User manual ROTEL RA-931

[. . . ] If the provided plug does not fit into you outlet consult your service agent. Route the power cord so that it is not likely to be walked on, stretched or pinched by items placed upon or against. Grounding: Do not defeat the grounding and polarization means of the power cord plug. Ventilation: Do not obstruct the ventilation slots or position the unit where the air required for ventilation is impeded. [. . . ] Analog Audio Connections Audio connections to and from the TCS are balanced XLR (Pin 2 = Hot (+), Pin 3 = Cold (-), Pin 1 = Ground), balanced ¼" (Tip = Hot (+), Ring = Cold (), Sleeve = Ground) and unbalanced ¼" (Tip = Hot (+), Sleeve = Ground). Safety Precautions WARNING: To avoid the risk of shock or fire, do not expose this unit to moisture. Do not remove the metal cover; there are no user-serviceable parts inside. -- 6 RA-931 TCS Twin Compressor System CONTROLS & INDICATORS 1Power ­ Switches the unit's power on and off. 2Instrument Input and Level ­ The front ¼" jack is intended for instrument level signals and the level control applies from 0 to 30db of gain to the signal. When using the front instrument jack, the rear inputs on Channel 1 are disconnected. 3Compression Controls (Attack, Release, Threshold, Ratio) ­ These four controls control the amount of compression and its' transient settings. These are continuously active throughout all V3 settings (V3 optimizes ranges for selected application). 4Noise Reduction Controls (NR Thresh, Shelf, NR Active LED) ­ These two controls set the noise reduction characteristics. Users can look at the LED to determine if the current NR is an expander or a gate by viewing it's dimming characteristics. When the LED simply turns on and off the NR is a gate, when it slowly fades in and out it is an expander. As the NR Thresh is increased, the noise reduction will become more sensitive to the signals. With release you want to increase the release time if you hear the compressor pumping, and you want to decrease it if it seems to lack sustain or dynamics. Expansion Basics ­ Expanders are basically the opposite of compressors such that they increase the dynamic range of a signal. Typically these are used to remove unwanted portions of a signal that are quieter than the working material. When there are gaps in the working material, the expander quiets signals beneath the noise reduction threshold to remove any unwanted sound and to increase lower level dynamics. An extreme variant of an expander is a gate, which mutes signals beneath the noise reduction threshold. Opto Basics ­ Optical compression is based on an optical ­ electric package made up of (in it's simplest definition) a light bulb and a photocell. Many classical compressors employed the use of opto-isolators, and it was a key element to their "sound". A properly designed opto based compressor is more musical that most VCA based designs. The opto-isolator acts on signal changes much like the eye reacts to light changes ­ smooth. Based on these characteristics it is felt optical compression works quite well in tracking situations. VCA Basics ­ Solid-state compressors make use of what is called a VCA (Voltage Controlled Amplifier). [. . . ] Take an Insert (¼ inch TRS to 2 ¼ inch TRS) cable and route the "Send" of the TCS into the EQ, then route the output of the EQ into the "Receive" of the TCS. Next boost the frequency bands on the EQ that you wish the TCS to be more sensitive to. The more you change on the EQ the more the TCS will compress that material. Typically the frequency range for sibilance is between 2kHz and 10kHz. - 15 - RA-931 TCS Twin Compressor System ADDITIONAL APPLICATIONS Setting up the TCS for sustain with a guitar amplifier If your guitar amp has a pre-EQ effects loop you can patch the TCS into it. [. . . ]