Hafler 945 User's Manual
Contents
1. Remote Control Diagram Functional Block Diagram Antenna Connections Initial Power Up Muting System Preamplifier Section Audio Line Level Inputs Video Switching_ Tape Inputs and Outputs Tone Controls and Tone In Out Mute Control Volume Control and Volume Control Indicator Balance Control Mono Control Headphone Output see AM FM Tuner Section AM FM Selector sss Up Down Tuning and Auto Selector Memory Presets 9 and 10 Preset Shift Front Panel Memory Preset Buttons 7 and Next Remote Control Storing Stations into Memory CIRCUIT DESCRIPTION Line Level Input Selector System JFET Buffer And Record Output Driver Muting System ADDITIONAL INFORMATION General Troubleshooting Hints Ground Loops FM Antenna anie AM Antenna cette Remote Control Battery Replacement Cleaning Maintenance SERVICE POLICY AND LIMITED WARRANTY 3 Motno Gorntrol xc ea t ees Tape Monitor Switching Volume And Balance Controls2. HA In VIDEO VIDEO IN SWITCHED AC LINE VOLTAGE LINE OUT MONITOR OUTLETS RATING LEFT CHANNEL ANTENNA BRACKET RIGHT CHANNEL A V OUT V ha 2 EPL 75 pu ANT 300 945 PREAMP TUNER REAR PANEL VIEW 240 VERSION 1 945 PREAMP REMOTE CONTROL VOLUME press left volume button for decreased volume press right volume button for increased volume pressing either volume button defeats MUTE TUNE press left button to change tuner down frequency press right button to change tuner up in frequency operation depends status of AUTO MAN front panel NEXT press to increment PRESET to next higher preset number 4 press to select PRESET 1 41 press to select PRESET 11 INPUT SELECTORS press to select CD TUNER A V 1 A V 2 or AN 3 Button on front panel lights green to indicate selected function 10 7 SELECTORS press to select TAPE 1 or 2 EPL Button on front panel lights red to indicate selected function See text for important operating details POWER press to change between READY and ON mode Power switch on front panel lights amber when in READY mode green when in ON mode 9 AM FM press to change between AM and FM 0 TONE IN OUT press to change between tone controls ON and OFF Button on front panel lights green when tone controls are active 11 MUTE p
3. Hafler HOME AUDIO Series 945 Preamp Tuner COMPONENTS 10 11 NOTICE IMPORTANT SAFETY INFORMATION The lightning flash with arrowhead symbol within an equilateral triangle is intended to alert the CAUTION A CAUTION T 0 4 user to the presence of uninsulated dangerous voltage within the product s enclosure that may 4 RISK OF ELECTRIC SHOCK be of sufficient magnitude to constitute a risk of _____DONOTOPEN _ NOT OPEN electric shock to persons WARNING TO PREVENT FIRE OR The triangle is intended to alert the user of the SHOCK HAZARD DO NOT EXPOSE THIS r of important operating and mainte EQUIPMENT TO RAIN OR MOISTURE 2 READ INSTRUCTIONS All the safety and operating instructions of your Hafler equipment should be read before power is applied to the equipment RETAIN OWNERS MANUAL These safety and operating instructions should be retained for future reference HEED WARNINGS Al warnings the equipment and in the operating instructions are important and should be followed FOLLOW INSTRUCTIONS All operating and use instructions are important and should be followed HEAT The equipment should be kept away from areas of high temperature such as heater vents radiators stoves ovens fireplaces VENTILATION The equipment should be used in an area suitable for proper ventilation Care should be taken not to impede airflow in and around the cabinet Do not mount
4. via the switch when no tone control action is desired The tone controls also limit the total bandpass of the line amplifier The Mute control is for turning off the Line outputs useful when it is desired to temporarily interrupt the signal to the amplifier The Mute mode is active when the Volume Control Indicator is flashing green The Mute mode is accessible only from the Remote Control Pressing either Volume button on the Remote Control will automatically de activate the MUTE mode This motor driven Volume Control affects the level of signal present atthe Line Output and Headphone jacks This control may be rotated by hand at the front panel or via the Up Down Volume buttons on the Remote Control The Volume Control Indicator will flash green either during the muting delay period when the unit is first turned on or when the MUTE mode is activated via the Remote Control This front panel control alters the proportion between right and left output volumes In the full counterclockwise position only the left channel will be heard In the full clockwise position only the right channel will be heard The Balance Control is useful for balancing the acoustic output of the system between left and right speakers as well as being useful for system troubleshooting The Balance Control is not available from the Remote Control The Mono button converts stereo sources to monophonic or can be used to feed a monophonic input from one channel into
