Pro-Ject Phono Box S2 Ultra


Discrete MM/MC phono preamplifier

Phono Box S2 Ultra – Luxury and audiophilia combined!

The Phono Box S2 Ultra is like no other phono preamplifier in its segment. The incredible success of our Phono Box Ultra 500, incited us to introduce this marvelously sounding phono preamp into our regular S2 line. The solid metal casing protects against interference and the internal design remains as spectacular as before.

We are offering a fully discrete, OpAmp less design, which enabled us to realize an incredibly harmonious sound. On top of leaving out operational amplifiers we decided to use polystyrene capacitors, which significantly contribute to the high end sound of the Phono Box S2 Ultra. These capacitors are known amongst audiophiles as the holy grail for phono preamplifiers. The split RIAA equalization enables a pin-point accurate representation of the RIAA curve, a luxury many other phono preamps do not possess.

Compatible upgrade power supply: Accu Box S2


  • Audiophile Performance
  • No Operational Amplifiers used
  • Audiophile-grade polystyrene capacitors
  • Precise split RIAA equalisation
  • Switchable Subsonic filter –18 dB @ 20Hz
  • Switchable input impedance/capacitance
  • Four adjustable gain levels
  • Solid metal casing protects from interferences
  • Outstanding sound quality
  • Available in silver or black

Technical Specifications

Input impedance 10 Ohm/ 100 Ohm/1 kOhm / 47 kOhm
Input capacitance 100 pF/ 220 pF
Gain switch 40dB/43dB/60dB/63dB
Subsonic switch -18 dB @ 20 Hz
Signal-to-noise ratio 89 dB V (MM)
THD 0.00052%
RIAA accuracy < 0.4 dB / 20 Hz – 20k Hz
In/Out sockets 1 pair RCA connectors
Power consumption 18 V / 80 mA
Outboard power supply 18 Volt DC/ 500 mA
Dimensions ( W x H x D ) 103 x 37 x 119 mm
Colour silver or black
Weight 570 g without power supply


Manual [pdf]


Hi-Fi Choice reviews the Phono Box S2 Ultra

UK, 05.2019

Conclusion: With a consistently impressive performance and the ability to handle upmarket cartridges, this is a flexible and attractive phono stage that deserves to be high on any audition shortlist at the price.


Ed Selley

Golden Ear Award 2021

1st place in the “Phono Preamp up to € 2000” category!


Malte Ruhnke

Golden Ear Award 2021

2nd place in the Phono Preamp category.


Andreas Eichelsdörfer

Hi-Fi World reviews the Phono Box S2 Ultra

EN, 04.2019
This little phono stage does a wonderful job: Fantastic sound and fantastic value! Pro-Ject should be congratulated!



Martin Pipe

Mint reviews the Phono Box S2 Ultra

DE, 10.2019
BUILD: solid aluminum housing
SOUND: From a very emotional point of view, one of the most rousing, most intense preamps of this test – independent of the price!