Specifications measured from balanced inputs to balanced outputs on the HPA4 line amplifier:
THD < -125 dB (0.00006%)
SNR > 135 dB, unweighted, 20-20 kHz
SNR > 137 dB, A-weighted
Frequency response – 0.003 dB at 10 Hz, -0.001 dB at 20 kHz
– 3 dB bandwidth exceeds 0.1 Hz to 500 kHz
Output impedance 60 Ohms
Output noise < 1.9 uV at unity gain, 20-20 kHz
Maximum input and output voltage, 20 Vrms (+28 dBu)
Crosstalk < -133 dB @ 1 kHz, -116 dB @ 10 kHz
HPA4 features:
256-step stereo volume control – line output
256-level stereo volume control – headphone output
Relay input selection
Two stereo balanced line inputs
Two stereo unbalanced line inputs
One stereo balanced line output
One balanced mono summary output
One balanced THX-888 XLR4 headphone output
One unbalanced THX-888 TRS headphone output
Independent control of headphone outputs and line outputs
Balance management
Color touch screen
Two 12-volt trigger ports
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