Adcom 7705 Stereo System User Manual
Contents
1. Scottsdale Arizona 85255 Monday Friday United States of America 9 00 AM to 5 00 PM MST www adcom com service adcom com UNDER NO CIRCUMSTANCES SHOULD YOUR UNIT BE SHIPPED TO OUR FACTORY WITHOUT PRIOR AUTHORIZATION OR PACKED IN OTHER THAN ITS ORIGINAL CARTON AND FILLERS For fax inquires please include a return fax or voice number for the reply When calling or writing about your GFA 7705 07 be sure to note and refer to its serial number as well as the date of purchase and the dealer from whom it was purchased In the event the unit must be returned to our factory for service you will be instructed on the proper procedure when you call or write for a Return Authorization For warranty coverage a copy of the original proof of purchase is required If you have no original copy please contact your dealer to obtain a duplicate copy If the original shipping carton and its fillers have been lost discarded or damaged a duplicate carton may be obtained from our Service Department for a nominal charge Always ship PREPAID VIA UNITED PARCEL SERVICE UPS OR OTHER APPROVED CARRIER DO NOT SHIP VIA PARCEL POST since the packaging was not designed to withstand rough Parcel Post handling FREIGHT COLLECT SHIPMENTS WILL NOT BE ACCEPTED UNDER ANY CIRCUMSTANCES 14 GFA 7700 7707 Specifications Power Rating To ElA CEA 490 A Requirements 200 Watts continuous average power per channel into 8 ohms at any frequency between 20Hz and 20kHz with all2. as practical GFA 7705 07 Features e Precision matched devices used throughout the signal path e Independent power supplies for each channel e Fewer gain stages improve signal reproduction accuracy e Custom toroidal power transformer provides better regulation and greater peak current capability e ADCOM Universal pre prepped chassis and internal power supplies for easy in field upgradeability from 5 to 7 channel configuration e Independent thermal overload and distortion LEDs for all 5 to 7 channels e S A F E Circuit Self Annealing Fuse Equipped automatic reset protection circuit in the event of speaker or speaker wire dead short e High quality gold plated 5 way binding posts e High quality gold plated RCA jacks e Large independent internal heatsinks for greater cooling capability of output devices e Convenient 12 VDC power ON OFF triggering e Heavy gauge anodized aluminum front panel e Cooling vents for greater efficiency and cooler operation while driving low impedance loads Table of Contents Introduction Warranty Information sd cc02 ce csesseaccnincsessesainceissine nO nap to 4 Description of Unit 20 Amp Device Notification 4 Rear Panel tadas 5 O 7 Installation amp Hookup Unpacking the GFA 7 205 07 a sesiese seis cvowssss eerigvines sea 9 Placement of the GFA 7705 07 cccccssscccsccceececcescceessceeesaceeesaceesaees 9 QUICK Conn ction Diagram osc dsec
3. should not be defeated in order to accomodate standard 15 amp household wall outlets Please consult with your dealer and or licensed electrician for conversion of a 15 amp outlet and panel circuit to a 20 amp circuit distortion alert thermal protection iS 7 M 05 y Front Panel On Off Switch 5 The On Off Switch controls power to the power transformer and circuits of the GFA 7705 07 Whenever the GFA 7705 07 is energized the Power LED 7 will glow To turn the GFA 7705 07 on press the push button It will remain in the engaged position while the unit is energized To turn the GFA 7705 07 off press the push button in and release and it will move to the disengaged position Power LED 6 This LED will glow when the On Off Switch 5 is turned on and the GFA 7705 07 is energized The Power LED indicates that there is AC voltage being fed to the amplifier but it does not signify that all the amplifier s circuits are in operation If for example one of the Thermal Protection LED 8 glows that amplifier channel will not produce sound even though the Power LED may still glow When the GFA 7705 07 is turned off the Power LED will take some time to fade out completely It may take up to 30 seconds to fully extinguish NOTE Whenever a 12 Volt trigger connection is made to the GFA 7705 07 the Power LED will not illuminate whether the On Off Switch is pressed in or not until a 12V signal is present from the tr
