Pro-Ject Audio Systems
Pro-Ject Phono Box S3 B
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Best Phono Preamps · head-to-head
Pro-Ject Phono Box S3 B vs Cambridge Audio Alva Duo
A sourced, side-by-side comparison. Cambridge Audio Alva Duo is cheaper at $399. Every spec and price links to its source.
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Cambridge Audio
Cambridge Audio Alva Duo
$399
Full spec sheet
✓ marks the stronger figure where "more" — or "less", for price and weight — is unambiguously better.
| Spec | Pro-Ject Phono Box S3 B | Cambridge Audio Alva Duo |
|---|---|---|
| US price | — | $399 Cambridge Audio USA direct price |
| Brand | Pro-Ject Audio Systems | Cambridge Audio |
| Released | — | — |
| Cartridge support | MM and MC | MM and MC |
| Gain (dB) | 40/45/60/65 dB, plus an additional +6 dB available via the balanced XLR outputs | MM: 39 dB; MC: 60 dB @ 1 kHz |
| Snr (dB) | MM: 103/110 dB(A); MC: 85/90 dB(A) | MM: >90 dB; MC: >70 dB (grounded inputs, 20Hz-20kHz, ref 1V output) |
| Riaa accuracy | <0.3 dB (20 Hz - 20 kHz) | ±0.3 dB (30 Hz - 20 kHz) |
| Input capacitance pf | 50/150/300/400 pF selectable | 100 |
| Subsonic filter | 20 Hz, 18 dB/octave rolloff | Yes |
| Thd percent | MM: <0.001% @1kHz, <0.008% 20Hz-20kHz; MC: <0.005% @1kHz, <0.01% 20Hz-20kHz | MM: <0.0025%; MC: <0.20% (1kHz, 20Hz-20kHz bandwidth, THD+N) |
| Output level | Balanced XLR and single-ended RCA outputs | 300 mV nominal |
Sources — Pro-Ject Phono Box S3 B: project-audio.com (verified 2026-08-12). Cambridge Audio Alva Duo: cambridgeaudio.com (verified 2026-08-12).
What's the difference between the Pro-Ject Phono Box S3 B and Cambridge Audio Alva Duo?
Where the two actually differ on the specs we track (7 of 8). Matching specs are omitted.
- Gain (dB): Pro-Ject Phono Box S3 B 40/45/60/65 dB, plus an additional +6 dB available via the balanced XLR outputs vs Cambridge Audio Alva Duo MM: 39 dB; MC: 60 dB @ 1 kHz
- Snr (dB): Pro-Ject Phono Box S3 B MM: 103/110 dB(A); MC: 85/90 dB(A) vs Cambridge Audio Alva Duo MM: >90 dB; MC: >70 dB (grounded inputs, 20Hz-20kHz, ref 1V output)
- Riaa accuracy: Pro-Ject Phono Box S3 B <0.3 dB (20 Hz - 20 kHz) vs Cambridge Audio Alva Duo ±0.3 dB (30 Hz - 20 kHz)
- Input capacitance pf: Pro-Ject Phono Box S3 B 50/150/300/400 pF selectable vs Cambridge Audio Alva Duo 100
- Subsonic filter: Pro-Ject Phono Box S3 B 20 Hz, 18 dB/octave rolloff vs Cambridge Audio Alva Duo true
- Thd percent: Pro-Ject Phono Box S3 B MM: <0.001% @1kHz, <0.008% 20Hz-20kHz; MC: <0.005% @1kHz, <0.01% 20Hz-20kHz vs Cambridge Audio Alva Duo MM: <0.0025%; MC: <0.20% (1kHz, 20Hz-20kHz bandwidth, THD+N)
- Output level: Pro-Ject Phono Box S3 B Balanced XLR and single-ended RCA outputs vs Cambridge Audio Alva Duo 300 mV nominal