Hafler DH-110 Stereo Amplifier User Manual
Contents
1. 15 12 RM024 RP022 RM0 RCO RCO RCO RCO RC RCO RCO RM SPI SRI SRI SPI SAI 028 18 RM024 15 RM025 24 RM024 RM025 RM044 RM035 29 RC023 RC029 RC023 RC042 RCO44 44 RC038 6 46 RC029 RCO RC043 17 23 34 B 6 SP111 SAI SLI 16 12 Rii channel corresponding values have designations above 100 Cl C2 C4 cs C6 C7 C8 C9 C10 Cll CI2 C13 C14 C15 C16 C17 C18 C19 C20 c21 c22 C23 C24 C25 C26 C27 C28 C29 C30 C3l C32 c33 C34 c35 CM c37 C38 c39 C40 C4l DI D2 D3 10 mE polypropykne 50v 120 pF polypropylene 50v 220 pF polypropykne 50v 10nF polypropylene 50v 22 mfd NP ekctmlytic 50v 220 mfd NP ekctmlytic 10 220 mfd NP ekctrolytic 10 nF polycarbonate 50v nF polycarbonatc 50v 25 nF 1 poiypropykne 50v 6 8 nF 1 polypropylene 50v 1000 mfd NP ekctrolytic 1 5 nF polypropykne 50v IO nF polypropylene 50v 22 mfd NP ekctrolytic 50v 470 mfd low ESR electrolytic 25v 470 mfd low ESR electrolytic 25v 470 nF polypropylene 50v 68 pF polypropylene 50v 10 nF polypropylene 50v 22 mfd NP electrolytic 50v 470 mfd low ESR electrolytic 25v 470 mfd low ESR electrolytic 25v I 5 nF polypropylene 50v nF polycarbonate 50v 47 nF polycarbonate 50v 470 nF polycarbonate 50v 4 7 mfd NP ekctrolytic2. EPL SEND wae B je o 36 5 OUTPUT B OUTPUT VIA PHONE J ACK il a 9 9 23 ava LO x PHONO 1 o3 DO C2 d esce L pe DAL 0 C17 O 14 nH PHONO 2 CABE D 12 AV 10 BA GROUND E P POSTS Twisted Wires 72 R 2 red B h l green m NET DIRECT i J13 1234 L 0000 ejo ol7 b 52 524 53 mE 5 8 4 9 4 1234 36 sim 2 e 600060000009 5000 0000 POWER SUPPLY 2 ein 19 Sza 52 3 53 1 2 T S1 SWITCH PINS SEEN FROM BOTTOM OF CIRCUIT CARD 54 7 Transformer shown wired for 120 Volt primary For other voltages 800 chart at right ACCESSORY OUTLETS 20 LINE AMPLIFIER R38 C27 R41 R46 FILTER R 4 9 50 1 8 vil S7a O C25 c30 3 TO RIGHT MUTE POWER SUPPLY GROUND s LEFT amp gt CHANNEL SIGNAL GROUND P os e CIRCUIT CARD LAND MUTING SHIELD GROUND POWER SUPPLY RAILS CHASSIS GROUND MALE CONNECTOR PIN FEMALE CONNECTOR SLEEVE da L SWITCH CLOCKWISE DEPRESSED POWER TRANSFORMER WIRING 5 100 120 220 240 DH 110 PREAMPLIFIER SCHEMATIC DIAGRAM 8 85 SSS LEFT CHANNEL SHOWN 015 57 C30 AND R50 ruse moa vea LARGE CIRCUIT CARD IS PC14c Copyright 1985 All rights reserved CABLE PIN ASSIGNMENTS
3. J22 TO J23 A PIN 1 AUXL 2 TUNER L 3 RECORD L 4 LINE GND L 5 SHIELD GND 6 AUXR 7 RECORD f 8 TUNERR 9 LINE GND R 10 PHONO 2 R 11 PHONO GNDR 12 PHONO 2L 13 PHOND1R 14 PHONO GND L 15 PHONO 1L J24 TO J25 B PIN 1 GUT LINE L 2 SHiELD 3 WT LINE R 4 SHIELD 5 EPL SEND R 6 EPL RETURN R 7 SHIELD 8 EPL RETURN L 9 EPL SEND L ID SHIELD 11 1 L 12 TAPE2L 13 SHIELD 14 TAPE2R 15 TAPE 1R 21 KIT PARTS LIST Minor variations may sometimes be encountered in value or appearance These will not affect performance Some items may have been used to package the kit for NON COMPONENT BACK SIDE shipment Cover black MS138 Bottom plate MS137 Front Panel extrusion black MEI 14 Front subpanel MS132 Back panel black MS136 1 Side piece MS135 Power transformer TALI8 PC 12A circuit board KB037 PC 13 circuit board assembly KF319 PC 14C circuit board assembly KF346 2 Cable assembly interconnect 011 AC tine cord WA016 2 Grommet U shape plastic 12 127 Wire red 22 gauge Wire green 22 gauge Wire black 22 gauge Wire white 18 gauge Wire yellow 18 gauge Wire blue 18 guage Wire bare 18 gauge Bag 1 2 Capacitor 10 000 pF 0 01 uf CP111 2 Capacitor 120 pF CP112 2 Capacitor 220 pF CPI16 2 Lockwasher X4 external tooth HW121 1 Nut volume control M8 x 75 14 2 Plug 15 right angle XM019 2 Resistor 1 1K ohms RM025 brown brown black brown 2 Re
4. The DH 110 preamplifier is a versatile component with sophisticated circuitry which has been made remarkably easy to build by individuals with many years of experience in the design and engineering of the finest performing audio kits and in the preparation of their manuals Kit building should be fun and we am certain you will find this to be so Fatigue increases the risk of error so take a break rather than push to early completion There are relatively few separate components in this design to make it easy to pack everything away if need be Your work area should have good lighting and the proper tools The tools should include 1 A 40 to 60 watt pencil soldering iron with 3 16 or smal ler tip which reaches 700 F 2 60 40 60 tin ROSIN CORE solder 1 16 diameter or smaller 3 A damp sponge or cloth to wipe the hot tip of the iron 4 A wire stripping tool for removing insulation This can be asingle edge razor blade but inexpensive stripping tools are safer faster and easier A medium blade screwdriver about 1 4 wide Needle nose pliers a long narrow tip Diagonal or side cutting small pliers Large gas or slip joint pliers ON tA A 1 4 Spin tite nut driver may be helpful but is not necessary A soldering gun is not recommended The unfamiliar user is more likely to damage the etched circuit boards with its higher heat potential and unbalanced weight
5. 60 Affix the self adhesive serial number label to the center rear of the bottom You may wish to secure the smaller Allen wrench for the knobs to the bottom of the unit with tape 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 AC LINE CONNECTIONS 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
6. Tapes may be duplicated by selecting the playback tape recorder on the Selector switch and recording on the second machine PHONO AMPLIFIER The button in the lower left of the front panel selects either Phono 1 in the OUT position or Phono 2 The switch may be operated to compare two cartridges while music is playing but if them is no cartridge connected to one input noise or RF interference may cause a small au dible transient The phono signal is accurately RIAA equalized and amplified 34dB at 1kHz then passed to the Selector switch at line level MONITOR SWITCH To facilitate tape recording with tape decks which pro vide an independent monitoring facility the DH 110 pro vides this second selection function When it is OFF the regular Selector switch determines what signals are heard When the Monitor switch is turned to either Tape 1 or Tape 2 the line amplifier is quietly disconnected from the signal being recorded and is connected to the tape playback in stead This enables direct comparison of the signal source with the taped replica without affecting the recording pro cess Tape decks which do not provide separate record and playback heads are not able to utilize this comparison Note Do not turn the Monitor switch to Tape 1 if the Selector is also set to Tape 1 Likewise avoid simultaneous Tape 2 settings on both switches Feedback will occur and there is a possibility of damage When the Monitor switch is no
7. 1 16 ampere 60 mA slo blo 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 FOR OVERSEAS USE ADDITIONAL RACK MOUNT END CAP INSTALLATION Every DH 110 is supplied with front panel accessory end caps which adapt it to a standard 19 rack panel and with a 5 32 Allen wrench which fits the mounting screws Remove all power and signal connections from the DH 110 On a protected surface such as a towel remove the two cover screws on each side of the bottom and slide the cover back Remove the screws in each corner ofthe front panel Exchange the end caps they slide outward If you are careful you will not dislodge the LEDs from the
8. 25v 47 mfd NP ekctrolytic 16 100 nF polycarbonate 50v 1000 mfd electrolytic 50v 1000 mfd electrolytic 50v 22 mfd ekctmlytic 50v 100 nF polycarbonate 50v 22 mtd ekctrolytic 50 v 100 nF polycarbonate 50v 47nF polycarbonate 50v 4 7 mfd NP ekctmlytic 25v 4 7 mfd NP ekctrolytic 25v 22 mfd electrolytic 50v IN4003 IN4003 IN4003 IN4003 IN4003 IN4003 INS2SIF 22v Zener 1 IN4003 IN4003 INS2SIF 22v Zener I96 IN4003 IN5240B 10v Zener 5 LED LED LM3IT Positive Regulator LM337T Negative Regulator LM393 Dual Comparator 414C Transistor 416C Transistor 416C Transistor 550B Transistor 556B Transistor 546B Transistor 550C Transistor seketed 560C Transistor seketed 550C Transistor seketed 560C Transistor seketed 560B Transistor 550B Transistor 560B Transistor 550B Transistor 2 FET Transformer Power Fuse 1 0 Slo Blo AGC 111 CPII2 CP116 11 CNII6 CNII2 CN112 CC123 CC123 CZ14 2115 CPII4 CPIII 6 CL111 CL111 CPI18 CP144 CN116 CL111 CP1 14 CC123 114 CCHS CN118 CNII9 125 CL124 CL124 CL117 CC125 125 CC14 CNII8 CN118 CL117 QD115 19 PC12a CABLE PIN NUMBERS R55 Left Right SELECTOR TUNER Oy E CO CD VIDEO Es O 1 O Tego R23 TAPE 2 Sg AM 221 231 J5 J241BI J25 1B RECORD R21 2 OUTPUTS J 3 AY 7 C J6 5 5 B
