I have only heard a SC7. It sounds a lot like the 3650. It had a more accurate detailed sound compared to earlier preamps like the 33,3300,3600,etc.. I dought any of the Esotic type preamps sound like the earlier Marantz equipment. I would think the SC6 will have more in common with the SC7 then the SC8 circuit wise. Have you tried doing searches for reviews or SC6 vs SC8 searches?