Things I’ve produced…

Get Depression Baby on Kindle, Paperback, Hardcover or Audiobook! (FYI, it’s about the Great Depression…not being sad.)
Things I use and recommend…
Apogee Duet USB Audio Interface
This baby stays permanently in my go kit. It’s also a standard part of my mobile Skype podcasting rig. I have tried many audio interfaces over the years. I tried the multichannel UA Apollo when it first came out (because I love me some UA plugins!), but promptly returned it because the sound didn’t compare to my humble Duet. (I ended up going with the Apogee Symphony for my multichannel studio needs.)
The Duet allows for two inputs and four outputs (two balanced TRS outputs plus a stereo headphone output that you can use for a cue mix if you’re DJing, etc. (See my post on my mobile Skype podcasting rig.) My unit is a number of years old, but seems to work fine with El Capitan on both my MacBook Pro and Mac Mini (studio machine).
The Duet comes with Apogee Maestro software which you’ll need for some functions, but many of the important functions can be performed from the multifunction hardware control. The hardware is obviously simple in design and has a satisfying heft to it. I don’t love the detachable harness for the in/out jacks, but there’s really no way to have those as part of the body on a unit this size.
Love this stuff! For workouts, post-workout…and I swear that, ahem, friends tell me it’s just the thing for a hangover. Zero calories, but contains BCAAs, the building blocks for dem muscles.