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SERVICE POLICY AND LIMITED WARRANTY

Your DH-110 Preamplifier has been carefully engineered

to provide many years of use without maintenance or ser-
vice. Factory 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
owner’s 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:

1. Complete shipping address (Post Office Box numbers

are not acceptable for UPS return)

2 . Serial number (if not on the unit).

3 . Copy of dated bill of sale (for service under warranty)

4. Description of malfunction. If it is intermittent, please

indicate this.

5 . You may also wish to attach your address directly to the

unit, or to the line cord.

All service work is guaranteed for 90 days.

Warranties apply only to the original purchaser, and are

void  if the  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 component 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.

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Summary of Contents for DH-110

Page 1: ... DH 110 INSTRUCTIONS for ASSEMBLY and OPERATION LM132 3 00 Please refer to this serial number in all communications regarding this equipment THE DAVID HAFLER COMPANY 5910 Crescent Boulevard Pennsauken New Jersey 08109 ...

Page 2: ...s 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 Contro...

Page 3: ... 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 ...

Page 4: ...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 i...

Page 5: ...t 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 Outp...

Page 6: ... 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 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 list...

Page 7: ...nections 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 1 Make a good mechanical connection to hold the wire in position while heat and ...

Page 8: ... Allow the excess to flow away onto the 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 lis...

Page 9: ...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 0 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 0 Select the main PC 14 circuit board assembly with the fuse in place and the rear bracket installed and a rub...

Page 10: ...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 and tin the strands to secure them Six in...

Page 11: ... 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...

Page 12: ... 0 RIGHT n n IGHT PHONO LEFT PHON i 1 6 IN 02 13 03 15 1 15T1 I 1I I ot60 04 SELECTOR MONITOR TONE r I I _EPL I 1 1 PHONO M SlA R t K s 3 FLAT ROUND D13 D14 ...

Page 13: ...FT LINE r 0107 J Q xo T c21 012 oE Cl9 I 1 I 1 Ql R44 izJ 141 R144 011 0 D5k 0 Fl v I E 1 co 0 0 527 0 Do EO M l D6 D7k 0 c34 0 C36 0 C32 v R66 R56 llll h R65 8 6 g 3 Ic38 R62 K TUK 8 III1 I R57 0 6 R45 iD12 VOLUME R59 R64 L R R26 ...

Page 14: ...e 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 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 0 Install the appropriate loading capacitors at the pairs of holes identified E F G and H bel...

Page 15: ...k 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 ti...

Page 16: ...le accepts plug in cables you can usually overlook its internal wiring capacitance as it will likely be within the 50pF 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 cartr...

Page 17: ...d 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 ...

Page 18: ... w 1 CD Video Phono 1 Phono 2 Tuner Record Out EPL Send EPL Roturn PHONO 1 C 2 B C R TONE FILTER EPL Treble Bass SAL VOL v v 0 0 1 LINE OUTPUTI To Right Channel r K Switched E Direct FUNCTIONAL BLOCK DIAGRAM 1 8 ...

Page 19: ...4 RM035 RCO29 RC023 RC029 RC023 RC042 RCO44 RCO44 RC038 RC0l6 RC028 RC046 RC029 RC017 RC043 RC0l6 RC023 RC015 RC0l5 RM034 SPI I2 SRl I2 SR111 SPI I3 SAI I6 SP111 SA1 16 SLll2 C l 5 ET0 Cl1 Cl2 Cl3 Cl4 Cl5 Cl6 Cl7 Cl8 Cl9 C20 c21 c22 C23 C24 C25 C26 C27 C28 C29 C30 C3l C32 c33 C34 c35 CM c37 C38 c39 C40 C4l Dl D2 D3 D4 D5 D6 D7 D8 D9 D10 Dll D12 D13 D14 ICl IC2 IC3 Fl 10 mF polypropykne 5Ov CP111 1...

Page 20: ...L I 1 L 7 l0g000 QQJ 527 R a rbd 1 I3 L I4 I pm I 0 8 _ 7 513 b 6 R 1 black SWITCH PINS SEEN FROM BOTTOM OF CIRCUIT CARD NOTE Tranaformu shown wind for 12OVolt primary For other vo1tag a 8 chart at right P ER ACCESSORY OUTLETS U Cl8 00 07 b s2c S2d s3a 50 08 4 0 00 1 2 3 4 5 6 1 6 2 3 4 5 t 2 3 4 1 2 3 4 3 0 010 OOOOOOOOQOOO 10000 0 0 0 0 1 I I POWER SUPPLY 2 0 e s2a S2b S3b s3c 10 012 ...

Page 21: ...PLIFIER SCHEMATIC DIAGRAM 8 85 LEFT CHANNEL SHOWN TO QlS S7 C30 AND RSO LARGE CIRCUIT CARD IS PC14c CABLE PIN ASSIGNMENTS J22 TO J23 A PIN 1 AUX L 2 TUNER L 3 RECORD L 4 LINE GND L 5 SHIELD GND 6 AUX R 7 RECORD R 8 TUNER R S LINE GND R 10 PHDN02R 11 WON0 GNDR 12 PHDND2L 13 PHOND 1 R 14 PHOND GND L 15PHONOlL J24 T O J25 B PIN 1 GUT LINE L 2 SHIELD 3 WT LINE R 4 SHIELD 5 EPLSENDR 6 EPL RETURN R 7 SH...

Page 22: ...s RM025 brown brown black brown Resistor 22 IK ohms RM035 ted red brown red Resistor 1 megohm RM044 brown black black yellow Set screw 8 x 3 16 Socket 4 pin bottom entry Washer volume control M8 flat LED red Shrink tubing 1 HP122 XM012 HWlll QD119 HR135 Nut 4 40 KEP Nut 6 32 KEP Nut 10 32 KEP Nut control shaft M7 x 75 Nut 3 8 Lockwasher 3 8 Screw 4 40 x 5116 Screw 4 40 x 5 8 black screw 4 40 x 7 8...

Page 23: ...r 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 s...

Page 24: ...Printed in USA ...

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