9. Also because he may not wait long enough for it to reach operat ing temperature each time it is switched on poor solder connections are more likely Pencil irons are much lighter and easier to use and there is no waiting time when solder connections follow in sequence as in kit building Make sure you have a holder for it though and always unplug it when you take a break Proper Soldering There are four steps to make a good solder connection Make a good mechanical connection to hold the wire in position while heat and solder is applied 2 Heat the junction of the wire and lug or eyelet with the bright shiny tip of the iron 3 After heating for a couple of seconds apply solder to the junction It should melt immediately and flow smoothly around both surfaces 4 Allow the connection to cool undisturbed Remember that the connection is made by the solder not by mechanically attaching the wire to the terminal Usually the wire is looped through the lug and crimped in place but some prefer to just place it through the hole and rely on the stiffness of the wire to hold it while soldering Eyelet connections of course are handled this way Good solder connections are essential for trouble free noise free operation A good solder joint does not require much solder around the conductors Never butter par tially melted solder on the joint as it is useless A good connection looks smooth and bright because the solde
10. Information describes its installation Adjacent to the Phono 1 input sockets are two Ground terminals on the back panel These thumbscrews provide for connection of separate ground wires often provided on turntables or as part of their audio cables This chassis ground may sometimes reduce the hum level of a system when it is connected to an earth ground such as a cold water pipe or the ground wire of 3 wire house wiring However the need for such connection varies with indi vidual situations After the system is operative using a phono source experiment with and without an earth ground to determine which provides the lowest hum and use that IMPUTS Tuner CD Video These are high level line 50 millivolts or more signals from FM AM or TV tuners or compact digital audio disc video disc or VCR players These inputs are grounded at the selector switch when they are not chosen for listening The input impedance is approximately 33K ohms INPUTS Tape 1 Tape 2 These are at line level and impedance They connect to Tape Play outputs on the tape deck They are not grounded when unused since they can be connected by either the main selector switch or the Tape Monitor switch They are terminated with 1 megohm resistors to avoid a possible switching transient RECORDING OUTPUTS These connect to the Line Inputs of tape decks The two pairs of outputs are wired in parallel Thus two tape recor ders receive identical signals
11. These outputs are buffered with a series resistor and have an output impedance of 1 5K ohms To provide full specification performance the total tape recorder load should not be lower than 10K ohms i e two 20k ohm recorder inputs on each channel Because it is possible that a preamplifier s overall per formance may be adversely affected by rectification ef fects that can result from unpowered electronic circuits in the tape decks when they are connected to the Recording Outputs it is recommended that tape recorders be switched on when the preamplifier is in use This is a commonly overlooked cause of less than ideal preamplifier performance Signals at these outputs are at line input level phono signals are first amplified and equalized These outputs are unaffected by external processing circuits or by the DH 110 s Mono Filter Tone or Volume controls Only sig nals indicated by the Selector switch are available includ ing the other tape input so tape copying is provided using either recorder as a source LINE OUTPUTS Two pairs of outputs are provided for your power amplifier connection The set labelled Via Phones is suggested for those who regularly listen through head phones as an alternative These are wired so that when headphones are plugged in the signal is disconnected from the power amplifier Two purposes are thus served Since many headphones require fairly high volume control set tings you avoid inad
12. iron When properly done the wire is uniformly bright and no larger than before The hookup wire supplied with this kit does not normally need tinning for it is pre tinned Wiring the Kit If any components are unfamiliar to you checking the pictorial diagram should quickly identify them Or the quantities and the process of elimination as you check the parts list will help The pictorial diagram is necessarily distorted to some extent for clarity so that you can trace every wire in a single overall view for verification as you work To prepare a wire means to cut the designated length from the length of that color and strip about 1 4 of insula tion from each end The wire supplied in the kit is 18 and 22 so you can set adjustable wire strippers accordingly The transformer leads are 18 and the line cord is 16 Be careful that you do not nick the wire when you strip it that can happen more easily if you do not use wire strippers for that weakens it The wire supplied in this kit is bonded stranded which provides exceptional flexibility with re sistance to breakage for easier use Whenever a connection is to be soldered the instruc tions will so state or indicate by the symbol S If more than one wire is to be soldered to the same point they will be indicated by S 2 S 3 etc If soldering is not called for other connections have yet to be made to that termi nal They would be more difficult if th
13. lug 8 Solder lugs 5 6 and 7 28 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 Prepare 13 blue wire Connect end to outlet D lug 4 Place this and the following wire over the transformer 30 Prepare 124 length of yellow wire Connect one end to outlet D lug 8 31 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 J Connect the shorter line cord conductor to outlet D lug 8 S 3 Connect the other conductor to lug 4 2 33 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 7 Plug the two flat wire assemblies onto the pin con nectors on 14 35 J Prepare a 196 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 th
14. panel Replace the cap screws and nuts only finger tight at first Check the alignment of the panel around the knobs before tightening fully Then replace and secure the cover PHONO CARTRIDGE CAPACITOR LOADING The cartridge manufacturer usually specifies in their instructions the optimum load or termination for the car tridge The needed capacitance is expressed in picofarads pF The DH 110 is supplied with pairs of two values of capacitors plugged into the sockets behind the rear circuit board at the Phono inputs one for each channel One of these values is likely to accommodate the majority of available cartridges with most high quality connecting ca bles within the accepted tolerance of 5OpF If no informa tion is available we suggest first trying the 120pF which is installed in the Phono 1 input The total capacitive load is the sum of three numbers Turntable cable capacitance from its manufacturer Preamp input capacitance DH 110 30 pF Compensation capacitor value you desire The specified load from the cartridge manufacturer You need to know the cable capacitance from either the turntable maker or the cable supplier if they are separate Unfortunately this is not always readily available and it can vary widely but lower capacitance cables invariably are more expensive If you must guess use 60pF per foot If your turntable accepts plug in cables you can usually overlook its internal wiring capacita
