Alto SR400A, Service Manual, Page: 4 / 26

Test Result
Model No：SR400A Test Date: Tester：MO GUO ZHU
Test Item 1. Input
Sensitivity
2. Signal/Noise 3. Distortion at
1W
4. Distortion at
Rated
5. Frequency
Response
Test Conditions
Test Result
FLAT Rated
Output 30V/18V
Load 4Ω/8Ω
FLAT Rated
Output 30V/18V
Load 4Ω/8Ω
FLAT Output
at 2V Load 4Ω
FLAT Rated
Output 30V/18V
Load 4Ω/8Ω
FLAT Output at
1W REF-3dB
Load 4Ω
Low OUT -9 ±0.5 dBV 70↑ dB 0.5↓ % 0.4↓ % 22Hz~22KHz↑
Hi OUT -8±0.5 dBV 68↑ dB 0.5↓ % 0.8↓ % 25Hz~22KHz↑
TUNER dB dB % %
LINE
CD dB dB % %
AUX dB dB % %
TAPE dB dB % %
TUNER dB dB % %
AUX2
CD dB dB % %
AUX dB dB % %
TAPE dB dB % %
TUNER dB dB % %
AUX3
CD dB dB % %
LOW -50±0.5 dBV 60↑ dB 0.8↓ % 0.3↓ % 22Hz~22KHz↑
HI -50±0.5 dBV 60↑ dB 0.5↓ % 1↓ % 25Hz~22KHz↑
24V dB dB % %
MIC
UNBAL dB dB % %
MIC dB dB % %
LINE dB dB % %
24V dB dB % %
MIC-2
UNBAL dB dB % %
MIC dB dB % %
LINE dB dB % %
24V dB dB % %
MIC-3
UNBAL dB dB % %
MIC dB dB % %
LINE dB dB % %
24V dB dB % %
MIC-4
UNBAL dB dB % %
Remark 1
. When the above items are tested, short circuit the 1st and the 2nd pin of 313115-1 (DSP) CN1. After the
test, remove the short circuit terminal.
2. Load connection: connect LOW output with 4Ohms, and connect HIGH output with 8Ohms.
3. Please check if the bass BOOST circuit is OK. If bass output is below 18V(ON LOAD), BOOST
circuit does not operates. If bass output is above 18V(ON LOAD), BOOST circuit starts operation.
4. FR test: use AP to scan DSP ON and DSP OFF respectively. Refer to the attached figure for frequency
response curves.
Authorization by： Check by：
SPECIFICATIONS
01-2