User manual RANE ME 30B

[. . . ] The OL indicator lights up if any section of the ME 30B is within 3 dB of clipping. Occasional blinking of this LED is acceptable, but if it remains on more than intermittently, turn down either the LEVEL control or reduce the output level of the preceding component to avoid audible distortion. BYPASS switch: When the red LED is lit, this indicates that the unit is in the BYPASS mode: signal is routed directly from the Input to the Output without passing through any active circuitry (often referred to as "hard-wire bypass"). Use this switch to compare equalized and unequalized material, or to bypass the EQ section in the event of power loss or unit failure. [. . . ] Unbalanced operation involves using only pin 2 or tip as signal, and pin 1 or sleeve as sheild or ground. It is not necessary to short any inputs to ground--it doesn't hurt, it's just not necessary. Balanced output requires using pin 2 or tip, and pin 3 or ring for the signal. The signal exists differentially between the two balanced leads; ground is not involved. EXPANDING Expanding and/or daisychaining the Inputs and Outputs normally uses the ¼" jacks. Three parallel Input connectors allows driving a second signal processor or amplifier without special cabling. SIGNAL LEVELS Signal levels from -10 dBV to +4 dBu are considered normal and within range (at least 20 dB of headroom exists above these levels). These require an external mic preamp. IMPORTANT NOTE CHASSIS GROUNDING If after hooking up your system it exhibits excessive hum or buzzing, there is an incompatibility in the grounding configuration between units somewhere. Your mission, should you accept it, is to discover how your particular system wants to be grounded. Try combinations of lifting grounds on units that are supplied with ground lift switches or links. If your equipment is in a rack, verify that all chassis are tied to a good earth ground, either through the line cord grounding pin or the rack screws to another grounded chassis. Units with outboard power supplies do NOT ground the chassis through the line cord. Make sure that these units are grounded either to another chassis which is earth grounded, or directly to the grounding screw on an AC outlet cover by means of a wire connected to a screw on the chassis with a star washer to guarantee proper contact. Manual-3 OPERATING INSTRUCTIONS Insuring the proper level of gain though the ME 30B is just as important as adjusting the equalizer bands. Improper gain distribution is a common cause of loss of system headroom and less than optimum noise performance. The OVERLOAD LED informs of an imminent or passed overload to the equalizer. Occasional blinking of the OL with program source material is fine, indicating optimized signal-tonoise performance of the ME 30B. Run the ME 30B with an input signal that is as hot as possible without the OL lighting more than occasionally. The BYPASS switch allows comparison of equalized versus un-equalized signal. It is also useful in adjusting the level of the ME 30B for unity gain and best signal-to-noise performance. The gain of the ME 30B is optimized when there is no sound level difference between the bypassed and the active positions. The overall gain range of the level control for the ME 30B is off to +6 dB for unbalanced operation, or off to +12 dB for balanced operation. The level difference between the equalizer in bypass or active can be significant. [. . . ] Using these devices to analyze the response of the room and the sound system is the only accurate means available for setting an equalizer properly. A little goes a long way in improving sound quality, too much and the mix is spoiled. If modest amounts of equalization (6-8 dB) do not solve the problem, it is best remedied by other means. Avoid adding large amounts of boost below 63 Hz, especially when using vented bass cabinets. [. . . ]