15. the line cord All service work is guaranteed for 90 days Warranties apply only to the original purchaser and are void ifthe Preamplifier has been modified without factory authorization or if parts have been substituted which in the factory s opinion are not suitable or if the Pre amplifier has been physically or electrically abused or used for some purpose for which it was not designed or in tended Technical assistance to help you locate the source of a problem may be obtained by calling the Hafler Company Technical Service Department at 609 662 6084 between 8 am and 4 30 pm eastern time It will be helpful to know the serial number and the results of any tests you have per formed However we do not recommend that you attempt your own servicing unless you are knowledgeable in this regard If you return a properly functioning Preamplifier for service or a checkout a charge will be made for the checkout time required as well as for packing and ship ping WARRANTY FOR FACTORY ASSEMBLED UNITS The assembled DH 110 is warranted for three years from the purchase date including parts labor and normal return shipping costs from the factory to the owner within the continental United States The owner is responsible for shipment to the factory and must submit a copy of the dated bill of sale WARRANTY FOR KIT BUILT UNITS The parts in a DH 110 kit are warranted for a full year from the purchase date If a defective compon
16. 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 15 Prepare a 1 piece of green wire and form it into a 12 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 16 J Prepare a 1 piece of red wire and form it into U as before Connect it in like manner to holes C and D on the back of the board 17 J Select the two 10 000 pF capacitors and install them on the front of the board at locations C1 and C101 18 7 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 7 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 34 off of one conductor Strip both ends the usual 4 and tin the strands to
17. ues will accommodate most Moving magnet cartridges These have output levels intended for normal phono in puts 0 5 millivolts per centimeter or higher and are the most popular Some high output moving coil design car tridges are not sensitive to capacitive loading so they may be used with either input Though some phono cartridges are comparatively free of loading sensitivity if the cartridge manufacturer specifies the proper load capacitance which is the sum of the preamp s internal capacitance and the cables you use as well as the above described capacitor the most accu rate sound will be obtained by following that recommenda tion If you have chosen the DH 110 for its sonic attributes you will be more likely than most to be aware of these dif ferences and will want proper cartridge termination The Additional Information section of this manual de tails the determination of the loading capacitor for a specified cartridge load It also describes how the resistive load of the phono inputs may be changed if needed from the standard 47K ohms Moving coil design cartridges often require an auxiliary step up transformer or pre preamplifier head amplifier because of their low output signal The DH 110 has provi sion for internal addition of an accessory Hafler pre preamplifer which you or your dealer can install at any time This enables the Phono 1 input to accommodate such cartridges directly The Additional
18. 0 a par ticularly fast easy and enjoyable construction project which you will likely complete in one evening We suggest that you read the installation and operation sections of this manual carefully even though much may be familiar to you There are some subtle and significant points which may be new and their proper appreciation will enable maximum satisfaction with your DH 110 We wish you to have the very best in sound CONTENTS Installation Page 4 Additional Information 16 Operation at 5 Functional Block Diagram 16 Assembly Instructions 7 Component Values 19 Building the 9 Schematic Diagram 20 PC 14 Diagrams 12 Kit Parts List 22 If a Problem Arises 15 Service and Warranty 23 Overseas AC Line Connections 15 Pictorial Diagram Insert INSTALLATION The DH 110 is provided with accessory Rack Mount end caps in addition to the standard end caps installed on the unit These accessory caps extend the width of the front panel to that of a standard 19 rack with appropriate mounting holes Installation instructions are detailed later in this manual under Additional Information POWER CONNECTIONS As assembled units are normally w
19. 00 ohms 47 500 ohms 47 500 ohms 100 ohms 12 w 5 carbon film 100 ohms 2 w 5 carbon film 316 ohms 100 ohms 11 000 ohms 100 000 ohms inverse log taper potentiometer Treble 4990hms 1 100 ohms 11 000 Ohms 100 000 ohms inverse log taper potentiometer bass 316 ohms 1 100 Ohms 11 0000hms 11 000 ohms 1 100o0hms I megohm 22 100 ohms 270 ohms w 5 carbon film 1 800 ohms w 5 carbon film 270 ohms 4 w 5 carbon film 1 800 ohms 4 w 5 carbon film 4 708 ohms 4 w 5 carbon film 470 000 ohms w 5 carbon film 470 000 ohms w 5 carbon film 39 000 ohms 14 w 5 carbon film 10 000 ohms 4 w 5 carbon film 2 2 megohms 4 w 5 carbon film 680 000 ohms w 5 carbon film 270ohms w 5 carbon film 100 000 ohms w 5 carbon film 47 008 ohms w 5 carbon film 10 000 ohms w 5 carbon film 1800 ohms 5 carbon film 1 000 Ohms w 5 carbon film 1 000 ohms w 5 carbon film 4 640 ohms 4 w 5 metal film Phono Input Selector DPDT Source Selector Monitor Sckctor EPL switch 4PDT Mono switch 4PDT assembly Tone switch 4PDT Filter switch 4PDT assembly Power switch RM 045 RMO45 25 RM035 RM 35 RM043 RM043 RM RM035 35 RM036 RM 36 RDI2I RDI21 RM024 02 4 RM043 RM RM018 RM0 0 RPO29 43 27 RM027 RM046 RM RMO 46 36 RM036 RDI21
20. 2 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 to make sure it does not contact the stub of wire at hole A 23 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 24 C 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 With a pair of pliers carefully twist the 8 lugs on the AC outlets counter clockwise 1 6 turn or about 60 This will enable a wire to be passed horizontally through these lugs 26 Cut a 24 piece of the bare buss wire Slide it through lug 2 of AC outlet B and connect it to lug 1 and to lug 3 Solder lugs 1 and 2 27 Cut a 3 length of bare wire Slide it through AC outlet lugs 6 and 7 and connect it to lug 5 and to
21. THE nailer PREAMPLIFIER Monitor DH 110 INSTRUCTIONS for ASSEMBLY and OPERATION LM132 Please refer to this serial 3 00 number in all communications E regarding this equipment THE DAVID HAFLER COMPANY 5910 Crescent Boulevard Pennsauken New Jersey 08109 DH 110 SPECIFICATIONS The numbers in parentheses refer to the paragraph in the IHF specifications manual which defines the test procedure PHONO PREAMP SECTION Rated Output 3 Vrms 8 Hz 105 kHz Maximum Output 3 5 12 Vrms 20 Hz 20 kHz at recording output Total Harmonic Distortion Less than 0 0006 1 kHz 3 Vrms Frequency Response 3 13 0 0 25 dB 20 Hz 20 kHz RIAA Equalization Accuracy 0 0 1 dB 30 Hz 15 kHz Full Power Bandwidth 6 dB 4 Hz 210 kHz Sensitivity 3 7 12 5 millivolts Maximum Input Signal 1 kHz 3 8 300 millivolts 3 V 20 kHz Gain 34 dB kHz Input Impedance 47 000 ohms in parallel with 30 pF user adjustable Plug in capacitors are installed to increase this to 150 pF on Phono 1 250 pF on Phono 2 Signal to Noise weighted 3 12 87 dB Slew Rate 12 volts per microsecond LINE AMPLIFIER SECTION Rated Output 3 Vrms 4 Hz 210 kHz Maximum Output 3 5 14 Vms 20 Hz 20 kHz Total Harmonic Distortion 3 4 Less than 0 001 20 Hz 20 kHz Frequency Response 3 13 0 0 1 dB 20 Hz 20 kHz Full Power Bandwidth 6 dB 2 Hz 420 kHz Sensitivity 3 7 50 millivolts Maximum Input Signal 1 kHz 3 8 14 Vrms volume con
