The Pro-Ject Speed Box S2 offers a functional and convenient upgrade for many Pro-Ject turntables with a 16V AC motor without built-in speed control.

The Speed Box S2 acts as an AC generator for the turntable, replacing the fluctuant power consumption from a normal 16V power supply and regulating it. The result is a clean power signal and speed stability that allows the motor to perform optimally. The added convenience is that the S2 can shift frequency, for an easy electronic speed change between 33 and 45RPM at the push of a button.

Inside, the S2 makes use of high-quality materials in the quartz-controlled oscillator and filter circuits. Its small size and minimal aesthetic make it matches any other Box Design S2 Line components and preamps. Analog phono appreciators will appreciate that sound improvement and the fact that the metal case shields electronics while also blocking electromagnetic interference. Hi-Fi lovers will appreciate the high precision much like other Pro-Ject Audio Systems accessories.

Connection is simple, as the S2 is supplied with a link cable that plugs into your turntable instead of the normal power supply. There is also a wide range of compatibility (see below), and in some cases, the Speed Box S2 can add 78RPM compatibility when partnered with a special Speed Box Pulley. The optional accessory pulley allows older Pro-Ject turntables complete versatility.

The Speed Box S2 will not work with newer Pro-Ject turntables like the Debut Carbon or Debut III that feature a DC power supply. It will only work with older AC-powered turntables that feature a 16 Volt AC outboard power supply and do not already have built-in speed control. Its quartz oscillator is a significant upgrade from the Pro-Ject Speed Box II and features no mains interference.

For improved record player performance, pair this speed controller with a stylus cleaner, tonearm upgrade, or phono pre-amplifier. You’ll maintain the precise electronic speed regulation of your drive belt with no motor noise.

See more Pro-Ject Speed Box S2 specs here. Buy now and an extra year of warranty by registering your Pro-Ject product here.

Additional information
Weight 0.56 kg
Dimensions 10.4 × 10.3 × 3.6 cm



  • Nominal speeds: 33 and 45 r.p.m., optional 78 r.p.m.
  • Quartz oscillator Speed stability: +/- 0,001%
  • Length of power cable: approximately 40cm
  • Turntable connection: 16V/AC 190mA max. (3W power consumption max.)
  • Outboard power supply: 18V/500mA DC, suitable for your country’s mains supply

Privacy Preference Center