QSC RMX 1850HD

RMX Series Technical Service Manual 17
Calibrations Adjust RMX850 RMX1450 RMX1850HD RMX2450
Channel 1 bias: DC voltage across R146 R131 0.16 V 0.14 V 0.07 V 0.07 V
Channel 2 bias: DC voltage across R246 R231 0.16 V 0.14 V 0.07 V 0.07 V
Output current into shorted load
Channel 1: R139 & R140
Channel 2: R239 & R240
4–4.5 A 4–5 A 7.5–8.5 A 8.5–9 A
AC current when driving shorted load*
Channel 1: R139 & R140
Channel 2: R239 & R240
3.75–4.5 A 4.5–5.5 A 4.5–5.5 A 5.5–6.5 A
Clipping voltage into 2 ohms (RMS)
Channel 1: Adjust R139
for symmetry
Channel 2: Adjust R239
for symmetry
26–29 V 33.5–37.5 V 42–44 V 44–49 V
Clipping voltage into 2 ohms (peak)
Channel 1: Adjust R139
for symmetry
Channel 2: Adjust R239
for symmetry
36.8–41 V 47.4–53 V
59.3 –62.2 V
62.2–69.3 V
Idle AC demand* (at ambient temperature;
higher when hot)
0.4 A,
±10% 0.4 A, ±10% 0.6 A, ±10% 0.6 A, ±10%
*Figures shown are for 120V amplifiers; multiply current by 0.5 for 230V or 1.2 for 100V.
Table 1: Bias and current limit adjustments