5. IOOFS Operation of the 945 Preamp Tuner is straightforward and few operational problems should be encountered after a thorough reading and understanding of the owners manual The Functional Block Diagram provides an excellent picture of the signal flow and should be referred to along with the descriptive text If all controls are in the intended position and the Ready light is green check all system power connections interconnecting and speaker cables and fuses The 945 does contain one internal power fuse but this fuse should not generally blow unless a malfunction has occurred This fuse should be replaced only by aqualified technician and only with the exact type and rating of fuse originally supplied If this fuse is replaced and blows again within a short time disconnect all power immediately and return for service H all controls fuses cables etc seem to be functioning properly a process of one at a time component substitution should be employed until the defective unit is identified If only one channel is not functioning properly one at a time reversal of interconnect and speaker cables from left to right should reveal the malfunctioning component Ground loops are characterized by a low level hum or buzz in the system Loops are caused by a voltage potential difference between two points in a ground circuit and aggravated when multiple paths for a given circuit exist Noise free audio performance is dependent upon all g
6. Line Amplifier ree Tone Control System Headphone Amplifier AM FM Tuner hebes PERFORMANCE SPECIFICATIONS LINE AMPLIFIER Measured at Line Out HEADPHONE AMPLIFIER TUNER SECTION FM TUNER SECTION AM GENERAL INFORMATION All specifications are for 20 Hz 20 kHz unless specified otherwise FREQUENCY RESPONSE 0 1 dB into 33 000 ohms BANDWIDTH 10 Hz 150 kHz 3 dB into 1 Ok ohm load MAXIMUM OUTPUT 5 volts RMS TOTAL HARMONIC DISTORTION AND NOISE 0 02 2 volts RMS SENSITIVITY For 0 5 volts RMS Output 45 mV RMS SIGNAL TO NOISE RATIO A Weighted relative to 2 volts RMS output 100 dB INPUT IMPEDANCE 22k ohms OUTPUT IMPEDANCE 316 ohms TONE CONTROLS Bass 16 dB 20 Hz moving inflection variable turnover Treble 14 dB 20 kHz shelving 5 kHz fixed turnover MAXIMUM OUTPUT 4 volts RMS into 150 ohm load OUTPUT IMPEDANCE 150 ohms IHF USABLE SENSITIVITY Mono 6 5 dBf Stereo 12 dBf SIGNAL STRENGTH FOR 50 dB QUIETING Mono 11 dBf Stereo 34 5 CAPTURE RATIO 1 5 dB AM SUPPRESSION 60 dB ALTERNATE CHANNEL SELECTIVITY 63 dB TOTAL HARMONIC DISTORTION AND NOISE 1 kHz Mono 0 08 Stereo 0 3 SEPARATION 40 dB 1 kHz SIGNAL TO NOISE RATIO 65 dBf Mono 75 dB Stereo 70 dB SENSITIVITY 350 uV m SELECTIVITY 27 dB SIGNAL TO NOISE RATIO 60 dB AUDIO INPUTS Tape 1 Tape 2 EPL AV1 A
7. both channels The Mono mode is active when the button is lighted green For more features of the Mono Control see the AM FM Tuner Section The Mono Control is not available from the Remote Control The Headphone receptacle is a standard 1 4 stereo phone jack with the tip of the plug as the left channel the ring the right channel and the barrel ground The headphone driver circuit is separate from the main line amplifier to provide the extra power for driving headphone loads Inserting a plug into the Headphone receptacle will automatically turn off the Line Output Remember to reduce the Volume Control setting before unplugging the headphones since a normal listening level for headphones may correspond to a surprisingly high volume for loudspeakers AM FM TUNER SECTION The Tuner Section of the 945 Preamp Tuner has been configured to match the broadcast requirements of the intended country of destination For North America and some other areas channel spacing will be set to increment at 100 kHz intervals for FM and 10 kHz intervals for AM For Europe and some other areas channel spacing will be set to increment at 50 kHz intervals for FM and 9 kHz for AM Similarly the de emphasis curves are matched to the specific areas The AM FM Selector controls whether the tuner will be operated in the AM or FM band The status of the tuners operation will be indicated in the display window with the logo AM or FM Note that this con
8. s is in the de activated position red light OFF The Tone In Out button on the Front Panel or via the Remote Control activates the Bass and Treble Controls when the button is lighted green In the OUT mode button light is off the Tone Controls are completely removed from the signal path regardless of Bass and Treble knob position Control of Bass and Treble is not available via the Remote Control although preset tone settings may be enabled via the Remote Control Tone In Out button The Bass Control has a variable inflection or hinge point so that only the very low frequencies are affected by small amounts of knob rotation on either side of center This facilitates small amounts of low frequency corrections without noticeably altering the musical balance at upper bass frequencies As the knob rotation is increased further from center frequencies closer to 500 Hz are affected The Treble Control has a fixed hinge point at 1 kHz and has shelving action above 5 kHz This affords proper high frequency corrections without irritation from excessive boost at extreme high frequencies 13 MUE CONTROL VOLUME CONTROL AND VOLUME CONTROL INDICATOR BALANCE CONTROL MONO CONTROL HEADPHONE OUTPUT AM FM SELECTOR Activating the Tone Controls may cause a slight change in tonal balance even when both Bass and Treble controls are in their center detented position and therefore the Tone System should be disabled
9. such as equalizers etc The Tape Outputs are used to send the signal to the processor and the Tape Inputs are used to return the signal from the processor H only one signal processor is connected to the system and no tape deck Tape 2 is the preferred loop This allows Tape 1 to be used as an additional line level input If one signal processor and one tape deck is connected to the system it is usually preferred to connect the processor to Tape 2 and the tape deck to Tape 1 This will prevent the processor from affecting signals sent to the tape deck If it is desired to affect signals sent to the tape deck then connect the devices in the opposite order If two signal processors are connected to the system then a decision must be made as to which device should come first in the signal path This will depend on the type of device connected and the effect desired NOTE Though rare it is possible that some external devices connected to the Tape Outputs may cause slight distortion to the main signal path when that device is turned off This is due to possible semiconductor junction rectification unpowered circuits If this is suspected leave power applied to any device connected to the Tape Outputs during critical listening A common system malfunction can often be traced to inadvertently leaving a Tape Monitor button s engaged red light ON In case of no sound from a selected line level input check that the Tape Monitor button
