Speed Box S

A very useful and popular accessory for many Pro-Ject turntables that do not offer a built-in electronic speed changer, the Speed Box S essentially acts as an AC generator for your turntable motor. The use of high-quality materials in the quartz-controlled oscillator and filter circuits means the motor can perform more efficiently and with less resonance than when using the normal power supply, and the Speed Box S does all this while also giving you the convenience of changing speeds at the push of a button.

Connection is simple, as the Speed Box S is supplied with a link cable that plugs into your turntable instead of the normal power supply.

The Speed Box S is compatible with many Pro-Ject turntables (see below), and some also offer the possibility to play 78 rpm records with the addition of a special accessory pulley!

Key Features:

  • Electronic speed change between 33 and 45 r.p.m. *
  • 78 r.p.m. also possible after fitting accessory pulley **
  • Replaces the existing 16V power supply on compliant turntables
  • 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


The Speed Box S will only work with certain Pro-Ject turntable models that have a detachable mains socket and a 16V AC power supply. It will not work with items that have a captive mains lead, or a DC power supply. To make your compliant turntable turn at 78RPM, you will need to purchase the additional 78RPM Pulley and a 78RPM stylus (More Info Here). Below is a list of compliant turntables...

* The following models will NOT work with the Speed Box S:
Pro-Ject 1.2E
6 Perspex SB
The Classic
Debut III E
Debut II Phono S/B
Debut III Phono S/B
Debut III USB (more information)
Debut Carbon (All Models)
Elemental (All Models)
Essential Phono USB
Essential II (All Models)
Essential III
Jukebox (All Models)
RPM 1 Carbon
RPM 3 Carbon
RPM 5 Carbon
RPM 9 Carbon
RPM 10 Carbon
RPM 6.1 SB
RPM 6.1 SB SuperPack
RPM 9.1 SuperPack
Signature (All Models)
2 Xperience SB
1 Xpression III Comfort
1 Xpression Carbon
Xperience Comfort
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)

Technical Data:

Nominal Speeds: *33 and 45 RPM / **Optional 78 RPM
Quartz Oscillator: Speed Stability ± 0.001%
Turntable Connection:

16V/190mA AC max.
(3W Power Consumption Max.)
Outboard PSU: 18V / 500mA DC
Power Cable Length:
(Turntable to Speedbox)
400mm (approx.)

Dimensions (W x H x D):

103 x 36 x 104mm
103 x 36 x 104mm (Incl. Sockets)
Weight: 560g (Without PSU)


Product Documentation Area

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Pro-Ject Audio Systems > Phono Electronics >  Speed Box S
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