Want More Bass

Why did you switch to tubes?
Do you like the rest of sound except bass quantity or the bass is your main consern?

If that's the case you should get either sub or the speaker that goes deeper with bass and have higher efficiency.
You may also vary some room arrangements that may(or maynot)become neccessary after changing amplification components.

For the sub I'd recommend buying a pair of such so you can select much higher crossover point(upto 80...120Hz) letting your speakers and amps work only from midrange or upper bass region. You can get used pair of Vandersteen 2WQ for arround $2k. There might be a need of faster subs and I'm sure that for the budget there are and I'm the one to give another option to consider for further posts.

P.S. For anyone who does not know the author's speakers it only takes to click on his system to find out. In this case it is not neccessary to speak about it Nth time as it already said.

I found the Rogue 66 Mag preamp simply horrible in the botton octaves, rolled off by maybe 50hz, soggy/loose until ~160hz. If you want true deep bass your speakers have to go, but no matter what killer bass speaker you buy won't create what it's not fed, unless you buy speakers with built-in sub amps, of course. I would pesonally ditch the Rogue 66 before looking for new speakers....

Thanks all. I AM fearful of the sub-speaker integration difficulty. My speakers are Linn's and I don't want to spend the $ on the Linn Sizmik sub. I like the REL Strata III sub, but am thinking that a full-range pair of speakers might be a better way to go. (I'd rather not deal with the cabling either.) I really could go either way but which is easier and which is better... I really hate fussing!

Was thinking of the following: Vandersteen 2CE sigs (but they may be too wide physically).

Rogue recommends the Vandersteens. In Montreal last month I heard them and many other good things running on tubes, such as: Verity Audio, Focus Audio, Meadowlark Audio.

I do, however, find it hard to belive that my pre-amp could be at issue... I did a lot of research and never heard about any complaints with the low-end output of the sixty-six.

If you happy with the sound of your speakers as they are aside from a desire for greater lower frequency response my suggestion would be for you to add a quality subwoofer to your present system. I have owned Sunfire and REL subwoofers, different models of each, and believe that for sheer bass output the Sunfire line is the better choice, but the REL line will integrate better with your Linn speakers.

A cautionary note:
Once you start with subwoofers, it is hard to go back. They are very addictive

Believe that your preamp is the issue, for it is or at least very well could be to blame, partly or fully. I've tried nearly a dozen modern preamps lately, tubes and SS, active and passive, the 66 was the worst of the lot in terms of bass performance, and the difference was not at all subtle. Try a cheap Creek passive for kicks if you would like to find out just how much you're missing down low (assuming your source has high enough output to drive your amp).