High pitched buzz caused by Squeezebox Touch?

I've noticed that when I have my Squeezebox Touch plugged in and hooked up to my main system and running through my DAC, I hear a low level high frequency buzz coming from my tweeters. I've checked all cabling thoroughly. The only thing that eliminates the buzz is keeping the Squeezebox Touch out of the system. Here's the weird part: the buzz does not go away immediately upon detaching the unit. It takes about an hour to completely disappear. When i hook it back up, everything's fine for about 20 minutes and then the buzz is back.

Is this caused by that damned switching power supply in the SB? If so, which PS upgrade will do the best job of elimating it. I can't afford the Bolder mods, so that's not an option.
What amplifier are you using? I was getting a high pitched whine from my Touch when within several feet of an EL84 amplifier. No problem with a solid state amplifier. I switched power supply to CIA stand-alone unit with no effect on the RF issue. I don't recall a 20 minute delay.
My system is: Classe' Delta series 2200 amplifier, Conrad-Johnson CT5 preamplifier, PS Audio Perfect Wave DAC/Transport and Thiel 3.7 speakers. Cabling is Shunyata. I spoke with Wayne at Boulder and he suggested moving the Touch away from my other components. Voila! The buzz is dramatically reduced.. It had been sitting directly next to my DAC.

I'm still getting some RFI and a faint buzz, which I suspect maybe a combination of the switching power supply and the Touch itself....but the noise, so far, is only audible from a foot away. Wayne's a good guy. He'll get my business.
Ok. Posted too soon. The buzz is back and, again, the only way to remove it is to remove the power supply from the equation. What I find odd and impossible to explain is why it takes an hour for the noise to begin and an hour after the removal of the offending device for the noise to disappear. It makes trouble shooting a real bear. One thing is certain: the SB Touch/ power supply is the source of the noise. We'll see if a linear power supply solves the problem.
Not that anyone appears too interested, but I've isolated the buzz. It has nothing to do with the Squeezebox Touch or the power supply. It turns out to be built up stactic electricity and I can make the resulting noise go away immediately by applying a static guard sheet to my interconnects and cables. I hear Nordost sells something for this, but i suspect it costs $300. Boy, this has been a real audio snipe hunt. LOL.