Yesterday I finally AB tested my 5842 vs. $4500 Atma-Sphere MP-3 line stage only w/V-Cap upgrade ($600 SRP IIRC.)
The rest of the system is superb, as follows: Huge custom server/streamer built summer of 2021 has 4x the power of Chord's M-Scaler and more power than a $30k Extreme player; running HQ Player's most advanced filters/algorithms (separate outboard NUC runs Room library function only) > Holo Audio May KTE3 DAC > preamp > Atma-Sphere's class D mono blocks (ETA this month) > AudioKinesis Gina satellite w/AudioKinesis Space Generator reverberant field accessory speakers. Two kilo-watt sub amps > four AudioKinesies subs in a distributed array. All Clarity Cable.
MP-3 outperformed my 5842 in every way. Bass clarity was improved a lot as was the nuance and illusion of a human being playing an electric bass. The program was live, starting with just bass, electric piano and maybe some percussion. The size of the venue went from largish on my 5842 to sounding like it was outdoors; the walls and ceiling of my room seemed to disappear. Detail, clarity and transparency improved with more of see-through effect; the presentation more closely mimicked big electrostatic panels. Image separation improved as did the space between the images. The stage and images appeared to form a large, natural and beautiful arc from a center seat row 3 to 5. The music had more swing, verve and emotional connection, that effect that makes you savor to the last and final silence.
I was prepared for my 5842 to outperform the MP-3; no dice!
The MP-3 is a world class preamp IME.