the tube rectifier function in a dual rec head deals specifically with the power supply response. it softens the response, and is responsible for one of the elements of the rectifier amps "3D tone."
that combined with the lack of power section negative feedback in 'modern' mode is what makes the low end flex in and out, back and forth, because the low end resonance you hear (FEEL :shock: ) is not a static equalization curve, it comes from the speaker impedance in relation to what the amp is putting out, and flexes and shifts depending on what it's being fed from the guitar.
combine that with the 'modern' mode preamp's layered fundamental, asymmetrical (?) overdrive, and razor-blade cold-clipping circuit crock pot concoction of artery clogging slow roast tone stew, and you understand why they put fucking diamond plate on the facia. :twisted:
to answer your question though, the 2:90 doesn't provide tube power rectification, but what it does offer that the dual rec DOES NOT, is Simul-Class power operation, which is basically 2 of the 4 tubes operating in class A, and 2 of the 4 tubes operating in class AB. I'm sure you're aware of class A operation being associated with low-wattage, flubby, slow, open, FAT tone.... :idea: So while the 2:90 doesn't do tube power rectification, the power section adds a SIGNIFICANT amount of coloration to the input signal, due to the simul-class power section. It adds the similar flexing effect to being pushed hard, only instead of power rectification providing the power flex, it comes from the class A half of the power section. (why everyone refers to the 2:90 as it being a 'musical' power amp)
Not exactly the same sound as tube rectification, because tube rectification feels like it comes from somewhere separate, almost like there is some sidechained compressor pumping the low end from 60hz down when you dig in... 8) but it does soften the recto pre tone in the similar way as the head power section does.
and at the same time, the 2:90 DOES offer Modern and Deep modes, which shift frequencies and resonance at the power section even further, to get it basically at the same weight class as the power section of a dual rec using tube rectifier power settings. i've never cranked my 2:90 outside of bedroom levels with the two modes engaged, but i would assume that because it does have some amount of negative feedback, it would be better behaved at crazy loud levels, whereas the dual rec will lose it's ability to resonate as well as it was if you push it too hard...the low end will sound absolutely brutal up to a point, and then if you go any louder on the master the low end will start to fall apart like lonestar cleans :roll: and you'll have to either reduce the gain or roll off a lot of preamp bass. good thing the master will blow out windows anywhere near 9 o'clock.
being that the Recto Pre is actually a self-contained approximation of the SOUND of a dual rec head, with the power section and transformers included, i can assume that the 2:90 would carry it well past the levels of decibel necessity and retain its fundamental bass resonance louder than an actual head would.
