Perfect Performance

This power supply is designed to give you flawless, reliable power every time you turn on your audio system. It works quietly and consistently to make sure your gear performs at its absolute best.

Thanks to its double regulation and super capacitor smoothing, the output stays rock-solid — even when the power from your wall is not stable. This means no sudden drops, spikes, or noise that can spoil your listening experience.

The power supply is custom-made for each output voltage, anywhere between 3.3V and 20V, with a maximum current of 3A. You choose the exact voltage you need, and Nereneas builds it specifically for your gear — it’s not user-configurable after purchase.

Its low-noise design and clean power delivery help your phono preamps, DACs, and headphone amps reveal hidden details and deeper silence in your music. You’ll hear your favorite albums with more clarity and emotion — exactly as the artists intended.

Technology & Innovations

Smarter Design for Quieter Sound

Most cassette decks, including high-end models, feature multiple gain stages and switches in the signal path, which are also used for recording monitoring. The circuits that read VU meter information are integrated into the same path. These factors in the long signal chain:

• Introduce phase shift, which compromises the soundstage

• Add distortion

• Add noise

• Reduce the bandwidth, affecting overall sound quality

CASSIUS is different because it features a smart design with a short signal path, made up of only two stages, and operates with no overall negative feedback loop. The EQ curve is cleverly integrated into the input stage, providing two key benefits:

• Ultra-low noise input stage: By applying the EQ curve here, the sound remains clean and clear, without relying on feedback-based corrections

• Short signal path: With a minimum number of gain stages, CASSIUS maintains the shortest possible signal path, resulting in less overall noise and distortion for a clearer, more detailed sound that stays true to the original recording

Additionally, CASSIUS features:

• High input impedance, allowing it to work seamlessly with nearly any cassette deck tape head, ensuring broad compatibility without compromising performance

• No electrolytic capacitors in the signal path, ensuring that no low-quality components interfere with the purity and precision of your audio, contributing to overall transparency in the sound

• No switching elements in the signal path, ensuring that there are no added distortions or noise caused by relays or switches, keeping the signal clean and pure

With CASSIUS, you bypass the entire signal path from your cassette deck by connecting directly to the tape head. This means you get all the benefits of a state-of-the-art playback circuit, ensuring the purest and clearest sound with no extra noise or distortion added

Precision Without Compromise

Most cassette decks, even high-end models, rely on multiple gain stages and additional circuits, leading to signal loss, noise, and distortion. CASSIUS takes a different approach. By connecting directly to the tape head, it bypasses the entire signal path, ensuring the cleanest, clearest signal possible.

• CASSIUS features a fully balanced design, using ultra-low noise components for the input stage, which is hand-matched for perfect performance

• High Gain Requirement: The signal level from the tape head is typically 200 µV, and to bring it to line level, the gain needs to be 10,000. This means that even the smallest imperfections in the circuit can have a significant impact on performance

• No Global Feedback Loop: Unlike other designs that rely on a global negative feedback loop to correct errors, CASSIUS operates without one. Due to its fully balanced design, any drift in the input offset is directly reflected at the output, amplified by the high gain. This makes precise trimming of the input stage even more critical to maintaining optimal performance

• Hand-Trimmed for Accuracy: To maintain extreme precision, the residual offset in the input stage is trimmed by hand, individually for each unit. After just two minutes of operation, the offset stabilizes at around 10 µV, making it negligible compared to the signal level

• Stable Performance in All Conditions: To minimize temperature drift, CASSIUS uses high-precision resistors with an accuracy of 0.01% and 5 ppm/°C in the signal path. This ensures that playback remains stable and consistent, preserving the accuracy of the sound, especially in the lower frequencies where bass control and detail are crucial

• The high-precision components, including 0.01% resistors and 1% MKP capacitors, ensure that the EQ curve is highly accurate, with an accuracy of +/- 0.1 dB. This results in exceptionally clear and dynamic sound, capturing the true details and nuance of your cassette tapes. The EQ curve for both Type I and Type II/IV cassettes ensures a natural and lifelike reproduction, with no distortions

This level of precision ensures CASSIUS offers the highest quality cassette playback, making sure your tapes sound as pure and detailed as possible. No compromises, just incredible sound.

