Where's My Bass?

I agree with all the above. Also, by itself, this may not be enough, but you might try one or more power cords. It worked for my originally lean sounding system.

They suck on bass, but have great midrange, and that is where the music lives

Eleonida, you have not mentioned what powercords in your system. But i agree with Mrowlands that powercord has a big influence on low/high frequency extensions especially the one connected to the source gear like cd player or dac. It may be worthwhile to spend some time to free-audition powerchords if they are available in your area.
From my experience - pc of thicker gauge copper conductor (AWG11 or 9)generally provides the "warmth" and lowers the bass extension, very apparent in the case of floorstander speakers. And smaller copper or silver plated conductors with teflon insulation provides high frequency "airiness" and apparent hf extension. Even for an electric techy, i don't quite fully understand the exact measurement of these properties. They are definitely NOT due to the current carrying capacity because source gear current demands are extremely small. It might have something to do with the larger conductor surface capacitance & cable twist inductance, type of insulation material, forming natural repeating LC networks along the whole length of the pc which somehow filter the brightness-causing artifacts out of the power supply. So when a salesman states that a longer pc sounds "smoother", he got a point right there from his experience, but not able to offer any scientific explanation. Anyway he probably has an entire sample stock of pc's at his disposal to try out and made that conclusion.

With the above observation learnt, i have recently reconstructed two pieces of pc's from a fellow audiophile's discards. They were "bright" sounding API 313's which has silver coated conductors. After dismantling API to recovered all the materials, added a single 7-strand pvc insulated copper wire (AWG 18 i think) each for line & neutral, woven in the style of a very reputable brand of pc, which i will not name here.

I'm now auditioning these two diy'ed hybrid pc's. The result is quite astounding. They have a refined hi-end sound compared to the original API 313's and they perform very well in the power monoblocs at the moment. However they sound too heavy in the bass (i have over compensated!) at the cd player position.

Sorry to have rambled on this diy stuff. But this is my $0.02 "missing bass" point i wish to make. Enjoy!

Eleonida

I have found that tonal balance in a high end system can be a fine line to walk and one change like a tube or a wire will switch the balance the other way around to being too warm or bass heavy. Hang in there you are may be closer than you think.

Without knowing the (1) amp power rating, it's hard to identify why your set up is lacking of bass. Besides those, the (2)room size, (3)position of speaker are the two most important factors that directly affect the bass response. Cables, tubes, are minor contribution to the lack of bass compared to the (1),(2), and (3)variable above.