Speaking from the perspective of a Bass 400+ playing bandmember with one guitar player pointing a 3 channel Dual Rec into my right ear and the other pointing a Racktifier into my left during rehearsal, I have to say unequivocally that the 2 channel Dual Rectifier Rackmount is to my ears more focused, organic (like a 1969 Marshall Super Lead on a steroid rage) and ultimately just bassier (useful, palm muting chug) and just more up front, ballsier with more of the legendary Dual Rec character shining through. It's almost as if relative to the 2chDRR, that the 3chDR has a bit of solid state injected into its DNA. All that being said, the 3chDR is in its own right a killer amp, just not up to the standard set by a good 2 channel DR.
On the issue of a complete lack of volume, I agree with the board: something's must be awry cause even assuming tube rectification and vintage channel cloning your ears should be aching something fierce with that sucker "dimed". Take it apart and make sure all the tubes are flush with the sockets? Play it while the lid's off and make sure all the tubes are glowing gently and not overheating or arcing. Check cable and connections to your cab. Once, the jack on my Recto Cab was acting up. Try removing the two middle tubes and one rectifier tube (either one) and try switching out tubes to the outer sockets to isolate a bad tube. Hopefully it's something simple.