10. the need for factory service The Hafler945 Preamp Tuner is warranted to the original owner non transferrable for seven years from the date of purchase including parts labor and return shipping costs within the Continental United States Alaska and Hawaii This warranty applies only to products sold in the United States Of America For warranties outside the USA please contact your local agent It is the owners responsibility to pay shipping preferably United Parcel Service UPS to the factory collect shipments will not be accepted Units under warranty should be accompanied by a copy of the dated Bill Of Sale Use the original carton and all packing material with the RA number clearly marked on the outside of the package Be sure to include a return address the RA number adaytime telephone number and a brief description of the difficulty including whether it occurs continuously or intermittently This warranty gives you specific legal rights You may also have other rights which vary from state to state 19
11. yielding high bandwidth and excellent stability The feedback loop contains two user selectable paths one conventional path for flat response and another path allowing insertion of a tone control network This arrangement allows maximally flat response and the shortest cleanest signal path when tone control action is not required The output of the Line Amplifier is capacitor coupled to the output of the preamplifier The Tone In Out button allows complete removal of the tone controls from the signal path This switching is accomplished with the same type of CMOS FET electronic switch used for the Input Selector This switching arrangement eliminates signal degradation due to mechanical switch contacts and allows the electronic switch to be located very close to the Line Amplifier circuitry The Bass Control is of a moving inflection variable turnover type and the Treble Control is of a shelving variable turnover type These types of tone controls offer the best tools for modifying tonal balance without introducing unwanted side effects See Operation Section for further information The Muting System monitors the power supply voltage During the power up cycle the Audio and Headphone Outputs are muted until the regulated voltages reach a predetermined level and then remain muted for several seconds to allow all circuitry to stabilize During power down or in cases of excessively low AC line voltage the Audio and Headphone Outputs a
12. DOW See Inset DISPLAY ILLUMINATES ONLY IN TUNER MODE A AM FM indicates whether tuner is in AM or FM B AUTO lights when tuner is in AUTO tuning mode C FM station D tuning of station frequency FREQUENCY indicates frequency of selected AM or 50 kHz European Models Only indicates 50 kHz in FM mode MEMORY indicates that memory is ready to accept new PRESET assignment F STEREO lights when an FM broadcast is in stereo MONO mode overrides this indicator G CH indicates PRESET number selected TUNED lights when usable station is selected MHz kHz indicates MHz in FM mode kHz in AM mode m SELECTORS press to select TAPE 1 or TAPE 2 EPL Button lights red to indicate selected function TAPE 1 overrides INPUT SELECTORS TAPE 2 EPL overrides 1 See text for important operating details INPUT SELECTORS press to select CD TUNER 1 2 or AN 3 Button lights green to indicate selected function selecting input simultaneously selects corresponding video input 8 VIDEO RECORD TAPE 1 A V IN VIDEO IN VIDEO SWITCHED AC LINE VOLTAGE LINE OUT ra A OUTLETS RATING LEFT CHANNEL 2 wer ANTENNA BRACKET DAAC RIGHT BUTIN CHANNEL AIV OUT CD FM ANT AM ANT UNSWITCHED LINE CORD TAPE 2 EPL 75 pu ANT OUTLET CONNECTOR 300 OHM 945 PREAMP TUNER REAR PANEL VIEW 120 VAC VERSION 6 VIDEO RECORD
13. V2 AV3 CD AUDIO OUTPUTS Line Out Record 1 Record 2 EPL AV Headphone VIDEO INPUTS Video 1 Video 2 Video 3 VIDEO OUTPUTS Monitor Record FRONT PANEL CONTROLS Power Tuner Memory Presets Tuner Preset Shift AM FM Selector Tuner Memory Mono Tone In Volume Balance Bass Treble Tuner Up Down Tuning Tape 1 Tape 2 EPL Audio Video Input Selectors REMOTE CONTROLS Up Down Volume Up Down Tuning Preset Next Preset 1 Preset 11 Audio Video Input Selectors Tape 1 Tape 2 EPL Power AM FM Selector Tone In Mute CONVENIENCE OUTLETS 120 VAC MODELS 1 Polarized Unswitched 2 Polarized Switched 1 Grounded Switched 240 VAC MODELS 1 Reverse IEC Unswitched 2 Reverse IEC Switched PHYSICAL DIMENSIONS 17 Wide x 11 3 5 Deep x 2 1 2 High excluding feet Faceplate 17 or 19 Wide 43 2 cm Wide x 29 5 cm Deep x 6 3 cm High excluding feet Faceplate 43 2 cm or 48 3 Wide POWER CONSUMPTION Excluding Convenience Outlets 20 watts Max INSTALLATION RACKMOUNTING VENTILATION PLACEMENT UNE VOLTAGE The 945 Preamp Tuner is supplied in either a 17 Black Version or a 19 Silver Version The 19 model has rackmounting holes provided for installation in equipment racks The holes are on standard spacings though the faceplate height is not standard size The 945 produces very little heat during operation and therefore requires no special considerations for ventilation The preamp tuner s
