Re: MKIV vs. Dual Rectifier gain?
Marks have straight up cascaded gain. As you increase it it gets smoother and more compressed.
Rectos have one of the preamp tubes as a cold clipping circuit. It makes the amp sound more distorted with less gain, which makes them sound gritty and less compressed at the same relative levels of distortion.
Marks have a very singing lead tone. Everything is instantanious. Super tight, but not tight to a fault. Their natural voice is somewhat honky, which is what gives them that distinctive lead and rhythm sound.
The lack of compression is what gives a Recto it's distinctive rhythm response. It makes them more percussive with more touch sensitivity than a Mark. It's also why they're somewhat mediocre for leads. They kind of fall flat in that department.
The texture of the gain only tells part of the story. Both amps feel completely different to play through. Marks are fast and forceful. Single notes feel powerful and chords crisp. Their response is pretty straight forward.
Rectos are slower and more three dimensional. There is a distinct delay between the sound of your pick attack and the amp rising to full force and you can control the length of that delay using your pick attack and muting technique. It gives you the ability to rapid fire palm mutes in tight succession, then switch techniques and drop huge power chords that take a moment or two to unfold.
It's probably pretty obvious that Marks are my preference for lead and Rectos for rhythm, although both will do either job quite well. I generally gig my Mark V over my Recto because it's less sensitive to volume than my Roadster is... Rectos have to be moderately loud before they start producing the sound that made them famous.
And FWIW, I own an old 2 channel and a Roadster and IMO the Roadster has a far better lead tone than the 2 channel.
