Tube Preamps with Bass?

Aronov Audio LS-9000 tube preamp together with top of the line Mapleshade power cord (and, presumably any other great power cord) has tremendous bass slam, along with natural, musical sound throughout the entire audible range. See review in soundstage.com for introduction to Aronov line.
If you already have your ideal amp, then EVS Ultimate Attenuators (from tweakaudio.com) which attach directly into RCA input jacks of amp eliminate one interconnect, and allow all that your amp is capable of in bass slam, weight, and dynamics. Used in single source system, such as one where you listen only to CD's. Retail is $350, although I got mine for less as a used item on Audiogon.

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.