4. these is the U type spade connectors at least 0 25 wide and maximum width of 0 57 The terminal will also accept bare wire up to AWG10 and banana type plugs single or dual See CONNECTING THE GFA 7705 07 for more information Outputs 2b Chassis knock out for future expansion channel card output binding posts GFA 7705 only WARNING THERE ARE NO USER SERVICEABLE PARTS OR FUSES INSIDE THE GFA 7705 07 In the event that the amplifier s rear panel circuit breaker fails to reset opens again when power applied to unit and unit turned on you must refer the amplifier to ADCOM Factory Service or ADCOM Authorized Service Center Do not open the amplifier nor remove the topcover Hazardous and Potentially Lethal Voltage Present and Warranty may be voided 12VDC Triggering 3a ADCOM has provided the installer the ability to control the OFF ON function of the GFA 7705 07 bya 12Volt DC output jack on the rear of certain pre amplifiers and tuner pre amplifiers When using this feature the front panel Power Switch must be left in the in on position To connect you will need a monaural mini phone plug to monaural mini phone plug cable of appropriate length not included to reach from the rear panel of the amplifier to the rear panel of the pre amplifier Contact your dealer for information on using this feature with ADCOM and other brand pre amplifiers Although 12VDC is optimal the circuit will operate from appro
5. to the attention of your ADCOM Dealer or ADCOM Customer Service Department A special note on hum When there is a low volume hum audible throughout your speakers even with the main volume turned all the way down you likely have a common phenomenon known as ground loop A ground loop is basically a difference in ground voltages between two or more components which are connected electrically and which creates multiple current paths where there must only be one This difference in potential creates a 60 Hz low level sound approximately a low A that appears to hum It can be caused by adding new components to your system but that does not imply there is anything electrically wrong with any new component With the advent of audio video and home theater systems the problem has become commonplace Generally the cause is the Cable TV incoming signal line This new incoming line may add an additional ground at a different potential from the AC line ground of your other equipment Symptom Possible Reason Possible Solution Power LED does not glow AC Power Cord 4 not plugged in Plug in AC Power Cord 4 No sound AC Breaker 3b opened Reset AC Breaker 3b 12V Trigger Connected but not activated Turn on 12V Source Unit Power LED glows Preamp or source unit is not on Make sure whole system is on but no sound Connections in rear are loose Verify all connections on rear of amp One channel not Input 1 or Output 2 connec
6. ADCOM GFA 7705 amp GFA 7707 S A F E HIGH CURRENT MULTI CHANNEL POWER AMPLIFIERS THE FOLLOWING PRECAUTIONS AND SAFETY INSTRUCTIONS ARE REQUIREMENTS OF UL AND CSA SAFETY REGULATIONS Warning To reduce the risk of fire or electric shock do not expose ATTENTION this unit to rain or moisture POUR PR VENIR LES CHOCS LECTRIQUES NE PAS UTILISER CETTE FICHE POLARISEE AVEC UN PROLONGATEUR UNE PRISE CAUTION DE COURANT OU UNE AUTRE SORTIE DE COURANT SAUF SI LES LAMES PEUVENT ETRE INSEREES A FOND SANS EN LAISSER AU RISK OF ELECTRIC SHOCK CUNE PARTIE A D COUVERT DO NOT OPEN CAUTION AVIS RISQUE DE CHOC ELECTRIQUE NE PAS OUVRIR TO PREVENT ELECTRIC SHOCK DO NOT USE THIS POLARIZED PLUG WITH AN EXTENSION CORD RECEPTACLE OR OTHER OUTLET UN LESS THE BLADES CAN BE FULLY INSERTED TO PREVENT BLADE EXPOSURE The graphic symbol of a lightning flash with an arrow point within a triangle signifies that there is dangerous CAUTION voltage within the unit and it poses a hazard to anyone POWER LINES removing the cover to gain access to the interior of the unit Only qualified service personnel should make Any outdoor antenna must be located away from all power lines any such attempt OUTDOOR ANTENNA GROUNDING Meet da of an z poe na If an outside antenna is connected to your tuner or tuner preamplifier be mole ado e od tdo ies sure the antenna system is grounded so as to provide some protection necessary to refer to the ins
