User manual HAFLER XL-600

[. . . ] The XL-600 uses a quiet, continuously variable speed fan to cool the entire chassis Cool air must circulate freely into the side vents and out the rear vent. Allow at least one inch on each side, and at least three inches to the rear for unimpeded flow. AC Line Connections and Switching NOTE: BE SURE YOUR AMPLIFIER IS WIRED FOR YOUR LOCAL LINE (MAINS) VOLTAGE BEFORE CONNECTING AC POWER! 2 The XL-600 is normally wired for use on 120 Volt 60 Hz power lines. If your line (mains) voltage is different, you will require the optional export multi-voltage transformer, which accommodates voltages from 100 to 240 VAC, at 50-60 Hz. [. . . ] If you hear a loud sharp "thump" from the speakers, or no sound is heard after the relay engages and signal is applied, consult the section "In Case of Difficulty" at the end of this manual. Mono / Stereo Switch This switch should be left in the STEREO position, unless bridged operation is desired, as outlined in the section "Monophonic Operation". Speaker Fuses The fuse holders on the back panel provide a measure of protection against excessive power output to the speakers. A spare pair of 10 ampere fast blow fuses has been included, for testing purposes, or high power applications. IF THE MANUFACTURER OF YOUR LOUDSPEAKER RECOMMENDS A SPECIFIC FUSE VALUE, OBTAIN TYPE 3AG OR AGC AGC 3AG FUSES AND INSTALL THEM IN THE BACK PANEL FUSE HOLDERS. THE EXCELINEAR CONCEIT The purpose of the Excelinear technology is to detect and then minimize all possible non-linearities, or distortions. This is done by subtracting the output of the amplifier from its input, A perfect amplifier would have no residual signal. The test described below enables you to hear only the difference signal- the sum total of all audible 6 amplifier distortion, It will already be exceedingly low on the XL-600 as you receive it because each amplifier channel has been factory adjusted using a typical loudspeaker load. But when the XL-600 is connected to your own speakers, careful readjustment by a technician may yield some slight improvement. The test is as sensitive as one's hearing, and much more precise than available measurement technology because it is able to reveal the audible effect of all distortions - even those which have not yet been identified or quantified!This is a very useful amplifier comparative technique which supplements conventional distortion measurements. With the XL-600, the total of all residual distortion products will be on the order of 60 dB or more down across the audio band - a substantial improvement over other amplifiers, where 40 dB figures are among the best. Only a few amplifiers cannot be subjected to this test: those which are phase inverting, and those which have floating (not grounded) outputs, or those which cannot tie together the output grounds. The XL-600 provides a unique internal adjustment for "fine tuning" each channel when it is connected to your speakers. This "tweaking" may fairly be described as significant only to those persons with "golden ears". The rest of us who simply wish to indulge ourselves with fine sound need not be concerned with this consummate pursuit of perfection. The range of adjustment provided is within the defined operating specifications of the amplifier. Misadjustment will not damage or impair the performance of either amplifier or speaker. The region of change is several octaves above the range of human hearing. [. . . ] If no sound is heard once the relay engages and an input signal is applied, check all input and output connections, as well as the back panel speaker protection fuses. In addition to the internal 15 ampere line fuse, there are four 10 amp rail fuses, None of these internal fuses are intended to be user replaceable, and a blown condition usually indicates a need for professional service. FACTORY SERVICE & LIMITED WARRANTY If you encounter any difficulty or have any questions concerning your XL-600 amplifier, please call our Customer Service Department weekdays, 8 am to 3:30 pm Mountain Standard time, at 602-967-3565. All units being returned (regardless of warranty status) must receive a Return Authorization (RA) Number. [. . . ]