User manual RANE MQ 302S

[. . . ] OPERATORS MANUAL MQ 302S STEREO GRAPHIC EQUALIZER QUICK START If this is your first equalizer, please do yourself and your speakers a favor and read at least the first five pages. "An ounce of prevention. . . , " and all that. The MQ 302S is a stereo equalizer, so adjusting any slider affects both channels simultaneously. Begin by setting all sliders to their center detent (0 dB), and the INPUT LEVEL to its center detent (0 dB). [. . . ] However, this document contains suggestions for external wiring changes that should ideally only be implemented by trained technical personnel. Safety regulations require that all original grounding means provided from the factory be left intact for safe operation. No guarantee of responsibility for incidental or consequential damages can be provided. (In other words, don't modify cables, or try your own version of grounding unless you really understand exactly what type of output and input you have to connect. ) THE ABSOLUTE BEST RIGHT WAY TO DO IT Use balanced lines and tie the cable shield to the metal chassis (right where it enters the chassis) at both ends of the cable. A balanced line requires three separate conductors, two of which are signal (+ and ­) and one shield. The shield serves to guard the sensitive audio lines from interference. Only by using balanced line interconnects can you guarantee (yes, guarantee) hum-free results. Chassis tying the shield at each end also guarantees the best possible protection from RFI [radio frequency interference] and other noises [neon signs, lighting dimmers]. THE NEXT BEST RIGHT WAY TO DO IT The quickest, quietest and most foolproof method to connect balanced and unbalanced is to transformer isolate all unbalanced connections. Your audio dealer can recommend such a transformer. The goal of transformer adaptors is to allow the use of standard cables. With these transformer isolation boxes, modification of cable assemblies is unnecessary. Virtually any two pieces of audio equipment can be successfully interfaced without risk of unwanted hum and noise. Another way to create the necessary isolation is to use a direct box. Originally named for its use to convert the high impedance, high level output of an electric guitar to the low impedance, low level input of a recording console, it allowed the player to plug "directly" into the console. Now this term is commonly used to describe any box used to convert unbalanced lines to balanced lines. THE LAST BEST RIGHT WAY TO DO IT If transformer isolation is not an option, special cable assemblies are a last resort. The key here is to prevent the shield currents from flowing into a unit whose grounding scheme creates ground loops (hum) in the audio path (i. e. , most audio equipment). Do not be tempted to use 3-prong to 2-prong "cheater" adapters to lift grounds. This is a dangerous and illegal practice. It is true that connecting both ends of the shield is theoretically the best way to interconnect equipment ­ though this assumes the interconnected equipment is internally grounded properly. Since most equipment is not internally grounded properly, connecting both ends of the shield is not often practiced, since doing so can create noisy interconnections. [. . . ] Varies widely, from very low mic-levels to quite large line-levels. limiter A compressor with a fixed ratio of 10:1 or greater. The dynamic action prevents the audio signal from becoming larger than the threshold setting. Linkwitz-Riley crossover The most preferred active crossover design. [. . . ]