14. an attempt to mate to a two wire ungrounded receptacle use a grounding adaptor with the grounding tab or wire suitably connected to earth ground NON USE PERIODS During periods of extended non use the power cord should be unplugged from the power source 1 12 13 14 15 16 17 18 CLEANING The equipment should be cleaned only as detailed in the operating instructions OBJECT AND LIQUID ENTRY Care should be taken so that objects and or liquids such as cleaning fluids or beverages are not spilled into the enclosure of the equipment DAMAGE REQUIRING SERVICE Hafler equipment should be serviced by qualified service personnel when A The power supply cord or plug has been damaged or B Objects have fallen or liquid has been spilled into the equipment or C The equipment has been exposed to rain or D equipment does not appear to operate normally or exhibits a marked change in performance or E equipment has been dropped or the enclosure has been damaged SERVICING The user should not attempt to service the equipment beyond that which is described in the operating instructions All other service should be referred to qualified service personnel CARTS AND STANDS The equipment should be used with carts or stands only of sufficient strength and stability for the use intended An equipment and cart combination should be moved with care Quick stops and starts excessive force and uneven sur
15. at flexibility of connection and control the Tape Loops are probably the most complicated portion of the 945 to understand and operate Therefore a thorough reading of this section is strongly recommended Consultation of the Functional Block Diagram will aid in understanding the signal flow inside the unit TAPE DECK CONNECTIONS The Tape Inputs are electrically the same as the other line level inputs but are selected via the Tape Monitor 1 and 2 buttons Activating these switches red light ON breaks the main signal path after the Input Selector buttons and allows monitoring of a tape deck s output during recording or playback The Tape Outputs feed an audio signal to a tape recorders input The signal present at Tape 1 Out is the same as indicated by the Input Selector buttons The signal present at Tape 2 Out is also the same as indicated by the Input Selector buttons unless Tape 1 is selected Under this condition the signal present at Tape 2 Out is the same as Tape 1 Input This arrangement allows dubbing from Tape 1 to Tape 2 If only one tape deck is connected to the system Tape 2 is the preferred input This allows the Tape 1 input to be used as an additional line level input If two tape decks are connected to the system and tape copying is to be performed connect the source deck to 1 and the destination deck to Tape 2 SIGNAL PROCESSOR CONNECTIONS The Tape Loops may also be used for connection of signal processors
16. cesses memory locations 11 through 19 that there is no memory 10 The selected memory location is indicated in the display window underneath the CH logo The memory presets available from the front panel are also available from the Remote Control but use a different set of buttons The Next button may be used to increment the tuner to the next higher preset number The 1 or 11 buttons may be used to jump from one group of preset numbers to another This avoids having to press the Next button repeatedly to access a distant preset number Example The tuner is set to preset 4 To get to preset 13 press 1 1 then press Next twice To store a station into a memory location first set the tuner to the desired broadcast station Then press the Memory button A MEMORY logo will appear in the display for about four seconds During this period press the desired preset button 1 through 9 or 10 with 1 through 9 The station will now be committed to that memory location Note that any station AM or FM may be stored in any location The tuner will automatically switch between AM and FM according to the station stored It may be most convenient to store the stations in numerical order or to store them in descending order of most frequently used or to use 1 through 9 for FM and 11 through 19 for AM Storing stations into memory is not available from the Remote Control The 945 has the ability to detect FM stations b
17. ction Additional Information As soon as the 945 Preamp Tuner is plugged into AC power the Power Switch will glow amber indicating a low power stand by mode When the unit is turned ON the front panel Power Switch or Remote Control the Power Switch light will turn green and the Volume Control Indicator will beginto flash green Once the muting delay period has passed and the power supply has stabilized the light will turn steady green unless MUTE was selected when the unit was previously turned off The Preamp Tuner is now ready to enjoy The muting will reactivate immediately and the Power Switch tum amber upon loss of AC line voltage operating the Power Switch or if line voltage falls below a level which precludes proper operation of the Preamp Tuner s circuitry All selected operating modes that were set when the unit was turned off will resume when the power is turned on again It will not however remember some of the set operating modes if AC power is lost entirely Tuner Presets and selected inputs will be retained in memory for a few days PREAMPLIHER SECTION The audio input jacks labelled CD AN1 A V2 and AN3 are identical line level inputs These inputs along with the internal AM FM Tuner are selected via the front panel Input Selector buttons or via the Remote Control The selected function wil be indicated by a green light on the corresponding button LINE OUT This output feeds the selected input signal to th
