Pro-Ject Phono Box RS Review

by crackler01

Today I have another preamplifier on my desk and I will tell you everything about it in the latest Pro-Ject Phono Box RS Review article.


The Pro-Ject Phono Box RS is a testament to precision engineering and sonic finesse, designed to elevate the audio experience for vinyl enthusiasts. Crafted by Pro-Ject Audio Systems, renowned for their commitment to high-fidelity audio, this preamplifier enters the realm of audio reproduction with promises of pristine sound quality and exceptional build.

Pro-Ject Phono Box RS Review

Pro-Ject Phono Box RS Specifications

  • Input impedance, variable: step-less 10ohms – 1.200ohms A
  • Input capacitance/impedance: 100pF, 200pF, 300pF, 420pF and 520pF */47kohms B
  • Input impedance, fixed: 10ohms A
  • Input gain (+ 6dB using XLR sockets): 40dB and 50dB B / 60dB A
  • Noise floor: 91dB (A-weighted)
  • THD: 0,019%
  • De-emphasis curve accuracy: 20Hz – 20kHz / max. 0,3dB
  • Subsonic filter: at 20Hz with 12dB/octave
  • Input: 1 pair RCA/phono sockets, 1 pair XLR sockets
  • Line-level output: 1 pair RCA/phono sockets, 1 pair XLR sockets
  • Wiring XLR sockets: 1 ground, 2 “hot” and 3 “cold”
  • Outboard power supply: ±18V/250mA DC, suitable for your country’s mains supply
  • Power consumption: 150mA DC, <1W in standby

A: typical for low output MC cartridges, B: typical for MM cartridges or high output MC
*Input capacitance is irrelevant for low-output MC cartridges.

You can download the manual here->Pro-Ject Phono Box RS Manual

Design & Build Quality

The Pro-Ject Phono Box RS catches your eye with its sleek and functional design. Made from high-quality aluminum, it feels solid and looks sophisticated. The matte finish not only adds style but also helps reduce vibrations that could affect sound quality.

Every detail of its design is carefully considered. The front panel has easy-to-use buttons and a volume knob that turns smoothly, giving a sense of precision. Connecting cables at the back is a breeze thanks to clear labels and a well-organized layout.

Its size is just right, fitting well into any audio setup without taking up too much space. Plus, the aluminum body protects against interference, ensuring your music stays clean and clear without outside disturbances.

Inside, the Phono Box RS is like a well-organized orchestra. Different parts are neatly separated to prevent any interference between them. This, combined with top-notch components and advanced shielding, shows how serious Pro-Ject is about keeping your music pure.

Pro-Ject Phono Box RS Inside View

Even the little details, like the feet it sits on, are smartly designed. These feet not only keep it stable but also stop vibrations from messing with the delicate electronics inside, keeping your music sounding its best.

In short, the design and build of the Pro-Ject Phono Box RS are not just about looks. It’s a mix of smart engineering and craftsmanship that ensures your analog music gets the respect it deserves, giving you an amazing listening experience every time.

Audio Performance

The Pro-Ject Phono Box RS excels in making your vinyl records sound incredible. It’s like having a magic box that brings out every detail and richness from your favorite albums.

When you listen through this preamplifier, the music feels alive. It captures the warmth and depth of vinyl, making it sound clear and full-bodied. The instruments and vocals come through with amazing clarity, letting you hear every subtle nuance and emotion in the music.

One thing that stands out is how clean the sound is. There’s no unwanted background noise or distortion; it’s just pure, high-quality audio. Even when you crank up the volume, it stays crystal clear without losing its richness.

Pro-Ject Phono Box RS Silver

This box is great at preserving the original sound of your records. It does this by carefully adjusting the different frequencies so that what you hear is exactly how the artist intended it to be. The soundstage it creates is wide and immersive, making you feel like you’re right there in the studio with the musicians.

Whether it’s the soft strumming of a guitar or the punchy beats of a drum, the Phono Box RS handles it all beautifully. It brings out the best in your vinyl collection, making every listening session a delight for your ears.

