5
11.
Crosstalk
It is necessary to align the output transformers when testing the crosstalk. Therefore, turn the transformer outputs
by 90° to each other and both by 45° to the rear panel. Terminate the 100V-outputs with nominal load and feed a
1kHz signal with -10dBu to the B-channel. Measure the crosstalk at the 100V output of the A-channel using a
selective band pass filter and suitable measuring equipment. Turn the upper transformer for minimal reading.
Apply a 1kHz signal with -10dBu at the A-channel and measure the crosstalk at the B-channel. Crosstalk
attenuation on both channels has to at least
≥
80dB .
12. Noise interference
- U(F) = external voltage un-weighted with B = 22 Hz … 22 kHz, effective value (IEC 268-1)
- U(G) = noise voltage, frequency-weighting filter according to CCIR-468-3, quasi peak weighted (IEC 268-1)
- U(A) = interference voltage A-weighted, dB(A), effective value (IEC 268-1)
- Signal-to-noise ratio referenced to the maximum output voltage at nominal load, A-weighted
- All inputs have to be terminated with 50
Ω
each; during the noise interference measurement, the outputs have to
be without load
Power amplifier
Output
U(F)
dBu
U(G)
dBu
U(A)
dBu
IN(A)
dBu
S/N-R.
dB
LEVEL control up
DPA 4245, 4260
100V
-55
-45
-57
-102
100
DPA 4245, 4260
70V
-58
-47
-60
-102
100
DPA 4245, 4260
25V
-68
-56
-70
-102
100
DPA 4245, 4260
Direct
-64
-52
-66
-102
100
LEVEL control down
DPA 4245, 4260
100V
-57
-47
-59
-
-
DPA 4245, 4260
70V
-59
-50
-61
-
-
DPA 4245, 4260
25V
-70
-58
-72
-
-
DPA 4245, 4260
Direct
-66
-54
-68
-
-
13. Settings when shipped
BRIDGED MODE
switch set to
NORMAL
.
INPUT ROUTING
switch set to
DUAL/STEREO
.
LEVEL
control all the way right.
14. Dimensions and Weight
Power amplifier
Weight
Dimensions in mm
DPA 4245
20.5kg
483 x 132.5 x 385.5
DPA 4260
22.5kg
483 x 132.5 x 385.5