18. e power amplifier A V OUT This output feeds any selected audio input signal except A V3 to a video recorder This may be done to allow an audio recording along with a video signal or for an audio only recording ANS is blocked from this output to avoid possible feedback conditions A V3 is for playback viewing purposes only or is recommended to be used as the recording destination unit when dubbing from one video device to another The video input jacks labelled Video 1 Video 2 and Video 3 are selected simultaneously with the corresponding audio AN inputs When A V1 or A V2 is selected the video signal is fed to both the Video Record and Video Monitor Outputs through separate buffer amplifiers In most cases the Video Monitor Output will be connected to the video input of a television receiver monitor and the Video Record Output will be connected to the video input of a video recorder for dubbing purposes When A V3 is selected the video signal is fed to the Video Monitor Output but the Video Record output is de activated to prevent possible feedback conditions AN3 is for playback viewing purposes only or is recommended to be used as the recording destination unit when dubbing from one video device to another 12 5 and OUTPUTS CONTROLS IN OUT The 945 incorporates two Tape Loops for use with audio tape decks or other input output signal processors Due to the gre
19. es of outdoor antennas Some may be optimized for directionality while others may be optimized for high gain It is best to seek local advice for analysis of your specific reception conditions In addition to the 300 ohm FM antenna terminals a standard F type 75 ohm coaxial antenna connector has been provided The use of this input using coaxial cable is recommended for outdoor use to minimize noise interference This input should also be used for connections to FM cable services Again seek local advice for choosing a cable type for your application 18 AM ANIENNA The loop antenna supplied will offer excellent reception in most situations It is directional antenna requiring orientation perpendicular to the radio station s transmitter Because of its directional behavior it will offer the quietest least background noise signal on high to medium strength stations compared to a straight wire antenna However the loop antenna is not the most sensitive and therefore may not satisfactorily receive medium to weak stations especially in automatic tuning modes For maximum sensitivity a straight wire as long as practical should be connected to the AM terminal This type of antenna is relatively non directional and will not yield the best signal to noise ratio but will allow reception of the largest number of stations REMOTE When using alkaline batteries in the remote control expectancy of the batteries will be ab
20. faces may cause the equipment and cart combination to topple POWER LINES An outdoor antenna should be located away from power lines OUTDOOR ANTENNA GROUNDING H an outside antenna is to be used with the Hafler Tuner be sure that the antenna system is grounded so as to provide some protection against voltage surges and built up static charges Section 810 of the National Electrical Code ANSI NFPA No 70 1 984 provides information concerning supporting structure grounding of the lead in wires to an antenna discharge unit size of grounding conductors location of antenna discharge unit connections to grounding electrodes and requirements for the grounding electrode See Figure 1 FIGURE 1 Antenna Lead In Wire Ground Antenna Discharge Unit NEC Section 81 0 20 Electric Service Equipment Grounding Conductors NEC Section 81 O 21 Power Service Grounding Electrode Svstem NEC Art 250 Part H 2 TABLE OF CONTENTS PERFORMANCE SPECIFICATIONS General Information INSTALLATION Rackmounting_ Ventilation Placement Line Voltage OPERATION CONNECTIONS Power Cord Connection Convenience Outlets Front Panel View Diagram Rear Panel View Diagram
21. hould be located at least several inches away from components that contain large power transformers such as power amplifiers due to the possibility of audible hum or buzz from magnetic gt radiation The 945 Preamp Tuner is available in either 120 VAC or 240 VAC 50 60 Hz versions Make sure that the unit is configured for your local AC line voltage before attempted use The configuration is labelled directly above the power cord entry point OPERATION CONNECTIONS POWER CORD CONNECTON CONVENIENCE OUTLETS Units wired for 240 VAC are supplied without AC power cords Local agents will supply cords with male connectors appropriate to the local standard Units wired for 120 VAC are supplied with a detachable AC power cord The female connector plugs into the receptacle provided on the rear panel This power cord is a standard IEC Type 320 3 wire 16 gauge assembly Should replacement ever be necessary be sure to replace it with an identical cord Never remove the grounding pin from the male end of the cord In applications where a grounded wall outlet is not available a ground adaptor should be employed with the ground tab or wire of the adaptor connected to a suitable earth ground Units wired for 720 VAC have a total of four outlets for connection of associated components The polarized Unswitched Outlet is powered at all times which should generally be used for a turntable or tape deck The remaining three Switched Outlets one g
