Our take on the Pro-Ject Tube Box S

by Dave Bar

Experience the vacuum tube difference

Few things go together quite like the relaxed sound of vinyl and the warm glow of vacuum tubes. Pro-Ject understands. They've been building high-performance turntables and electronics for years. Their Tube Box S phono preamp is a shining example of all that expertise. Connect it to your 'table, and this sweet little tube preamp will lend depth and spaciousness to the sound of your LPs. It's an addictive experience that will keep you listening deep into the night.

A big upgrade from stock turntable inputs

Many receivers and amplifiers these days lack the phono input you need to hook up your turntable. And when manufacturers do include one, they often use low-cost, low-performance circuitry that sounds lifeless and flat. Pro-Ject's Tube Box S neatly solves that problem. It boosts and equalizes the tiny voltages generated by your 'table's phono cartridge to deliver a robust, line-level signal infused with detail and three-dimensional presence. Pro-Ject's dual-mono design dedicates one tube per channel for maximum channel separation and superior stereo imaging.

Flexible operation

This preamp's inputs are compatible with either moving magnet or moving coil cartridges, to ensure proper matching with virtually any turntable and cartridge combination. And no matter what kind of phono cartridge you mount on your turntable, this versatile preamp gives you a range of input impedance/capacitance and gain settings to optimize its performance with your system. The Tube Box S also includes a subsonic filter to reduce low-frequency turntable rumble that can result in wasted amplifier power.

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Highlights:

dual-mono design using two dual-triode ECC83 (12AX7) vacuum tubes for optimal channel separation
compatible with moving magnet and moving coil phono cartridges
audiophile-grade polypropylene WIMA capacitors
adjustable input impedance/capacitance and gain settings for more accurate cartridge matching
subsonic filter to reduce low-frequency rumble and wasted amplifier power (-12dB at 20 Hz, non-switchable)
all-metal chassis for improved shielding from vibration and electromagnetic interference
external power supply for reduced noise and interference
gold-plated RCA connectors for corrosion-free signal transfer
signal-to-noise ratio: 84dB (MM), 67dB (MC)
THD: 0.01% (MM); 0.05% (MC)
RIAA response accuracy: 0.4dB (20-20,000 Hz)
gain: 40dB (MM), 60dB (MC)
4-1/16"W x 2-15/16"H x 6-1/16"D
warranty: 2 years
Our 60-day money-back guarantee

Hands-on research from the Crutchfield Labs (what are the Labs?)

What’s in the box? | In-depth notes

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What's in the box?

Download owner's manual

Turntable (MM/MC) tube pre-amplifier
AC power adapter (with attached 5' DC cord)
3 AC plug inserts (US/EU/UK)
Instructions For Use

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Features

Tube Phono Preamp (MM/MC): The Pro-Ject Audio Systems Tube Box S for MM and MC is a very high-quality phono cartridge preamplifier. This unit produces a lively and powerful performance with convincing sound staging and emotional presentation.

Metal Case: The phone preamplifier features a metal case that shields the electronics from vibration and electromagnetic interference.

Dual-Mono Circuitry: The Pro-Ject Tube Box S utilizes dual-mono architecture with two double triode tubes (12AX7A -ECC83) for optimum channel separation.

MM/MC Compatible: The Pro-Ject Tube Box S phono preamplifier offers amplifications and RIAA equalization for MM and MC cartridges.

Subsonic Filter: There is a Subsonic filter selection switch located on the rear of the unit. The Subsonic filter helps to reduce low-frequency rumble and wasted amplifier power.

Gold-Plated RCA Connections: The Pro-Ject Box S is equipped with a pair of gold-plated RCA connections for the output stage and input stage. The gold-plate RCA connectors offer corrosion-free signal transfer.

Power Requirements: The Pro-Ject Tube Box S turntable preamplifier operates off of standard household current using the included external power supply. The outboard power supply helps reduce noise and interference.