# Pro-Ject Phono Box S3 B vs Cambridge Audio Alva Duo: specs and price compared

A sourced, side-by-side comparison of the Pro-Ject Phono Box S3 B (Pro-Ject Audio Systems) and Cambridge Audio Alva Duo (Cambridge Audio) among phono preamps.

## Side by side

| Spec | Pro-Ject Phono Box S3 B | Cambridge Audio Alva Duo |
| --- | --- | --- |
| US price | not published | $399 |
| Brand | Pro-Ject Audio Systems | Cambridge Audio |
| 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 |

## Key differences

- 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 Yes
- 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

## Sources

- Pro-Ject Phono Box S3 B: https://www.project-audio.com/en/product/phono-box-s3-b/ (project-audio.com, verified 2026-08-12)
- Cambridge Audio Alva Duo: https://www.cambridgeaudio.com/usa/en/products/hi-fi/alva/alva-duo (cambridgeaudio.com, verified 2026-08-12)

Canonical: https://frontdeskreview.com/gear/phono-preamps/pro-ject-phono-box-s3-b-vs-cambridge-audio-alva-duo/
Cite: Per The Front Desk Review, Pro-Ject Phono Box S3 B (not published) vs Cambridge Audio Alva Duo ($399) — sourced spec-by-spec comparison at https://frontdeskreview.com/gear/phono-preamps/pro-ject-phono-box-s3-b-vs-cambridge-audio-alva-duo/
License: CC BY 4.0.