22. o mechanical switch contacts and allows the electronic switches to be located close to therear panel inputs for minimum signal path lengths and reduced interchannel crosstalk The output of the audio Selector System is followed by a very high input impedance JFET buffer pair to establish negligible CMOS switch loading for low distortion and to provide a low impedance source for the Tape Outputs and the Volume and Balance controls The Control Logic creates digital codes fed to a CMOS FET electronic selector switch These inputs are selected simultaneously with the corresponding audio inputs The selected video input is fed through separate wide bandwidth 6 dB amplifiers for each of the Video Monitor and Video Record Outputs Only Video 1 and Video 2 signals are available at both the Video Monitor and Record Outputs Video 3 blocked from the Video Record Output to prevent feedback from occurring The Tape Monitor buttons drive CMOS FETelectronic switches to break the line input path to insert tape input signals This switching arrangement allows optimum signal routing by placing the switches close to the Tape Input jacks and the Input Selector System The 945 Line Amplifier is a Class A JFET design employing a differential input stage driving a complementary high gain output stage symmetrically driven for balanced slew rate and low harmonic distortion This topology uses only four active devices per channel and extremely short loop feedback
23. on a carpeted shelf or in a sealed enclosure Allow for proper clearance above the equipment WATER AND MOISTURE The equipment should not be used in or around water such as bathtub sink or swimming area Also the equipment should not be used in areas prone to flooding such as a basement POWER SOURCES The equipment should be connected only to a power source of the same voltage and frequency as that listed on the rear panel above the power cord entry point POWER CORD PROTECTION Power cords should be arranged so that they do not interfere with the movement of objects in the room people fan blades utility carts etc Also care should be taken that the cord is not pinched or cut and placed so that it is not in danger of being pinched or cut as in under a rug around a tight corner etc POWER CORD GROUNDING The power supply cord is of a three wire grounded type designed to reduce the risk of electric shock sustained from a lve cabinet It is assumed to be of suitable length for most uses of the equipment The use of extension cords and power strips is discouraged unless they are of suitable rating to deliver the required total current for safe operation of all connected equipment Furthermore extension cords or power strips must provide the same three wire grounded connection It is important that the blades of the equipments plug be able to fully insert into the mating receptacle Never defeat the grounding connection on the plug in
24. out one year CONTROL under normal usage BATERY REPLACEMENT The batteries will require replacement when the remote control ceases to function or the effective range reduces Be sure to replace the batteries with the same type as specified on the rear of the remote housing Alkaline batteries though not necessary will give the best performance It is recommended that the batteries be removed from the remote control if the unit is to be left idle for extended periods CLEANING If the faceplate should become soiled it may be cleaned with a slightly damp soft cloth and if necessary MAINTENANCE a mild detergent Do not use any abrasive cleaners or solvents Unplug the power cord before attempting cleaning operations There are no user serviceable parts or adjustments inside the 945 Preamp Tuner and all servicing should be referred to qualified authorized personnel SERVICE POLICY AND LIMITED WARRANTY If you encounter any difficulty or have any question concerning your 945 Preamp Tuner please our Customer Service Department weekdays 8 a m to 3 30 p m Mountain Standard Time at 602 967 3565 Should you have any doubts as to whether the Preamp Tuner is malfunctioning and requires service please call us before sending in for repair All units being returned regardless of warranty status must receive a Return Authorization RA number In addition we can offer troubleshooting assistance that may simplify or even eliminate
25. re instantly muted to avoid extraneous noises The muting is accomplished by grounding the Line Output jacks and disconnecting the output of the Line Amplifier using a relay with gold contacts 16 HEADPHONE AMPLIFIER AM FM TUNER The Headphone Amplifier utilizes separate special purpose operational amplifier to drive the high current demands of headphone operation This provides the extra power necessary for driving difficult headphone loads and leaves the main signal path uncompromised for signals to power amplifiers The Headphone jack is equipped with a sensing switch that automatically turns off the Line Output when headphones are plugged in Antenna signal input to the FM Tuner section is via either balanced 300 ohm thumb screws or via an unbalanced 75 ohm F Type connector Antenna signal input to the AM Tuner section is via unbalanced thumb screws The FM front end features dual gate FET s for exceptional rejection of spurious noises and the reduction of IM distortion in the presence of high level signals Tuning is accomplished via a voltage controlled varactor diode driven by digitally synthesized Phase Lock Loop system Twin ceramic filters in the IF stage have flat group delay characteristics improving selectivity phase linearity and lowering distortion The audio output features multi stage multiplex filters for removing the 19 kHz pilot tone ADDITIONAL INFORMATION GENERAL TROUBLE SHOOTING HINTS GROUND
