The low gain of a line stage is usually for low volume listening or if you have a super high gain power amp. I think some people in old days needed it when taping. The high gain should be the "normal" setting. If you care to retube your SP10 power supply's tube and transistor, I was told by true sound in bay area, it will rivial today's new top preamp even in resolution. A classic preamp.
audio research sp-10
hi..i'm fairly new to tubes. i have an AR sp-10 pre, AR d-125 amp, vandersteen 2ci speakers, and a shanling t-100 cd player. running the cd player on the tube output of the shanling. my music tastes run the gamut from synthpop/techno...to sarah mclachlin, and josh groban. the system seems just a tad bright to me, which it seems it shouldn't with all the tubes i'm using. i've put the sp-10 on "high gain" which seems to help...is it "bad" to use the high gain on a regular basis? also..my speakers are biwired..but with no name wires..any suggestions for compatable speaker wires and or interconnects (using legend interconnects right now) or any other suggestions would be appreciated. thanks in advance :)