Those are all options and not standard. You can order one of those features or all of those features. So if you are buying a used amp, you'll need to ask specifically what it has.I don’t think there’s much difference from a 2016 to 2021 but their is a difference on the 2013. For 2016 and till current, they now have a old/new switch. Based on my opinion, I think the old switch is more aggressive and the new switch is more cleaner and mid focused. They have the mid scoop switch which is self explanatory on what it does. I think you can get more into the Nitro territory with it on. And last they have the drop B+ switch on the back which lowers the voltage and gives the amp more sag. I personally would go with 2016 or newer just for the extra features and a 2016 model is what I use. Bought it new and have used it ever since.
While we’re kinda on the same subject, does anyone know the difference from an older Nitro (2008) vs a 2021 model? I figured it has a better clean channel but I was curious to know anything else that would be different.Those are all options and not standard. You can order one of those features or all of those features. So if you are buying a used amp, you'll need to ask specifically what it has.
I believe the newer ones have better clean channels if that is important to you.
While we’re kinda on the same subject, does anyone know the difference from an older Nitro (2008) vs a 2021 model? I figured it has a better clean channel but I was curious to know anything else that would be different.