Cheap passive DI as ground loop fix...?

[Gothic]

So, I got an annoying ground loop noise issue that came up after I built my desktop. Didn't pay much attention to it since the noise pretty much disappeared when recording a few covers but I'm seriously recording some stuff now and it's become a problem.

Thing is, I cannot pinpoint the issue. I get that dreaded buzz along with a touch of computer noises/EMI. The latter is greatly alleviated using humbuckers and/or copper foil shielding (along with turning off every led in there) but the former, not so much.

The setup is simple. Bass over to a (USB powered) Tascam US122l, to the PC. I got a power strip with only a lamp (no noise there, tested), the PC PS and the monitor PS. I use headphones exclusively.
Already tried all USB ports, tried removing literally everything else that's plugged into the PC (including the monitor) to no avail.

Now, many suggest those USB ground loop isolator thingies. Which is fine but I just find them iffy and there are too many stories about them going tats up at random times so... I'd rather not. Plus, they're even more expensive than a cheap passive DI, which is what I'm thinking as a solution to this.

So, plan is: get a cheap passive DI with a ground lift option, plug the instruments into that and from the DI to the interface. I'm thinking that'll pretty much solve this without breaking the bank and setting up a new PC again (which I plan to anyway but not at this very moment).

Thoughts? Suggestions? I'm eyeing the Palmer Pan 01. At less than 50 euros, it seems ideal for the job.
And by the way, that's the only job it'll do. I have no intentions of using it live. I have a DG B7K ultra with a DI out I use for that.

Many thanks in advance!

 

[silky smoove]

Grab a cheap Hosa Sidekick and try it. The ground lift may fix it or might just point you to a different problem. Either way you won’t be out much and will have a workshorse passive DI that’s remarkably flat for the ultra-low price.

EDIT: The B7K Ultra has a ground lift. Why not try that before spending any money?

 

[Gothic]

Grab a cheap Hosa Sidekick and try it. The ground lift may fix it or might just point you to a different problem. Either way you won’t be out much and will have a workshorse passive DI that’s remarkably flat for the ultra-low price.

EDIT: The B7K Ultra has a ground lift. Why not try that before spending any money?

Well, I feel like an idiot. Didn't even cross my mind...

I'm gonna try it today after work and see what's what. Still, I'd prefer something passive I can just leave there. The Sidekick you mention is nowhere to be found in Europe, however...

 

[Gothic]

So... I tried the ground lift on the darkglass. It sorta alleviates -part- of the noise but raises a lot of other questions. Thing is, I still have noise but I only get that sort of 50hz white noise/static while only using a VST with some kind of distortion. Using only the preamp pedal, all is pretty much quiet but run a guitar through lepou and bam! Noise. Also tried the neural dsp vst. Again, noise. Tried both through the pedal and without, without much difference so I'm kinda sorta ruling out ground loop noise. Doesn't really sound like that anyway.

Another thing is, I remember I didn't get any noise back when I was using my (very old) laptop. And not on battery, either, the thing was plugged in 24/7 and I'd even disconnected the battery at some point, too, since it was pretty much dead.

I'm baffled. Any ideas? Could it just be my interface? It's quite old, after all. But then again, why wouldn't I have noise on the laptop?