Kettle,
Not sure which is the best tube amp; but, I would like to comment on your thoughts about getting away from the long balanced interconnects. All the information that I have read indicates that long preamp interconnect cables are a better option than long speaker cables. This is due to the much lower current levels present in the interconnect cables. Fifty feet shouldn't be too long due to the superior common mode rejection intrinsic with the balanced design. My vote would be to stay with the interconnects and separate mono amps if you can.
Not sure which is the best tube amp; but, I would like to comment on your thoughts about getting away from the long balanced interconnects. All the information that I have read indicates that long preamp interconnect cables are a better option than long speaker cables. This is due to the much lower current levels present in the interconnect cables. Fifty feet shouldn't be too long due to the superior common mode rejection intrinsic with the balanced design. My vote would be to stay with the interconnects and separate mono amps if you can.