TurntablePSU.comReviews and Technical Analysis
Pro-Ject SpeedBox SEII
Overview
The $599 Pro-Ject SpeedBox SEII is a Variable Frequency Drive (VFD) that uses PWM to generate the sinewave signal. The clock source for the microprocessor is a 12MHz crystal oscillator with a frequency stability of .01% (100 PPM). The display uses 3 large LEDs to indicate speed and the front panel has 3 buttons to switch between 33/45 RPM and to control the output frequency for each speed in 0.1 RPM steps. A long press of the standby button changes between 33/45 RPM and a short press enters/exits standby mode.
The case of the SpeedBox SEII is a one piece aluminum extrusion with black anodized finish. The end panels are 0.062" thick aluminum with black anodizing.
The SpeedBox SEII is powered by a 120VAC input, 16VAC 1A output wall wart and the PSU has two outputs: one for 16VAC motors and one for 120VAC motors (60Hz version) or 230VAC motors (50Hz version), both rated at 3W maximum, but not simulatneously. The output voltage is fixed. On 50Hz models, the SpeedBox SEII uses 50 Hz for 33 RPM and 67.5 Hz for 45 RPM, so the turntable belt must be installed on the small spindle of the pulley (33 RPM). On 60Hz models, the SpeedBox SEII uses 44.44 Hz for 33 RPM and 60 Hz for 45 RPM, so the turntable belt must be installed on the large spindle of the pulley (45 RPM). The manual advises the user to start in 33 RPM mode and switch to 45 RPM rather than starting in 45 RPM mode.
The turntable can be used at 78 RPM if the motor is fitted with the optional pulley. The SpeedBox SEII output is switched to 45 RPM display (67.5/60 Hz) and the platter will spin at 78 RPM. 33 RPM is not available in this mode and 45 RPM becomes 78 RPM.
Specifications
Nominal Speeds...........................33 and 45 RPM (78 RPM Optional with modified pulley).
Speed Stability.............................0.01% (100PPM)
Distortion (Freq Generator)............Not Available
Distortion (115VAC output)............Not Available
Pitch Control................................20 step/0.1 RPM
Output Power...............................3W
Reduced Voltage..........................Not available
Turntable Connection....................16VAC and 120VAC
Outboard Supply..........................120VAC input 16VAC 1A output
Dimensions..................................4.05"W x 5.67"L x 2.83"H
Weight.........................................3 lbs. (w/o wall adapter)
Retail..........................................$599
Pro-Ject SpeedBox II
Overview
The $129 Pro-ject SpeedBox II is a dual frequency supply that uses 2 fixed frequency crystals to generate the 33/45 RPM sinewave signal. The clock source for 33 RPM is a 2.912 MHz crystal (60 Hz) or a 3.2768 MHz Crystal (50 Hz). The clock source for 45 RPM is a 3.93216 MHz crystal (60 Hz) or a 4.433618 MHz crystal (50 Hz). All crystals have a frequency stability of .01% (100 PPM). There is 1 button on the front panel for switching between 33 and 45 RPM (long press) and switching between standby and run (short press); two LEDs are used to indicate 33 or 45 RPM.
The SpeedBox II is housed in a one piece aluminum extrusion with aluminum front and rear panels.
The SpeedBox II is powered by a 120VAC input, 16VAC 1A output wall wart and the PSU has one output to the turntable with 16VAC. On 50 Hz models, the SpeedBox II uses 50 Hz for 33 RPM and 67.5 Hz for 45 RPM, so the turntable belt must be installed on the small spindle of the pulley (33 RPM). On 60 Hz models, the SpeedBox II uses 44.44 Hz for 33 RPM and 60 Hz for 45 RPM, so the turntable belt must be installed on the large spindle of the pulley (33 RPM). The manual advises the user to start in 33 RPM mode and switch to 45 RPM rather than starting in 45 RPM mode. There is no tempo or calibration adjustment for either speed.
The turntable can be used at 78 RPM if the motor is fitted with the optional pulley. The SpeedBox SEII output is switched to 45 RPM display (67.5/60 Hz) and the platter will spin at 78 RPM. 33 RPM is not available in this mode and 45 RPM becomes 78 RPM.
Specifications
Nominal Speeds...........................33 and 45 RPM (78 RPM with optional pulley)
Speed Stability.............................0.01% (100PPM)
Distortion (Freq Generator)............Not Available
Distortion (115VAC output)............Not Available
Pitch Control................................Not adjustable
Output Power...............................3W
Reduced Voltage..........................Not available
Turntable Connection....................16VAC/3W on 2.5mm connector
Outboard Supply..........................120 or 240VAC input 16VAC 500mA output
Dimensions..................................4.05"W x 4.05"L x 1.42 H
Weight.........................................1.2 lbs.
Retail...........................................$129