User manual PEAVEY CS 1200X

[. . . ] A A lntended to alert the user to the presence of uninsulated "dangerous voltage" within the product's enclosure that may be of sufficient magnitude to constitute a risk of electric shock to persons. Intended to alert the user of the presence of important operating and maintenance (servicing) instructions in the literature accompanying the product. CAUTION: Risk of electrical shock - DO NOT OPEN!CAUTION: To reduce the risk of electric shock, do not remove cover. Refer servicing to qualified service personnel. [. . . ] This voltage then becomes the level at which the associated mixer must operate in order to drive the amplifier to full output. The CS 1200X sensitivity controls are calibrated in decibel volts values rather than RMS voltage (usually listed in typical mixer specs), and as such are more useful, since most contemporary mixers employ LED arrays to indicate mixer output levels and are calibrated in decibel volts. Knowing the power amplifier sensitivity rating in decibel volts will allow the mixer operator to know the status of the power amplifier by noting which LED on the mixer is peaking. Obviously, the LED labeled the same or closest to the sensitivity rating of the power amplifier will indicate full power output of the system. Operation at levels above this rating will cause the power amplifier to clip (produce distortion) unless the associated amplifier has a compressor/limiter to minimize this distortion. Patent #4, 3 l&053), is included in the CS 1200X, and the advantages should be obvious. Without DDT, the sound engineer must "ride gain" on the mixer or employ an outboard limiter in order to prevent amp clipping. With DDT the sound man can relax more and enjoy the "ride. " For maximum mixer headroom (which in 14 turn really is maximum compression range), the input sensitivity control should be set at Ihe maximum clockwise setting. This is always the best setting to start with. If, however, the amptifier is used in a small club, church, or studio application where the full-output capability of the power amplifier is seldom needed, or there is no need for large amounts of headroom capability, the full-clockwise setting may not be the wisest choice. Then too, such applications often require low system noise. In this case, it is possible to reduce the overall system noise at the expense of headroom capability by increasing the power amplifier sensitivity as in the following example: if, instead of a sensitivity rating of +3 dB V, we adjust the CS 1200X to a rating of + t2dB V, overall system noise wilt be improved by 9 dB, and the system headroom will decrease 9 dB. DDT'lM COMPRESSION The CS 1200X is a compact and powerful amplifier that features a new type of dynamic compression. This compression system enables the user to maximize the performance of the amptifier/speaker combination. We have determined through much research that the compression circuitry should prevent the power amplifier from running out of headroom (clipping) and should be as simple to operate as possible to avoid undue complication for the user. This compression system is activated by our exclusive DDT compression circuitry, which senses conditions that might overload the amplifier and activates compression when clipping is imminent. In other words, compression takes place whenever signal conditions exist that prevent the amptil`iers from faithfully reproducing the input signal. In this case, threshold is clipping itself, and no specific threshold control is provided. This technique effectively utilizes every precious watt available from the power amplifier. Techniques using external compressors/limiters are usually less effective, severely limit output power levels and require additional controls, and add complexity to an already complicated system. The DDT system is an automatic, hands-ofl`approach to Ihe problem of amp clipping. Because of the dynamics of music and vocals, it is quite common lo activate the DDT compression circuitry almost constantly during a high-level performance, since this is what it was designed to do: i. e. , to maximize the dynamics available from the amplifier within its power-output capabilities regardless of power supply/AC line voltage variations and load impedance selection. [. . . ] For more information on grounding, write for our free booklet "Shock Hazard and Grounding. " Power supply cords should always be handled carefully. Never walk or place equipment on power supply cords. Periodically check cords for cuts or signs of stress, especially at the plug and the point where the cord exits the unit. The power supply cord should be unplugged when the unit is to be unused for long periods of time. [. . . ]