One thing I haven't seen mentioned is the 2Ci's have adjustments for the mid and treble drivers on the back of the speaker right near the cable connections. I would check these and make sure they are not set on the high side, e.g. +2 dB. I had 2Ci's for over 10 years and never thought they were bright. I've never heard the SP-10 or D-125 but all reviewers have said the SP-10 was, if anything, on the dark side. Not sure about the D-125, but I don't think bright would apply to it either. You might want to try some good quality budget cables like Kimber Hero interconnects and 4TC/8TC speaker cables in place of the no-name stuff you have. Doubt that is the cause of the brightness but it might alleviate thin bass that could give the same impression.
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 :)