A small-format stereo power amplifier: one RCA input, 2 x 40 W into 4 ohms and 12 V trigger in and out. It suits rooms of 10-15 m², desktop speakers or duty as the power stage for a streamer.
Amp Box S3: where it fits
The Amp Box S3 is a power amplifier: it takes a stereo signal whose volume is already set by a preamplifier, streamer or DAC and drives the loudspeakers with it. For this version Pro-Ject redrew the board and the circuit topology to lower distortion and improve the signal-to-noise figure. The maker states that it was voiced to come as near as it could to the sonic character of a valve amplifier.
The uses suggested by the manufacturer are varied: a hi-fi system in rooms of 10-15 m², driving desktop monitors at close range, the power stage partnered with a streamer, an extra zone in a multiroom installation, channels of a home cinema set-up, in-wall or ceiling speakers. The 12 V trigger sockets, one in and one out, switch it on and off together with the other components.
The metal enclosure guards the circuit against vibration and interference. The speaker terminals take 4 mm banana plugs, spade lugs, pins or bare wire. The power supply is an external universal unit rated at 20 V and 3 A, and the amplifier weighs 385 g, so it is easy to place behind a television, on a desk or inside an equipment cabinet.
Specifications
- Type: stereo power amplifier
- Power: 2 x 23 W into 8 ohms, 2 x 40 W into 4 ohms
- Power at peak: 50 W per channel into 4 ohms
- Bandwidth: 20 Hz to 20 kHz within 0.7 dB into 4 ohms
- Channel separation: better than 68 dB at 20 kHz
- S/N ratio: 87 dBV, 100 dBV A-weighted, into 4 ohms
- Distortion: below 0.02% with 10 W into 4 ohms
- Voltage gain: 31 dB
- Input: one RCA pair, 25 kohm impedance
- Speaker terminals: for 4 mm banana plugs, spade lugs, pins or bare wire
- 12 V trigger: input and output on 2.5 mm two-pole jacks
- Power supply: external universal unit, 20 V / 3 A DC
- Size (WxHxD): 103 x 36 x 118 mm
- Weight: 385 g, power supply excluded
- Finishes: black, silver
