If a Problem Arises

If neither LED lights when you first turn on the power switch, turn the unit off immediately. Check the fuse. Check the polarity of the LEDs. Check the power transformer wiring for proper connections for your line voltage. Look for a short caused by a stray strand of wire, or for a solder splash on the circuit board. A print of the circuit pattern in this manual enables you to check out a doubtful connection which might include a solder bridge.

If there is no audio output, is the monitor switch OFF? Is the EPL switch OUT? Is the wiring of the phone jack cor- rect? Are the plugs seated properly on the flat ribbon cables-not offset by one pin? Is the Phono pushbutton switch in the correct position? Check the PC-12 for a solder splash between the circuit paths. A sharp knife can correct that.

If there is noticeable hum; turn off the unit and reverse the line cord. Make sure the preamp is not too close to the power amplifier (or that the turntable is not too close, either). Check for a defective connecting cable, or turn- table ground wire. Inside the preamp, the screws for the thumb nut ground connections must be tight, both to the PC-12 board, where the lockwasher under the screw head contacts the circuit ground, and to the back panel, where the lockwasher must break through the paint to the metal. Also, the PC-14 rear bracket mounting screw near the power transformer must be tight for a good ground con- tact.

A spare 1/10 ampere slo-blo fuse is supplied with the kit. A larger value fuse will not provide protection in the event of a fault. If the replacement fuse blows, the unit should be returned to the factory for competent service.

AC LINE CONNECTIONS FOR OVERSEAS USE

The power transformer supplied with the DH-110 has dual tapped primary windings. By arranging these two windings in various series-parallel combinations, line vol- tages of 100,120,200,220 and 240 volt 50/60 Hz lines can be accommodated.

The diagrams below show the connections for altema- tives to the 120 volt connections shown on the pictorial diagram. When connected for 200-240 volt lines, the line fuse should be changed to l/16 ampere (60 mA) slo-blo.

IOOV

2 4 0 V

ma--//---K/W d B L A C K

DH-110 specifications

The Hafler DH-110 is a revered preamplifier recognized for its remarkable performance and versatility in the audio industry. First launched in the early 1980s, the DH-110 developed a reputation for delivering high-quality sound reproduction, making it a favorite among audiophiles and home theater enthusiasts alike.

One of the key features of the Hafler DH-110 is its dual-mono design, which ensures that the left and right channels are processed independently. This configuration helps to eliminate crosstalk and maintain clarity, particularly in complex musical passages. The DH-110 employs high-quality components throughout its circuitry, including metal film resistors and film capacitors, which contribute to a clean signal path and minimize distortion.

The preamplifier offers a wide range of inputs, accommodating various sources such as turntables, CD players, and tape decks. The inclusion of a phono stage for both moving magnet and moving coil cartridges is a standout feature, allowing vinyl enthusiasts to achieve optimal sound quality from their records. This versatility is enhanced by selectable input sensitivity, ensuring that each source can be tailored for the best performance.

Additionally, the DH-110 supports tone control, featuring bass and treble adjustments that enable users to dial in their desired sound signature. While some audiophiles prefer a pure, unaltered sound, the option to adjust bass and treble can be appealing for customizing the listening experience.

The design of the DH-110 exudes classic elegance, incorporating a simple yet functional aesthetic with a robust chassis designed to minimize resonance. The front panel includes clearly labeled knobs and buttons, ensuring ease of use during operation.

In terms of connectivity, the Hafler DH-110 includes both tape monitoring loops and multiple outputs, allowing seamless integration into existing audio systems. The preamplifier can be connected to various power amplifiers, delivering a balanced audio experience that meets the demands of both casual listeners and serious audiophiles.

In conclusion, the Hafler DH-110 is a testament to quality engineering, offering superior performance, versatility, and user-friendly operation. Its combination of advanced technologies, including a dual-mono architecture and high-grade components, make it a timeless choice for anyone seeking to enhance their audio experience with a reliable preamplifier. Whether for home theater use or critical listening, the DH-110 continues to be a solid investment for audio enthusiasts.