I think we need to define “reamping” and then understand about the standard types of signals (line level, mic level, instrument level etc.).
As
@PelliX said there are many definitions of “reamping” nowadays. The video above really doesn’t explain the different audio levels between instrument, DI plugged into a mic preamp level, and +4Db balanced whether it be an XLR mic style or in a balanced 1/4” TRS style.
Back in the olden days (of 24 track 2” multitrack tape), you would always record the mic’ed up sound(s) via a microphone(s) while simultaneously using the the DI of an instrument or vocal or whatever you wanted into a separate track along with the mic’ed track. Back then as Pellix said, you would have a male XLR to male XLR turn around adapter and run the high output of the tape machine (+4 balanced) which is much higher than a guitar amp is designed to deal with. Essentially a DI box in reverse. Typically The “reamp box” takes recorded DI +4Db balanced signal from the tape machine and bumps it back down to instrument level which lets you take that DI signal and plug it into any amp and/or pedals which are also instrument level. You could use the DI to try it plugged into any amp in your collection. Back then most big studios had very talented and creative studio techs who would build an additional box that let you adjust gain and impedance to match the particular pickups and/or amps in the sweet spot.
The first commercially available “reamp” box was designed, patented and sold by John Cuniberti starting in the early nineties. John recorded and produced everything from most of the Dead Kennedys records to Joe Satriani starting with
Surfing With The Alien and he has done every Satch record since. He was smart enough to patent it and get a trademark for “Reamp”. After the word reamp sorta became a generic word for lots of stuff. It kind of became like calling every tissue paper regardless of brand “Kleenex”. He sold all his IP, Reamp name and trademarks to Radial Engineering in the mid 2000’s. I’ve found that a great companion to my original Cuniberti Reamp and Reamp V2 is a tiny little box Radial makes called a Dragster which does help adjust the impedance and load characteristics of whatever PU and amp combination you want to reamp.
I hope I was clear enough, but it’s basically and traditionally knocking down a high output +4 line level signal from your tape machine, interface or whatever down to instrument level which lets you experiment without committing anything permanently to the track. Once you have the amp to reamp chosen, you would typically mic the amp you’ve reamped onto a 3rd channel. It’s always a good practice to record a DI along with your amp mic’s just for good measure. If you’re on a DAW, you have unlimited tracks so there’s no penalty for always recording a dry DI of the guitar track along with a mic’ed amp.
Here’s my 2 Cuniberti Reamp boxes from the 90’s. A V2 and the purple original version.
en.antelopeaudio.com