Ultra Low Noise Design for Pure Sound

At NERENEAS, we believe in preserving the absolute transparency of your music, especially in analog playback. That’s why CASSIUS was designed with extremely low noise in mind, ensuring you hear your tapes exactly as they were meant to be heard—clear and pure, without any unwanted interference.

The input-referred noise of CASSIUS is an impressively low 0.4 nV√Hz, which is far below the inherent noise level of a typical cassette deck tape head. In fact, the DC resistance of a cassette deck tape head is usually around 300 ohms, resulting in a noise contribution of approximately 1.3 nV√Hz—higher than what CASSIUS introduces. This means that CASSIUS ensures your sound is clearer and purer, with minimal interference, allowing you to fully enjoy the analog warmth of your tapes.

We’re not fans of Dolby noise reduction systems, as they often compromise the sound by applying artificial processing that alters the natural character of the music. CASSIUS, on the other hand, is built with a commitment to transparency, offering you a pure and unmodified signal path. There’s no signal processing—just true, unaltered analog reproduction, staying true to the artist's intent. With CASSIUS, you get the closest thing to a direct connection with the original recording—preserving the authenticity and depth of every note

Ultra Wide Bandwidth for Exceptional Sound

A tape head preamplifier doesn’t just amplify the signal - it also plays a key role in how the music is reproduced, ensuring the soundstage is precise and natural. One important factor is phase shift, which can affect the placement of instruments and vocals in the stereo field.

CASSIUS is designed to avoid phase shift in the signal path:

• The signal path has an ultra-wide bandwidth, ensuring that the tape head’s signal is amplified without introducing phase shift. This keeps the soundstage clear, deep, and natural, with precise instrument placement and a lifelike presentation

• The EQ curve is integrated into the input stage, meaning that the signal path is not affected by additional gain stages. This minimizes any negative impact on the bandwidth and ensures that only the EQ circuit influences the sound, maintaining the most natural playback possible

With CASSIUS, you experience a clean, full-bodied sound that allows your cassettes to sound exactly as they were meant to - with the right depth, clarity, and dynamics.

Better Signal Switching

Most cassette decks use low-quality switches, such as transistors, which are placed directly in the signal path. These switches can have leakage, degrading the performance of the signal and introducing unwanted distortion and noise. CASSIUS avoids this problem by using high-quality components to keep the signal pure and clear. Both the EQ curve and gain are switched using latching relays, controlled by a microcontroller to ensure precise and noise-free switching. These relays are not in the signal path, meaning they do not add any distortion or noise to the audio. This ensures the integrity of your sound is preserved at all times

Pure Power for Clear Sound

CASSIUS features a high-quality internal power supply, designed to deliver clean and steady power for optimal performance. It uses a custom toroidal transformer with separate windings to ensure that the audio and digital circuits are completely isolated, preventing any interference. This approach reduces noise and ensures that the cassette deck's signal remains as pure as possible, delivering the best sound quality.

Exclusivity and Craftsmanship

CASSIUS was never designed or intended for mass production. It is a truly exclusive product, assembled by hand with great care and attention to detail. Every component is carefully selected and matched to ensure the best sound quality and precision.

We do not keep stock for CASSIUS—each unit is made to order. If you wish to own one, you must pay in advance, with a waiting time between 3 to 6 months for assembly. CASSIUS will never be available in specialized shops, and it can only be purchased directly from NERENEAS. This limited availability adds to the exclusivity and ensures that each CASSIUS is a one-of-a-kind masterpiece for the most discerning audio enthusiasts and collectors.