Variable Load Drive (Vld) - Electro-Voice Contractor Precision CPS4.5 Owner's Manual

70 V Mode
The 70 V mode allows connection of 70 V loudspeaker lines (Direct Drive) in high impedance mode (HZ) without using output
transformers. In this case the maximum number of loudspeakers connected to an output channel is only limited by the
amplifier's output power (500 W for CPS4.5/8.5 or 1000 W for CPS4.10). This mode should be used if the distance between
amplifier and speaker is larger than 50 metres (approx. 150 feet) and/or a high number of small speakers (e.g. ceiling
speakers) is used.
100 V Mode
The 100 V mode allows connection of 100 V loudspeaker lines (Direct Drive) in high impedance mode (HZ) without using
output transformers. In this case the maximum number of loudspeakers connected to an output channel is only limited by the
amplifier's output power (500 W for CPS4.5/8.5 or 1000 W for CPS4.10). This mode should be used if the distance between
amplifier and speaker is larger than 50 metres (approx. 150 feet) and/or a high number of small speakers (e.g. ceiling
speakers) is used.

2.8 Variable Load Drive (VLD)

Selecting an output mode, as described in the previous chapter, provides an extremely practical way of matching amplifiers
and connected loudspeaker systems. Table 2.3 shows all possible combinations of output power and connected load for
power amps operated in low-impedance mode. Retrofitting an optionally available Remote Control Module (e.g. RCM-810)
allows freely programming individual amplifier channels via Variable Load Drive (VLD). For power amplifier models CPS4.5
and CPS8.5 it is possible to freely select the output power in a range between 100 watts to 500 watts for loads ranging from 2
ohms to 10 ohms per channel. For the power amplifier model CPS4.10 it is possible to freely select the output power in a
range between 100 watts to 1000 watts for loads ranging from 2 ohms to 10 ohms per channel. Additionally, the Remote
Control Module RCM-810 allows switching a 50 Hz High-Pass filter on per channel. This may be advantageous when driving
small or medium sized full-range cabinets to eliminate unwanted sub-frequency content in the audio signal.
For using VLD in a power amplifier with a Remote Control Module installed, please proceed as follows:
Set the DIP-switch MODE (see page 8) to „2 Ω/VLD" for power amplifier channels to be operated in VLD mode.
•
• Use the DIP-switch OUTPUT (see page 10) to select DUAL or PARALLEL output mode for power amplifier channels to
be operated in VLD mode. VLD is not available in the BRIDGED output mode.
• Use IRIS-Net (see page 15) to configure output power, impedance and High-Pass filters of individual channels. Detailed
information on the configuration, control and monitoring of amplifiers with Remote Control Modules installed can be found
in the documentation that comes with the IRIS-Net software application.
The configuration of power amplifier channels is stored nonvolatile in the Remote Control Module. Please keep in mind that
the VLD configuration in IRIS-Net only affects channels set to „2 Ω/VLD" mode. Operation modes 4 ohms, 70 V and 100 V are
Illustration 2.6: CH 1 in 70 V mode
Illustration 2.7: CH 1 in 100 V mode
CONTRACTOR PRECISION SERIES
Owner's Manual 11