dm38 TM Table of Contents Important Safety Instructions .................................................................... 2 Introduction..................................................................................................... 3 Installation....................................................................................................... 4 Unpacking................................................................................................. 4 Positioning ................................................................................................ 5 Connections..................................................................................................... 5 Connecting the Mains Supply Cable................................................... 5 Connecting the Loudspeakers .............................................................. 5 Connecting the External Ground ......................................................... 6 Bridging..................................................................................................... 6 Running-in period................................................................................... 6 dm38 Input Selections ............................................................................ 6 Comments on the different dm38 inputs ........................................... 7 Operating Instructions ................................................................................. 8 Electronic Protection and Reliability........................................................ 9 Specifications for the dm38....................................................................... 13 Care and Maintenance................................................................................ 14 Troubleshooting........................................................................................... 15 Service............................................................................................................. 16 Warranty......................................................................................................... 17 Warranty Registration Form ..................................................................... 18 Page 1 dm38 Important Safety Instructions This product shall be connected to a MAINS socket outlet with a protective earthing connection. Weighs 55kg (120 lbs.) per unit. Shipping weight- 85kg (187 lbs.). Never lift the amplifier by yourself. Always use two people to unpack or move the amplifier. Always bend at the knees when lifting. Do not strain your back. Designed for indoor use only, the dm range of amplifiers are not protected against liquids. They should not be exposed to dripping or splashing and no objects filled with liquids, such as vases, should be placed on them. The dm38 is produced in two models designed to operate on different main power supplies. 110V model (Halcro item 411-005): 100 - 120V, 45-65Hz 240V model (Halcro item 411-006): 220- 240V, 45-65Hz The Amplifier's Positive Loudspeaker Terminal can generate Hazardous Live Voltages. To comply with International Safety Standards only use Loudspeaker cables with well insulated terminals such as WBT-0660. Always switch the amplifiers to Stand By or OFF before touching these terminals or adjusting loudspeaker connections. Never obstruct the airflow to the heatsinks. Contains no user serviceable parts. Do not attempt to open any of the amplifier compartments, as this may expose you to dangerous voltages and will void the warranty. All compartments are sealed at the factory. If the seals are broken, the warranty will be void and all service costs will be charged to the owner. Requires F 10A L 250V fuse (if operating on 220 ­ 240V) or F 15A L 110V fuse (if operating on 100 ­ 120V) for continued protection against the risk of fire. Never bypass or use any other type of fuse. The fuse is located on the bottom of the amplifier, near the master ON/OFF switch. Warning do not use any cables longer than 3M TM 120lb CAUTION RISK OF ELECTRIC SHOCK DO NOT OPEN . Page 2 dm38 TM Introduction Congratulations on purchasing the HALCROTM dm38 Stereo amplifier. HALCROTM designs and manufactures the only "Super Fidelity" amplifiers in the world. This "Super Fidelity" amplifier reproduces with better than 99.9997% purity of all tones across the entire audio range. The concept behind the electronic design was to create an amplifier, which did not color the sound with its own electronic characteristics. i.e. recreate the original sound as it was at the time of recording. Please enjoy the HALCROTM audio experience. HALCROTM has enjoyed creating perfect audio reproduction for the world's music connoisseurs. If you desire to contact HALCROTM to give us feedback on your purchase or for general enquiries; please feel free to: email us at admin@halcro.com or phone + 61 8 8238 0807 or fax + 61 8 8238 0852 Page 3 dm38 Installation TM Ensure you have read the Important Safety Instructions section on page 2, prior to installing your HALCROTM amplifier. If you require assistance in the unpacking and installation of your HALCROTM amplifier, please contact your dealer. PLEASE NOTE: When lifting the unit, always use two people. The unit must be lifted by placing your hands under the middle of the bottom compartment. Do not lift the unit under the top compartment. Unpacking 1. Unscrew the 4 knurled knobs at the base of each box. Then remove the upper part of the container by lifting directly upwards, till it clears the top of the amplifier. 