Reviewed on: SoundStage! Solo, September 2020
I measured the Magnius using a Clio 10 FW audio analyzer. Note that my focus with these tests is on measurements that confirm these devices’ basic functionality. All measurements were made at the high gain setting.
This chart shows the frequency response of the left and right channels at 1mW, unbalanced output into a 32-ohm load, referenced to 1kHz. In the right channel, it’s excellent: -0.003dB at 10Hz, -0.021dB at 20kHz, and -0.079dB at 50kHz. The left channel is even better: -0.0005dB at 50kHz. Channel matching is excellent, with the left just 0.008dB above the right at 1kHz. The result was similar for the balanced output: right channel -0.004dB at 10Hz, -0.023dB at 20kHz, and -0.106dB at 50kHz, with the left channel -0.118dB at 50kHz.
Here you can see how the frequency response from the unbalanced output differs with 32-, 250- and 600-ohm loads, all referenced to 1mW at 1kHz, right channel. The differences between the three loads were insignificant; this was also the case with the balanced output.
This chart shows the unbalanced output of the Magnius vs. total harmonic distortion (THD) into 32-, 250- and 600-ohm loads at 1kHz, driven through the XLR inputs. Rated power (all with 1% THD, frequency unspecified) is 2W into 32 ohms, 300mW into 300 ohms, and 150mw into 600 ohms. My measurements at 1kHz showed output into 32 ohms at 1.84W at 0.5% THD and 1.93W at 1% THD. Into 250 ohms, the numbers were 278mW and 285mW, respectively. Into 600 ohms, the numbers were 117mW and 121mW.
From the RCA input, I wasn’t able to get such high numbers, as the amp wouldn’t go into clipping even when driven with the Clio’s maximum 3Vrms unbalanced output. The maximum unbalanced output from the RCA input was 1.33W into 32 ohms, 170mW into 250 ohms, and 71mW into 600 ohms, all well below 0.01% THD.
This chart shows the balanced output of the Magnius vs. total harmonic distortion (THD) into 32-, 250-, and 600-ohm loads at 1kHz, driven through the XLR inputs. Rated power (all with 1% THD, frequency unspecified) is 5W into 32 ohms, 1W into 300 ohms, and 500mW into 600 ohms. My measurements at 1kHz showed output into 32 ohms at 4.68W at 0.5% THD and 4.82W at 1% THD. Into 250 ohms, the numbers were 1.12W and 1.15W, respectively. Into 600 ohms, the numbers were 470mW and 480mW.
Here you can see the harmonic distortion spectrum and noise floor of the Magnius at 2.3W into 32 ohms, unbalanced. This is a typical result from a solid-state headphone amp. It’s primarily odd-order distortion, which is more sonically objectionable, but I had to push the amp 0.3W past its rated power to get it to distort to this degree, and it’s highly unlikely you’ll ever need to play it this loud, or that you’ll use a source device with a high-enough output voltage to push this amp into this much distortion.
Output impedance is rated at 0.1 ohms, frequency unspecified. At 1kHz, I measured 0.16 ohms from the unbalanced output, 0.11 ohms for the balanced output. Thus, the Magnius will have no audible effect on the frequency response of your headphones or earphones.
. . . Brent Butterworth
brentb@soundstagenetwork.com
