3 INSTALLATION / 4 OPERATIONUSER MANUALVORTEX 6, 4, 2.6 and 200VP.16WARNING !SPEAKON connectors marked with the lightning flashes indicate high vol-tages that are potentially life threatening.Wiring to these terminals requires installation by an instructed person orthe use of ready-made leads or cords.Custom wiring should only be carried out by qualified personnel.To prevent electric shock, do not operate the amplifier with any of theconductor portion of the speaker wire exposed.NOTE:For reasons of safety and performance, use only high-quality fully insu-lated speaker cables of stranded copper wire. Use the largest wire size thatis economically and physically practical, and make sure the cables are nolonger than necessary.IMPORTANT:When connecting speaker cabinets in parallel, always use all the contactsin both SPEAKON connectors. If not, this may cause permanent damage tothe connectors and considerably reduce performance.4.1 Controls4.1.1 Volume ControlA microprocessor-controlled DCA (Digital Controlled Attenuator) with a controlresolution of 12 bits per channel is integrated into the signal path. This meansthat the signal is not subject to an A/D followed by a D/A conversion withassociated losses.Using a DCA instead of the “conventional” VCA significantly reduces distortionand, at the same time, it improves the noise characteristics. A volume controlwith 41 notched settings controls the DCA via a microchip.These settings have been selected to correspond to human hearingcharacteristics (logarithmically) and therefore guarantee an optimal range ofsettings for practical applications. Each channel can be set individually exceptwhen operating in mono modes whereby only channel A is active.Set the volume to zero before turning on the amplifier to prevent the occurrenceof sudden high volume levels which may cause damage to your hearing and/orthe speakers.The volume controls are also used to set the CAI address. (See 5.2.2 CAI AddressSettings)