Tip & How-To about Audio Players & Recorders
This is applicable to the PMP powered mixers regarding an undocumented issue of polarity of speaker connections.
Failure of the "A" side of these units can happen if Speakon to 1/4 inch speaker cables are used and IF the barrel of the 1/4 inch plug becomes grounded. This can happen from careless handling or from intentionally trying to parallel another device from the output which results in a ground being placed on the barrel of the 1/4 inch jack on the "A" side of these mixers. The barrel of a 1/4 inch on the "A" side is the "hot" from the amp.
Upon analyzing the circuitry, these mixers internally invert the audio signal to the "A" side and then the speaker connections reverse the polarity again. Behringer does this to easily allow "bridged" operation of the amplifier.
This creates a hazard that can result in blowing the "A" side amp of these mixers.
If one ONLY uses Speakon connectors everywhere it is NOT a problem, but anytime 1/4 inch plugs are used in the speaker cable system, the hazard exists.
Posted by Fred... on
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