So, Thomas Mayer Differential 10Y, Allegri + passive, Vinnie Rossi L2, Berning ZOTL Pre One? Drums beating and beating,… then stop.

In my acoustically treated space, having the loudspeakers sing freely without anything between them, with all electronics on the side wall, the preamp's influence on the sound for the four mentioned is less than 15% to my ears which I regularly check. It is perhaps not fair to forget the subtle mix of character—I'm not allowed to use the word 'distortion' here, lol—between Nenuphar/Bakoon versus each of the contenders. Different pairings with other amps slightly changed the picture.

Anyway, what Thomas managed with his 10Y push/pull preamp is something that's probably closest to traditionally accepted perfection. Enough said.

Townshend's Allegri+ is a little guy only in physical dimensions. It produces a great soundstage with touches of eerie psych effects.

Berning's ZOTL is ruthlessly accurate. Maybe David's grandparents were German too?

Eclipsing lunar and stellar L2? Highly transparent, easy and fun to play with and with that one distinct advantage from the claimed and confirmed S/N ratio which produces this feeling of calmness which allows for no impurities. I'd conclude that for SET lovers, I'm certain that all four will provide a lot of satisfaction.

What am I going to do you ask?

Nobody could stop me now. I'm writing Vinnie asking him to sell me this L2. Yes, good evening to you. My name is Dan and I'm an addict!

PS. If you're curious about my extended playlist, here goes:

1. Au/Ra – Panic Room – link
2. Grandson – Bury Me Face Down – link
3. July Talk – I've Rationed Well –  link
4. Rainbow Kitten Surprise – Cocaine Jesus – link
5. Alabama Shakes – You Ain't Alone – link
6. Regina Spektor – On The Radio – link
7. Mariza – Medo – link
8. Rag'n And Bone Man – St. James  (Bluestown) – link
9. Koko Taylor & Willie Dixon – Insane Asylum – link
10. J.S. Bach – Easter Oratorio – link
11. Saint, Sahale – Dune (Buddha Bar- Armen Miran & Ravin) – link
12. Perfume Genius – Grid – link
13. Warp Brothers – Cokane – link
14. No Blues – Ya Dunya – Rageen Rambling – link
15. Taraf de  Haidouks – Gipsy Lament – link
16. E Lucevan le Stelle – Tosca – G. Puccini – link
17. Astrud Gilberto, Stanz Getz and João Gilbert – Corcovado – link
18. Csik Zenekar – Most Mulik Pontosan – link
19. Goat – Words (Commune) – link
20. Brian Jonestown Massacre – Just Like Kicking Jesus – link
21. Ane Brun – How To Disappear Completely – link
22. Timber Timbre – Lay Down In The Tall Grass – link
23.  Rachel Yamagata – Nobody – link
24. Willis Earl Beal – Too Dry To Cry – link
25. The Record Company – Turn Me Loose – link
26. The Outlaws Blues Band – I Tried To Be A Good Boy – link
27. Two Feet – I Feel Like I'm Drowning – link
28. Phildel – Dare (Disappearance Of the Girl) – link
29. Mercan Dede – Sufi Dreams – link
30. Jessie Reyez – Gatekeeper – link
31. Jason Ricci & New Blood – The Way I Hurt Myself – link
32. John Coltrane – A Love Supreme, P.2 Resolution  MCA Records – link
33. Miles Davis & John Coltrane – Teo – link
34. The Jazz Singers – Franklin Mint Record Society  disk 6 face A
35.  R. Strauss – Also sprach Zarathustra, Deutsche Gramophon – link

PPS: I tried dozens of different tubes now. The L2 advantage is that one can micro fine-tune the sound character of the loudspeaker/amplifier interaction.

A: One needs a bit more resolution, more clarity, less "velvet and honey": go PX4, SV811, 183/483 (5V 45) or TAK 300B (last being borderline between A and C).
B: One needs a bit more soul and sexiness: 300B is the soul-ution (TAK, Elrog, Sophia Electric).
C: One is already balanced but longs for a bit more meat on the bones and presence: 2A3 and 6A3 are clear winners for me, with the JJ 40 coming out on top.

The L2 ⇒ Berning VT52 ⇒ Nenuphar combo in my room is really magical. The best sound you and I heard together back in the old room was less than 75% of what I'm hearing now. I purposely didn't mention speed as an individual character point because the OTL amp supersedes any such influence from the L2, being OTL-ightspeed itself.