Pro-ject’s new £269/€299 S3 Amp Box power amplifier tips the scales at just 385g. If you Google ‘what weighs 385g’ the answers include a can of Coke, a jar of Nutella and an American football. Or two adult hamsters. Contrast that with Naim’s Statement amplifier, a thousand times heavier at 385kg (packing weight). Equivalent to a racehorse. 

Facts that will no doubt be useful for your next pub quiz. They also emphasise one of the S3’s main differentiators – it’s tiny. Admittedly the same size as Pro-ject’s other smaller Box electronics, but at 10x4x12cm WHD you won’t have trouble fitting it into your system. It could even get lost on the average desktop. 

A Class D stereo power amplifier, the S3 Amp Box has been voiced slightly warm to emulate the sound of tube electronics. That’s not the norm for low cost Class D amplifiers, which tendency to favour clarity and detail over tonal qualities. Pro-ject says that new PCB technology has endowed the S3 Amp Box with low distortion and a good signal to noise ratio. 

Facilities are simple. A power input, a single pair of RCA inputs and four speaker terminals take up most of the rear panel. There are also trigger connections to improve integration with other Box electronics. Or use the power switch on the front. Silver and black finishes are available.

Pro-ject says the S3 Amp Box is ideal for nearfield use, including desktop systems. Or for driving architectural speakers installed in walls or ceilings. It’s also powerful enough (23W into 8Ω) to fill rooms up to 15 sq m in size, depending on the matched speakers. 

A phrase that set us thinking here. What speakers would suit the S3 Amp Box? Indeed more broadly, what speakers suit lower-powered amplifiers per se? The answer isn’t always intuitive. The S3 Amp Box for example: –

  • will probably struggle with the Elac Debut B5.2 that would otherwise seem a good match. At only 86dB sensitivity the speaker needs more grunt to give of its best
  • should be able to blow your roof off playing into the £13k / 91kg Klipsch La Scalas. At 105dB sensitivity even a good headphone amplifier can get them rocking. 

Sensitivity isn’t the only factor though, it’s a complex subject. Also an important one if the HiFi Starter is going to get a well matched system. It’s all too easy to pair highly-regarded components only to find they don’t quite gel. 

So, we’ll cover the subject soon in a separate article. What factors affect how much power a speaker needs? And which speakers should work well with low-powered amplifiers? Meanwhile we’re trying to grab a listen to the S3 Amp Box to test its mettle. We’ll report back if and when we do.