Frequency Response
This first figure (above) shows the stereo frequency response of the Steelhead for its MC input (and 400 ohms), with input values of .1, .4 and .6 mV. There is an interesting upwards curve starting at ~4kHz.
In comparison, here (above) is the frequency response of the XONO (@ 475 ohms). The curve exhibited by the Steelhead (although small) is not present here.
2. Phase Response:
Above is the phase response for the Steelhead. Phase response is most basically the ratio of the phase output to the phase input.
For comparison, here is the phase response of the XONO.
3. Idle Channel Noise:
Above is idle channel noise for the XONO. The Steelhead has almost a 10-20 dB lower noise floor than the XONO for much of the auditory spectrum. Also interesting is that this how much louder this is than the idle channel noise for the MM cartridge (see below).
4. Intermodulation Distortion (w/ 2 frequencies: 19 kHz and 20 kHz [both at 0.6mV])
5. Crosstalk vs. Frequency
The crosstalk for each of these is pretty good. Each line in the above graph is a channel trace of the amount of signal in the empty channel from the one that has signal. The low values of the red curve, and perhaps also the higher values of the blue curve at LOW frequencies could be the result of timeouts that occured during testing. As a sidenote, a timeout occurs with the AP as it records several values, and uses a settling algorithm to provide a final value for the measurement being taken. If the results are too varied, it has difficulty producing the settled value and instead provides an average of the last six values. The low frequency values were marked with the timeout symbol "T" when conducting this test.
Also of note, crosstalk is frequency-dependent: there is a +6dB increase in crosstalk for frequency octave.
Below are selected results for the moving magnet level inputs. Both units were set to 100 pF. The XONO was set to 47 ohms and the Steelhead was set to 50 ohms.
1. Frequency Response
That's a big jump! The above frequency response for the Steelhead demonstrates the output for swept frequencies at input voltages of 5, 7, and 10 mVrms.
2. Phase Response
The Steelhead MM phase response.
3. Idle Channel Noise
Notice how the noise floor of the MM setting is lower than the above MC setting. Also notice the peaks at 8 and 16 kHz. Strange.
4. Intermodulation Distortion (IMD)
This is the IMD for the Steelhead. The 1 kHz frequency peak is pretty substantial. The input for the IMD test was again 19 and 20 kHz test tones.
5. Crosstalk vs. Frequency
more to come: THD+N vs. Frequency and THD+N vs. Amplitude.
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