Review: DigiZoid ZO2 and FiiO "Rocky" E02i Headphone Amplifiers Page 3

Measurements: FiiO E02i Rocky

Frequency response

20 Hz to 20 kHz, -1.12/+0.28 dB

Output power (1% THD)

130 mW at 32 ohms

30 mW at 250 ohms

Output impedance

3 ohms at 1 kHz

S/N ratio (1 mW, A-weighted)

-81.5 dB

Total harmonic distortion (1 mW/1 kHz)


I measured the Rocky's performance using my Clio FW and NTI ML-1 audio analyzers.

Into a 32-ohm load (a common impedance for passive headphones), with volume set at maximum, the Rocky delivered 130 milliwatts at 1% total harmonic distortion (THD). Into a 250-ohm load, power output at 1% THD was 30 mW. Frequency response into a 32-ohm load is reasonably flat, falling to -1.12 dB at 20 Hz and rising to +0.28 dB at 20 kHz. Response into a 250-ohm load was essentially the same: -0.97/+0.30 dB. The bass boost function boosts bass by a maximum +3.05 dB in a broad peak centered at 160 Hz. - Brent Butterworth