Effective recommendations to add warmth & smoothness while keeping bass control

Tube Preamp with Solid State Amplifier is my method of choice.  I like the 3D sound stage and tube smoothness yet the drive and dynamics of a robust solid state amp that only tube amps can dream of. 

My forever amp is a McIntosh MC312 and I have been using a Cary Audio SLP-05 two chassis preamp with 6SN7 tubes and a tube rectifier.  With the right cables and tubes the smooth, polished liquid gold tone of this system is to die for.  

I recently added a recent new gen take on the classic McIntosh C22 preamp, the MK-iv.  Definitely a step into the darker, bassier realm.  

To greatly add to that sound, I swapped in a set of JJ ECC83 "MG" Tubes- WOW !!!  The "MG" stands for mid gain, which puts the gain of this tube between a 12AX7 and 5751.  THE TONE OF THIS JJ ECC83 "MG" is freaking dark and bass enhanced !  Is by far the darkest, most classic tubiest sounding tube I have ever heard !  The thing made my system slam- incredible punch and impact- and even right out of the box there was zero noise, sibilance or unclean treble- gone- !  Just a super incredible smoothness that took some time to get used to.  

If you like your sound tubey to the max, get a newer gen McIntosh tube preamp- MKIV and C2300 and up- and get a pair of these JJ ECC83 MG- best $40 you will ever spend in hifi.  

Thanks for sharing, @avanti1960.  I did have a chance to audition a tube preamp paired with a solid-state McIntosh amp at a local dealer here in WPB about 2–3 years ago. It had a very dark, thick and slammy sound—exactly what you’ve described. I wasn’t sure if I liked it at the time, but I’d love to revisit it. I’m certainly intrigued by the lack of sibilance part.  

I almost rule out the Freya+ based on the comments from Stereophile or others...

In general, the tube mode of the Freya + sounded a little warm, rich, and forgiving—all attributes sought by many. The bass was rich and weighty, which I found quite enjoyable for passive listening, but I preferred the solid state buffer mode for its uncolored directness. (quoted from Stereophile)

The lower gain of the SS active mode from my Saga 2 offers similar character too.

The Freya + in its vacuum tube mode offers pleasing presence and warmth but without obscuring detail or disrupting musical balance. (quoted from Stereophile)

I am not sure if a tube pre can be considered acceptable once the details and tonal balance are compromised. Sorry, Freya+.

Last night, I actually swapped the D90 with the Laiv Micro R2R DAC, and through the Saga 2, the soundstage I perceived was noticeably larger. The sound became more lush and richer, and the combo tamed the shimmering treble. Although it does not completely eliminate sibilance, the overall sound is noticeably smoother and less fatiguing with poorer recordings.