Pro-Ject Brings Balanced Drive to the Head Box S3 B and DS3 B

The launch represents a reset for a product concept Pro-Ject helped pioneer in the early 2000s, when it began offering high-quality phono stages, DACs and headphone amplifiers in compact metal enclosures rather than full-width hi-fi cases. By moving to smaller cabinets and outboard power supplies, Pro-Ject argued it could reduce electrical noise while also lowering manufacturing costs. This approach has since become common across the industry.

With the S3 B and DS3 B, the Austrian manufacturer is again endeavouring to lift the performance ceiling of compact components rather than chase headline specifications. Modern headphones, particularly planar magnetic and low-sensitivity designs, place far greater demands on amplification than earlier generations, and Pro-Ject says its new designs focus on delivering usable, controlled power rather than simply large wattage numbers on a datasheet.

Both models are built around what Pro-Ject describes as true, fully balanced signal paths, rather than simply providing balanced connectors wired in parallel to a single-ended circuit. As the company notes:

Many headphone amps have balanced connectors, but this does not mean that the amplification is truly balanced. Often, only the connectors are in parallel to the single-ended, unbalanced outputs.

In contrast, the new Head Box models support balanced signal chains from input to output, featuring RCA and XLR inputs, as well as 4.4mm Pentaconn and XLR headphone outputs.

While the two amplifiers share their compact metal chassis and overall architecture, they differ significantly in execution. The Head Box S3 B is designed as the more accessible entry point, using a pair of TPA6120A2 amplifier chips in its output stage and delivering up to 820mW of balanced output power. Pro-Ject claims this is enough to comfortably drive around 98 per cent of existing headphones while maintaining low noise and high clarity. Sonically, it is described as rich and open, with a high level of detail.

The Head Box DS3 B moves further upmarket with a fully discrete amplifier design and up to 1.5W of balanced output into 30 ohms, intended to handle more demanding and lower-efficiency headphones. Pro-Ject characterises the DS3 B as adding greater warmth and authority compared with the S3 B, reflecting both its higher power delivery and discrete topology.

That emphasis on controlled, real-world power is a deliberate stance from the company, which subtly takes aim at some competitors’ marketing. Pro-Ject says:

Many offers, especially from the Far East, show huge power figures in the data sheet. This looks nice, but it does not guarantee the best sound quality. Like with speaker amplifiers, the correct combination gives the best sound.

Both amplifiers are housed in full-metal enclosures and are manufactured in the EU, aligning them with Pro-Ject’s wider S3, DS3 and RS2 electronics families. Despite their compact footprint, they are intended to function as serious desktop or rack-based headphone amplifiers for listeners building balanced headphone systems around modern DACs and streamers.

In Europe, the Head Box S3 B will be priced at £329 | €399, while the Head Box DS3 B will retail for £629 | €699. Both models are scheduled to reach Pro-Ject dealers later this month, with additional regional pricing to be confirmed shortly.

For more inforrmation visit Pro-Ject