22. Z a Ci D13 12 HT LINE 7 LEFT LINE 2 2 FEN Pos NEG 11 1 ti 5888 2323 5883 SEEMS UTE PE ie eGR RE i 12909 0109 QAB z 1 8 Q9 Q13 z O 0 g F 2 D D 8 5 EG 0107 Ee de T cn a Q8 Q7 Qt E ee E E z DC oe Du NEL Me pee Fo 11 a I oa Sais 5 D7F 4010 Ko 5 i O tt 1 1 i C32 Ry L C40 S C119 CI9 R66 R56 To Yo 865 2 EBB g R2 FT TTT 57 VOLUME ve R59 G4 G3 G2 G1 2 R45 R 4 L RUSSE TREBLE a 5 BAL N N 2 41 R44 L A888 R C39 127 C128 4 9 Q R pee cup d L Mic 144 R39 R25 R26 wire to hole Q which is between the center lugs of Jll and 512 S The wire should not protrude sig nificantly beyond the front surface of the board to avoid coming in contact with a connector To assure a good solder connection bare wire should be visi ble on the circuit side of the board Connect the green wire to hole P in like manner S 44 C At the rear of the phone jack connect the black wire from the first group lugs 2 and 3 to PC14 eyelet G3 S 45 Select the other group of three wires and connect the black wire to PC 12 hole T S Connect the red wire to hole S between 11 and J112 S Connect the green wire to hole R S Make sure the wires do not protrude significantly beyond the outside surface of the board 46 7 Connect
23. ad from the rear into holes E F G and H to engage the sockets while you solder the pins and then remove the capacitors Be sure solder flows freely around each mounting pin for a good connection Sometimes these pins do not ac cept solder easily 13 The proper way to install the 24 phono input sockets is to first insert a phono plug on the end of one of the audio connecting cables supplied in the kit so that the center contact will not be deformed in the mounting process Adjacent to the center hole for 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 A wooden toothpick will keep them open 14 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
24. can be mended by simply soldering a small piece of wire across it Do not allow much build up of solder on the tip of the iron or it may fall onto adjacent circuitry and cause a short cir cuit When soldering to an eyelet or hole on the board insert the wire from the components side and apply the iron to the bottom leaving some bare wire exposed so that you can see that the eyelet is then filled with solder for a secure bond A round wooden toothpick is suggested so that you can heat and clear an eyelet of solder if it hinders your in serting the wire Some builders prefer to clear every eyelet first with a touch of the iron and toothpick Others connect the lead by bringing it up to the center of the eyelet on top of the board applying the iron from the bottom of the board and pushing the lead in as the solder in the eyelet melts If the wire has first been tinned usually no addi tional solder is necessary but it is a good practice to push the wire through and then back it up a bit to be sure solder fills the eyelet On the bottom of the board make certain a bright shiny flow is evident from the wire onto the circuit pattern on the board Tinning refers to the process of applying a light coat ing of solder to the bared wire end This keeps all the strands secured and also makes a good connection easier Simply touch the wire with the iron for a couple seconds and apply solder Allow the excess to flow away onto the
25. e connection was al ready soldered Every connection in the kit will be sol dered when it is complete After soldering a connection it is best to clip off any excess lead length to minimize the possibility of a short circuit and for neatness Be sure that uninsulated wires cannot touch adjacent terminals or the chassis metalwork When the instructions call for twisting two or three wires together the length of wire indicated anticipates a fairly tight uniform twist by hand of three full turns every two inches If you find the wires too short loosening the twist will gain some needed length Take the time to be accurate and neat and you can be sure that your completed preamplifier will meet the per formance of a factory assembled unit and can continue to perform properly for years to come Check your work and make sure the entire step has been completed before plac ing a check mark in the space provided and continuing on to the next step BUILDING THE KIT Partial mechanical assembly of the kit provides protec tion for major components during shipment Most of the hardware thus used is included in the quantities listed in the parts list The exception is that used to install the rear mounting bracket on the PC 14 as this is considered an in tegral assembly Only the two screws securing the bracket to the side pieces need be removed along with the hardware securing the front sub panel Dismount the power transformer and rem
26. e fuse S All eyelet connections should be soldered on the bottom of the board for secure connections 36 Select the white wire from the tear grommet Con nect it to eyelet W on PC 14 S 37 Select the blue wire from the grommet Connect it to the side lug of the power switch S 38 Select the yellow wire Connect it to eyelet T 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 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 42 0 Connect the short black wire from the forward lug of the phone jack to eyelet G2 S 43 There are two gr
27. el after each change reversing only one cord at a time CAUTION Do not indiscriminately disconnect and reconnect a power amplifier when other components are turned ON Use the DH 110 muting circuit for protection against loud noises With the power amp connected to a switched convenience outlet on the DH 110 turn the preamp OFF reverse the amplifier line cord and then turn the preamp ON Use connecting cables of high quality and treat them with care Unplug cables by grasping the connector not the cord to maintain good connections We have no evi dence that special connector platings are required but the surfaces should be free from grease fingerprints or any contaminate that may prevent a firm and complete connec tion Some audiophiles are convinced that a good contact cleaner is an important adjunct to a high quality music sys tem It does not usually reduce noise to connect each compo nent to an earth ground This may even aggravate a ground loop problem for good earth grounds are hard to find and unsatisfactory grounds are likely carriers of RFI The previous suggestions may also help reduce RFI In difficult cases RFI filters can be purchased for insertion between the line cord plug and the wall outlet or a device called a ferrite bead may be installed in the phono stage by a competent technician If you use a pre preamplifier and find that it is RF sensitive increasing the cartridge com pensation capaci
28. ent is found on a circuit board or in the kit simply return the individual part to the factory prepaid together with the serial number and the date of purchase It will be replaced at no charge If you cannot locate the cause of a problem in your DH 110 return it to the factory along with a copy of the dated bill of sale and a check for 30 If the difficulty is solely a defective part the unit will be returned to you prepaid and your 30 less shipping and packing charges will be re turned to you If the problem is found to be an error in your assembly of the kit the unit will be put in proper working order and returned to you prepaid This warranty is void if the kit has not been completely assembled or if other than rosin core solder has been used Units assembled with acid core or silver solder or paste flux will be returned unserviced This warranty gives you certain rights You may also have other rights which vary from state to state PC13 23 Printed in USA
