Tube Preamps with Bass?

Isn't the bass slam really a product of the speakers and the amp? Maybe I'm naieve, but it seems like you may be trying to solve the problem with the wrong component. I'd be interested in what others have to say on this.

Bobo, When a change to a "better" power cord is made on a DAC or preamp there can be an improvement in apparent bass extension, and slam. You are correct that this performance has to be within the capability of the source component design, and presumes audition somewhere else has already demonstrated what the downstream amp and speakers are themselves capable of delivering.
When I began to use the top of the line power strip from Mapleshade for all my source components, there was improvement in bass extension, and slam! This was easily heard by non-audiophile family members, as well as by those who are supposed to hear the difference. Even a bigger improvement was noted when the same basic design in a power cord connected the amp directly into its own unmodified AC wall outlet. As Mae West was known to remark, you never know all of your capability, or something suggestive implying the same idea.
Someone just put up for sale an Aronov LS-9000 preamp, and I notice the ad mentioned the bass performance. No, not a relative of mine, although a set of reliable Audiogon ears.

have your slam too:Biamp,tubes on top.keep your Pass pre and use the x250 for the bass.I didn't try everything in my set-up, but that was the only way I found to have tubes AND slam.

Meant to start that out with: Have your tubes and get your slam too:

Bobo, If a loudspeaker is capable of the lowest audible bass, it's possible that a preamp with poor bass extension will not allow the speaker to show what it can do. I tried the Hovland HP-100 with my full range speakers. It sounded fantastic except the whole bottom octave was missing.
Bigkidz, you have an excellent short list. The deepest bass I have heard from a tube preamp was the Thor TA-1000. It was every bit as deep as a high quality solid state preamp. Unfortunately it is $10,000. Maybe $5000 used.
Of those you mentioned I think the most positive comments I've heard were for the Joule and the Blue Circle.
The Supratek mentioned above has a big following on Audiogon. If for some reason you don't like it, you could probably sell it in a heartbeat.