Pro-Ject Power Box S3 Phono Power Supply and Filter - Black

One Filtered Supply for Your Turntable and Phono Stage

Your turntable and your phono preamp are the two lowest-signal devices in your system — and both of them probably run off a plastic wall-wart. The Power Box S3 Phono replaces both with a single filtered supply, feeding your turntable and your Phono Box from one compact aluminum chassis.

Two outputs, two purpose-set voltages, one power cord instead of two. It's the most affordable meaningful upgrade you can make to a Pro-Ject analog front end.

Why Clean Power Matters Most at the Start of the Chain

A phono cartridge produces a few thousandths of a volt. Everything downstream is amplifying that signal enormously — and amplifying whatever noise arrives with it. Get the power clean at this point in the chain and the benefit carries through every component after it.

The S3 Phono moves the supply outside the component entirely, where it can't contaminate the audio circuit, and applies sophisticated DC filtration with linear voltage regulation and low-ESR capacitors. On the turntable side, expect noticeably better speed stability. On the phono stage side, a lower noise floor — which translates directly into more of the quiet detail that makes vinyl worth the trouble.

Two Outputs, Set to the Right Voltage

The outputs aren't generic. One is set at 15V for Pro-Ject DC turntables; the other at 18V for Pro-Ject Phono Box preamps. Both are regulated to within 0.5%, with 1000mA available across the two outputs combined — ample for a turntable and phono stage running together.

A rigid aluminum casework shields the internals against electromagnetic interference, and the chassis is deliberately compact — roughly four inches square and under an inch and a half tall, so it tucks behind the rack or beside the deck without demanding a shelf. Handmade in Europe.

Black or Silver

Available in both finishes to match the rest of your Pro-Ject Box Design components, or to simply disappear behind them.

Before You Order — Check Compatibility

Your turntable must be a 15V DC model. The S3 Phono is built for Pro-Ject DC-motor turntables and Pro-Ject phono preamps specifically. It is not a universal supply.

Not compatible with these turntables: X8, Xtension 9, Xtension 10, Xtension 12, RPM 5, RPM 9, RPM 10, and Signature models. For those decks, Pro-Ject recommends the Power Box RS2 Phono or the Power Box RS Uni TT instead — call us and we'll point you to the right one.

If you're unsure which supply your turntable takes, check the label on its existing wall-wart or the input on the plinth, or give us a call with your model number.

Specifications

• Turntable output: 1 × 15V (±0.5%)
• Phono preamp output: 1 × 18V (±0.5%)
• Maximum output current: 1000mA, both outputs combined
• Input supply: 18V / 1000mA
• Filtration: Linear voltage regulation with low-ESR capacitors
• Housing: Rigid aluminum, shielded against electromagnetic interference
• Dimensions (W × D × H): 4.05" × 4.17" × 1.45"
• Weight: 0.81 lbs
• Finish: Black or silver
• Origin: Handmade in Europe

Frequently Asked Questions

Will this work with my turntable?
It works with Pro-Ject turntables that run on 15V DC, which covers a large part of the current lineup — but not the X8, Xtension 9, Xtension 10, Xtension 12, RPM 5, RPM 9, RPM 10, or Signature models. Check the voltage printed on your deck's existing power supply, or call us with your model and we'll confirm before you order.

Do I need both a turntable and a phono preamp to use it?
No. You can power just one and leave the other output unused. That said, the value proposition is strongest when you're feeding both — you're cleaning up power at two consecutive points in the most sensitive part of your system.

What will I actually hear?
Two distinct improvements. From the turntable, better speed stability, which shows up as firmer pitch and more solid bass. From the phono stage, a lower noise floor, which lets quiet detail and decay come through instead of getting lost. Together they add up to a clearer, more resolved presentation from records you already know well.

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