29. eplacing and RIO on the main circuit board See the board dia gram in the center of the manual The input resistance is determined by the parallel com bination of RI 101 and R2 201 each of which is 93 1K ohms white orange brown red A different value of RI 101 will change the desired load to the value RT in accor dance with the formula 93 1 RI 1 93 1 RT To simplify the following standard 1 values of RI will provide desired loads RT as shown all in Kohms RI Value Kohms Desired Load Kohms 11 3 10 17 8 15 24 9 20 34 8 25 44 2 30 56 2 35 Metal film type resistors are recommended for lowest noise MINIMIZING NOISE IN THE SYSTEM Your choice of separate components is the right way to secure the best performance from a music system but the wide band characteristics complexity of the best sys tems may also not conceal the introduction of ground loops and noise pickup especially RFI radio frequency interference With exceedingly high quality equipment we may become conscious of distractions that would be ig nored on a lesser level Careful interwiring practice will greatly reduce the likelihood of such problems The DH 110 is a very quiet preformer There can be oc casions where even the finest equipment exhibits hum or noise due to irregularities in its interconnection The sim ple expedient of reversing line cord plugs will often reduce hum Listen to the hum lev
30. hed low frequency response will not reflect small angular move ments from the detent As the control is turned further frequencies closer to 500 Hz are affected so the effect is more apparent The Treble control has a fixed hinge point at IKHz and has a shelving action above 5kHz This affords proper correction without irritation from excessive boost at the extreme VOLUME CONTROL This step action control was selected for its very accu rate tracking between channels and for its low contact dis tortion Clockwise from the 12 o clock position it increases in increments of roughly 1 dB From 12 o clock coun terclockwise it progresses in increasing increments to full attenuation HEADPHONE JACK A 3 circuit shorting jack is connected so that the tip is the left channel in series with one set of line outputs so that the power amplifier is automatically disconnected when the headphones are plugged in We recommend that you turn off the power amplifier before you connect head phones or that they be plugged in before the preamplifier is turned on to guard against needless transients Be sure the volume is turned down before headphones are discon nected ASSEMBLY INSTRUCTIONS There are three basic rules for success in electronic kit building 1 Read the instructions carefully and follow them in or der 2 Make secure solder connections which are bright and smooth 3 Check your work carefully after each step
31. ired for 120 VAC 50 60 Hz as in the USA unless they are specially iden tified on the carton In the Additional Information section you will find diagrams of alternate wiring of the power transformer to conform to other line voltages The power regulation of the DH 110 will provide full per formance with line voltages which may vary substantially from the standard Units wired for 120 volts for instance will work properly with line voltages between 95 and 130 volts Accessory AC outlets are provided on the back panel for other equipment One unswitched outlet is provided for a turntable or tape recorder whose mechanical system may require disengagement through its own power switch Most units including power amplifiers tuners and many tape recorders and record players may be connected to the switched outlets for convenient remote switching from the preamp s front panel The DH 110 power switch has been tested to provide adequate capacity for any Hafler power amplifier and typical related equipment You should heed the maximum power rating printed on the back panel of the unit INPUTS Magnetic Phono There are two pairs of phono inputs identified as Phono and Phono 2 These are independent and thus they may have different capacitive termination for differing car tridge requirements As assembled Phono 1 is provided with a compensation capacitor of 120 picofarads and Phono 2 is provided with 220 picofarads One of these val
32. it EPL SWITCH This is the External Processor Loop Engaging this switch enables a signal processing device to be inserted in the preamplifier signal path Such devices include equaliz ers time delays or ambience simulators expanders com pressors and noise reduction systems Since the switch permits bypassing the processor loop an unpowered de vice in the EPL circuit will not deteriorate the DH 110 per formance as might be the case with switched off tape decks in the Record Outputs The EPL switch can also function as an additional input selection TONE SWITCH Until this button is depressed all tone control circuitry is completely removed from the signal path Activating this button may cause a slight change in the tonal balance even when both Bass and Treble controls are in their me dian detent position Potentiometer tolerances preclude coincident mechanical and electrical centering The tone control circuitry limits to an extent the total bandpass of the DH 110 Operation of the Tone button will be silent if it is depressed in a natural deliberate manner Rapid switching may gen erate small transient pulses BALANCE CONTROL This adjusts the proportion of left and right channel sig nals to the Line outputs In its detented center position the channels will be matched to 0 1 dB Only the Left signal will be heard with the control fully counterclockwise and only the Right signal at the other extreme The ideal
33. itched AC outlets on the back panel One of the red LEDs on the front panel will light indicating that the preamp is functioning Typically it will be the left most LED indicating that the Selector switch is determining the signal source At turn off it is normal for the LED to fade slowly as the operating voltages decline DELAYED TURN ON An internal muting circuit prevents the voltage tran sients which may occur at turn on or turn off from causing annoying noises blown fuses or damaged loudspeakers At turn on the Line Outputs but not the Recording Outputs or EPL Send output will be held near ground po tential for a few seconds until the internal voltages have stabilized and the unit is ready for operation Only a faint output can be heard during this time At turn off whether by operating the preamp s power switch or as a result of external AC failure a brown out pulled plug or blown house fuse the line output will be instantaneously lowered Following power interruption the muting circuit will initiate a few seconds delay before allowing full signal at the line outputs SIGNAL SELECTION Your choice of signal sources is usually indicated by the Selector Switch identified by the adjacent lighted LED This switch passes line level signals direct to the Record ing Outputs and to the EPL Send output as well as to the Mono switch and subsequent line amp controls Either or both tape recorders may record this source
34. nce as it will likely be within the 50 tolerance Short cables are desirable because total cable capacitance can itself be higher than the total specified load The lowest you can go in compen sation is to leave that capacitor out It is why a good preamp design has a low input capacitance As an example Recommended cartridge load 320 pF The turntable has a three foot cable and they say it is 60pF foot Subtract 3 X 60 180 So far we still need 140 pF Subtract the DH 110 input capacitance 30 Compensation capacitor required 110 pF This is close enough to the 120pF supplied that Phono 1 can be used without change INFORMATION If you require new capacitors we suggest that you purchase if possible either polypropylene or polystyrene types These premium grades have been selected for all critical circuits in the DH 110 because of their superior audio performance Their leads should be formed like those presently installed and they must extend at least but not more than 3 8 beyond the capacitor body to avoid a short circuit to the back panel Some fastidious users prefer to solder the compensation capacitors in place once a final value has been determined to preclude any less than perfect socket contact as time passes PHONO CARTRIDGE RESISTIVE LOADING As supplied the phono load resistance of the DH 110 is 46 55K ohms which is accurate loading for most car tridges This value may be changed if need be by r
