User manual CROWN DC-300A II

[. . . ] DC-300A II POWER 40 CHANNEL 1 30 20 I0C CHANNEL 2 30 40 20 50 10 50 10 0 0 Some models may be exported under the name Amcron. ® ® Applies only to 120 VAC North American units. © 1996 by Crown International, Inc. , P. O. The DC-300A II is produced by the Professional Audio Division of Crown International, Inc. Trademark Notice: Amcron ® Crown ® Com-Tech ® IOC ® IQ , , , , System ® and Macro-Tech® are registered trademarks of Crown International, Inc. Other trademarks are the property of their respective owners. K80002D9 5/96 YEAR 3 THREE YEAR FULL WARRANTY 3 YEAR WORLDWIDE SUMMARY OF WARRANTY The Crown Audio Division of Crown International, Inc. , 1718 West Mishawaka Road, Elkhart, Indiana 46517-4095 U. S. A. [. . . ] Your amplifier can provide an excellent damping factor of 750 or more from DC to 400 Hz in Dual mode with an 8 ohm load. Higher damping factors yield lower distortion and greater motion control over the loudspeakers. A common damping factor for commercial applications is between 50 and 100. Higher damping factors may be desirable for live sound, but long cable lengths often limit the highest damping factor that can be achieved practically. (Under these circumstances, Crown's ® IQ System ® is often used with Crown's premium Macro-Tech, Com-Tech ® and Reference series amplifiers for easy monitoring and control of units located very near the loudspeakers. ) In recording studios and home hi-fi, a damping factor of 500 or more is desirable. 3. 3. 3 Output Connection Consider the power-handling capacity of your load before connecting it. Crown is not liable for damage incurred at any time due to a load being overpowered. The use of loudspeaker protection fuses is highly recommended (see Section 3. 3. 4). Also, please pay close attention to the precautions in Section 4. 1. Page 12 DC-300A II Power Amplifier 3. Draw a line through the two points with a pencil, and continue until it intersects the "Source Resistance" line. Draw a pencil line from the mark on the "Source Resistance" line through the mark on the "2-Cond. Cable" line, and on to intersect the "Annealed Copper Wire" line. The required wire gauge for the selected wire length and damping factor is the value on the "Annealed Copper Wire" line. If the size of the cable exceeds what you want to use, (1) find a way to use shorter cables, (2) settle for a lower damping factor, or (3) use more than one cable for each line. Options 1 and 2 will require the substitution of new values for cable length or damping factor in the nomograph. For option 3, estimate the effective wire gauge by subtracting 3 from the apparent wire gauge every time the number of conductors of equal gauge is doubled. So, if #10 wire is too large, two #13 wires can be substituted, or four #16 wires can be used for the same effect. filters described in Section 3. 3. 2. Install the input wiring according to the instructions in Section 3. 3. 2. Another problem to avoid is the presence of large subsonic currents when primarily inductive loads are used. Examples of inductive loads are 70 volt step-up transformers and electrostatic loudspeakers. Inductive loads can appear as a "short" at low frequencies, causing the amplifier to produce large low-frequency currents and unnecessarily activate its protection circuitry. Always take the precaution of installing a high-pass filter on the amplifier inputs when a predominantly inductive load is used. A three pole (18 dB per octave) filter with a ­3 dB frequency of 50 Hz is recommended. [. . . ] This is one reason why each unit bears the following label: CAUTION: To prevent electric shock, do not remove covers. sent "UPS ground. " (If the unit is under warranty, you may send it C. O. D. for the cost of freight via UPS ground. ) The factory will return it via UPS ground. Please contact us if other arrangements are required. Always use the original factory pack to transport the unit. 8. 1 Worldwide Service Service may be obtained from an authorized service center. [. . . ]