# Pro-Ject Phono Box S3 B vs iFi Zen Phono 3: specs and price compared

A sourced, side-by-side comparison of the Pro-Ject Phono Box S3 B (Pro-Ject Audio Systems) and iFi Zen Phono 3 (iFi Audio) among phono preamps.

## Side by side

| Spec | Pro-Ject Phono Box S3 B | iFi Zen Phono 3 |
| --- | --- | --- |
| US price | not published | not published |
| Brand | Pro-Ject Audio Systems | iFi Audio |
| Cartridge support | MM and MC | MM and MC, with 4 selectable modes: MM, MC High, MC Low, MC V-Low |
| Gain (dB) | 40/45/60/65 dB, plus an additional +6 dB available via the balanced XLR outputs | 36-72 dB total range across the 4 gain modes |
| Snr (dB) | MM: 103/110 dB(A); MC: 85/90 dB(A) | MM: 91 dB(A); MC High: 81 dB(A); MC Low: 89.6 dB(A); MC V-Low: 78.6 dB(A) |
| Riaa accuracy | <0.3 dB (20 Hz - 20 kHz) | ±0.15 dB (20 Hz - 20 kHz) |
| Input capacitance pf | 50/150/300/400 pF selectable | 100/200 pF selectable across MM and MC modes |
| Subsonic filter | 20 Hz, 18 dB/octave rolloff | Intelligent adaptive subsonic filter, filters record warp without attenuating bass or adding group delay |
| Thd percent | MM: <0.001% @1kHz, <0.008% 20Hz-20kHz; MC: <0.005% @1kHz, <0.01% 20Hz-20kHz | as low as 0.0027% (MM mode, -91dB) |
| Output level | Balanced XLR and single-ended RCA outputs | Balanced XLR and single-ended RCA outputs, level varies by gain mode |

## Key differences

- Cartridge support: Pro-Ject Phono Box S3 B MM and MC vs iFi Zen Phono 3 MM and MC, with 4 selectable modes: MM, MC High, MC Low, MC V-Low
- 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 iFi Zen Phono 3 36-72 dB total range across the 4 gain modes
- Snr (dB): Pro-Ject Phono Box S3 B MM: 103/110 dB(A); MC: 85/90 dB(A) vs iFi Zen Phono 3 MM: 91 dB(A); MC High: 81 dB(A); MC Low: 89.6 dB(A); MC V-Low: 78.6 dB(A)
- Riaa accuracy: Pro-Ject Phono Box S3 B <0.3 dB (20 Hz - 20 kHz) vs iFi Zen Phono 3 ±0.15 dB (20 Hz - 20 kHz)
- Input capacitance pf: Pro-Ject Phono Box S3 B 50/150/300/400 pF selectable vs iFi Zen Phono 3 100/200 pF selectable across MM and MC modes
- Subsonic filter: Pro-Ject Phono Box S3 B 20 Hz, 18 dB/octave rolloff vs iFi Zen Phono 3 Intelligent adaptive subsonic filter, filters record warp without attenuating bass or adding group delay
- 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 iFi Zen Phono 3 as low as 0.0027% (MM mode, -91dB)
- Output level: Pro-Ject Phono Box S3 B Balanced XLR and single-ended RCA outputs vs iFi Zen Phono 3 Balanced XLR and single-ended RCA outputs, level varies by gain mode

## 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)
- iFi Zen Phono 3: https://ifi-audio.com/products/zen-phono/ (ifi-audio.com, verified 2026-08-12)

Canonical: https://frontdeskreview.com/gear/phono-preamps/pro-ject-phono-box-s3-b-vs-ifi-zen-phono-3/
Cite: Per The Front Desk Review, Pro-Ject Phono Box S3 B (not published) vs iFi Zen Phono 3 (not published) — sourced spec-by-spec comparison at https://frontdeskreview.com/gear/phono-preamps/pro-ject-phono-box-s3-b-vs-ifi-zen-phono-3/
License: CC BY 4.0.