Meyer Sound Documentation

The MPS-482HP Power Supply is powered on and off with the AC Power switch.

The Fuse, Voltage and Load Current LEDs are useful for verifying if a channel fuse is open/blown, whether each channel output has voltage, and whether the connected loudspeakers are receiving DC power and audio.

MPS-482HP Power Supply Channel LEDs

Red Fuse LEDs (1-2)

A lit red LED indicates a blown or open fuse on that channel. If the Red LED is lit, power down the MPS-482HP Power Supply and check for shorts on the loudspeaker cabling before replacing the fuse.

Tip

To replace a fuse, use a screwdriver to gently turn the appropriate fuse cover (open: counterclockwise; close: clockwise).

Fuse Access

Blue Voltage LEDs (1–2)

The blue Voltage LEDs indicate whether voltage is present for the channel outputs. These LEDs should be lit when the MPS-482HP Power Supply is powered on. The MPS-482HP Power Supply’s intelligent circuit protection shields connected loudspeakers from surges and shorts. When a blue Voltage LED is unlit and its corresponding green Load Current LED is off, a surge or short has been detected for the channel. If a surge or short is encountered, or the Red LED is lit, power down the MPS-482HP Power Supply, inspect the loudspeaker cabling, and replace the fuse for that channel.

The table below lists the possible states for the Blue Voltage LEDs.

Table 1. Blue Voltage LEDs

State	Cause	Recommended Action
Unlit (all LEDs)	MPS-482HP Power Supply not powered on or is unplugged	Verify the MPS-482HP Power Supply is powered on and verify its power source.
Unlit (single LED)	Surge or short encountered for channel	Power down the MPS-482HP Power Supply; inspect the loudspeaker cabling for the channel.

Caution

When a blue Voltage LED is unlit, power down the MPS-482HP Power Supply,and inspect the loudspeaker cabling for that channel.

Green Load Current LEDs (1–2)

The green Load Current LEDs indicate whether loudspeakers are connected to the channel outputs and receiving power. If a green LED is not lit, check that the channel’s blue Voltage LED is lit and verify the cable connection to the loudspeaker.

The table below lists the possible states for the Load Current LEDs.

Table 2. Green Load Current LEDs

State	Cause	Recommended Action
Unlit (all LEDs)	MPS-482HP Power Supply not powered on or no loudspeakers connected	Verify the MPS-482HP Power Supply is powered on and verify its power source; inspect the loudspeaker cabling.
Unlit (single LED)	No loudspeaker connected	Power down the MPS-482HP Power Supply; inspect the loudspeaker cabling for the channel.
Glows brighter (single LED)	LED glows brighter as channel’s audio signal level increases	None required.

Caution

When a blue Voltage LED is unlit and its corresponding green Load Current LED is unlit, indicating a surge or short for the channel, power down the MPS-482HP Power Supply and inspect the loudspeaker cabling for that channel.

The MPS-482HP Power Supply has a powerCON 20 twist-lock AC input connector (line, neutral/line, earth). The connector can accept different power cable types for outlets used throughout the world. Make sure to use the correct power cable for the AC power in the area where it will operate. The MPS-482HP Power Supply operates at an AC voltage range of 100–240 V at 50–60 Hz.

The MPS-482HP Power Supply receives two channels of balanced audio via the two channel inputs. The inputs are equipped with two 3-pin XLR female connectors and a 6-pin Phoenix male connector, but only one set may be used at a time. The XLR input connector pinout is: pin 1, ground; pin 2, signal positive; pin 3, signal negative. Make sure to use standard balanced XLR cables with all three pins connected on both ends. The Phoenix input connector supports two channels with the following pinout (from left to right): pin 1, channel 1 ground; pin 2, channel 1 signal positive; pin 3, channel 1 signal negative; pin 4, channel 2 ground; pin 5, channel 2 signal positive; pin 6, channel 2 signal negative.

MPS-482HP Power Supply Channel Inputs

Channel inputs default to being routed to their corresponding channel outputs but channel 1 can also be routed to both outputs with the Link switch. This selection affects the input impedance (see Input Impedance for Linked Channel Inputs).

The Link switch determines how the two inputs are routed to the two outputs. When the Link switch is OFF (set to the down position), each input is only routed to its corresponding output (input 1 routed to output 1 and input 2 is routed to output 2).

When the Link switch is ON (set to the up position), input 1 is routed to both output 1 and output 2.

Link Switch Routing Examples

The following examples illustrate the routing applications for the Link switch.

Routing One Input to Two Outputs

To route input 1 to both channel outputs, set Link switch to ON.

Routing Each Input to its Corresponding Output

To route each input to its corresponding channel output, set Link switch to OFF.

Input Impedance for Linked Channel Inputs

When the Link switch is enabled, channel 1 input’s unbuffered source signal is transmitted in parallel to both channel 1 and 2 outputs. This selection causes the channel input’s impedance (normally 10 kOhms for one loudspeaker) to be reduced for each linked output. For example:

• one channel output, 10 kOhm input impedance

• two channel outputs, 5 kOhm input impedance

Note

To avoid distortion when linking channel inputs, make sure the source device can drive the total load impedance of the linked loudspeakers. Most source devices are capable of driving loads no smaller than 10 times their output impedance. To drive two loudspeakers linked from a single channel input, the source device should have an output impedance of less than 500 ohms.

The MPS-482HP Power Supply’s two channel outputs deliver DC power (48 V DC) and balanced audio to two loudspeakers. The channel outputs are Phoenix 5-pin male connectors.

MPS-482HP Power Supply Channel Outputs

The MPS-482HP Power Supply channel outputs are Phoenix 5-pin male connectors with three pins for balanced audio (positive, negative, and shield) and two pins for DC Power (positive and negative). The pins are clearly labeled on the MPS-482HP Power Supply rear panel.

MPS-482HP Power Supply Channel Outputs

The current draw for the MPS-482HP Power Supply and its connected loudspeakers is dynamic and fluctuates as operating levels change. Because different cables and circuit breakers heat up at varying rates, it is important to understand the following types of current ratings and how they affect circuit breaker and cable specifications.

V pk (drop) = I pk x R (cable total)

The minimum electrical service amperage required by an MPS-482HP Power Supply is the sum of the maximum long-term continuous current for all loudspeakers connected to the MPS-482HP Power Supply. An additional 30 percent above the minimum amperage is recommended to prevent peak voltage drops at the service entry.