- Category: Turntables
- Written by Chris Heinonen
- Published on 16 August 2012
Pro-Ject Debut Carbon Turntable On The Bench
Using the Platter Speed iOS app from Feickert Tools and the Ultimate Analog Test LP record, I was able to easily compare the speed accuracy of the Pro-Ject Debut Carbon with and without the Speed Box II in place.
The stock speed at 33 RPM is close, with deviations of -0.22% and +0.19%, but certainly not spot on.
At 45 RPM the lower deviation is higher, at -0.25% but the upper deviation is closer at +0.08%. Lowpass-filtered both results are even better, and those numbers are better to use as they represent a more likely real-world result. Adding in the Speed Box certainly made a measurable difference.
Now if you look at the raw data, we are only at +/- 0.11% for 33 RPM playback, but lowpass-filtered that is a remarkable 0.01% deviation, which I don't imagine many people being able to notice.
At 45 RPM the numbers are not quite as good, though that early error seems to throw it off, but in this case the numbers have the same mean frequency as without the Speed Box, but the variation is more centered instead of low.
Using the 1 kHz test track on the same LP, I measured the THD+N on the Pro-Ject Carbon, using all four permutations of the Speed Box II and Acryl-It Platter, and using a Pro-Ject Phono Box as the Phono Preamp.
Here you can see the Speed Box II makes a moderate, but measurable, difference. I'm a bit surprised to see that the Arcyl-It version scores worse both times, but that seems to be the case. From these numbers I do recommend picking up the Speed Box II if you want to get the most out of the Pro-Ject Debut Turntable, as it makes improvements in both sound and usability.