PRE420

This graph shows the frequency response of the PRE420 with the 40 Hz high-pass filter off. The amplitude response measures -0.020 dB at 10 Hz and -0.165 dB at 200 kHz. The bass response extends well below the 10-Hz limitation of the test equipment, and the high-frequency response extends well above the 200 kHz limit of the test equipment.

This graph shows the response of the 40 Hz high-pass filter. Response is -3 dB at 40 Hz with a slope of 12 dB/octave.

This graph shows that the differential phase is significantly better than ± 0.05 degrees from 10 Hz to 20 kHz.

This graph shows that THD+N does not rise with frequency - even at maximum gain. Measurement Bandwidth = 10Hz to 80 kHz, Gain = 30 to 60 dB, Output Level = +4 dBu

This graph shows that THD+N does not rise above noise - even at very high frequencies. The 500 kHz measurement bandwidth elevates the noise by 28 dB relative to a 20 kHz measurement bandwidth. Measurement Bandwidth = 10Hz to 80 kHz, Gain = 30 to 60 dB, Output Level = +4 dBu

This graph shows the Equivalent Input Noise (EIN) of the PRE420 as a function of gain. Measurement bandwidth is 20 Hz to 20 kHz. Input termination is 150 Ohms.

This graph demonstrates that the PRE420 is free of hum and noise. The highest tone is 60-Hz line-related hum and is at a level equivalent to an input level of -145 dBu. 180-Hz hum is at an equivalent input level of -149 dBu. 32k B-H FFT, Gain = 60 dB, 0 dBr = 0 dBu at input

This FFT plot shows that the PRE420 has very little harmonic distortion. The 1 kHz test tone is notched out with a THD analyzer to improve the resolution of the test. Distortion is exceptionally low. 2nd-harmonic distortion measures better than -111 dB. 3rd-harmonic distortion measures better than -122 dB. Note the absence of higher-order harmonics.

The above FFT plot shows that the PRE420 has very little harmonic distortion at high frequencies. The 10 kHz test tone is notched out with a THD analyzer to improve the resolution of the test. The 20-kHz 2nd-harmonic distortion measures better than -109 dB. The 30-kHz 3rd-harmonic distortion measures better than -118 dB.