26. ress to change between mute ON and OFF Volume Control Indicator flashes when mute is ON INFRARED EMITTER aim at Front Panel to send remote commands i 1 Li zae ie n n 4 7771 HAJ 1 H 143 Z 3avl 8 1 2 TI N heal at c jd NI 341 e ut 945 PREAMP TUNER FUNCTIONAL BLOCK DIAGRAM ONE CHANNEL SHOWN ANTENNA 5 INTIAL POWER UP MUTING SYSTEM AUDIO LINE LEVEL INPUTS AUDIO UNE LEVEL OUIPUIS VIDEO SMKEHNG simple T shaped dipole ribbon antenna has been provided for FM reception Connect its leads to the rear panel terminals marked FM 300 OHM For best results the arms of this antenna should be fully extended and mounted flat against a wall or equipment cabinet A type antenna has been provided for AM reception It is to be connected to the rear panel terminals marked AM ANT and GND This antenna is attached at one end by a snap in hinge As this antenna is directional it will usually be beneficial to allow the antenna to swing away from the body of the tuner orienting it for best reception The antenna may be completely detached for maximum freedom of placement by carefully prying it loose from the plastic hinge The antennas supplied will yield satisfactory reception in most situations For further information regarding these antennas as well as alternate antenna types consult the se
27. roadcasting in stereo and automatically switch on its multiplex decoder Stereo decoding is indicated by the logo STEREO visible in the display The background noise level of a stereo broadcast increases as signal strength decreases The tuner has the ability to detect low signal strength and automatically switch to mono to reduce this background noise There are situations particularly when a weak signal strength fluctuates that it is best to force the tuner into mono with the Mono Control Mono Mode is active when the button is lighted green as well as the STEREO logo in the display being extinguished The Mono Control is not available from the Remote Control 15 CIRCUIT DESCRIPTION RECHVER and CONTROL LOGIC AUDIO UNE LEVE INPUT SHECTOR SYSTEM JFET BUFFER AND RECORD OUTPUT DRIVER VIDEO SWITCHING TAPE MONITOR SWITCHING UNE AMPURER TONE CONTROL SYSTEM SYSTEM The Remote Receiver circuitry decodes the infrared pulses received from the Remote Control the front panel Infrared Receiver This decoded information is sent to the Control Logic which controls all internal signal routing and Front Panel indicators The Control Logic also receives input commands from the Front Panel buttons The Control Logic creates digital codes fed to a CMOS FET electronic selector switch This arrangement besides allowing convenient remote operation eliminates signal degradation due t
28. rounded two polarized are powered when the Power Switch is engaged as indicated by the switch s green light The grounded outlet is provided for equipment requiring a grounded connection Units wired for 240 VAC have a total of three reverse IEC outlets for connection of associated com ponents The Unswitched Outlet is powered at all times which should generally be used for a turntable or tape deck The remaining two Switched Outlets are powered when the Power Switch is engaged as indicated by the switch s green light for all models the maximum power available from the Unswitched Outlet is 200 watts The maximum total power available from the Switched Outlets is 800 watts This total power may be drawn from a single outlet or a combination of outlets Since some power amplifiers consume more than 800 watts at maximum output check the power amplifiers rating before connecting to these convenience outlets 5 D at 4 D 09 19 48 6 1 EN YN YON N ON UN N ON goooooooooogo oQooGo roe oO 9 0 B 945 PREAMP TUNER FRONT PANEL VIEW FRONT PANEL CALL OUTS POWER SWITCH 15 lights amber when in READY mode lights green when in ON mode INFRARED RECEIVER WINDOW 16 MEMORY PRESETS l 9 press to store AM FM stations 9 into memory See 6 press to recall AM FM stations l9 from memory 17 10 PRESET SHIFT 11 19 press simultaneou
29. rounds being at the same potential with a single path for each ground connection Ground loops can exist in two forms 1 loops created in audio interconnects and 2 loops created between earth grounded chassis Mounting components to a rack with metallic rails may introduce ground loops between associated equipment because the rails can introduce a second ground path The extent of this problem will depend on the grounding arrangements of associated equipment Ground loops can occur non rackmounted equipment though it is less common If ground loops occur and any other component in the system has a three wire grounded power cord the first step should be to use a ground adaptor with the ground tab or wire of the adaptor notconnected on the power cord plug of the preamplifier DO NOT cut off the grounding pin on the plug It may be necessary to use additional adaptors on other grounded components if more than two components are earth grounded In other words only one earth ground per system should exist Another potential source of multiple earth grounds is from coaxial antenna or cable service feeds for FM or video sources which usually are and should be earth grounded The ground adaptor s should cure this grounding problem as well 17 FM ANTENNA WARNING The use of ground adaptors with the ground tab or wire of the adaptor disconnected will eliminate safety feature of the grounded power This safety feature i
