23[7 Select the 6 black 5/8"screws, the 6 spacers, and 6 small nuts. Insert the screws from the outside of the back panel at the locations nearer the center of the panel (not in the end holes marked “Grounds”). Install a spacer on each screw and tighten them. Place the PC-12 assembly in position so that its two screws pass through the end holes. Install the nuts on the black screws, and tighten them.

240 Select the 2 small nuts and the 2 knurled thumb nuts. Install a nut on each of the Ground screws, making sure the lockwasher surface is tight against the panel. It must cut through the painted surface to make a chassis ground connection . Then add the thumb nuts.

25 0 With a pair of pliers, carefully twist the 8 lugs on the AC outlets counter-clockwise l/6 turn, or about 60º. This will enable a wire to be passed horizontally through these lugs.

26 0 Cut a 2¼” piece of the bare buss wire. Slide it through lug #2 of AC outlet B and connect it to lug #l and to lug #3. Solder lugs 1 and 2.

27 0 Cut a 3%” length of bare wire. Slide it through AC outlet lugs #6 and #7, and connect it to lug #5 and to lug #8. Solder lugs 5,6 and 7.

28 0 Prepare a 13” length of white wire. Connect one end to AC outlet C, lug #3. (S-2). Place this wire over the top of the transformer.

29 0 Prepare a 13” blue wire. Connect one end to outlet D lug #4. Place this and the following wire over the transformer.

30 0 Prepare a 12½” length of yellow wire. Connect one end to outlet D lug #8.

31 0 Select the two side pieces, the rubber grommet, and 4 sets of #6 hardware. Install the grommet in the side piece location adjacent to the power transformer when the flanges bend towards the outside of the unit. Before bolting this piece in position, pass the line cord through the grommet from the outside, and under the transformer. From the inside thread the 3 wires which come from the AC outlets and over the top of the transformer out through the grommet. Fasten both side pieces to the back panel.

32 0 Connect the shorter line cord conductor to outlet D lug #8. (S-3). Connect the other conductor to lug #4. (S-2).

33 0 Join the front and rear halves of the preamp so that the tabs on the main board rear bracket ate outside the side pieces. Select 2 sheet metal screws and fas- ten the bracket tabs to the side pieces.

34 0 Plug the two flat wire assemblies onto the pin con- nectors on PC-14.

35 IJ Prepare a 1%” piece of white wire. Connect one end to the rear lug of the power switch. (S). Connect the other end to eyelet Y of PC-14, nearest the fuse. (S). All eyelet connections should be soldered on the bottom of the board for secure connections.

36 q Select the white wire from the tear grommet. Con- nect it to eyelet W on PC-14. (S).

37 0 Select the blue wire from the grommet. Connect it to the side lug of the power switch. (S).

38 0 Select the yellow wire. Connect it to eyelet T on PC-14. (S).

The transformer leads may be shortened as desired for neatness, but if there is any possibility that the transformer may be connected for a different line voltage for use out- side the USA, be sure to leave each lead long enough for any alternative connection. We suggest that these leads be made just long enough that they can be twisted together for neatness, and placed outside the end piece where they can be later secured with a wire tie.

39 0 Connect the Red-Yellow lead to eyelet A in the tear comer of PC-14. (S).

40 0 Connect the two Red leads to eyelets B and C along the rear edge of the board. Solder both.

For 120 volt wiring as in the USA, the following lead con- nections are to be used. Refer to the alternative line vol- tage diagrams in the manual for other line voltages.

41 0 Connect each lead as follows and solder: Brown/White to eyelet D Black/White to eyelet E

Brown/Red to eyelet F Black/Red to eyelet M Brown to eyelet R Black to eyelet S

42 0 Connect the short black wire from the forward lug of the phone jack to eyelet G2. (S).

43 0 There are two groups of wires connected to the phone jack under PC-14. The red and green wires which connect to lugs 2 and 3 (these ate the lower lugs, adjacent to the circuit board edge) are to be connected to the upper (left channel) holes P and Q on the back panel circuit board PC-12, adjacent to the line outputs. Make certain you have the correct group. The black wire is not connected to the board. Instead, keep it twisted with the other wires until it is close to the board, then wrapped tightly around the red and green pair. Make sure no bare wine pro- trudes from the black insulation. Connect the red

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Hafler DH-110 manual

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.