Summary:
There have been a couple of revisions to the Ono. I have an 'early' one, and found that after it went back to Pass for some updating, it was a different animal. The basic modification was to the power supply- larger transformer, higher capacitance in the PS, etc. And it made a nice phono stage into a superb phono stage. Noise before was perhaps on par with what you could expect with a better SS phono section, such as what Bryston builds. After the mods, we're into another class altogether. To me, the more profound the silence, the deeper the soundstage, and the greater the transparency. Now that these are discontinued, they present an outstanding value, and Pass Labs is a fine company to deal with.

Strengths:
Quiet and dynamic

Weaknesses:
Can be a moving target

Summary:
Ive been looking to replace my aging but still capable JC design Vendetta phono and tried a few phono stages from Audio Research,BAT,Pass, Herron and Sutherland.
Overall the top two were the Pass and Sutherland.
Please realise that i prefer my sound with no euphonic colorations so the AR and BAT were too colored and noisy. I liked the FM Acoustics 122 for its smooth detailed presntation. The Ono came very close with very little coloration and excellent information retrieval with a smidgen of airiness lost compared with the FM. I chose the Pass over the FM because of its $$$ value and I still would rate the FM as the best Ive heard.

With its unlimited loading settings, I played around with several combinations on my Basis , Graham 2.My final cartridge set up was with a Benz Ruby rather than the parnassus Dct. The Lyra adding too much zing overall.My nect cartridge trial is the VDH frog.

Strengths:
Versatile loading and gain, balanced options all for $2500.
Dynamic sounding and fantastic transients.

Weaknesses:
Will reveal the flaws if arm and cartridge are not up to scratch. people who like euphonic may not like its 'warts" and all presentation

Similar Products Used:

Summary:
The ONO makes a few demands on the user. First, it should be mated with a fairly neutral-sounding cartridge. Despite a wide range of MC loads and MM capacity, this preamp really does justice to medium output moving coils, like Benz Micro Ruby II, and higher end Grado series. Given the options of balanced and unbalanced outputs, it allows very versatile matching to most preamp line inputs with minimal noise. It is the first phono preamp that I have used that provides WYHIWYG (What you hear is what you get). Great recordings really open up and sing. Conversely, it is unforgiving of mixing, staging, and timbral flaws.
Given the versatility of this unit, it represents a better value than some of the small boxes or cubes that are out there. One would have to spend stratospherically to achieve a significantly more open or better balanced sound picture. Be aware that a new phono preamp in the X-series is in the works.

Strengths:
Noise-free, open, and highly accurate; built like a tank

Weaknesses:
Cartridge, arm, and cable selection is critical to achieving
the best results from this beautiful machine.

Summary:
Bought it based on rave reviews and becos of Nelson Pass.I was quite disappointed considering that this is a $2000
phono amp and a Nelson Pass design. I am greatly impressed
with his amps particulary the 1.2 and anticipated a similar
natural single ended kind of sound.

Sad to say, this amp fails in two critical areas.
naturalness and ambience creation, 2 of the virtues and why i switched to analogue. After installing the Ono, I failed to be impressed with its
intrinsic character.

Sure, it was quick, lean and accurate but somehow, it made the music
sound more etched and artificial ie digital. Where is the air ?????Even after playing around with various loading combinations,
it made my Lyra Parnassus, Rockport Sirius/7000 combo soundlike a Cd player,
a mediocre one at that.


My salvation came in the form of the lowly $800 EntecBlack Cube which
combined the lushness of the AR PH3 and the exactness of the ONO. I
am still evaluating the Black Cube which is on loan from a friend but looks like I might be "downgrading' soon. Subjectively, The Ono has a wider stage but the Cube sounds more there.i have yet to fully experiment with
the EAR 834P but initial listening seems to be of a full midrange, airy nature but with a little tube noise.

5 stars for build quality, 3.5 stars for sound but $$$ Vs value is 3 stars.