Tube Preamps under $10k with deep bass extension

First Sound.

AudioNote M5.

BWS--after a long search (Including the Wyetech Opal)

CAT Ultimate will certainly go down to 20hz, but so will
the Audible Illusions Modulus III. Modulus III has better bass than the IIIa. I have the CAT and would certainly take it over the Audible Illusions, but the AI ain't bad. If you are primarily concerned with the bass however, you could take the AI and save a lot of money. You are right about the Hovland. I would say that it is missing the whole first octave, not just a part of it.

I will be getting a First Sound Presence Audio Deluxe Mk II 4.0 with dual power supplies next week. I believe that this unit is the same as the First Sound Paramount minus the volume control upgrade to Vishay resistors, some few internal wiring and component changes, gold front panel and gold knobs, so it should represent some of the best sound coming from this line. According to people in the know, even the ordinary Presence Audio Deluxe Mk II is stunning in its ability to provide dynamics and bass. I would expect from the overbuilt nature of the power supplies coming with the Deluxe 4.0 Mk II, that the bass and dynamics would be taken to another level. Since I intend to keep my CAT, I can finally provide a comparison between these two sometime late next week if anyone is interested.

i can see here the very wide meaning of phrase "under $10k" here especially for AI $1500 new?
there is also minimalistic AE3 that has the same level of performance at more less than half price AI but with smaller volume range and certainly gain(just 6dB), but the conversation here is to much higher levels of performance where preamp for the money spend should not bring neither brightness or dullness.
no comment about CAT though and that might be the the last one!