35. ng the hardware The wires from the phone jack go under the board Push the ends of the wires through the grommet 8 Select the small circuit board assembly PC 13 and two 4 screws With the circuit board uppermost position the assembly at the top of the large front panel opening so that the sockets on the board align with the pins from below and plug the board down ward onto the pins Make sure each pin is properly engaged Secure the assembly with screws through the panel Set the front panel aside and select the PC 12 circuit board The front of the board marks the component locations and J designations Most components mount on the front Always install them tight against the board and solder each lead on the back circuit side Then cut off all excess leads 9 Select the two 22 100 ohm resistors red red brown red and install them at locations R50 and R150 10 Select the two 1 100 ohm resistors brown brown black brown and install them at R21 and R121 11 0 Install the four 1 megohm resistors brown black black yellow at locations R22 R23 R122 and R123 12 Select the two 4 pin molded sockets These are to be installed at locations J26 and 5126 on the front of the board with the pins through the upper row of holes arrow at each location The lower row of holes provides access from the rear of the board for plug in capacitors Ib assure correct alignment of the sock et insert a capacitor le
36. nsumption 3 5 watts AC Convenience Outlets 3 switched 5 amp continuous 72 amp surge 1 unswitched 5 amp continuous Size 17 wide x 3 high x 8 deep 19 rack mounting accessories included Shipping Weight 12 5 lbs Net Weight 10 lbs Copyright 1985 All rights reserved INTRODUCTION Your preamplifier is the control center of your music system acting as an interface between the sound sources record players tape recorders FM and Video tuners and the power amplifier which drives the loudspeakers As the focal point of your system it should be attractive and easy to use versatile and yet functionally unobtrusive It should contribute a minimum of noise or distortion while providing signal amplification control of the signal level and applicable modification of the fre quency response The DH 110 achieves all these objectives with great versatility providing for two record players with magnetic cartridges two tape recorders a tuner and an additional stereo input for a compact digital audio disc player or video audio It also includes inputs and outputs for an external signal processor such as a graphic equalizer time delay device or noise reduction unit The performance of the DH 110 is exemplary and its assembly from an array of discrete components of exceptional quality should ensure reliability and longevity of its capabilities Exceedingly low noise and distortion is a hallmark of the DH 110 Noise is essentiall
37. oups 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 PC14 RIGHT LEFT PHONO RIGHT PHONO To Led oe L d iom eO 8 g 491u eziu O eely CN B 4 R141 Ssu c T se A 5 9ciu 61H gt a C 8 5 0 H 0cH lt to B 019 Q o pic o a o oa DEB amp O co 9IH T a 2 a 2 Td z z SEMEN 130880 o pe vzu 99 gt SH sir EM clu 8 J 1 M eR 5 j a 8 E m z n o 6HH e 3 m o 3Y gO Es lt 0ctu 9 5 sQ 019 2 x B 014 80 2 gui 1 EO 2 2 9014 Sol Bl N a aC o z Soiu 2 rio 2 gO 8 amp euu B Yx m Ioru Ln M Jas An Pe 5 ge 5 D c VE I
38. ove the side pieces A set of hardware includes a screw and a KEP nut with attached lockwasher Always install the lockwasher side first Screws are always inserted from the outside of the chassis unless otherwise specified 4 hardware is smaller in diameter than 6 To separate 4 nuts from the 6s use a long 4 screw to test We suggest you check off the parts as you unpack the kit and separate them in an egg carton for convenience 1 The flanges of the front sub panel bend towards the inside of the preamp Select the U shaped head phone jack mounting bracket and 2 sets of 4 hardware Install the mounting bracket on the out side of the front panel in front of the rectangular hole in the lower right comer 2 J Select the headphone jack its washer and nut Install it through the front panel with the single lug at the bottom The washer goes outside the bracket secured by the nut 3 Prepare 2 black wire Connect one end to the lower forward lug of the headphone jack S Place this wire through the panel 4 0 Prepare a 14 green wire but strip 3 8 of insulation from one end Prepare a 14 red wire Prepare a 14 black wire Start with the red wire 14 longer than the longer bare end of the green wire and the black wire 2 shorter than the green wire Twist these 3 wires together uniformly throughout their length Make about 3 com plete twists every two inches On the rear of the phone jack 8 n
39. r flows into every crevice when the parts am hot enough The iron must have a bright shiny tip to transfer heat eas ily to the junction That s why the damp sponge should be used frequently to wipe the tip and occasionally you must add a small amount of solder to the tip too If a connection is difficult to heat wet the tip with a small blob of solder to provide a bigger contact surface to the joint Once the solder flows around the conductors any movement must be avoided for a few seconds to allow a good bond When cool check the connection by wiggling the wire If in doubt or if the connection is not shiny m heat the joint u Excess solder may be removed from a connection by heat ing it and allowing the solder to flow onto the iron which is then wiped on the sponge ALL SOLDER USED MUST BE ROSIN CORE Never use acid core solder or any separate flux in elec tronic work Silver solder is also not suitable If in doubt about unmarked solder always obtain a fresh supply of rosin core solder We recommend 60 40 for easiest use Do not confuse it with 40 60 which is harder to melt The general procedure is to use a hot iron for a short time to heat a connection then add solder with the iron still in contact Remove the solderonce it flows and then remove the iron A cooler iron applied for a longer time is more likely to damage components or lift the copper circuit pat tern from the boards A break in the etched circuit
40. 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 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 Select the 4 AC sockets Snap these into the back panel holes from the outside 22 0 Select the PC 1
41. sformer make sure it is Clear of the screw hole in the back panel flange Check that a 1 10 ampere 100mA fuse is installed in the PC 14 clips and that the Red Yellow transformer lead connects to the corner eyelet A 54 A wire tie can secure the transformer leads to the side piece through the slot behind the PC 14 bracket These ties can be used only once and lock securely when the tail is pushed through the head end from the flat side Cut off the excess after pulling it tight 55 The two groups of output leads from the phone jack should be positioned at least 1 in from the side piece and straight to the rear of the PC 14 board then kept close to the bracket A wire tie is suggested at the rear comer You may wish to use the 3rd tie on the wiring to the AC sockets or on the output leads near the back panel 56 1 With 6 of the sheet metal screws install the bottom plate The 2 large holes should he near the phono inputs at the rear 57 Place the 4 rubber feet in the corners of the bottom plate They are self adhesive when you remove the paper backing 58 Slide one piece of the U shaped long plastic grommet onto the top flange of the front sub panel The other piece goes on the top flange of the back panel 59 Check to make sure that the flat ribbon cable as semblies are up close to the top of the unit away from the circuit board and slide the cover on from the tear Secure it with the 4 sheet metal screws