In essence, the Pro-Ject Phono Box RS isn’t just about making your records louder; it’s about making them sound incredibly good. It’s like giving your favorite albums a new life, letting you rediscover the joy and magic of analog music in stunning detail.

Functionality & Features

The Pro Ject Phono Box RS preamplifier is a device that amplifies the low-level signal from a phono cartridge to a line-level signal that can be fed to an amplifier or a speaker. It is designed for audiophiles who want to enjoy the best sound quality from their vinyl records. Here are some of the main features and functionalities of the Phono Box RS:

  • Can handle moving magnet (MM) and moving coil (MC) cartridges. Those are two types of phono cartridges that have different output levels and impedance requirements. The Phono Box RS allows you to switch between MM and MC modes via a switch on the back panel.
  • The unique feature that lets you adjust the input impedance loading of the phono stage. Impedance is the resistance that the cartridge sees from the preamplifier. The input impedance loading affects the frequency response and the output level of the cartridge, and different cartridges have different optimal impedance values. The Phono Box RS has a rotary knob on the front panel that allows you to vary the input impedance loading from 10 ohms to 1200 ohms, even while playing a record. This way, you can fine-tune the sound quality and match the cartridge’s specifications.
  • Fully passive equalization circuit. This means that it does not use any active components or feedback loops to correct the frequency response of the phono signal. The phono signal has a non-linear frequency response due to the way the vinyl records are cut and played, and it needs to be equalized to restore the original sound. The Phono Box RS uses only resistors and capacitors to achieve this equalization, which results in lower noise and distortion than active equalization circuits.
    Pro-Ject Phono Box RIAA and DECCA CurvesThe Phono Box RS has two equalization curves that can be selected via a switch on the back panel: RIAA and DECCA. RIAA is the standard equalization curve for most records, while DECCA is an alternative curve that was used by some record labels in the 1950s and 1960s, such as Decca, London, and RCA.
  • Balanced XLR and unbalanced RCA inputs and outputs. This means that it can connect to a variety of turntables and amplifiers. The balanced connections offer better noise rejection and signal integrity, especially over long cable runs. Unbalanced connections are more common and compatible with most devices.
  • A subsonic filter that can be activated via a switch on the back panel, which reduces low-frequency rumble and feedback from warped records or suboptimal turntable setups. The subsonic filter cuts off frequencies below 20 Hz at a slope of 12 dB per octave.
  • True dual-mono design. This means that each channel has its own dedicated circuitry and power supply, ensuring minimal crosstalk and interference. The phono stage uses high-quality components, such as SSM2019 from Analog Devices as input stages and Linear Technology LT1010 as high current buffer stage, to deliver ultra-low noise and distortion levels. The phono stage also has a very low output impedance of 50 ohms, which makes it insensitive to the selection and length of interconnect cables.
  • Sleek and elegant design, with a metal casing that protects it from vibration and interference. The front panel has a power switch and a blue LED indicator. In contrast, the back panel has the input and output connectors, the equalization and subsonic filter switches, and the power supply socket. The phono stage comes with two external power supplies, one for each channel, with a low standby power consumption of less than 1 watt. The phono stage is available in silver or black finish and has a compact footprint of 206 x 72 x 210 mm (W x H x D).

The Pro Ject Phono Box RS preamplifier is a reference-class phono preamplifier that offers exceptional performance and versatility for vinyl enthusiasts. It is capable of adapting to virtually any phono cartridge and offers a fully balanced signal path and passive equalization for optimal sonic performance. It is a must-have for anyone who wants to enjoy the full potential of their vinyl collection.

Sound Test

The difference here compared to cheaper preamplifiers is better control, detail and refinement. Good balance is just a starting point. Pro-Ject Phono Box RS presents its own, characteristic sound, but there is no inappropriateness or over-interpretation. What does this “sophistication” consist in?

First of all, on the skillful combination of selectivity and filling. The percussion cymbals, with which this can be heard perfectly, are strong, clear and at the same time delicate – they have “flow”, and detail, and they are not broken pots.

