the USB cable from the laptop and the tone went away?

I never noticed this sound coming from my previous set of speakers (PSB Silveri) that were hooked up to the system.

Why is the USB cable/laptop causing this? Is there a cure?

Mark

Was the laptop running on battery or on wall power? If it was on wall power, it could be a power issue related to the AC adapter or to the outlet that the laptop was plugged into.

It's running on wall power. I don't remember if it's plugged into Brick Wall surge filter or the Monster surge protector I have down there.

Could be that sound was there in the past but your old speakers couldn't reproduce it because of age, design or electronics.

If it's not already, try plugging the laptop into the same filter/surge protector as your pre/pro & amp.

I put the question about the high pitched signal on the Computer Audiophile website. It was suggested that I "float the ground". I found a 3 prong to 2 prong converter and plugged into the wall but the high pitched sound persisted. So I tried plugging it into the brickwall surge protector and that did the trick.

The fix was especially appreciated because I had borrowed a Chord Chordette Gem DAC to see if that would have any effect. Just the opposite, it magnified the high pitched signal by at least two to three times. Plus the DAC was adding a 'thump' sound. I immediately removed it from the system until I found the fix. I put it back into the system but the 'thump' was still there. I can't remember precisely when the 'thump' would occur. Sometimes right before the music started playing from the laptop. Sometimes at other random times. But like I said, I can't remember exactly. It was disturbing enough to make me remove it from the system.

As an FYI for those who might be interested. When I did listen to music through the DAC I couldn't really hear a difference. Music is played from a Dell laptop running Vista and Windows Media Player (version 11). The music files are WMA. I was given Audio Quest cables ($700) to connect the DAC to my 990. I would never spend this much money on cables but he offered so I thought what the heck. My amp is the Outlaw 755. This is the second DAC I've auditioned and found neither offered any improvement. If there was improvement it was so slight that it didn't justify the nearly $1000 investment.

If the high pitch sound went away when you used the surge suppressor I would check the polarity of the wall outlet you were using. If the outlet was hooked up backwards that might have produced the sound.