Reviewed on: SoundStage! Solo, January 2019
I measured the iFi Audio xCAN using a Clio 10 FW audio analyzer and a Neutrik NL-1 Minilyzer. Except as noted, I used the xCAN’s unbalanced analog input and unbalanced analog output, because I don’t yet have an adapter for 2.5mm balanced outputs I can use for measurements. Note that my focus with these tests is on measurements that confirm these devices’ basic functionality, and that gauge the efficacy of any special features and functions that might be measurable.
This chart shows the xCAN’s frequency response with all processing off, and with XBass II engaged in its three different modes (Bass, Presence, and Bass+Presence), with 1mW output into a 32-ohm load. With processing off, the response measures -0.14dB at 20Hz and -0.19dB at 20kHz. Bass mode boosts response by 9.96dB at 20Hz. Presence mode boosts response in a 4.12dB peak centered at 1288Hz. Frequency response did not change in 3D+ mode, and also did not change with 250-ohm and 600-ohm loads.
This chart shows the unbalanced output of the xCAN vs. total harmonic distortion (THD) into 32-, 250- and 600-ohm loads. Note that iFi’s power ratings are specified at 16, 50, 300 and 600 ohms, so some of my measurements are not directly comparable. Output into 32 ohms is 320mW at 0.5% THD and 336mW at 1% THD (iFi’s rating, in S-balanced/unbalanced mode, is 380mW into 32 ohms, THD unspecified). Output into 250 ohms is 46mW at 0.5% THD and 49mW at 1% THD. Output into 600 ohms is 20mW at 0.5% THD and 19mW at 1% THD.
Here you can see the harmonic distortion spectrum and noise floor of the xCAN, referenced to 3Vrms output at 600Hz into 32 ohms. The third harmonic at 1.8kHz is slightly more predominant than the second harmonic, which will sound a little more objectionable than an amp (like a typical tube amp) with predominantly second-harmonic distortion, but if you actually dare to listen at 3Vrms (280mW into 32 ohms), the distortion from the headphones will likely be far louder than the distortion from the amp.
I measured the unbalanced output impedance at 1.2 ohms at 1kHz; iFi rates impedance at <2 ohms for balanced and <1 ohm for unbalanced output. Regardless, the output impedance is low enough not to react significantly with the reactance of the headphones, and thus won’t change their frequency response.
. . . Brent Butterworth