7. able conditions Recommended capacitance of the speaker wire should not exceed 50pF per foot This insures high frequencies will not be rolled off 11 It is suggested that the three front channels follow this chart for speaker lengths and wire gauges Up 10 24 Tela dns AWG16 UP tO 36 PECL ces seeversceivsneeessedebesceteeess AWG14 Up tO DS Teel ensena A AWG12 Generally for the two rear surround channels longer runs of cable are needed but since less program material is being transmitted through the cable longer runs are acceptable Up tO 48 fel cev severe irse ene AWG16 UP LO 12 felaciones AWG14 Up tO 116 feet caviar scevesseweescedereeetertes AWG12 If longer runs are needed it is best to consult with your Adcom Dealer to maximize the performance of your system with your exact conditions All loudspeakers having a nominal impedance down to 4 ohms can be connected to and driven by the GFA 7705 07 The amplifier can drive these low impedance speakers at more than adequate power levels with no difficulty It should be noted here that many loudspeaker systems which are nominally rated at 4 ohms drop in impedance in some parts of their frequency range to as low as 2 ohms and sometimes less You will not experience difficulties even with these very low impedance loads unless you demand excessively high volume levels from your system It is not recommended that you run additional sets of speakers on any or all of the amplifiers i
8. channels driven at less than 1 THD 300 Watts continuous average power per channel into 4 ohms at any frequency between 20Hz and 20kHz with all channels driven at less than 1 THD THD Noise at 200 Watts into 8 ohms Typical RO 0 0086 A Saaascsnrnanveahausds e ai E cabins nedeanehae deca naearenaag eececahos EEE E E 0 0096 O sagan eed sehiceohosiaeesetensesdanieter E A 0 0156 OKA Zi A A ed 0 0201 THD Noise at 300 Watts into 4 ohms Typical A r E E E E E E se nacasiseaa ten cote deeauen A tenia taagiacareneatenne 0 0186 KZ Lis ir A RR 0 0214 Taco ctrl ptas 0 0354 DO ts OER 0 0311 Frequency Response 1 Watt into 8 ohms 20Hz to 20kHZ oocooccnccccnccnccncnccoo 0 0 22dB Power Bandwidth 3d0B o ooooccococncncccnnoncncnonncncncconncncnnnnononononnoncnocanonnos 3 Hz to 130kHz Dynamic Headroom into 4 OMMS ccc ce ceec ee eec sence eeeeeeeeeeeseenseeeeeeeeeeeeeeeeeeeeeeees 1 90 dB Signal to Noise Ratio A Weighted 200 Watts into 8 ohms 125 dB A E A o A E E evoas nied E E E T E T 29 dB Input Sensitivity tOr d Watt OUDOT mirerien e Ee E A A E E E EAE 0 1 volts for 200 Watts QUtPU nasa e a EE IEEE ER 1 40 volts INDUE IMPCdAaNC ei sisc52cccsases isn cdiecs colin NEERA E ERSEN E E ENEE 50kQ Damping Factor 20Hz to 2OKHZ 2 ccsiscnescoscecsccacnsscaceunaceesconcdsacasensedecebea dnd OESE EEs ra 2 800 General Power Available in 230VAC on special Order oo oocoococcoccccnnc
9. circuits are on its respective channel has been triggered and the amplifier is inoperative The thermal protection circuitry will typically be triggered by very high power demands into impedances much lower than the amplifier is capable of driving at those levels If any amplifier channel s output through the loudspeaker s ceases abruptly and its Thermal Protection LED glows you will know that its heatsink temperature has become unacceptably high and the circuitry is protecting the amplification devices Please note that the Power LED 7 will remain on and the amplifier will still be energized Once the temperature of the heatsink s drops to a safe operating level that amplifier will automatically resume operation Activation of the Thermal Protection circuitry in any of the amplifiers in the GFA 7705 07 is an indication that the amplifier has been over driven or that the load the loudspeakers are presenting to the amplifier is unreasonably low If you wish to prevent recurrent activation of the thermal protection circuitry you must reduce the volume level demands or correct the load impedance condition which may be causing activation of this circuitry S A F E Protection Circuit 8b Self Annealing Fuse Equipped Instead of blowing internal protection rail fuses in the event of a dead short to either a loudspeaker or speaker cable leads the GFA 7705 07 will enter into a self protect SAFE mode If the output of any channel of the ampli
