Harman Kardon CIT22 Owners Manual - Page 5

4 timizatiOvS0101176:C6rtant Voila a An amplifier's power capabilities are in almost direct proportion to the quality (and cost) of the power supply, power transistors and heatsink/chassis assembly. Since these three component groups dictate the maximum continuous power of an amplifier, they must be designed to handle all possible speaker loads, from 16 ohms all the way down to 4 ohms or below. Because you only own speakers of one impedance rating, in most cases either 8 or 4 ohms, you are forced to pay the penalties of compromise in either reduced capabilities or sound degradation. Speakers are not simply resistive loads. Instead they are complex and reactive, drawing disproportionately large "in-rush" currents in reaction to transient voltage signals. Because music is dynamic, with multiple instantaneous peak power demands, the speaker is constantly bombarded with short transient voltage drive signals and constantly drawing short "in-rush" currents. The overall long term voltage and power draws are not significantly higher than those of a resistive load. But at any given moment, peak "in-rush" currents must be delivered far in excess of the average demands. If these cannot be supplied by an amplifier design, distortion and reduced dynamic range result. Either current limiting could be imposed (which degrades sound quality when current demands trigger the limiting circuit) or, to avoid current limiting, the design had to be made to withstand the great power draw of 4-ohm loads. Unfortunately designs which could deliver continuous music amplification into 4-ohm speakers ended up penalizing 8-ohm speaker owners by delivering 33% to 50% LESS POWER! The Citation 22 and Citation 24 provide an elegant, affordable solution which optimizes their current and voltage for both 4 and 8-ohm speaker loads while actually improving sonic performance and yet does not overload the average music lover's budget. The solution is individual optimization for 4 and 8-ohm loads in your Citation Power Amplifier. For 8-ohm speakers, this means the amplifier can deliver an output voltage high enough so that the speaker can draw the current necessary for the amplifier's rated power output. Current needn't be limited since the 8-ohm impedance draws a predictably nominal amount. For 4-ohm speakers (which tend to draw more current), maximum voltage is reduced, causing the load to draw the correct amount of current for your amplifier's rated output. By designing so that optimum 8-ohm and 4-ohm power outputs are the same, Citation engineers have been able to realize very large cost savings, since the amount of heat dissipation in each mode is also the same. Heat sinks, power transistors and chassis can all be chosen based on common operating needs and 4-ohm loads are no longer the "worst case." An added benefit is higher power output for bridged-mono operation into 8-ohm loads, by simply selecting the 4-ohm (lower voltage range) mode, engaging the Bridged-Mono switch, and following the instructions on page 8.