User manual HAFLER SERIES 9303

[. . . ] 9303 / 9505 Installation & Operation ® ® an tr va no s USA IN T E HE MAD PROFESSIONAL POWER AMPLIFIER AMPL NOTICE - IMPORTANT SAFETY INFORMATION CAUTION RISK OF ELECTRIC SHOCK DO NOT OPEN !! The lightning flash with arrowhead symbol within an equilateral triangle is intended to alert the user to the presence of uninsulated "dangerous voltage" within the product's enclosure, that may be of sufficient magnitude to constitute a risk of electric shock to persons. The exclamation point within an equilateral triangle is intended to alert the user of the presence of important operating and maintenance (servicing) instructions in the literature accompanying the appliance. Furthermore, extension cords or power strips must provide the same three wire grounded connection. [. . . ] Wire the plug at the amplifier end of the cable the same as for the regular balanced input connection. OUTPUT CONNECTIONS The speaker output connectors are dual binding posts. These binding posts will directly accept 12 AWG wire or banana plugs and are spaced on 3/4" centers to accept dual banana plugs. MONOPHONIC USE For systems with high power requirements, the amplifiers can be configured for single channel bridged mono operation. To bridge the amplifier, set the rear panel STEREO/MONO switch to the Mono position; use only the left channel input, and connect the speaker to the red output binding posts. When the amplifier is bridged, the output is floating. Any speaker which requires a common ground from the amplifier output cannot be used in this application. Since a bridged amplifier shares the load between the two channels, the amplifier will effectively drive half of the load. Therefore, for bridged mono operation we recommend using an eight ohm load as the minimum impedance. ­2­ OPERATION POWER SWITCH The POWER switch is located on the front panel of the amplifier. An internal lamp indicates when it is turned on. Standard practice is to turn the amplifier on last and off first when switching components individually to prevent sending damaging transients, generated in the source components, to the speakers. It is possible to leave the power switch in the on position and switch the amplifier remotely through a power distribution block or preamp switched outlet. When doing so make sure the switch is rated for the current required by the amplifier. BALANCED/UNBALANCED INPUT SWITCH The BALANCED/UNBALANCED switch configures the input grounding when using the RCA phono input jacks. In the UNBALANCED position the balanced differential input return (­) port is grounded inside the amplifier. This prevents noise pickup or unstable amplifier operation caused by the open input. In the BALANCED position the differential amplifier inputs are connected to the hot (+) and (­) incoming signal connectors. GROUND SWITCH Ground loops are characterized by a hum or buzz in the system and are caused by a voltage potential difference between two points in a ground circuit. Ground loops are aggravated when multiple paths exist for a given circuit. Mounting components in a rack with metal rails may introduce ground loops between associated equipment, because the rails can establish an additional ground path. The CHASSIS/FLOAT switch allows you to select the amplifier grounding scheme for best system compatibility. With the switch in the CHASSIS position all signal grounds are referred to the chassis and power line ground. [. . . ] Connect the generator signal output to the tip and ring of a 1/4" plug and ground to the sleeve. Connect an AC voltmeter to the amplifier output binding posts. Adjust R1 to give the lowest voltage output from the amplifier. For a temporary adjustment when a signal generator and voltmeter are not available, use an FM tuner and tune it to an unused station as your signal source, and connect the output to the amplifier as described above. [. . . ]