There is a lot of upper midrange and treble here, this may need to be corrected by selecting an appropriate cartridge, but the quality of this part of the band is excellent. The piano is neither monotonously glassy nor dull, but vibrant and juicy, the attack is clear, and the decay is rich and pleasantly softening.

Pro-Ject Phono Box RS Back Side Connections


The tonal balance seems to be very well set – we have strong bass, saturated midrange and clear treble. Only when we put a much more expensive preamplifier next to it, we can hear that the Phono Box’s sound is a bit restricted and restrained. But thanks to this, the bass has great definition, it doesn’t go crazy, it doesn’t spread out, and yet it reaches low.

The sound of the Pro-Ject Phono Box RS preamplifier is not only correct but also very close to the natural operation of acoustic instruments operating in this frequency range.

Similarly, the midrange – transparent, reliable, neither shocking nor moving the listener with great images and fabulous vocals; However, you only need to listen to a few albums to understand how well he handles various tasks. It is a sound with high dynamics, a wide frequency response and very good resolution.

It seems to me that the tone of this preamplifier was tuned with Ortofon-type cartridges, which Pro-Ject itself would seem to confirm, describing the functional features of the RS using examples of Ortofon models.

That’s why it’s worth looking for a warm-sounding cartridge. Let’s take into account the incredible functionality of this device and we will see that it is outstanding for its price.

Price & Value

Now, let’s talk about the money side of things. The Pro-Ject Phono Box RS isn’t the cheapest piece of gear out there, but it’s got some serious bang for your buck.

Sure, it might be a bit pricier compared to other preamps, but here’s the deal: it’s worth every penny. You’re not just paying for a box; you’re investing in an experience. This thing brings out the best in your vinyl collection, making each record sound like a masterpiece.

Think of it this way: you’re getting top-notch audio quality. The sound is so clear and true to the original recording that it’s like rediscovering your music library all over again. Plus, its versatility means it can adapt to different setups, giving you that tailored sound you crave.

And let’s not forget reliability. This box is solid. You won’t be dealing with constant breakdowns or technical glitches. It’s built to last, so you’re not just buying a gizmo; you’re investing in a reliable companion for your music journey.

Sure, it might pinch your wallet a bit more than other options, but if you’re serious about getting the most out of your vinyl collection, the Pro-Ject Phono Box RS is a worthy investment. It’s not just a piece of equipment; it’s a gateway to a whole new level of audio enjoyment. And that’s something that’s truly valuable.

Pro-Ject Phono Box RS Video Review

Final Verdict

So, here’s the lowdown on the Pro-Ject Phono Box RS: it’s a game-changer for your vinyl setup.

This thing isn’t just another gadget; it’s a key player in your quest for fantastic sound. From its sleek design to the way it makes your records sing, the Phono Box RS is like a maestro conducting your audio experience.

Sure, it might ask for a bit more from your wallet, but trust me, it’s worth it. This preamp takes your vinyl collection and turns it into a symphony of amazing sound. It’s like giving your records a VIP pass to audio perfection.

And the best part? It’s not just about the fancy features or the slick design. It’s about how it makes you feel when you listen. The richness, the clarity, the pure joy of experiencing music in its truest form – that’s what the Phono Box RS brings to the table.

In the end, if you’re serious about your vinyl and want to elevate your listening experience to a whole new level, the Pro-Ject Phono Box RS is the real deal. It’s not just a piece of equipment; it’s a gateway to audio nirvana, where every crackle and note becomes a moment of pure musical bliss.

Pro-Ject Phono Box RS Pro & Cons


  • Exceptional sound quality with detailed and accurate audio reproduction
  • Versatile connectivity options for various turntables and systems
  • High-quality components and build for long-term durability


  • Relatively higher price compared to some alternatives
  • May require a bit of expertise or setup for optimal performance
The Pro-Ject Phono Box RS stands as a top-tier choice, delivering impeccable sound quality and versatile connectivity. While its premium price may be a consideration, its exceptional performance and durable build make it a compelling investment for audiophiles seeking unparalleled audio fidelity.
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