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I have an Emotiva XSP-1 preamplifier so I thought I'd test it's internal phono stage to compare with the Mofi StudioPhono I measured here: https://www.audiosciencereview.com/...ono-phono-preamp-homebrew-measurements.18676/
My equipment:
Hardware:
- Soundcard is a lowly ASUS Xonar DSX 7.1, but it actually has decent ADC performance when run at 44.1 KHz. ADC input used for signal analysis. ADC saturates at 1.025 Vrms. For signal generation, SPDIF out used.
- Benchmark DAC1 used as DAC for test signal generation.
- RatShack multimeter used to read voltages as needed.
Software:
- ARTA software on PC used for signal generation and analysis.
- Octave (Matlab clone) used for RIAA curve calculations.
Setup:
Soundcard SPDIF out -> Benchmark DAC1 -> XSP-1 phono stage -> Soundcard ADC -> ARTA Software
SPDIF connection is optical.
All other connections are single ended RCA.
Test #1: Gain @ 1KHz
Test not done because phono stage is internal to XSP-1 preamplifier.
Test #2: Overload margin referenced to 5 mVrms input
ARTA spectrum analyzer used to incrementally increase input until phono preamp clipped.
XSP-1 volume control used to keep signal below fullscale ADC at soundcard.
Results:
@ 60 Hz = 6 dB overload margin (clean to 10 mVrms input)
@ 1000 Hz = 22 dB overload margin (clean to 63 mVrms input)
@ 10000 Hz = > 40 dB overload margin (clean to >500 mVrms input)
These overload margins correspond to a maximum output voltage of about 6-7 Vrms before clipping. These margins are actually identical, within 1 dB, to those of the Mofi StudioPhono.
Test #3: RIAA Accuracy
ARTA Steps program used to sweep the phono preamp gain with 5 mVrms input.
Octave used to compare gain sweep with RIAA curve.
Results are shown.
RIAA accuracy is much better than Mofi StudioPhono.
Test #4: Distortion @ 1KHz
Signal input at +18 dB overload relative to 5 mVrms.
ARTA spectrum analyzer used to capture.
Results are shown:
Maximum is 3rd harmonic at approximately -78 dB below fundamental. This is significantly higher than Mofi StudioPhono which had about 95 dB between fundamental and highest harmonic.
Note: the power supply noise in the output is not due to the phono preamp. It is in the generator signal and shows up because the phono preamp is boosting that region by approximately 55 dB.
I would guess this is the same phono stage design as that reviewed by Amir here:
https://www.audiosciencereview.com/...measurements-of-emotiva-xps-1-phono-amp.7568/
My equipment:
Hardware:
- Soundcard is a lowly ASUS Xonar DSX 7.1, but it actually has decent ADC performance when run at 44.1 KHz. ADC input used for signal analysis. ADC saturates at 1.025 Vrms. For signal generation, SPDIF out used.
- Benchmark DAC1 used as DAC for test signal generation.
- RatShack multimeter used to read voltages as needed.
Software:
- ARTA software on PC used for signal generation and analysis.
- Octave (Matlab clone) used for RIAA curve calculations.
Setup:
Soundcard SPDIF out -> Benchmark DAC1 -> XSP-1 phono stage -> Soundcard ADC -> ARTA Software
SPDIF connection is optical.
All other connections are single ended RCA.
Test #1: Gain @ 1KHz
Test not done because phono stage is internal to XSP-1 preamplifier.
Test #2: Overload margin referenced to 5 mVrms input
ARTA spectrum analyzer used to incrementally increase input until phono preamp clipped.
XSP-1 volume control used to keep signal below fullscale ADC at soundcard.
Results:
@ 60 Hz = 6 dB overload margin (clean to 10 mVrms input)
@ 1000 Hz = 22 dB overload margin (clean to 63 mVrms input)
@ 10000 Hz = > 40 dB overload margin (clean to >500 mVrms input)
These overload margins correspond to a maximum output voltage of about 6-7 Vrms before clipping. These margins are actually identical, within 1 dB, to those of the Mofi StudioPhono.
Test #3: RIAA Accuracy
ARTA Steps program used to sweep the phono preamp gain with 5 mVrms input.
Octave used to compare gain sweep with RIAA curve.
Results are shown.
RIAA accuracy is much better than Mofi StudioPhono.
Test #4: Distortion @ 1KHz
Signal input at +18 dB overload relative to 5 mVrms.
ARTA spectrum analyzer used to capture.
Results are shown:
Maximum is 3rd harmonic at approximately -78 dB below fundamental. This is significantly higher than Mofi StudioPhono which had about 95 dB between fundamental and highest harmonic.
Note: the power supply noise in the output is not due to the phono preamp. It is in the generator signal and shows up because the phono preamp is boosting that region by approximately 55 dB.
I would guess this is the same phono stage design as that reviewed by Amir here:
https://www.audiosciencereview.com/...measurements-of-emotiva-xps-1-phono-amp.7568/