2. With an assistant, remove the plastic wrapping and foam pieces, then lift the amplifier from the base of the container. Remove the plastic covering from the unit. Please save it for later use. 3. Move the unit to its final location (see Positioning). White cotton gloves have been provided to prevent marking the amplifier while moving it in to place. Important · · Do not connect any cables as yet. Safely store the packaging so it may be used for future relocation of the unit, and for shipping if service is required. Page 4 dm38 Positioning TM We suggest that the dm38 be positioned as near to your loudspeakers as practical. This will reduce the length of the loudspeaker cable required. The sides of the unit house the heatsinks that are used to dissipate heat. The airflow to these should not be interrupted. Ensure there is at least 12 inches (300mm) clearance around the unit. Connections Connecting the Mains Supply Cable Plug the mains plug into the unit's socket, which is positioned, at the rear, on the base of the bottom compartment, which houses the power supply. Ensure the cable exits to the rear of the unit. Do not plug into the mains outlet. Connecting the Loudspeakers The dm38 has 4 loudspeaker terminals: · 2 x Positive + (Red Bezel). · 2 x Negative - (Black Bezel). All of the pure copper connections are finished with the highest-grade gold plating. · · · · Ensure the positive terminal of the amplifier connects to the positive terminal of the loudspeaker. This will ensure correct phasing of the audio signal. The loudspeaker terminals will accept spade or hook terminals. Only fully insulated terminal are to be used. Ensure the loudspeaker terminals are securely tightened. Do not over tighten or you may damage the terminals. When connecting loudspeaker cables always ensure the conductive surfaces are not touching each other. DO NOT SHORT-CIRCUIT THE TERMINALS. There maybe high voltages present at the loudspeaker terminals, which can be hazardous if touched. Always ensure the unit is switched to OFF or STANDBY mode when connecting or disconnecting loudspeakers. PRIOR TO TURNING ON THE UNIT, PLEASE CONTINUE TO READ THE FOLLOWING PAGES. Page 5 dm38 Connecting the External Ground TM The dm38 is equipped with a separate ground terminal. The ground terminal has a green bezel and is located under the power supply. This terminal may be used to reduce hum and ripple in some circumstances. Bridging You may bridge the HALCROTM amplifier, for details please email us at service@halcro.com A bridging kit is available through HALCROTM. Running-in period The dm38's electronic running-in period is completed at the factory. running-in period is not required. dm38 Input Selections The dm38 has three switch selectable inputs, each having a separate input socket. Both the input sockets and switch are mounted on the top rear panel. Input Styles Balanced voltage input Un-balanced voltage input Current-mode input Required output source impedance Low impedance. e.g., standard preamplifier or CD player etc. Low impedance. e.g., standard preamplifier or CD player etc. Very high: "infinite." Input socket XLR Input impedance 10kohms + 10kohms A further RCA RCA 10kohms 60ohms Page 6 dm38 Comments on the different dm38 inputs TM The balanced voltage input or current-mode inputs are most desirable for minimizing earth loop generated mains hum and ripple, or high frequency interference. Sources with current-mode outputs are rare and are most likely to have an RCA output socket. The advantages of this source are that: · · Earth loop generated mains hum and ripple are minimized. Cable, plug and socket generated interference is minimized (from poor connections which may be affected by sound vibration for example). The unbalanced input is quite satisfactory so long as earth loop generated mains hum and ripple is not a problem. All or some of the input sockets may have active sources simultaneously connected to them. The selector switch selects the input to be amplified. Page 7 dm38 Operating Instructions · TM · · · · · · Once the external cables are connected to the unit, ensure the master ON/OFF switch is in the OFF position. (The master ON/OFF switch is situated on the base of the lower compartment, near the mains socket on the unit. You will have to kneel on the floor at the back of the unit to access the switch). Plug the mains plug into a mains outlet. Switch the master ON/OFF switch to ON. The LEDs on the front and rear of the amplifier will glow red. This indicates that the unit is in standby mode. In this mode a small current is drawn from the mains supply, but the unit will not drive the loudspeakers. Press the mode switch once to switch between Standby and ON modes. (The mode switch is a small pressure switch accessed when standing at the front of the unit. It is located under the bottom lip of the top compartment. When the amplifier has been switched to ON, the LEDs on the front and rear will glow green. The amplifier is now ready to drive your loudspeakers. It is recommended that the unit be switched to standby when not in use. It is safer to turn the mains power off when not using the dm38. However the amplifier may be left on in the standby mode for prolonged periods. If you wish to turn the mains power off, the amplifier has a very minimal warm up period. Page 8 dm38 Electronic Protection and Reliability TM Electronic protection circuitry and amplifier reliability, alas, is an area sadly neglected by many high-end audio amplifier designers. HALCROTM has paid a great deal of attention to this area. Components Our components are selected for not only performance but reliability as well, for example: · All Halcro electrolytic capacitors are rated at a minimum of 105 degrees C instead of the usual 85 degree rating. The operational life of electrolytic capacitors is severely shortened at temperatures near the maximum temperature rating. This is shown in the table below. All Halcro integrated circuits are at least "industrial grade" rather than the usual "commercial grade". Industrial grade components are rated at least from ­40 degrees C to +85 degrees C whereas commercial grade components are only rated from 0 to 70 degrees C. In addition, the electronic specifications of industrial grade components are superior to commercial grade. Electrolytic capacitor temperature rating Mean lifetime at 40 degrees Centigrade Mean lifetime at 85 degrees Centigrade Mean lifetime at 105 degrees Centigrade · 85 C (most 50,000 Hours 2,000 Hours (0) commonly used) 105 C (used in 180,000 Hours 8,000 Hours 2,000 Hours Halcro amplifiers) Typical data from a highly respected manufacturer. Considering that most amplifiers run at significantly elevated temperatures, it can be seen from the table, that the Halcro high temperature rated capacitors are highly advantageous compared to the standard 85 degree rated devices. Page 9 dm38 Output current limiting TM In terms of maximum available output current, there are basically 3 amplifier type options: a. An amplifier with a reasonable limit placed on the maximum available output current. b. An amplifier with no limit placed on the maximum available output current, which will either blow a fuse or self destruct if excessive current is drawn, for example through a dead short. c. An amplifier with a very high limit placed on the maximum a ...