Hi there.For sometime i hear the dual rectifiers 2 channels are way better than the 3 channels.I own a 3 channel and the only thing I can complain is some lack of sustain.The notes seems to end to quickly (especially/only on solos) - even with different guitars and several pickups.My cabinet is a standard mesa 4x12.Maibe my tube configuration? (the original set is 6l6);I use bold/silicon.I use a boss turbo overdrive to put some sustain and it compresses a bit the notes and give it some digital sustain but with tube body.It works pretty well.But recently someone told me that the rackmount version is even better than the head version.Is this true?