10. d request the name of the carrier so a written claim to cover shipping damages can be initiated THE RIGHT TO A CLAIM AGAINST A PUBLIC CARRIER CAN BE FORFEITED IF THE CARRIER IS NOT NOTIFIED PROMPTLY IN WRITING AND IF THE SHIPPING CARTON AND PACKING MATERIALS ARE NOT AVAILABLE FOR INSPECTION BY THE CARRIER SAVE ALL PACKING MATERIALS UNTIL THE CLAIM HAS BEEN SETTLED Placement of the GFA 7705 07 During normal home operation the internal heatsinks of the GFA 7705 07 may become warm However there are instances during high level playback into low impedances when the heatsinks will become much warmer than usual To ensure the amplifier s long term trouble free operation it is necessary to provide adequate ventilation for the heatsinks Therefore the GFA 7705 07 should be kept away from external sources of heat such as radiators and hot air ducts The GFA 7705 07 should never be placed with other heat producing components in a cabinet or enclosure lacking free air flow The top and bottom panels of the amplifier s chassis have been provided with vents to allow the necessary cooling of the internal components It is imperative that these vents are not obstructed in any way We recommend that you do not stack other components on top of the GFA 7705 07 Not only will heat generated by the amplifier affect the performance of equipment stacked on top of the GFA 7705 07 but the free flow of air through the ventilating slots in the amplifier may be partial
11. e 2 Make sure that the power amplifier is at least six inches from the Preamp and or Processor Usually putting another component between them is sufficient to minimize the hum If this does not reduce the hum turn the system off and disconnect all Inputs from the amplifier If the hum still persists then call your Dealer or Service Center If the hum disappears re connect one RCA cable at a time to see if the specific cable or component is responsible If any or all cables cause the hum to appear subsitute with replacement cable s If hum continues to persist then the preamp or processor should be evaluated for proper operation by your Dealer or Authorized Service Center 13 Servicing ADCOM has a Technical Service Department to answer questions pertinent to the installation and operation of your unit In the event of difficulty please contact us for prompt advice Please have the following information readily at hand the unit s model and serial numbers and dealer from whom it was purchased If your problem cannot be resolved through our combined efforts we may refer you to an authorized repair agency or authorize return of the unit to our factory To aid us in directing you to a convenient service center it would be helpful if you indicate which major city is accessible from your home Please address mail inquires to Phone Fax or Email inquiries to ADCOM Service Voice 480 607 2277 8541 East Anderson Drive Fax 480 348 9876
12. fier becomes shorted the protection circuit will trip and the individual Thermal Protection LED for that channel will light The Protection LED will blink approximately every 5 seconds as the circuit will attempt to reset if the short has been corrected the amplifier will resume proper operation If the short is still present the channel will cycle off again The cycling of the protection circuit will continue until the short is corrected or the amplifier power is switched off WARNING Whenever connections to or from the GFA 7705 07 are being made be certain that the AC On Off Switch 5 of the amplifier is in the OFF position the AC Power Cord 4 of the amplifier is disconnected from the AC wall outlet and that all associated components are turned off Installation amp Hookup Unpacking the GFA 7705 07 Before your new GFA 7705 07 left our factory it was carefully inspected for physical imperfections and tested for all electrical parameters as a routine part of ADCOM s systematic quality control This along with full operational and mechanical testing should ensure a product flawless in both appearance and performance After you have unpacked the GFA 7705 07 inspect it for physical damage Save the shipping carton and all packing material as they are intended to reduce the possibility of transportation damage should the amplifier ever need to be shipped again In the unlikely event damage has occurred notify your dealer immediately an
