Benchmark HPA4 - Page 38

Instruction Manual for HPA4 with 1.0.X Firmware – REV B Page 38
Graph 7 - Frequency Response - Headphone Amplifier - 16-Ohm Load
The -3 dB frequency response of the headphone amplifier extends well beyond the 10 Hz to 200
kHz range of our AP2722 measurement system. The response is -0.125 dB at 20 kHz and -1.45 dB
at 200 kHz when driving a heavy 16-Ohm load. Compare this to Graph 6 (frequency response into
300 Ohms). The difference in frequency response due to the heavy 16-Ohm loading is minimal. The
difference due to loading is only 0.1 dB at 20 kHz and 0.6 dB at 200 kHz.
Notes:
• The scale on the left (dBr A) is dB relative to the output level at 1 kHz. The test used a
0-dBu test tone.
• Balanced inputs to headphone outputs, volume control set at 0 dB.
Audio Precision
07/16/18 11:55:30
Freq_Resp_Bal_HPA_16-Ohms.at27
ColorSweep Trace
Line Style Thick Data Axis
Comment Cursor1
Cursor2
1 1
Green Solid
4 Anlr.Level A
Left HP Out into 16 Ohms
*-0.125 dBr *-1.453 dBr
-3
+1
-2.8
-2.6
-2.4
-2.2
-2
-1.8
-1.6
-1.4
-1.2
-1
-0.8
-0.6
-0.4
-0.2
+0
+0.2
+0.4
+0.6
+0.8
-0.125
-1.453
d
B
r
A
10
200k 20
50
100 200 500 1k 2k 5k
10k
20k 50k
100k
20.5k
200k
Hz
dx=179.500 kHz
dy=-1.328 dB