Fezz Audio Omega Lupi (Evolution) Review

Fezz Audio Omega Lupi Evolution Tube Headphone Amp

One of the ever-elusive elements in audiophilia is the coveted “tube sound.” Everyone craves that analog, earthy sound that only tubes can provide. However, quality tube amps often come with a hefty price tag, as seen with the Fezz Audio Omega Lupi. Today, we explore the “Evolution” model, which, according to Fezz, sounds identical to the “Legacy” model, with differences only in build and price. When referring to the “Omega Lupi” in this review, please note we are discussing the “Evolution” version. Now let’s dive in and see what this amp can do. 

What’s in the Box

  • Fezz Omega Lupi vacuum tube headphone amplifier
  • 4 PCL86 vacuum tubes
  • Power cord
  • User’s manual
  • Cotton gloves
  • Vacuum tube protective cage

Fezz Audio Omega Lupi Evolution Tube Headphone Amp logo

Build Quality

The Omega Lupi is a formidable amp, measuring 340 x 355 x 150mm and weighing nearly 10 kg. It comes in various colors: Big Calm (burgundy), Black Ice (black), Burning Red (bright red), EverGreen (green), Moonlight (grey), Republika (white), and Sunlight (beige). We reviewed the Black Ice version.

The front panel features a quarter-inch headphone jack, a volume dial, and a gain knob for low, medium, and high impedance modes. The back panel includes two RCA connectors (one for input and one for parallel signal output), a power plug, and a ground switch. The top houses four tube slots, two output power transformers, and ventilation. Despite its robust build, the Omega Lupi is straightforward in terms of I/O and features, focusing on providing excellent sound quality rather than unnecessary extras.

Fezz Audio Omega Lupi Evolution Tube Headphone Amp back


The Omega Lupi uses four PCL86 tubes, which combine a triode and pentode in a single capsule. This dual-filament design enhances the amplifier’s ability to produce rich and dynamic sound. The push-pull AB1 configuration reduces distortion and improves linearity, resulting in more accurate and high-fidelity sound reproduction.

With a frequency response range of 20Hz-120kHz (-3dB) and total harmonic distortion (THD) below 0.3%, the Omega Lupi ensures that both low and high frequencies are reproduced accurately, delivering clean and undistorted audio.

Fezz Audio Omega Lupi Evolution Tube Headphone Amp side

Sound Impressions

Low End

The bass is a standout feature of the Omega Lupi. It delivers exceptional detail and separation in the low frequencies, with a visceral attack that enhances songs from any genre. Tracks like Wilco’s “Jesus, Etc.” and Bill Withers’ “Lovely Day” showcase the amp’s ability to follow basslines with precision and dynamic range. The Omega Lupi’s bass performance is characterized by a great sense of macro- and micro-dynamics, making it capable of handling complex bass lines with ease.


The midrange is sweet, musical, and highly detailed. Vocals from artists like Kacey Musgraves, Thom Yorke, and Nick Drake sound ethereal and engaging. The Omega Lupi excels in detail retrieval and dynamics, providing excellent instrument separation. Listening to tracks such as Neil Young’s “See the Sky About to Rain,” every nuance of the singer’s voice is captured, along with clear separation between instruments like the piano and guitar.

Top End

The treble is present and clean but slightly mellow compared to the low and mid frequencies. This smoothness can be beneficial, though, depending on the headphones used. Pairing the Omega Lupi with cooler-sounding headphones like the Abyss Diana MR, Focal Clear MG, and Sennheiser HD800S yields a balanced sound with extended highs. Warmer headphones like the Meze Empyrean II and Audeze LCD-5 might make the treble sound a little too smooth. Thus, careful selection of headphones is necessary to achieve the best sound quality.


The soundstage is ethereal and natural, offering an immersive listening experience. The Omega Lupi creates a fully engulfing space rather than a strictly lateral one, providing sublime audio immersion. This expansive soundstage enhances the overall listening experience, making it feel like the music surrounds the listener from all directions.

Optimizing Your Listening Experience

To fully appreciate the capabilities of the Omega Lupi, it’s important to consider headphone synergy. The amp’s powerful output can drive almost any headphones, but achieving the best sound involves pairing it with headphones that complement its characteristics. Cooler headphones help balance the smooth treble, ensuring a well-rounded and detailed listening experience. This consideration is crucial for audiophiles seeking to maximize the amp’s performance.


The Fezz Audio Omega Lupi Evolution Edition is a high-performing tube amp that excels in delivering rich, dynamic sound. While headphone synergy is crucial for optimal performance, this amp is a top contender for those seeking the ultimate tube sound experience. If you’re in the market for a premium tube amp, the Omega Lupi is definitely worth considering.

The Fezz Audio Omega Lupi is available at Audio46.

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