Intensity Pro - Crackly audio 1080i

This problem cropped up last year. I solved it by replacing the Intensity Pro with another one I bought off eBay.

Today it has the same problem. First thing I did was to replace it with 3 known good Intensity Pro's. Not a one of them worked without the crackly audio. Next I removed the Intensity Pro, removed all of the drivers then tried an Intensity Pro 4K with new drivers. Oh, and yes, I powered off and disconnected the power cable then drained the capacitors before each step.

The computer is isolated from the network. It's a video editing station only. That means no updates. Nothing changes.

My question is this, has anyone else experienced the same problem and was it corrected? If yes, how?

I can start out with a new OS if I have to but why if this is a known problem. Perhaps it could be thermal?

I have 4 Intensity Pro's and 1 Intensity Pro 4K. These are the best pieces of editing hardware. I'll not give up trying to make this work.

Anyone have any ideas?

Thanks,

Terry

I can only guess,…. could it be a ground loop problem ? > the way shielding of cables and cases are done, (earth potential)
Could it be bad connections or metal parts scraping to each other ?
A sound sample would help….

Thanks for reminding me of that possibility. Over the years I had forgotten the basics of video engineering. keep everything grounded properly. I have a dedicated outlet for my video editing computer but used a different outlet to plug in the audio amplifier. Duh @me.

I think I should go back to keeping notes of any and everything I do, even such a small thing as plugging an amplifier into a different outlet.

Again, many thanks!

Terry