Just watched the video until the very first "you might blow up your interface" comment - immediately labelled the guy as clueless and pressed stop. In these things it's very important to separate knowledge from bluster. If you make instructional videos it's really hard to be technically correct and be understood, so one route is to dumb it down so more people get the basics, but that often means you have to explain things wrong, so they're understood, or explain them right and have it go over their heads - especially as you have no idea of the existing knowledge base of every viewer. You will confuse some and annoy others with your simplifications.
However - what I learned when I was 17 about connecting things up is that you use your common sense and try things out. Carefully. No Youtube in 1973. Guitar amp. second hand tube amp, speakers, reel to reel, a couple of mics. All different connectors and sockets. Never ever blew anything up. Plug a guitar into a mic socket at the meter hit the stops quickly when you gradually turned up from zero. Connecting the loudspeaker output of a radiogram to the mic in did the same, but more! The line input was better, as long as I kept the level down. In the headphones I learned to heart distortion, hums and noises. Some mics seemed to hiss more than others when I turned the volume up. Eventually you get to know what works and to be able to compare and contrast results.
Nowadays why do people never do this any more? You ask strangers. If you have the bits - say a modest interface and a tube pre-amp, then why do you need other people at all? Surely you connect it up and then fiddle and experiment until you find the quietest system - which will be the best one for you. If you see on the net that a certain weird system is better, even though you have to stand on your head to do it - try it out carefully and use your ears. We're recording with quality as an aim - so we need to train our ears. It really is the most vital skill. We get posts from people who cannot even describe audio properly. We get people suffering from 'distortion' that turns out to be hiss. We get 'hum' that turns out to be data noise. We get 'buzzes' that turn out to be clicks etc etc. If people cannot describe in words what they hear, our regular contributors who spend a lot of their time trying to help folk have an arm tied behind their backs. Back in the 70s/80s when we had cassettes, we also had a choice. To hiss, or not to hiss? Some people recorded with Dolby on, then turned it off for replay. Some stalwarts didn't use it at all because to their ears hiss was better than the impact Dolby had on the recorded sound. Others would record with extra HF, then turn it down on replay. We had arguments on Dolby B and then C, and then DBX and the first experience many of us had of compression. Some people even used DBX as a compressor, as they liked what it did. others thought them mad. When I started teaching Music Tech to 16-20 yr olds I discovered only about 25% of a typical group could hear compresssion. prodding the in/out button was undetectable.
Sorry for the rant, but I really wish we could put health warnings on Youtube videos, because some do damage your musical health. People need to develop their own investigative and experimental skills. If you invent a great new system that works brilliantly for your music does it matter if plonkers on Youtube tell you never to do this because the world will end, your guitar collection melt down and your speaker cones fly across the floor.
Modern equipment gets sold with money back guarantees, umpteen day no quibble returns and then maybe a 3 year warranty. If it fell over the minute you reversed a connection, it would be a crap piece of kit wouldn't it?
I have been abusing equipment for over 40 years and have blown one loudspeaker because of sheer stupidity so I deserved it, and never damaged one item by incorrect connection. I've made loads of bangs, shreaks and crackles. I can describe the difference between a hum and a buzz, crackle and hiss. I never read instructions or manuals on the premise that if it's that stupidly designed I need to, the product is poor. If I get stuck, then, and only then do I look at a manual, because they take six pages to tell you how to connect the power, m and two lines to explain the vital functions. The you rely on a youtube video done by a 14 year old to explain how to do something because you don't wish to put the time in to learn your new bit of kit.
Grumpy old man mode off.
