Dynacord Power Amplifier DPA 4245, Руководство по обслуживанию

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4
6. Level CHANNEL A B
6.1. VOLTAGE AMPLIFICATION
Appliance Input U(E) Measuring point vU U(A) Load Frequency
DPA 4245 CH. A/B 0dBu Direct Out A/B 33.8dBu 37.8V
4
Ω
1kHz
DPA 4245 CH. A/B 0dBu 100V Output 42.2dBu 99.2V
28.5
Ω
1kHz
DPA 4245 CH. A/B 0dBu 70V Output 39.3dBu 71.6V
14
Ω
1kHz
DPA 4245 CH. A/B 0dBu 25V Output 30.2dBu 25.1V 1.8V 1kHz
DPA 4245 CH. A 0dBu BRIDGED OUT 39.8dBu 76V
8
Ω
1kHz
DPA 4260 CH. A/B 0dBu Direct Out A/B 34.9dBu 43V
4
Ω
1kHz
DPA 4260 CH. A/B 0dBu 100V Output 41.8dBu 95.2V
20
Ω
1kHz
DPA 4260 CH. A/B 0dBu 70V Output 39dBu 68.8V
9.8
Ω
1kHz
DPA 4260 CH. A/B 0dBu 25V Output 29.8dBu 24V
1.25
Ω
1kHz
DPA 4260 CH. A 0dBu BRIDGED OUT 41dBu 87.3V
8
Ω
1kHz
6.2. MAXIMUM INPUT LEVEL: U(E) = +21dBu
7. GROUND LIFT switch
The circuit ground (at the input or the output connector) is measured versus the common ground of the enclosure
(contact at the ground terminal, located on the rear panel - or common ground of the mains cord).
without input transformer GROUNDED : R = 0
Ω
with input transformer GROUNDED : R = 0
Ω
NOT GROUNDED: R = 5
Ω
NOT GROUNDED: R
→∞
8. Amplitude - Non-Linearities
- MBW = 80kHz
- all channels terminated with nominal load at nominal power, Direct Output at 8
Ω
or at 4
Ω
respectively, at
nominal power
Measurement DPA 4245 DPA 4260 Remarks
100V 70V 25V Direct 100V 70V 25V Direct
THD+N
<0.1% <0.2% <0.3% <0.05% <0.1% <0.2% <0.3% <0.05% 1kHz
IMD-SMPTE <0.1% <0.3% <0.5% <0.08% <0.2% <0.3% <0.5% <0.08%
60Hz, 7kHz
DIM 30 <0.2% <0.2% <0.2% <0.03% <0.2% <0.3% <0.3% <0.03% 3.15kHz,
15kHz
9. Frequency Response
The frequency response is linear. (mind the border frequencies)
fU -1dB fO -1dB fU -3dB fO -3dB
100V Output 60Hz 17kHz 45Hz 26kHz
70V Output 60Hz 17kHz 45Hz 26kHz
25V Output 60Hz 12kHz 45Hz 22kHz
Direct Output 60Hz 22kHz 45Hz 30kHz
10. Insert Attenuation
Drive the power amplifier in idling condition via the transformer outputs up to the nominal output voltage.
Connect the nominal load and measure the level changes.
DPA 4245 DPA 4260
100V Output
0,7 dB 0,7 dB
70V Output 0,8 dB 0,8 dB
25V Output 1,1 dB 1,1 dB