Phono Box S3 B

£349.00
  • MM and MC Capable
  • Dual Mono Design
  • Semi-Passive RIAA Equalisation
  • Superior low noise / low distortion

Find Your Local Retailer

How To Buy

As UK distributors for the brands we represent, our main focus is to give you all the information you need to help assist with your purchase. Once you have the information you need, we want to make the purchase process as simple as possible. So we give you up-to three options on how to buy our products.

Find Your Local Retailer

Our preferred option is for you to visit a nearby store and buy what you need locally. Our authorised stockists are some of the finest specialist hi-fi retailers in the country, and they're equipped to give you the best after-sales and set-up advice possible - all in person. To find your local retailer, either click the 'Buy In-Store' button on your product page for exactly the right recommendation, or head to our comprehensive Where To Buy tool.

Buy Now, Collect Locally

If you want the added convenience of only having to pop-in to store when you know the product you want has arrived, you can use our Click & Collect-style checkout process. With Buy Now, Collect Locally, your purchase takes place online and the product is then delivered direct to your local supporting retailer; ready for you to collect when you're ready. Click here to find out more about Buy Now, Collect Locally.

Buy Now

For smaller items, you can also have the ultimate convenience of purchasing directly through our website. The checkout process is entirely secure, so you can trust your information will be safe - and your desired product will arrive with you as quickly as possible.

Click here for full Terms & Conditions.

The Phono Box S3 B is a compact, affordable moving magnet and moving coil phono stage with dual-mono layout, discrete circuitry and balanced inputs and outputs. With its spacious, minimalist design layout, it is easily customisable to suit any connected cartridge, and offers unrivalled value for money and performance when connected to any matching analogue hi-fi system.

The Pro-Ject design team took the decision to employ fully symmetrical and discrete circuitry in the gain stage of the Phono Box S3 B. Discrete circuits involve no operational amplifiers (op-amps), and the result is a more neutral, natural, dynamic, and vivid sound. They are more complicated to put together and involve a greater variety of components, but the result when utilised in a well-organised electrical layout is a true high-end sound.

The Phono Box S3 B is extensively customisable so suit the moving magnet or moving coil cartridge it is connected to. With five Impedance (Ω), four Capacitance (pF) and four Gain options on offer, there are very few cartridges this box of tricks cannot accommodate.

As the Phono Box S3 B is equipped with both balanced inputs and outputs, it is also part of Pro-Ject’s True Balanced Connections concept. By connecting to a turntable with a moving coil cartridge and using one of Pro-Ject’s balanced connection cables, your analogue system can benefit from increased dynamics, less noise and improved signal-to-noise ratios. Going true balanced is like hearing parts of your music that were not there before.

This requires engineering that has never been seen at this price point and opens up iconic mid-level turntables, such as the Debut Pro, to the benefits of True Balanced Connections.

Elsewhere in the Phono Box S3 B design, the semi-passive RIAA equalisation stage is optimised for absolute accuracy and signal integrity. Depending on the outputs you are using, this stage is then either directly fed to the output stage (when using RCA outputs) or is connected to a balancing stage for onward balanced connections.

The Phono Box S3 B is finished in a steel chassis, covered by silver or black aluminium panels, for extreme rigidity and good electrical isolation. The neat minimalist aesthetic allows for good spacing between controls on the front panel and connections on the back panel, despite its smaller size. It also features an external power adapter, to keep the sensitive internal signals free from any interferences. 

True Balanced Connections

The interconnect cable between a record player and a phono stage is prone to pick up noise on the way. That noise and interference can stem from a lot of unavoidable sources, such as household applicances, wi-fi and bluetooth devices, other power cables and audio amplifiers. Unshielded (i.e. RCA) interconnects can amplify the picked-up noise and make it audible through your speakers, interfering with the pure musical signal.

Balanced (typically XLR) cable connections double the wires carrying the musical signal – with one side inverted. In this case noise still gets picked up by both wires, but with one side reversed. When the signals are re-joined at the phono stage, the picked-up noise is cancelled out by the opposing signals. The benefit of this is a louder, cleaner musical signal that has doubled in size with almost no remaining noise.

For more information about 'True Balanced Connections' click here.

Key Features:

  • NEW 5-pin mini XLR balanced input 
  • NEW balanced XLR outputs 
  • NEW fully symmetrical & discrete gain stage 
  • NEW easy settings adjustment on the faceplate 
  • MM & MC capable 
  • Dual mono design 
  • Semi-passive RIAA equalization 
  • Superior low noise / low distortion 
  • Aluminium casing protects against interference 
  • Available in silver or black 
  • Made in Europe 

Technical Data

Input impedance: 10, 50, 100, 1k, 47k ohms
Input capacitance: 50, 150, 300, 400 pF
Gain (+ 6dB using XLR Out): 40, 45, 60, 65 dB
SNR MM (40dB): 103dBV, 110dBV - ‚A‘ weighted
SNR MC (60dB): 85dBV, 90dBV - ‚A‘ weighted  
THD at 1 kHz: <0,001% MM, < 0,005% MC
THD (20Hz-20kHz): <0,008% MM, < 0,01% MC
RIAA-equalization curve accuracy: <0,3dB / 20Hz - 20kHz
Subsonic filter: at 20Hz with 18dB/octave
Input: 1x 5-pin mini XLR / 1x pair RCA phono sockets
Line-level output: 1x pair RCA, 1x pair XLR
Power supply DC: 18V/500mA
Power consumption: 18V/170mA DC, <0.5 W in standby
Dimensions: 206 x 55 x 153 (164 with sockets) mm
Weight: 930g without power supply
Note: We’re constantly updating our website to ensure all our listings are as accurate as possible. However, the images and text on this page can be subject to change without notice, and errors and omissions are excepted.

If you have any questions, please contact us.