13. ich has not been opened mishandled or tampered with in any way Always retain your original sales receipt as a proof of purchase Description of Unit The GFA 7705 07 is a 20 Amp Device The GFA 7705 07 is high power high current wide bandwidth design employing ADCOM s Fast Analog Transform F A T circuitry with direct coupled Power Rig output stages All channels are completely monaural from transformer secondaries through the output stages In order for this product to achieve its actual rated power output on all channels and to avoid repeatedly throwing popping the related electrical service panel circuit breaker it is critical that the amplifier be professionally installed on a 20 Amp household AC circuit and outlet preferably dedicated but at minimum one not shared with other large current draw appliances or devices Common 15 Amp household circuits are easily and inexpensively converted to 20 Amp configuration by any high voltage licensed electrician For this reason the GFA 7705 07 ships Factory equipped with a hard wired 20 Amp Plug on the AC Power Cord WARNING DO NOT DEFEAT THE 20 AMP PLUG OR HARDWIRED AC POWER CORD TO EMPLOY EITHER A 15 AMP OUTLET OR AUDIOPHILE TYPE DETACHABLE POWER CORD DOING SO WILL VOID PRODUCT WARRANTY MAY DAMAGE THE PRODUCT AND PLACE THE USER AT EXTREME RISKOF INJURY OR DEATH 1b LB LS Lp C N RS RB left back j left surround Y left front center right front SS right
14. iewing position left surround 4 right surround i speaker speaker Connecting the GFA 7705 07 Remember that the Left and Right designations are as you are sitting down in your listening viewing area On the rear panel the inputs and outputs are grouped in 5 or 7 bracketed sets one set for each channel They are as follows LB Left Back GFA 7707 only LS Left Surround LF Left Front C Center RF Right Front RS Right Surround RB Right Back GFA 7707 only 10 Inputs 1 To preserve the correct effects be certain to connect the RCA cables to the proper RCA input connector If the cables are color coded then use this sequence for the connections AP E veces Left Front A E O Right Front A deeds cae T Center White with Blue Stripe see eee eee eee Left Surround White with Red Stripe ce cece ee esse cece eee Right Surround The recommended maximum RCA cable capacitance should be less than or equal to 30pF per foot when measured between the two conductors and less than or equal to 50pF per foot when measured between one conductor and the shield Outputs 2 NOTE The GFA 7705 07 is polarity correct That is it does not invert phase from input to output Any positive signals at its inputs will appear as a positive signal at its outputs In connecting the amplifier to the loudspeaker it is vital to maintain proper polarity positive to positive nega
15. iggering source product Please refer to Section 3a 12VDC Triggering Distortion Alert LEDs 7 The Distortion Alert circuit is a unique ADCOM distortion detection system which reads all forms of non linear distortion such as THD IM slew induced clipping etc The Distortion Alert LEDs will light when distortion reaches approximately 1 regardless of impedance voltage current phase angle or the reactance of the loudspeakers which the amplifier is driving Sometimes when the amplifier is in use the LEDs may occasionally flicker during high volume listening particularly if you are driving low impedances This flickering is no cause for concern The LEDs are simply warning you that the amplifier is approaching its maximum power output into the particular loudspeakers you are using If however the Distortion Alert LEDs glow brightly or are illuminated most of the time during playback you are over driving the amplifier and should turn down your volume control to reduce the listening level otherwise it may cause the Thermal Protection to be activated or in extreme cases damage your loudspeakers Thermal Protection LEDs 8a The GFA 7705 07 is provided with both a thermal protection circuit and a current overload circuit which will shut down the individual amplifier s channels if its heatsink temperature reaches 85 C or the amplifier s outputs are shorted The Thermal Protection LEDs will light when either of these protection
