User manual YAMAHA CP20E

[. . . ] · Connect this unit's power cord only to an AC outlet of the type stated in this Owner's Manual or as marked on the unit. Failure to do so is a fire and electrical shock hazard. · Do not scratch, bend, twist, pull, or heat the power cord. A damaged power cord is a fire and electrical shock hazard. [. . . ] See "Turning On the Power" on page 11 for more information. B POWER indicator This indicator lights up when the CP20E is turned on. C PROTECTION indicator This indicator shows the status of the protection system. See "Protection System" on page 11 for more information. D TEMP indicator This indicator lights up if the temperature of the CP20E's heatsinks exceed 85 degrees Celsius. Note that this indicator only serves as a warning. It does not indicate operation of the protection system. E Level controls These controls are used to adjust the volume level of each channel. Since the gain of each amplifier channel is fixed, these controls work by attenuating the input signal from between ­ dB and 0 dB. They are detented controls, which means they can be set to any one of 31 positions. Detents protect against accidental adjustment, allow repeatable setting, and make it easy to set both channels to the same volume. Usually these controls are set to maximum and volume levels are controlled from the source equipment, typically a mixer. F CLIP indicators These indicators light up when a channel's output signal distortion exceeds 1% (i. e. , clipping). Output signal clipping is usually due to excessive input signal levels. If a channel's output signal does clip, that channel's limiter circuit is activated to prevent further signal distortion. It's okay for a CLIP indicator to light occasionally, but if it lights frequently, the LEVEL control should be turned down a little. G LEVEL indicators These indicators show the output signal level of each channel. The CP20E can also be placed horizontally on the floor or a suitable table. The CP20E uses a variable-speed low-noise fan to regulate the system temperature, which draws air in from the front and expels it from the rear. For correct operation, it's important that the air flow at the front and rear of the CP20E is not blocked or restricted in any way. If the CP20E is mounted in a portable rack with removable front and rear covers, be sure to remove the covers before using the CP20E. Connecting Inputs Warning: Turn off all equipment before making any connections. The inputs for each CP20E channel comprise of one 1/4" phone jack and one XLR-3-31-type connector. Both connectors are electronically balanced, although they can also be used with unbalanced sources. For optimum performance, use only quality screened cables for input connections. Under no circumstances should you connect more than one sound source to the same channel. The inputs are designed to work with line-level sources, such as mixers, CD players, and other professional audio equipment. The 1/4" TRS (Tip-Ring-Sleeve) phone jacks are wired as follows: sleeve­ground, tip­hot (+), and ring­cold (­). TRS phone plugs should be wired as follows. Tip (hot) 1/4" TRS phone plug Ring (cold) Sleeve (ground) To connect an unbalanced source to an INPUT jack, connect the ring (cold) terminal to the sleeve (ground) terminal, as shown. Tip (hot) 1/4" TRS phone plug Ring (cold) Sleeve (ground) The XLR-type connectors are wired as follows: pin 1­ground, pin 2­hot (+), and pin 3­cold (­). [. . . ] When the CP20E is turned off, the output relay opens immediately, disconnecting the speakers, and preventing unwanted sound as the CP20E shuts down. If during normal operation the protection system detects that a heatsink has overheated or a DC offset is present at a speaker output, the output relay opens, disconnecting the speakers, and the PROTECTION indicator lights up. Once the heatsink has cooled down, or the DC offset removed, the protection system automatically closes the output relay, reconnecting the speakers, the PROTECTION indicator goes out, and normal operation is resumed. Heatsink overheating is typically caused by inadequate ventilation and it's important that you investigate the cause and resolve it (see page 13 for more information). [. . . ]