This article is a guide on how to prevent the Open Circuit fault indicator from displaying on a PowerMatch amplifier screen when using single channel mode to drive 70V / 100V (Hi-Z, constant voltage) loudspeakers.

Symptom

When a PowerMatch amplifier is using single channel mode to push 70V / 100V (Hi-Z, constant voltage) speakers, it is possible to see a fault indicator on the output module of the amplifier.

Relevant Product(s)

• PowerMatch PM4250
• PowerMatch PM4250N
• PowerMatch PM4500
• PowerMatch PM4500N
• PowerMatch PM8250
• PowerMatch PM8250N
• PowerMatch PM8500
• PowerMatch PM8500N

Resolution

1. Connect the PowerMatch amplifier to ControlSpace Designer.

2. Right-click the amplifier module in the software and open Properties.

3. To the right of Alarms, click Setup.

4. Uncheck Open circuit detected to disable it.

In addition, when driving a constant voltage speaker in single channel mode, please note that you will need to modify the channel's limiter.  

1. In ControlSpace Designer, after selecting the corresponding speaker EQ curve on the amplifier channel, a padlock icon will appear, indicating that the Limiter's settings have been locked.

2. Double-click to open the SpeakerPEQ module, click Save EQ As..., and rename the .seq file to save it locally.  For the example below: "DS40F-50V-mode.seq".  After this, the three processing blocks in the red box (above) will be unlocked.

3. Double-click to open the unlocked Limiter processing module, and change the threshold values of V Peak and V RMS to 71.0 and 50.0 respectively.