Hafler DH-110 manual

each socket, the board is marked to indicate the side of the hole on which the center mounting tab should be positioned, so that it will be soldered to the widest part of the circuitry on the back side. Leave the phono plug in the socket while bending and soldering is completed. If you do not bend the center tab quite flat against the board, it is easier for solder to flow under the tab for a good connec- tion. Solder both outer socket lugs first (they need not be bent over), and then the center tab on each socket. At J9 be careful that a solder bridge is not made between the center contact and the adjacent circuit track. Be sure holes Q and S are not filled with solder when installing sockets J 11 and J 1 1 1. A wooden toothpick will keep them open.

14 0 Select the two right angle 15-pin plugs, and install their shorter pins at locations J22 and J24 at the top of the board, so that the bent pins point toward the upper edge. Be sure these sockets are tight against the board, and make certain that every pin connec- tion is properly soldered. Examine each connection closely to make sure there are no solder bridges between the tracks.

150 Prepare a 1” piece of green wire, and form it into a ½” wide “U”. This wire connects on the back of the board between holes A and B. Allow this wire to sit a bit above the board, as it is a jumper which you may wish to remove at some future date, if you install a pre-preamplifier for a moving coil cartridge. After soldering be sure you cut off any excess wire on the front, so it cannot short to the input socket.

160 Prepare a 1” piece of red wire, and form it into a “U” as before. Connect it in like manner to holes C and D on the back of the board.

170 Select the two 10,000 pF capacitors and install them on the front of the board at locations C1 and C101.

180 Select the 2 long bright screws, the 2 lockwashers, and two of the spacers. Place a lockwasher over each screw first, and insert the screw from the back

(circuit side) of the board into one of the mounting holes next to the rear jumpers. Add a spacer on the components side, and tighten it. Set the completed board assembly aside.

19 0 Select the back panel, the AC line cord, and the plas- tic strain relief. Separate the two conductors at the end of the cord for 2”. Cut 3/4" off of one conductor. Strip both ends the usual ¼", and tin the strands to secure them. Six inches from the longer end make a sharp V in the cord by bending it back on itself. Install the strain relief as shown in the drawing. The small end of the strain relief is nearest the stripped ends. Crimp the two halves of the strain relief together around the cord with heavy pliers to par- tially form it before insertion into the back panel.

Then grip the larger portion of the strain relief with the tips of the pliers, squeeze it tightly, and insert the end of the cord and the strain relief through the panel hole from the outside. Note that the hole has a flat on one side, and the strain relief is installed so that the cord is horizontal.

This is the most difficult step in the kit. Patience, and a friend’s help, if available, will make this job easier. Safety requirements dictate that this be a tight fit. Some persons might find it helpful to bolt on a side piece (with the flanges out) to add rigidity to the back panel, as well as a support to press against the back panel while you squeeze the strain relief and pull the line cord through. The fixture snaps into pos- ition when it is fully inserted. Remove the side piece if you attached it.

20 0 Select the power transformer and 2 sets of #6 hardware. Install the transformer next to the line cord so that the leads are in the lower comer below the strain relief.

21 0 Select the 4 AC sockets. Snap these into the back panel holes from the outside.

220 Select the PC-12 circuit board assembly and the 2 flat cable interconnecting assemblies. Plug one end of each cable onto the pin connectors at the top of the board so the cables extend past the back of the board. The marked edge of the cable is not signifi- cant. Now check socket J1 to make sure it does not contact the stub of wire at hole A.

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.