16. ly obstructed This is particularly important if your system includes low impedance loudspeakers which are difficult to drive or you will consistently demand high volume levels from the amplifier and speaker system If you observe these recommendations the GFA 7705 07 will perform reliably in any reasonable environment You should also pay attention to such normal considerations as protection from excessive dust and moisture Occasional vacuuming of accumulated dust on the chassis panels and around the ventilating slots should be all that is required The optimal performance of your new GFA 7705 07 will ultimately depend on the care with which you make the connections between the amplifier preamplifier surround sound decoder and the loudspeakers All input and output signal connections should be made only with high quality low capacitance shielded cables following the recommendations in the Inputs and Outputs section of CONNECTING THE GFA 7705 07 Quick Connections For those of you who are in a hurry to hook up your amplifier into your system we have included this quick connection section The wiring is straight forward and expeditious if you use the proper cables and follow this diagram exactly If you have any difficulties or questions please refer to the appropriate section of this manual for complete descriptions and instructions center gt Y 5 inputs 1 left front L gt right front speaker speaker listening v
17. n the GFA 7705 07 in order to insure the integrity of the system If you choose to add remote speakers in another room it is strongly suggested that a switching system to disconnect the non home theater speakers be incorporated when the surround sound home theater mode is in operation A device such as the Adcom GFS 300 or GFS 600 Speaker Selector is strongly recommended A Speaker Selector enables you to maintain integrity while giving you the flexibility to add speakers throughout your house CARING FOR YOUR GFA 7705 07 Great care has been taken by ADCOM to ensure that your amplifier is as flawless in appearance as it is electronically The front panel is a heavy gauge high grade aluminum extrusion carefully finished and anodized for durability The chassis top cover and rear panel are heavy gauge steel that has been powder coated and baked to ensure a lasting finish If the front panel top or sides become dusty or fingerprinted they can be cleaned with a soft lint free cloth slightly dampened with a very mild detergent solution or glass cleaner DO NOT SPRAY OR POUR LIQUIDS OF ANY KIND ON THE GFA 7705 07 12 Troubleshooting Resolving Problems Use the chart below to solve common situations that don t require professional attention If the steps stated in POSSIBLE SOLUTION do not resolve your problem then please contact your ADCOM Dealer or call the ADCOM Customer Service Department Any problems not covered here should be brought
18. nconccncnnnncos 120VAC 50 60Hz Power Consumption Continuous All Channels Driven Idle 5 Chameleon aed ebeacscabeaetecdemeders 120W Idle 7 ChaimMeliourciciaiocia iia cadn RERAN 170W 200 watts X 5 Ch into 8 OMS iio atan 2200W 200 Watts Xx Z CAMINOS ONMS snesena dns asus peer vndoabyeacs voted eweeatesceaud Guam tes 2700W Chassis Dimensions H x W x D eceeeeees 8 5 216mm x 17 432mm x 17 5 444 5mm Maximum Dimensions H x W x D 9 3 8 238mm x 17 432mm x 18 5 470mm Unit Weight GFA 7705 oooooococcnococonrnocccnononococonroronnonrnrnoncncnrnnonocnnnncccnos 69 5 lb 31 5 kg Unit Weight GFA 77O7 casita cd a 78 2 lb 35 5 kg Weight Packed GFA 7705 cccsecececeeececeeneeeeeeeeeeesseneeeeseeeeeeeeseeeeeeeeeeees 81 5 lb 37 kg Weight Packed GFA 7707 ccceccececeecececeeneeeeeeeeneeeeeeneneeeseeeeeeeeeeeeeeeeeeeees 90 4 lb 41 kg Specifications subject to change without notice ADCOM 8541 East Anderson Drive Scottsdale Arizona 85255 Voice 480 607 2277 Fax 480 348 9876 www adcom com gfa7705 07_manual_v1
19. ord exits from the unit ANTENNA DISCHARGE Clean unit only as recommended in its instruction manual lt UNIT c A TO EXTERNAL ANTENNA The power supply cord of the unit should be unplugged from the wall outlet TERMINALS OF RADIO RECEIVER when it is to be unused for a long period of time POWER SERVICE GROUNDING ELECTRODE SYSTEM GROUND WIRE a b e g interior metal water pipe Care should be taken so that objects do not fall and liquids are not spilled GROUND CLAMPS into the enclosure through any openings BONDING JUMPER d This unit should be serviced by qualified service personnel when ll E ONEN SEET INTO A The power cord or the plug has been damaged or THE EARTH IF REQUIRED BY LOCAL B Objects have fallen or liquid has been spilled into the unit or CODES SEE NEC SECTION B10 21 11 C The unit has been exposed to rain or liquids of any kind or NOTE TO CATV SYSTEM INSTALLER D The unit does not appear to operate normally or exhibits a marked change in performance or This reminder is provided to call the CATV system installer s attention to E The device has been dropped or the enclosure damaged Article 820 22 of the National Electrical Code that provides guidelines for proper grounding and in particular specifies that the cable ground shall be DO NOT ATTEMPT SERVICING OF THIS UNIT YOURSELF connected to the grounding system of the building as close to the point of REFER SERVICING TO QUALIFIED SERVICE PERSONNEL cable entry
