PRO-JECT Stereo Box RS


Integrated amplifiers

The boxes of Pro-Ject's Box Design are very compact and can be stacked like LEGO bricks: phono preamps, headphone amps, integrated amps, preamps and power amps, monoblocks, docking stations, D/A converters and USB DACs, media boxes, streamers, players and transports, receivers, tuners - simply anything that is needed in one's audio life. Welcome to the world of Pro-Ject.

Function and form

Ease of use

Even though I had the Stereo Box RS connected to Bowers & Wilkins 802 Diamonds through the most of my auditioning. I was taken aback for a moment when listening to Oblivion soundtrack (M83) – the amp sounded so powerful and competent that I referred to its manual to see the power capabilities. With 2x 120 W (specified into 4 ohms, guaranteed stability down to 2 ohms) the Stereo Box RS should have no issue with any speakers, yet you need more power for dynamic response in big rooms you can always upgrade to separates (Pre Box and Amp Box, 2x 180 W) or to monoblocks (1x 195 W). By using a separate power supply (PS Box RS) the power capacity of the system raises the bar to 2x 250 W / 4 ohms). That is the LEGO beauty of the Pro-Ject.

The Stereo Box RS accepts a balanced input or five single-ended inputs. The set of outputs comprises of 1 pair of speaker terminals, phono and tape output, subwoofer output and variable output.

There is one issue - speaker terminals are too close one to another – if your cable is not equipped with bananas then you may have a problem. I tried two pairs of cables terminated with spades and was not successful with either. Due to proximity of terminals it is also not safe to operate just bare wire. The bananas are the only convenient option.

All the Pro-Ject units come with great toggle switches that lend a touch of Nagra-look to the devices, especially when combined with perfect aluminum craftsmanship.

Bass management


The Boom Boom of Johnny Lee Hooker (at really high volume) exhibited such a raw and electrically charged blues maelstrom that I my feet started to tap. There is a certain threshold to loudness, however. When you listen too loud the Pro-Ject loses its control a bit and the music shrinks dynamically. If this is your problem then the solution is to ugrade to a more powerful RS box.

Clarity & delicacy


No Way Out (Peter Gabriel, UP) surprised me with how easily the RS boxes differentiated between a bass and a double bass. The Pro-Jects highlighted the ambience of both instruments and revealed that one was recorded drier with a close miking technique whereas the other is the result of mixing DI and an amp's mike. Considering the price of the boxes I have found such a level of resolution quite exceptional.

The powerful bass is usually - in our thinking - linked to wardrobe-sized amplifiers so the fact that it was really powerful through a such mini device caused a jaw-dropping effect with the visitors I had in my house during the review's period.

Tonal accuracy

Temporal resolution

I like how Pro-Ject rendered David Russell's acoustic guitar in Mertz's Hungarian fantasy (Art of the Guitar, Telarc). I have already heard this piece in higher quality but not at this price point. The guitar is sweet, analogue and seduccing yet very resolved, defined and transparent. I had Lumin streamer on hand at the time of this review and it sounded quite coloured in comparison. The Pro-Ject is much more real which also means less forgiving.

Spatial resolution

Soundstage width
Soundstage depth

The vocal tracks - like La Grande Sophie's Quelqu´un d´antre - were beauiful. I heard no sibilance or frequency imperfections, the sound was natural and clean. Sure, when you compare the Pro-Ject RS to much pricier high-end gear then you may lack a thing or two, but in its category the RS boxes excelled with juicy, dynamic and resolved sound that was very entertaining.

Most of my audtioning was done with the CD transport and the DAC connected via the´Sonic´communicator with AudioQuest Forest (this is what Pro-Ject recommends). When I switched to Toslink the sampling frequency automatically dropped to 88 kHz. This also may be the reason for the music to become more sterile and fuzzy.

Price as reviewed:25 000,- Kč

Recommended resellers

AQ s.r.o., Červenka, tel. +420 585 342 232

Associated components

  • Sources: Accuphase DP-78, Pro-Ject DAC Box and CD Box RS
  • Amplifiers: Pro-Ject Stereo Box RS, Accuphase 2410 and A-60
  • Interconnects and speaker cables: Krautwire Fractal, Audioquest Forrest, Pro-Ject
  • Loudspeakers: Bowers & Wilkins 802 Diamond
  • Power conditioning: Nordost Thor (modified), Nordost Valhalla, Block Audio Snakeblock



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