42. sistor 22 IK ohms RM035 ted red brown red 4 Resistor 1 megohm RM044 brown black black yellow 6 Set screw 48 x 3 16 HP122 2 Socket 4 pin bottom entry XM012 Washer volume control M8 flat HWIII 2 LED red QD119 1 Shrink tubing 1 HR135 Bag 2 10 Nut 440 KEP HK111 6 Nut 6 32 KEP 12 4 Nut 10 32 KEP HK113 Nut control shaft M7 x 75 115 2 Nut 3 8 HK119 2 Lockwasher 38 HW118 6 Screw 4 40 x 5116 HA113 6 Screw 4 40 x 5 8 black HP112 2 screw 4 40 x 7 8 HAI 14 6 Screw 6 32 x 10 black 13 4 Screw cap head 10 32 x 1 black HPI 14 12 Screw sheet metal 6 black HP116 8 Spacer threaded 38 long HZ112 2 Thumb nut 4 40 HK122 3 Washer control shaft M7 flat HW113 Bag 3 4 AC outlet 015 Bracket phone jack MS133 4 Foot square plastic HR134 Grommet rubber HR128 Nut phone jack 2 x I HK117 Phonejack 7015 6 Pushbutton black HD121 24 Socket phono input I Strain relief black HR144 Switch power 81112 j Ties wire nybn HR138 Washer phone jack M12 2 flat HWI 19 Bag 4 2 End Caps regular MCI11 2 Knobs flat HDIIS 4 Knobs round HDI17 Bag 5 1 Audio cable pair WAO017 2 End Caps rack mount MC112 Fuse 1 10 ampere Slo Blo SF022 Wrench Allen 5 32 cap screw HZ138 Wrench Allen 48 set screw HZ139 SERVICE POLICY AND LIMITED WARRANTY Your DH 110 Preamplifier has been carefully engineered to provide many years of use without maintenance or ser vice Fac
43. situation would find symmetry in room acous tics and in the electronics but this realization is rare Stereo reproduction is at best a splendid illusion and the function of the Balance control is to optimize this illusion in the listening space Sound wave reflections from walls furniture and people can unbalance the stereo stage With judicious application of the balance control much of the attendant distortion of stereo imaging can be overcome With the preamplifier in the Mono mode it will be easier to use the Balance control to centrally position the apparent sound source This mono setting can then serve as a useful reference point though the appropriate balance setting may vary from recording to recording in the stereo mode Our point is that Balance and Tone controls are intended to facilitate the most satisfying sound to the listener it is appropriate that they be used to this end BASS and TREBLE CONTROLS The Tone Switch must be IN for these controls to be ef fective At full rotation each control provides about 17 dB of boost clockwise or cut counterclockwise at the fre quency extremes from the center flat detent position The Bass control has a variable inflection or hinge point so that only the very low frequencies are affected by small amounts of rotation either side of center This facili tates low frequency corrections without noticeably alter ing the musical balance but speakers with diminis
44. t in the OFF position the LED at the Monitor switch will light in place of the Selec tor LED reminding you that tape playback has been selected The following controls affect all signals which are heard through speakers or headphones They have no effect on the signals to the recording outputs MONO SWITCH When this button is IN left and right channel informa tion is combined and the composite signal is fed to both left and right outputs In this mode the sound image should appear to be centrally located between the loudspeakers Critical listeners sometimes choose the mono mode for system evaluation for it enables you to isolate system re sponse from the complexity of stereo effects This switch is also useful when listening to monophonic program mate rial It cancels the unwanted vertical phonograph modula tions which are heard as noise from monaural records FILTER SWITCH This is a low frequency cutoff to remove much of the signal below 25 Hz such as noise turntable rumble or loudspeaker turntable feedback Even in cases where the speakers may have little response at these frequencies this filter can be useful Very low frequencies can modulate audible midband signals so eliminating this interference can improve overall clarity Note The Filter button should be OUT when the DH 110 is turned ON to avoid a switching transient during the first minute of operation If it is IN at turn on wait one minute before releasing
45. the black wire of the second group to PC14 eyelet Gl S 47 0 Select the 2 red LEDs To install these with correct polarity observe the tiny flat on the LED flange which marks the cathode lead This must he towards the near end of the PC 14 board or Phono switch S 1 when the LED is attached to the front near the edge When the nipple of the LED is pointed toward you with the flat on the left bend the leads together with long nosed pliers upward at a right angle so the bend will be 7 10 from the back surface of the LED about 34 Solder the LEDs to the front holes on the under side of PC 14 with the bent portion of the leads emerging on the top side Each LED protrudes through the front sub panel hole Solder both leads on each LED 48 Cut two 1 2 lengths of the black plastic shrink tubing Slide a piece of tubing over each LED from the front so only the nipple of the LED protrudes Shrink the tubing around the LED body by holding a lighted match near the tubing This will prevent back light from reflecting on the sub panel 49 Select the two flat knobs 2 set screws and the smal ler L shaped Allen wrench Place a screw on the end of the wrench and thread it into each knob Install these knobs on the switch shafts above the LEDs The set screw should engage the flat on each shaft 50 _ In like fashion install the remaining set screws in the 4 round knobs and fix them to the flatted shafts on the o
46. ther controls 5 I _ Taking care not to use excessive force install the 6 black pushbuttons on the switches 52 J Select a pair of end caps either the standard ones or those for rack mounting and the black front panel extrusion Place the front panel in position taking care to insert the LEDs into their holes and check for sufficient clearance around each knob It is possible to shift the phone jack bracket slightly or the mounting of an individual control by resolder ing if necessary for correct alignment Slip each end 14 cap into the slots of the front panel Select the 4 cap screws and nuts and secure the end caps with the large Allen wrench 53 Install the appropriate loading capacitors at the pairs of holes identified E F G and H below the phono input sockets on the back panel board The correct choice is discussed in the Additional Information section of this manual In lieu of more specific in formation we suggest the 120 pF values at E and G for Phono 1 and the 220 pF values at F and H for Phono 2 Bend one lead around the capacitor so it is parallel with the lead at the opposite end The leads should extend more than 196 from the body but must not be longer than 3 or they might touch the metal back panel Plug each into adjacent pairs of holes Now check to make sure that there are no strands of power transformer leads or the line cord that are unsoldered Where the line cord passes under the tran
