Calculating Impedance - US Blaster USB 7132 Owner's Manual

USB 7132 / 7133 / 7134
Professional Power Amplifier

CALCULATING IMPEDANCE

Measured in ohms, impedance is a measure of AC resistance. Loudspeakers generally come in 16, 8
or 4 ohm varieties. Amplifiers have a low limit to what impedance they can drive without being
overloaded, there is not usually an upper limit. The PA series can drive any impedance between an
open circuit and no less than 2 ohms when in stereo and between an open circuit and no less than
4 ohms when bridged.
If the speakers are wired in series, just add their impedances together. If they are in parallel there is
a simple rule: two impedances the same will equal half the individual impedance, for example 8 & 8
= 4 or to take this further, four 8 ohm drivers = 2 ohms (16 & 16= 8 / 8 & 8 = 4 / 4 & 4 = 2).
Table for specification
ITEMS
OUTPUT
POWER
DISTORSION
INPUT
SENSITIVITY
VOLTAGE GAIN
S/N RATIO
FREQUENCY
RESPONSE
CH. SEPERATION
© US Blaster Europe BV
CONDITIONS
8 Ohms 0.1%
THD 1KHz
4 Ohms 0.1%
THD 1KHz
2 Ohms 0.1%
THD 1KHz
Bridged Mono
8 Ohms 0.1%
THD 1KHz
Bridged Mono
4 Ohms 0.1%
THD 1KHz
Power 1W
4 Ohms 1KHz
Rated power
4 Ohms 1KHz
Output rated power
(Level at Max.)
Output rated power
Rated power 1 KHz
+A (Level at Mid)
1 KHz=0dB/-0.5dB
(Level at Max.)
Rated power
4 Ohms 1KHz
USB 7132 USB 7133
200W RMS 300W RMS
x 2 Channel x 2 Channel
300W RMS 400W RMS
x 2 Channel x 2 Channel
400W RMS 500W RMS
x 2 Channel x 2 Channel
600W RMS 850W RMS
800W RMS 1000W RMS
0.2% 0.25%
0.03% 0.055%
775 ±30mV 950 ±30mV
31dB 31dB
0.2% 0.25%
10--30K 10--30K
67 dB 70 dB
USB 7134
450W RMS
x 2 Channel
700W RMS
x 2 Channel
900W RMS
x 2 Channel
1400W RMS
1800W RMS
0.3%
0.06%
1400 ±30mV
31dB
0.3%
10--30K
65.5 dB