The Pro-Ject Tube Box S2 is a phono preamplifier designed for vinyl enthusiasts. As the successor to the Tube Box S, this model stands out with its meticulous design and high-quality components, aimed at optimizing the vinyl listening experience.
At the heart of the Tube Box S2 are two ECC83 (12AX7) tubes, one per channel. These tubes deliver the warmth and richness characteristic of tube amplification while maintaining precision and dynamics. A major advantage of the Tube Box S2 is the ability to replace these tubes, allowing users to experiment with different models to customize the sound signature to their preferences.
The input stage uses carefully selected FET transistors for their ultra-low noise and distortion-free performance, ensuring a clean initial amplification of the phono cartridge signal. The RIAA equalization is implemented in two stages, with both active and passive circuits, for optimal accuracy.
The Tube Box S2 excels in versatility, being compatible with both moving magnet (MM) and moving coil (MC) cartridges. To perfectly adapt to any setup, Pro-Ject has included numerous adjustment options accessible from the front or rear of the device.
The gain is adjustable on the front panel with six levels available (40, 43, 50, 53, 60, 63 dB), allowing you to optimize the output level based on the cartridge and the rest of your hi-fi system. The input impedance can be set to five values for MC cartridges (10, 100, 470, 1k, 2k ohms), while it is fixed at 47k ohms for MM cartridges.
The input capacitance is also adjustable with six settings (50, 150, 270, 370, 490, 590 pF), enabling fine-tuning of the cartridge’s frequency response. A switchable subsonic filter (20 Hz, 12 dB/octave) completes these options, eliminating unwanted infrasonic disturbances.
The Tube Box S2 delivers exceptional sound reproduction, characterized by great transparency and a precise soundstage. The bass is deep and controlled, the midrange is rich and warm, and the treble is remarkably pure. Dynamics are preserved, faithfully reproducing even the subtlest nuances of vinyl recordings.
On complex compositions, the Tube Box S2 demonstrates authority while maintaining finesse and nuance. The absence of harshness in the high frequencies ensures a comfortable listening experience, even during extended sessions. The characteristic warmth of tubes adds an organic and engaging dimension to the music without compromising precision.
Compared to its predecessor, the Tube Box S, the S2 brings several notable improvements. The fully discrete design and use of higher-quality components contribute to increased transparency and a more precise soundstage. The expanded adjustment options, particularly for gain, allow for better compatibility with a wide range of phono cartridges.
The reinforced chassis and attention to vibration isolation also enhance overall performance by reducing interference and unwanted noise. These advancements make the Tube Box S2 a phono preamplifier capable of competing with much more expensive models.
Yes, the Tube Box S2 is perfectly suited for low-output MC cartridges thanks to its high gain settings (up to 63 dB) and variable impedance options.
Refer to your cartridge’s specifications for recommended impedance and capacitance. For gain, start with the lowest setting and gradually increase until you achieve a satisfactory sound level without distortion.
Yes, the ECC83 (12AX7) tubes are replaceable. You can experiment with different models to subtly alter the sound signature to your liking.
Like all tube-based devices, the Tube Box S2 benefits from a short warm-up period (about 10-15 minutes) to reach optimal performance.
The lifespan of ECC83 tubes typically ranges between 5,000 and 10,000 hours of use, depending on the quality of the tubes and usage conditions.
It is best to use the Tube Box S2 with a turntable that does not have a built-in preamp. If your turntable does have one, make sure to disable it to fully enjoy the qualities of the Tube Box S2.
Olivier
This preamp is a little gem. I'm rediscovering so many details in my LPs, depth, bass, and a bright top end. The RIAA curve is followed to the letter.
Comment from October 04, 2026 — Experience from September 21, 2026
Olivier
For those who appreciate the warm sound of tubes, they will not be disappointed. I noticed a slight background noise when not listening to music, but it does not detract from the sound quality. This preamp is compatible with a wide variety of cartridges.
Comment from November 11, 2022 — Experience from January 08, 2018
Eric
Huge gain! Real change since it's been paired with my Onkyo TX RZ820 amp. Previously, my Pro Ject turntable was directly connected to the amp's phono input, and since then, it's like night and day...
Comment from December 10, 2019 — Experience from November 19, 2019