47. tor may help moving coil cartridges do not require a specific value or try connecting a 0 01 mfd capacitor across the phono input jack that feeds the pre preamplifier Even for experienced engineers RFI pre sents problems which often demand that they simply try and try again Tape 2 law 1 FILTER CD Video 124 Treble Bass BAL VOL Phono 1 2 Phono 2 ans 1 i i MONO 2 i Tuner Y LINE OUTPUTS To Right Record Out Channel EPL Send EPL Return Switched Phone Direct FUNCTIONAL BLOCK DIAGRAM COMPONENT VALUES All resistors are 1 watt I Metal Film unless otherwise noted RI R2 R3 R4 R5 R6 R7 R8 R9 RIO RII RD RB R4 RIS R16 RI RB RI9 R20 Rl R22 R23 R24 R25 R26 R27 R28 R29 R30 R31 R32 R33 R34 R35 R36 R37 R38 R39 R40 R41 R42 R43 R44 R45 R46 R47 R48 R49 R50 R52 R53 R54 R55 R56 R57 R58 R59 R60 R6l R62 R63 R64 R65 R66 R67 R68 R69 51 52 53 54 5 56 S7 S8 93 100ohms 93 100 ohms 1 100 ohms 22 100 ohms 22 100 ohms 147 0 ohms 147 000 ohms 22 100 ohms 22 100 ohms 47 500 ohms 47 500 ohms 00 ohms 12 w 596 carbon film 0 ohms 12 w 596 carbon film 11 000 ohms 3 ohms 00 ohms 147 8 ohms 000 ohms 499 ohms megohm 1 100 ohms Imegohm I megohm 1100 ohms 100 000 ohms linear taper potentiometer Balance 50 000 ohms log taper potentiometer Volume 147 000 ohms 17 400 ohms 17 400 ohms 82 500 ohms 82 5
48. tory assembled units undergo many physical and electrical tests before shipment The circuit board in kits is similarly tested to meet all primary specifications before it is packed Nevertheless shipping damage can occur or human error may intervene to make service necessary Because many of the components in this refined design are not readily available and because substitution of apparently similar parts can easily compromise its perfor mance we strongly recommend that you make use of our complete factory service facilities or order exact re placement parts from the factory It is the owner s responsibility to return the unit freight prepaid to the factory service facility Units shipped freight collect will not be accepted Shipment should be made via United Parcel Service whenever possible We will not be responsible for damage caused by parcel post shipment repairs in this case will be made solely at the owners expense Be sure you insure for the full value of an assembled unit Use the original carton and packing materials and en close all of the following Complete shipping address Post Office Box numbers are not acceptable for UPS return re Serial number if not on the unit O2 Copy of dated bill of sale for service under warranty AR Description of malfunction If it is intermittent please indicate this You may also wish to attach your address directly to the unit or to
49. trol 20 dB Gain 20 dB 1 d B Input Impedance Greater than 25 000 ohms Signal to Noise weighted 3 12 dB Slew Rate 12 volts per microsecond Rise Time 2 5 microseconds maximum Phono in Line out 10 Vp p 1 kHz square wave load is 10 000 ohms in parallel with 10 nF Crosstalk 3 14 down 72 dB any input to any output Separation 4 2 greater than 82 dB 1 kHz greater than 52 dB 20 kHz Gain Tracking Error 4 4 less than 0 5 dB Maximum Output Noise less than 350 microvolts wideband less than 95 microvolts A weighted with 1 Kohm input termination volume full CW Bass Control 217 dB 20 Hz moving inflection variable turnover Treble Control 17 dB 20 kHz shelving 5 kHz fixed turnover Filter Response 3 dB 25 Hz 6 dB 15 Hz 12 dB 8 2 Hz 25 dB 3 Hz Filter Cutoff 3 13 2 2 1 3 13 2 2 2 25 Hz 12 dB octave GENERAL SPECIFICATIONS Semiconductors 30 transistors 3 ICs 12 diodes 2 LEDs Inputs 2 Phono Tuner Compact Disc or Video 2 Tape recorders EPL Outputs 2 Tape buffered 2 Line EPL Headphone Jack Controls Volume Balance Bass Treble Input Selector Phono 1 2 Selector Monitor Selector Mono Stereo Filter External Processor Loop Tone Control Engage Power Intermodulation Distortion Both SMPTE and CCIF IMD at operating levels from phono input to line output are below the residual of currently available instrumentation AC Supply Voltage 100 130 and 200 260 VAC 50 60 Hz Power Co
50. umbered positions identify the 6 lugs in a counter clockwise rotation with the 2 lug at the bottom in line with the front lug and the 6 lug at the top Insert the longer bared end of the green wire through the 8 lug and connect it to lug 7 Solder both lugs Connect the red wire to lug 6 S 5 Prepare another 14 green wire with 3 8 stripped from one end Prepare one end of a 14 black wire Do not strip the other end Prepare another 14 2 red wire Start with the longer green wire end longer than the red wire and the bare end of the black wire 1 2 shorter than the red wire Twist these together as before Insert the longer end of the green wire through lug 3 of the phone jack and connect it to lug 4 Solder both lugs Connect the red wire to lug 2 S 6 Select the power switch and two 4 screws Install the switch above the headphone jack so that the body of the switch is offset to the outer edge of the panel 7 J Select the main PC 14 circuit board assembly with the fuse in place and the rear bracket installed and a rubber grommet in the bracket Select the 6 larger nuts and washers for securing the controls to the front sub panel The two largest sets are used for the selector switches the volume control is the smallest size next to the power switch the 3 other sets go on the 3 central control shafts Be sure all the locating lugs on the controls engage the holes in the panel be fore securi
51. vertent high signal levels to your speakers And a power amplifier which is turned off can not degrade the quality of signal to the headphones which is otherwise a possibility We recommend that you turn off power amplifiers before connecting headphones or that they be plugged in before the system is switched on as a precaution The Direct outputs provide conventional signal levels independent of the headphone circuit If headphones are plugged in the level of the Direct output will be greatly reduced These outputs should not be used when head phone use is anticipated The performance specifications will be met so long as the input impedance of the power amplifier is 10K ohms or higher and the cable capacitance is less than 10nf This is no problem with typical interconnecting cables up to 10 feet If you are planning to use very long cables between preamp and power amplifier special low capacitance cable can be obtained EXTERNAL PROCESSING LOOP Send is an output at line level for the purpose of driving an external signal processor such as an equalizer time delay or noise reduction unit Like the recording outputs the load impedance should not be less than 10K ohms The EPL Return input impedance is 33K ohms and should also be at line level The EPL Return can also function as an additional high level input switched from the front panel OPERATION When you turn on the DH 110 power is also applied to the sw
52. y inaudible in the absence of a signal and distortion of all types both steady state and transient is at or below the threshold of the finest mea surement capabilities These excellent characteristics are maintained far outside the customary 20 Hz to 20 kHz band and signals well beyond that are handled without the need to restrict bandwidth Precise interchannel balance at all frequencies is main tained with close tolerance components and RIAA phono equalization is engineered to very narrow limits maintain ing accurate phase relationships and correct spatial perspectives as well as exceptional unit to unit consis tency The tone controls which can provide contouring of response for individual needs when switched in are nor mally isolated from the circuit for ruler flat response The components in the DH 110 have been selected for their superb audio performance as well as for their reliabil ity They have been incorporated in the unique Hafler fully complementary symmetry push pull circuit in a carefully designed circuit board layout which reduces crosstalk and maintains separation for a synergistic audio result that defies comparison regardless of cost Those who have chosen to build the kit will find that its step by step instructions will ensure a properly working unit even for the novice builder A substantial amount of preassembly has enabled us to check out each kit in nearly every aspect of performance and makes the DH 11
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