Mkrawcz,
The Aleph J’s are buttery smooth. It was my first “solid state” single ended Class A build. But…The Alpha Nirvana absolutely destroys it in resolution, detail, neutrality and dynamics. On the Aleph J you can play just about anything…but you can walk away from the performance. With the Alpha Nirvana it will hold you to the chair. Depends on what you want really.
Aleph J board with Vcap ODAM:


Alpha Nirvana (designed by Hugh Dean of AKSA), with several parts upgrades:

For a blend of the sonics of the above two designs, Zen Mod’s Aleph J Zen is a good compromise:

Soundstaging is similar on all 3 as a lot of that also depends on your speakers, directivity control, room treatment, etc…that being said, the Alpha Nirvana does do some interesting tricks with placement of performers in the vertical plane.
It’s important to use the right amount of power depending on the loudspeaker:
One thing I have noticed with the NX Otica’s (given the multiple drivers) is that despite the sensitivity, it really does come alive with more power and also higher gain amplifiers. The bass was satisfying with two triple 12 inch OB subs per side, but it really didn’t come to it’s own until two quality sealed subs were also added to the mix. The room is not too large but medium sized, about 14 feet wide, 30 feet deep, 12 foot ceiling. Seating position was about 8-9 feet away. Listened to this setup numerous times. The above amplifiers were very good with the Otica’s but they still felt a little restrained compared to a good 100 watts/ch. That’s where a Class AB design or a well designed Class D pulls through. My buddy currently is enjoying the Denafrips Thallo which is Class A/AB. But he’s building a Purifi Class D out of pure interest

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Best,
Anand.