Bose F1 812

77
TEST PROCEDURES
13. Noise Test
13.1 Short the input jacks at the Input 1 XLR connector and at the Input 2 1/4” TRS jack. Set the
Input 1 and Input 2 volume controls to the NOON (12 o’clock) position.
13.2 Measure the output noise level at J4 and J5. It should be <-60dBu, A-Weighted with a 20Hz
to 22kHz filter.
14. Gain and THD+N Tests
14.1 Set the Signal Input switch to the LINE position. Set the Input 1 volume control to MAXIMUM
(fully CW). Set the Input 2 volume control to MINIMUM (fully CCW).
14.2 Apply a 6KHz, -20dBu signal to the Input 1 XLR connector.
14.3 Measure the output level at the J4 (Twiddler) connector. It should be +18.5dBu, +/- 2dB.
Measure the THD+N level. It should be < 0.5%.
14.4 Apply a 100Hz, -20dBu signal to the Input 1 XLR connector.
14.5 Measure the output level at the J5 (Woofer) connector. It should be +25.0dBu, +/- 2dB.
Measure the THD+N level. It should be < 0.5%.
15. Equalizer Curve Tests
15.1 These tests are performed using a balanced differential input to the Input 2 1/4” TRS bal-
anced input jack. Set the input 2 volume control to MAXIMUM (fully CW). Set the Input 1 volume
control to MINIMUM (fully CCW).
CAUTION: You MUST disconnect the AC line cord from the unit when connecting the
driver wiring harnesses to the amplifier PCB outputs at J4 and J5 below. The smaller heatsink
plate on the amplifier PCB has high voltage (400V) on it when the unit is connected to AC mains.
15.2 Connect a 4 Ohm, 250 Watt load resistor to the SMPS/Amplifier PCB’s J4 (Twiddler)
connector. Connect the signal measure-
ment lead across the 4 ohm load and
through the Switching Amplifier filter to
the DB meter.
Apply a 20Hz, -25dBu signal to the Input
2 1/4” TRS balanced input jack. Ensure
the output gain and THD+N levels are in
accordance with the Twiddler output test
table at right.
Input
Frequency
Output Level at J4
(Twiddler Output)
500 Hz Twiddler Out < 5 dBu
700 Hz Twiddler Out = 6.0dBu +/-1dB
700 Hz THD+N < 0.5%
1 KHz Twiddler Out = 9.0dBu +/-1dB
1 KHz THD+N < 0.5%
2 KHz Twiddler Out = 11.4dBu +/-1dB
2 KHz THD+N < 0.5%
4 KHz Twiddler Out = 13.8dBu +/-1dB
4 KHz THD+N < 0.5%
7 KHz Twiddler Out = 15.7dBu +/-1dB
7 KHz THD+N < 1.0%
10 KHz Twiddler Out = 16.0dBu +/-1dB
10 KHz THD+N < 0.5%
20 KHz Twiddler Out = 9.4dBu +/-1dB
20 KHz THD+N < 0.5%