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If you own a Pro-Ject turntable, this little black box is a must have. First, it lets you change speeds between 33-1/3 and 45 rpm with just the touch of a button — no need to manually move the belt. But what really impressed us is the way it stabilizes the record platter's rotation speed. Even slight speed fluctuations can detract from the magic of vinyl sound, but with the Speed Box II in place, your records will spin with greater speed accuracy and rock-steady consistency. When we plugged it in to one of our Pro-Ject RM 1.3 turntables, we immediately heard tighter, more defined bass. Vocals sounded fuller, with added "body" and presence, lending a greater sense of sonic realism. Pitch accuracy for instruments with long decay times, such as piano, was spot on. Overall, the music seemed to flow just a little easier from a quieter background.

The Speed Box II makes an easy and cost-effective upgrade. Simply plug it into your turntable's AC jack, then connect it to power with the supplied transformer. That's all it takes to enjoy enhanced performance and convenience.

Product Highlights:

  • compatible with turntables that use Pro-Ject's 16 Volt AC power supply, including the Debut, xPression III, and RM models
  • provides electronic speed change between 33-1/3 and 45 rpm playback
  • quartz-generated high-precision electronic speed regulation
  • small size allows placement near turntable
  • metal case shields circuitry from vibration and electromagnetic interference
  • LED speed indicators
  • microprocessor control of all functions
  • external power supply reduces chance of noise and interference
  • 14" DC cord connects to Pro-Ject turntable
  • weight: 20 ounces
  • 4"W x 1-1/2"H x 4-1/2"D
  • warranty: 2 years
  • Our 60-day money-back guarantee

Pro-Ject Speed Box II Reviews

Average Customer Review:

4 Reviews

Pro-Ject Speed Box II

Written by: Anonymous from Irmo, SC on October 4, 2012

Crutchfield Customer Review (What's this?)

This certainly makes a difference to the sound quality of your Pro-Ject turntable. Very easy to hook up. The instructions state that the power cord that comes with this replaces the power cord to your turntable, so I did change it out, but I don't think it is necessary. The cable from the turntable to the Speed Box is 14", not 18", but that did not really matter, although the extra 4" would have allowed it to be placed where I originally wanted to. The blue light is extremely bright, especially if your room is dark. You now use the button on the Speed Box to turn the turntable on. Switching speeds is a plus. Turntable is definitely quieter in 33, but there is a little hum in 45. Not noticeable, and I play more 33s so I rarely hear it. I highly recommend this product.

Pros: Increased sound quality. Speed change. Quiets 33 operation.

Cons: Cord still needs to be a little longer. Not as long as stated in the Crutchfiield discription, which is 18'. It is actually 14". Initial price seems high, but really, once you get it, you see why it is costly. I don't see why the light is so bright, but if that is all I can really find to complain about, that says a good deal.

Great tweak for the price

Written by: VinceC from Charlotte, NC on November 21, 2011

Crutchfield Customer Review (What's this?)

Certainly a great improvement to the sound of your Project turntable. The clean power seems not only to stabilize the speed, but also seems to quiet the motor. Essentially it cleans the sound; backgrounds are quieter, highs are cleaner, lows are cleaner. The small size is a plus.

Pros: Small size, improved sound

Cons: The cable from the SpeedBox to the motor is a little short limiting placement options.

Serious Design Flaw

Written by: Karl H from Provo, Utah on June 16, 2011

Crutchfield Customer Review (What's this?)

The speed box works as advertised and works well at changing speeds and maintaining accurate speed. However, one thing that Pro-ject did in the design is quite unbelievable - they made the cord that plugs into your turntable's motor - only 1 FOOT LONG! Seriously? This means that the box has to go literally right next to your turntable. I own the Pro-Ject RM 1.3 turntable and it is obviously a work of art that is really meant to sit alone on its own table or shelf. Putting the speed box next to it just looks ridiculous. So now I've got to order an extension cord for the cable that goes to the motor. Found one on another website. Just ridiculous that for this price they couldn't give you 3 feet of cable so that you could put the box on the shelf below the turntable.



It's worth the purchase

Written by: Glen from New York, NY on April 13, 2011

Crutchfield Customer Review (What's this?)

Most people that are purchasing this will probably consider the convenient
change in speed as the primary purpose. For me and considering all the other
reviews, speed is a secondary benefit. The primary benefit is the better sound
quality from this external power supply. For a small box, its got a bit of weight.
It fits conveniently under my pro-ject xpression iii and is easy to set up. There
are enough professional reviews extolling the virtues of getting this upgrade for
you to read and they are all correct. I'm just saying as a normal guy that likes
playing records, that this is the real deal and this should be part of your pro-ject



Hands-on research

What's in the box?

Download owner's manual

  • Electronic turntable speed-change (33/45 rpm) unit with attached 14" DC cord
  • AC power adapter (with attached 6' DC cord)
  • Instructions

Product Research


Overview: The Pro-Ject Speed Box II permits electronic speed change of select Pro-Ject turntables (that do not have built-in electronic speed change) between 33 and 45 rpm.

Note: Only Pro-Ject turntable models with main socket power supply of 16V/19mA AC (max.) are compatible.

Metal Casing: The unit's metal case shields the electronics from vibration and electromagnetic interference.

Electronic Speed Regulation: The Pro-Ject Speed Box II utilizes Quartz-generated high precision electronic speed regulation and filter circuits to provide speed stability. All functions are microprocessor controlled.

Dual Speeds: The Speed Box II performs speed change by the push of a button between 33 and 45 rpm.

Connections: The Speed Box II features an attached 14" DC cord which replaces your Pro-Ject turntable's existing power supply. The included AC adapter of the Speed Box II then plugs into the back of the Speed Box II and into AC wall outlet.


  • Speed Change: 33 and 45 rpm
  • Power Output: 16V/190mA AC (+/-3%)
  • Outboard Power Supply: 16V/500mA AC
  • Quartz Oscillator: Speed stability 0.001%

Our Product Research Team

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