RUNNING POWERED SPEAKERS FROM AN IMAC

The simplest and cheapest way would be to run a 3.5mm stereo mini to RCA cable from the headphone jack to the powered speakers.

The jack is actually a dual output jack, headphone and digital optical, so for better quality you could get a digital to analog converter (DAC) with optical input and use a mini-Toslink to Toslink cable to the DAC, then use its RCA outputs with a standard RCA cable to the speakers.

I'm sure you could find one at Best Buy or Radio Shack but it will cost several dollars more and the quality won't be any better.

Do you have a source other than the iMac, an mp3 player or laptop, with a headphone jack you can plug the cable into? That would tell you whether the static is coming from the iMac or the cable/speakers.

If the static is still there with a different source you might move that setup to a different location to see if there's interference from something else in your computer room.

The object is to isolate the variables one at a time until you discover the problem.

I'm stumped by the static issue. I've done setups like yours from several Mac laptops and an iMac and never had an issue with static.

When you say the static is "pretty much gone" when you're using the iPad mini it might indicate that the issue is with the headphone jack on your iMac. But if the static isn't completely gone I'm not sure if that's the problem.

You could try squirting some contact cleaner into the headphone jack on the iMac and plugging the mini-stereo cable into it several times to clean the contacts.

Or try switching from the wireless mouse to a wired mouse to see if interference from the wireless might be the problem. But if you still have some static using the iPad I'm not sure that would be a solution.

Good, yes, it does seem as if you've isolated the problem to the Radio Shack cable. If you want to be sure that's the issue it might be worth it try a different cable, such as this one. The Monoprice cables are of excellent quality at reasonable prices and they ship the same day you order.

An external DAC would be the next step up and while I don't have any experience with the Dragonfly since I've always used the optical output on Macs, it has a great reputation.