30. s intended to reduce the risk of electric shock should an internal fault in the equipment result in an electrically live chassis Therefore this method of ground isolation should be employed only when absolutely necessary rather than as a general practice When using a ground adaptor for isolation make sure that the power cord plug is inserted into the receptacle in the same orientation if no adaptor were present to maintain the same hot neutral polarity SPECIAL NOTE ON VIDEO CABLE GROUNDS As mentioned above the ground conductor of cable service and antenna feeds should be connected to earth ground Often however due to long feed lengths especially in apartment distribution systems this ground wil be of poor quality and could be a source of noise This interference is usual characterized by high frequency noise rather than a hum or a buzz such interference is experienced a separate earth ground connection should be made from the cable outlet nearest the audio video equipment to a known good earth ground If ground loops exist due to potential differences in the interconnects in rack mounted systems then it is advisable to isolate the preamplifier chassis from the rack rails This may be accomplished by sandwiching a thin sheet of insulating material ie plastic washers or several layers of electrical tape etc between the rack and the preamplifier and securing the unit with non metallic ie nylon etc hardware I
31. sly with PRESETS 9 to store AM FM stations 1 1 19 into memory See 6 press simultaneously with PRESETS 1 9 to recall AM FM stations 1 1 19 from memory AM FM SELECTOR 18 press to change between and FM status indicated by AM or FM in display window MEMORY press before selecting PRESET to store displayed station into memory MEMORY indicator will light in display window for about 4 seconds MONO press to change between STEREO and MONO operation Buttons indicator will light green when in MONO In TUNER mode STEREO indicator in display window will extinguish when in MONO mode TONE IN press to change between tone controls ON and OFF Button s indicator will light green when BASS and TREBLE controls are active 19 VOLUME CONTROL BALANCE CONTROL HEADPHONE JACK BASS CONTROL 20 TREBLE CONTROL RACKMOUNTING HOLES 19 version only VOLUME CONTROL INDICATOR shows rotational position of VOLUME CONTROL lights steady green for normal operation lights flashing green for MUTED operation AUTO MANUAL press to change between AUTO and MANUAL modes of TUNING button in MANUAL mode AUTO indicator in display window will extinguish TUNING press left button to change station frequency down press right button to change station frequency up in MANUAL mode each press of button increments frequency one channel spacing up down in AUTO mode tuner will seek up or down to next usable station DISPLAY WIN
32. t may be necessary to insulate other components so that only one component is directly connected to the rack rails The ribbon dipole antenna supplied wil offer excellent reception in most situations To maximize the reception potential of this antenna a few guidelines should be followed fully extend the arms of the dipole mount the antenna as high as possible mount the antenna away from large metal structures orient the antenna perpendicular to the direction of the radio stations transmitter Some experimentation will be necessary in less than optimum reception areas or where reception of a distant station is desired Often an adjustment of a foot or so in antenna position can affect reception noticeably A number of alternate indoor antennas are available from traditional rabbit ears to antennas designed specifically for high quality FM reception Although these units offer little or no advantage over the ribbon dipole in terms of gain or directivity they are typically table mounted offering greater flexibility in placement mobility For the ultimate in FM reception especially in difficult reception areas an outdoor antenna is recommended There are two basic types of poor reception conditions Urban areas may be characterized by strong signals but those signals can be interfered with by reflections from tall structures Rural areas may be characterized by weak signals from distant stations There are many typ
33. trol is really needed only when manually tuning or storing presets The Preset buttons described below will automatically switch between AM and FM according to the station stored in memory 14 UP DOWN TUNING and SHECTOR MEMORY PRESEIS L9 and 10 PRESET SHIFT FRONT MEMORY PRESET 1 111 AND NEXT REMOTE CONTROL STORING STATIONS MEMORY MONO CONTROL Pressing the left tuning button will change the station frequency down the band Pressing the right button will change the station frequency up the band The Auto Selector controls whether the tuning buttons will change the station frequency by one channel spacing Manual Mode or automatically move to the next usable station Auto Mode The status of this mode is indicated in the display window by the logo AUTO In most situations the Auto Mode is most useful as it allows the tuner to increment automatically to the next usable station avoiding multiple button strokes to find a station However the operation of the Auto Mode is keyed to signal strength so weak stations may be missed in the Auto Mode Therefore when searching for a weak station use Manual Mode The 945 has a total of 18 memory preset locations that may be used for storing and recalling either AM of FM stations The Memory Preset buttons 1 through 9 access memory locations 1 through 9 Pressing the 10 Shift button simultaneously with 1 through 9 button ac
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