The rare 300w Coliseum stereo power amp is in fact based on two Triple Rec power sections. Nothing to do with the Mark Series Coliseum amps. 'Coliseum' is just a word, not a circuit designation. Since it's based on the Triple power section(s), its negative feedback and overall filtering are designed like a Recto amp, not a Mark. It even has a 'modern' mode that decouples the neg. feedback like in the red channel from a Recto amp.