i had a hot-rod version of the rogue 99, & yes, it's coloured. besides, nice as mark o'brien is, he ain't up-front about the output impedence of his preamp. he states its 100 ohms - real-world experience told me 2400 ohms is more likely. i, too, had extremely poor bass response, most likely due to a long cable-run between the 25k-ohm input-impedence of my active x-over, and the high output-impedence of the rogue. i, too, had noise problems w/this unit - ewe could hear any rheostat-light in the house being adjusted thru my speakers! took a while to figure out what *that* was! ;~) while the rogue had better soundstage depth than the linn kairn it replaced, the kairn bested it in all other areas.
not satisfied w/the rogue, but still wanting that *toob* sound (those colourations *were* kinda nice!), i then tried the cary slp98. ($1300, used). better than the rogue in all areas, especially in accuracy & frequency extension. (and this was their stock wersion - they, also, offer a *hot-rod* wersion.) no impedence problems w/this unit, which is rated at 600 ohms output impedence, which my field-testing confirmed.
i'd have stopped my preamp search here, but yust after i got the cary, i came across a melos music-director at a reasonable price, & i yust had to try it - i *loved* a melos sha-gold i'd heard several years ago, but couldn't afford it then. well, the melos is in another league all-together, imho. at ~$2k used, i don't see how it could be beat. (regarding s/f pricing, btw, i dunno about the s/f line-2, but the line-3 can be had brand-gnu for <$2.4k, delivered...)
oh, one more thing - both the cary & the melos have a tape monitor, which the rogue doesn't have. i like this for my dbx-3bx, which i can now keep out of the signal, except when in use. not possible w/the rogue, so i dint have it hooked-up. also, the cary & the melos have balance controls, which the rogue doesn't have... and, regarding the rogue 66, if ya get the built-in fono, don't ya have to lose the balance control?