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Pro-Ject Tube Box S

Vacuum tube phono preamplifier for moving magnet and moving coil cartridges

Item # 252TUBXSB

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Contact our Virginia-based experts.
Discontinued item
1 question - 5 answers

Item # 252TUBXSB

Need help?
Contact our Virginia-based experts.

About the Pro-Ject Tube Box S

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.

Product 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
  • MFR # Tube Box S-BK

What's in the box:

  • 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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Crutchfield response

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More details on the Pro-Ject Tube Box S

Stacey B.
The Pro-Ject Tube Box S replaces these items:

Product Research


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 phono 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.

  • Input: 100-240V~50/60Hz, 0.4A
  • Output: 18V AC, 1.0A.

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Customer Q&A

Crutchfield asked: Why did you buy this?
Need a phono preamp as the Anthem AVM 60 does not have one where my Marantz 8802A does. [ Mike  Jun 02, 2017 ]
Wanted to upgrade Pre-amp, came highly recommended. [ Patrick  Dec 14, 2016 ]
Tubes are neat, can't afford a full size tube amp. [ Rufus  Jul 14, 2016 ]
Highly rated around the web. [ Brian  May 01, 2016 ]
Tube sound [ David  Dec 09, 2015 ]

1 question already asked

The stock pic doesn't show in/out for rca jacks ....turn able. goes to box...then to phono input on receiver, thus cleaning up sound?
[ Scott  Dec 11, 2015 ]
5 answers
There is one set of RCA inputs (for turntable) and one set of RCA outputs on the back, plus a post for the grounding wire.
[ Rufus  Dec 11, 2015 ]
It has the in/out rca jacks in the rear. The turntable goes to the in jacks and the tube box s out jacks go to your receiver. Don't use the phono in jacks on your receiver use an aux or some other analog in,
[ Billy  Dec 11, 2015 ]
Yes rca cables from turn table to the box then from box to receiver. a lot of new receivers do not have a phono input on them and you have to use a box like this.
[ Craig  Dec 11, 2015 ]
There are in & out RCA jacks. You would not use the phono input on your receiver since that input contains a pre-amp, instead you would use another RCA input such as a cd input.
[ Thomas  Dec 11, 2015 ]
yes 1 set in 1 set out. This is for an amplifier without a phono amplifier, so to be safe, I would plug into an aux. So out from the turntable into the Turntable amp, and out to the receiver
[ James  Dec 11, 2015 ]

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