Project Speed Box S2

A useful and high-quality automatic speed-changer for Pro-Ject turntables.
Manufacturer: Project
Availability: In stock
Manufacturer part number: Project Speed Box S2
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Project's Speed Box S2 electronic speed changer is available from Harrow Audio in either Black or Silver. Get the convenience of push button speed control on older Project turntables. Compatibility list is below.


The Speed Box S will only work with Pro-Ject turntable models with a detachable mains socket and a 18V, DC power supply. To turn at 78RPM, users will need to purchase the additional 78RPM Pulley and a 78RPM stylus. Below is a list of compliant turntables...

* The following models will NOT work with the Speed Box S: 
Pro-Ject 1.2E
Debut III E
Debut II Phono S/B
Debut III Phono S/B
Debut III USB (more information)
Debut Carbon (All Models)
Essential Phono USB
Jukebox (All Models)
1 Xpression III Comfort
Xperience Comfort 
RPM 6.1 SB
RPM 6.1 SB SuperPack
RPM 9.1 SuperPack
Xtension (All Models)

** The following models will NOT turn at 78 RPM: 
Essential (all models)
RPM 1 Genie (all models)
Debut III E
Xperience (all models including Basic+, 2Pack, VPack and Super Pack)
6 Perspex/ Perspex Anniversary
RPM 9 (all models including 9.1 and 9.2)
RPM 10 (all models, including 10.1 Evolution)

The Speed Box S2 offers a functional and convenient upgrade for many Pro-Ject turntables with a 16V AC motor that do not already have built-in speed control.

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

Inside, the Speed Box S2 makes use of high-quality materials in the quartz-controlled oscillator and filter circuits. Externally it is stylish, compact and minimal - matching any other Box Design S2 Line component. 

Connection is simple, as the Speed Box 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 S can even add 78RPM compatibility, when partnered with a special Speed Box Pulley.

Key Features:

  • Electronic speed change between 33 and 45RPM (see below)
  • 78RPM also possible after fitting accessory pulley (see below)
  • Replaces the existing 16V turntable power supply
  • Quartz-generated high precision electronic speed regulation 
  • Creates a cleaner AC mains signal for your turntable
  • Allows the motor to run more efficiently and with less resonance

Technical Data

Input Power: 18V DC
Output Power: 16V AC / 190mA (3W max.)
Nominal Speeds: 33 / 45 RPM
78 RPM with Optional Pulley
Speed Stability: ± 0.001%
Power Cable Length: Approx. 400mm
(Turntable to Speedbox)
Dimensions: 103 x 36 x 104mm
103 x 36 x 115mm (Incl. Sockets)
Weight: 560g
Products specifications
Item Condition New