Hafler DH220 free download

File name Hafler-DH220 pwramp.pdf

THE POWER AMPLIFIER INSTRUCTIONS for OPERATION and KIT ASSEMBLY CAUTION: IF THE SPEAKER FUSES BLOW, SOME DISTORTED SOUND CAN BE HEARD. THEREFORE IF AMPLIFIER MALFUNCTIONS, ALWAYS CHECK FOR BLOWN FUSES FIRST. THE DAVID HAFLER COMPANY 5910 Crescent Boulevard, Pennsauken, New Jersey 08109 Hafler DH-200 Power Amplifier serial number in all communications INTRODUCTION The Hafler DH-220 is a two channel audio power amplifier designed to the very highest performance standards. It is available either as a kit, or fully assembled. Its 115 watt per channel power rating is sufficient for driving all loudspeakers in home applications, and its design assures extremely low distortion of all types. A combination of high performance, dependability, reliability, and moderate price is in the Hafler tradition of using the very latest technology to provide outstanding value. The DH-220 circuit is a refinement of the DH-200 design, a Hafler landmark which has achieved worldwide recognition, and has elicited glowing reviews since its 1979 introduction. As in the DH-110 preamplifier, particular attention has been paid to component quality, using polypropylene or film capacitors wherever feasible, for example, for superior sound. Combining the latest power MOSFET technology with uniquely simple and effective circuit topology reduces distortion of all types, and at all power levels, over the full audio frequency spectrum, to the vanishing point. In addition to its pace-setting performance achievements, the conservative mode of operation accomplishes a new high in long term reliability and exceptional resistance to abusive operating conditions. This is one of the direct benefits of MOSFET utilization in overcoming a serious limitation of conventional transistors - their tendency to self-destruct under other than normal operating conditions. So rugged is the DH-220 that it can deliver more than ten amperes into a short circuit! The speed - measured as the slew rate - of this design delivers unmatched transient linearity, revealing the most delicate shadings, textures and nuances of the music, surpassing the capabilities of the most revealing loudspeakers and cartridges by a wide margin. Coupled with its unconditional stability, and ability to deliver adequate power into any loudspeaker load, the result is absolute freedom from listening fatigue. The longer you listen to this phenomenal amplifier, the more certain you will be that you could not have made a better choice. The oversized power transformer and bridge rectifier; the massive heat sinks; the conservative operating levels of the MOSFET output devices - all are evidence of the design efforts to achieve exceptional reliability simultaneously with state of the art sonics and specifications. And this circuit is convertible to a high power monophonic amplifier with comparable stability and specifications. The fully complementary, symmetrical push-pull circuit, which is direct coupled throughout (except at the input