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Resumen del manual
All rights reserved. CONTENTS Specifications........................2 Additional Parts List...................5 Functional Diagram....................2 Operation............................6 Installation ..........................3 Notes on the Circuitry..................6 Component List.......................4 Additional Information .................7 Parts Placement Diagram...............4 Warranty and Service Policy.............8 Schematic Diagram....................5 INTRODUCTION The DH100 Preamplifier must surely represent the highest quality per dollar of any audio product manufactured in this decade. Initial response to the performance of this unit, during ^•development and testing, has been unusually enthusiastic. The ^Puality arises from the meticulous application of good engineering practice — respect for the fragility of the audio signal; simple, straightforward circuitry; careful component selection and testing; generous circuit card topology, and use of precision tolerances where they contribute significantly to performance. The design philosophy of the DH100 exemplifies simplicity INSTALLATION 1.0 MOUNTING The DH100 Preamplifier is intended for table top or shelf mounting. No rack mount provision is made. It is important that the Preamplifier not be placed directly on top of power amplifiers or other high-current devices; otherwise hum fields may be intercepted by the Preamplifier and heard in the loudspeakers. It is not necessary to provide much ventilation to the DH100, however it is a good rule to allow air circulation around any electrical device. 2.0 POWER CONNECTIONS Preamplifiers are supplied with transformers for standard United States line voltage. Wide variations are tolerated, between 100 volts and 130 volts. For overseas use, an International transformer is available which accommodates line voltages between 200 and 260 volts (Hafler Part Number TA127). It is recommended that the Preamplifier be connected directly to a wall or floor outlet, and not to an extension cord, •articularly if the Preamplifier is being used to switch a power mplifier. 2.1 ACCESSORY OUTLETS Two outlets are provided, both controlled by the Preamplifier POWER switch, and adequate to operate a DH-120, XL-280 or DH-500 power amplifier and a tuner or tape transport. In some countries the AC convenience outlets are not provided. 3.0 OUTPUT CONNECTIONS Output jacks are labeled ‘L’ for left channel and ‘R’ for right channel. 3.1 LINE OUTPUT These jacks connect to the power amplifier input jacks of your system. The signals at the Line Outputs are affected by the BALANCE, VOLUME, BASS, and TREBLE Controls and the MUTING circuit. Note that the DH100 is not meant to drive audio cables longer than six feet. 3.2 RECORD OUTPUT CONNECTIONS These are signal outputs to a tape recorder, for making recordings from PHONO, TUNER, and AUX inputs. You will use a ‘line’ input on your tape recorder (not a microphone input!) and adjust the tape input level controls for a good meter reading. Note that a tape recorder or other signal source connected to the TAPE input of the DH100 may not be recorded. The MUTING circuitry does not protect the RECORD outputs. 4.0 LINE INPUTS A LINE LEVEL input is a general purpose input (as opposed ^Wo an equalized input, like PHONO) which expects a standard nominal voltage for proper operation. Most equipment for use with a preamplifier — tuners, tape decks, etc. — have an output that more or less conforms to this standard voltage. and economy. To achieve this we have provided only those functions that are primary to a good audio system, and we have been most careful to see that the integrity of the electronics conforms to a high standard. Although it might be thought that a low-cost preamplifier would not find its place among higher-priced components, the DH100 may change such thinking, for its ability to preserve the detail rendered by expensive cartridges, power amplifiers and loudspeakers is most impressive. We invite you to compare its performance with the highest-rated preamplifiers, and to tell us of your findings. All the line level inputs, TUNER, AUX (Auxiliary), and TAPE, in the DH100 have the same signal capability and may be used for other than their labelled purpose. For instance, a tape recorder or video sound source may be connected to any of these inputs. The ‘sound’ output from most home computers may be connected to these inputs as well (see ADDITIONAL INFORMATION.) You must observe Left and Right Channel symmetry (ie: connect Left to Left and Right to Right) between the DH100 and any signal source connected to it. The PHONO, TUN ER, and AUX switches are self-cancelling; that is, the last button pushed releases the previous button. Note, however, that the TAPE switch is not part of this selfcancelling group and that it supersedes any other input you may have selected. Be certain to check the position of this switch if your preamplifier sometimes seems ino...