User manual ART HD231

[. . . ] HD131 SINGLE CHANNEL 31 BAND 1/3 OCTAVE GRAPHIC EQUALIZER HD215 DUAL CHANNEL 15 BAND 2/3 OCTAVE GRAPHIC EQUALIZER HD231 DUAL CHANNEL 31 BAND 1/3 OCTAVE GRAPHIC EQUALIZER IMPORTANT SAFETY INSTRUCTION ­ READ FIRST This symbol, whenever it appears, alerts you to the presence of uninsulated dangerous voltage inside the enclosure-voltage that may be sufficient to constitute a risk of shock. This symbol, wherever it appears, alerts you to important operating and maintenance instructions in the accompanying literature. Please Read manual. Read instructions: Retain these safety and operating instructions for future reference. Heed all warnings printed here and on the equipment. Follow the operating instructions printed in this user guide. [. . . ] When balanced, the tip is High (+), the ring is Low (-) and the sleeve is ground. To use unbalanced use a mono ¼" phone cable, this will automatically ground the ring to the sleeve. 4 EUROBLOCK CONNECTIONS Insert the wires, and then snug down with the set screw. The entire barrier strip can be removed for quick service without disconnecting the individual wires. SIGNAL LEVELS Signal levels from -10dBu to +4dBu are considered normal with maximum levels of approximately +22dBu balanced or +16dBu unbalanced. Do not connect microphones directly to the equalizer. Most Microphones, as well as instrument pickups, require a preamp to get the signal level up to a line level. The outputs of the equalizer are also designed to connect into line level inputs and should not be connected into sensitive Microphone or Instrument Inputs for best results. CHASSIS GROUNDING The equalizers are equipped with a rear panel Ground Lift switch. This should normally be set to the Ground position. After set up, if your system exhibits excessive hum or buzzing, the problem may be a due to a ground differential between your equalizer and other equipment in the same system. The Ground Lift switch lets you try several combinations to minimize system hum. NOTE: ALWAYS TURN YOUR AMPLIFIERS DOWN BEFORE CHANGING GROUNDS. Try different combinations of lifting grounds on units that are supplied with ground lift switches or make sure all chassis are connected to earth ground, either through the AC Power cord ground or by the front panel rack mount screws. If the HD series equalizer is mounted in a grounded rack of equipment, the ground to the case of the equalizer may be lifted to prevent multiple ground paths, which may cause a ground loop to occur. 5 OPERATING INSTRUCTIONS Before starting to equalize your sound system there is some information you should know and procedures you should follow. Your equalizer is equipped with a bypass switch. The bypass switch, when activated, lights the bypass LED and cancels all equalization settings while allowing signal to flow directly through the unit at unity gain. Also included is a range selection switch with LED indicators, +/-6dB = green, +/-12dB = yellow. In addition to the range selection switch there is an output level control potentiometer. The level control operates between off and +6dB. Note: If there is too much gain, your equalizer has a red LED Clip indicator that illuminates when signals are within 6dB of clipping. If the Clip LED flashes occasionally, this is okay, but if this LED is steadily on you should reduce the level control. INITIAL SET UP Here are some tips to help you with the initial set up: 1. Set channel output levels to the center detent 0dB on the front panel. [. . . ] Applied Research and Technology will, without charge, repair or replace, at its option, defective product or component parts upon prepaid delivery to the factory service department or authorized service center, accompanied by proof of purchase date in the form of a valid sales receipt. Exclusions This warranty does not apply in the event of misuse or abuse of the product or as a result of unauthorized alterations or repairs. This warranty is void if the serial number is altered, defaced, or removed. A R T reserves the right to make changes in design or make additions to or improvements upon this product without any obligation to install the same on products previously manufactured. [. . . ]