There's a difference between compressing for a mix and limiting for mastering. It's standard practice to do those in separate steps, but an argument could be made for doing both in one pass if you're trying to minimize the number of analog tape generations. But your recordings are digital, so I...
I've owned and/or used dbx 166, Project1 266 (original version), 3630 and MDX4600. I would recommend the dbx. I would not recommend the 3630 or MDX4600. The 3630 I had was just meh. The particular MDX I used noticeably degraded the sound when put in the signal path, even when bypassed. Maybe it...
If the computer is used to download mp3 files, it's going to be online. That means you will want to stay up to date on security fixes. If that weren't the case you could potentially just get a setup that works and leave it alone for years. A studio I work in is still using a Windows 7 machine...
An old OS is just going to be progressively less compatible with available hardware and software. I wouldn't go that route. Using a current OS isn't going to be any more annoying, all things considered.
You don't need a super high end computer to do audio work until you start doing a ton of...
Pic of my office. Today is "easy," a film festival. I have a theater company loading in tomorrow. Some productions have separate sound and lights ops and a stage manager calling cues. Some will integrate lighting cues into QLab and the stage manager will just hit the button.
Here's a typical 2x2 interface. It entirely replaces the function of your headphone port and much more. There are cheaper ones, this is just a common one.
https://www.sweetwater.com/store/detail/Scar2i2G4--focusrite-scarlett-2i2-4th-gen-usb-audio-interface
The transformer is built into the...
There are a couple of these where I work. They seem to work okay. There's a stereo version.
[Edit] I have no idea if this will cure your noise problem, but it does have a ground lift and presumably uses a transformer...
A generally more reliable solution would be an audio interface (AI, ironically). Another possible solution would be a passive stereo direct box with a ground lift. I'd just go for the AI. Ideally, connect via balanced cables and connectors.
I saw Superstar on what was probably it's first run in Los Angeles. It makes me wonder how they managed to get a similar effect with a presumably entirely different lighting system.
I ran the recording through Spectralayers. The software wasn't able to consistently distinguish between the guitar and mandolin. Sometimes it would appear on a separate track, sometimes it would stay mixed with the guitar.