ProJect Tube Box S3 B Phono Pre-amplifier

Audiophile tube warmth

ProJect Audio Systems Tube Box S3 B is a audiophile phono preamplifier that brings true analog warmth to your vinyl playback. It features a fully symmetrical and discrete gain stage, balanced 5-pin mini XLR input, and balanced XLR outputs.

Adjust settings easily from the front panel, and enjoy clean, interference-free performance thanks to its robust aluminium chassis. Available in silver or black and made in Europe, the Tube Box S3 B is a compact yet powerful upgrade for any serious vinyl setup.

"B" stands for balanced

The symmetrical design is the real standout feature!

Connect your turntable with the 5-pin mini XLR cable & profit of the balanced signal path. Symmetrical, or also called balanced, transmissions consist of a hot and a cold (also called + and -) signal. Both signal chains effectively carry the same musical information.

A true balanced gain stage can now extract the final musical information out of the +/- signals, subtract and remove all noise that could potentially be added along the transmission. Given there are two separate signal chains, what was also needed was two individual amplifier sections.

Definitely unseen in this price range & the best and cleanest amplifier for your phono signal!

Product Features

• 5-pin mini XLR balanced input
• Balanced XLR outputs
• Fully symmetrical & discrete gain stage
• Easy settings adjustment on the faceplate
• 2x ECC83 tubes (replaceable)
• MM & MC capable
• Dual mono design
• Semi-passive RIAA equalisation
• Superior low noise / low distortion
• Aluminium casing protects against interference
• Available in silver or black
• Made in Europe

Technical Specifications

Tube assembly
2x ECC83 (12AX7)

Input impedance
10, 50, 100, 1k, 47k ohms

Input capacitance
50, 150, 300, 400 pF

Gain (+ 6dB using XLR Out sockets)
40, 45, 60, 65 dB

Signal / Noise ratio MM (40dB)
97dBV, 105dBV - 'A' weighted

Signal / Noise ratio MC (60dB)
83dBV, 88dBV - 'A' weighted

THD at 1 kHz
<0,005% MM, < 0,01% MC

THD (20Hz-20kHz)
<0,1% MM, < 0,03% MC

RIAA-equalisation curve accuracy
<0,4dB / 20Hz - 20kHz

Subsonic filter
at 20Hz with 18dB/octave

Input
1x 5-pin mini XLR / 1x pair RCA phono sockets

Line-level output
1x pair RCA, 1x pair XLR

Power supply DC
18V/1000mA

Power consumption
18V/800mA DC
<0.5 W in standby

Dimensions (W x H x D) 
206 x 81 x 153 (164 with sockets) mm

Weight
1010g without power supply