20. surround NX right back NN O S 2 C rae tigger z gt S input 3 3 input input E input g input E input o 2 2 2 S 3 3 3 3 E 3 3 8 8 8 8 g 8 120VAC ee 2 2 2 e S E 2 ca 2 S 3 gs 35 3o gs o ar D Power Amplifier Serial number O Model GFA 7705 Power consumption max 2500W 2b 2 3a 3b 4 Inputs 1 The audio inputs for the GFA 7705 and 7707 are through high quality gold plated RCA jacks to minimize high frequency losses noise etc They will accept standard RCA type plugs one for each of the five channels Front L Left Center Front R Right Surround L Left and Surround R Right To insure that the performance designed into the GFA 7705 07 is preserved you should use the highest quality shielded audio cables possible There are many cables which are color coded and specifically designed for this application Your Adcom dealer can help select the best cable for your needs See Connecting the GFA 7705 07 for more information Inputs 1b Chassis knock out for future expansion channel card input jack GFA 7705 only Outputs 2 The GFA 7705 07 s connections to the loudspeakers are made through high grade 5 way gold plated binding post terminals There are two terminals for each speaker which are colored RED for the positive output and BLACK for the negative output The binding posts will accept a variety of connector types the most secure and prevalent of
21. tive to negative On the GFA 7705 07 the positive terminal is color coded RED and labeled and the negative is color coded BLACK and labeled The positive terminal on the corresponding loudspeaker will be color coded RED or will be labeled pos positive 8 ohms or 4 ohms The negative terminal on the speaker will be color coded BLACK or will be labeled neg negative C Common G or ground It is necessary that your speaker cables be terminated with U type spade connectors These will give the most contact area insuring long term reliability The spade connector should have a maximum width of 0 57 inches and an opening width of no less than 0 25 see diagram on right gt max 0 5 0 25 min To properly connect the speaker cable to the binding posts turn the insulated head of the binding post clockwise until the wire or connector is firmly secured Finger pressure is sufficient and you should not use pliers or other tools which could damage or over tighten the binding post assembly The binding posts have been designed in such a way that finger pressure is all that is required to cause a pinching action among the different metal surfaces to ensure proper connection It is very important to use the correct size of wire in order to avoid unnecessary loss of amplifier power in the cable reduction of amplifier damping factor and other undesir
22. tors Verify both sets of connections on that producing sound and or disconnected or loose channel Speaker disconnected shorted Verify connections at speaker cable in Thermal LED Blinking Internal protection engaged tegrity Bring to Dealer or Service Center Hum from all speakers Ground loop difference in ground If cable TV is present see Note 1 at any volume voltages between components If cable TV is not present see Note 2 Hum from all speakers Problems with source unit CD tape Try different source tuner tape etc hum goes up or etc or RCA cables connecting that and or different RCA cable down with volume source unit to the preamp Hum from the amplifier itself Some major appliance dimmer halogen or Make sure all appliances dimmers and fluorescent light is creating interference suspect lights are off Note 1 Cable TV systems can sometimes contribute to ground loop problems which cause hum To determine if your cable system is the contributing factor disconnect the Cable TV incoming signal line round 750 at the wall or the first component to which the cable is connected to i e the cable box or VCR If the hum is no longer present you must insert a 750 Ground Loop Isolator before reconnecting the line You should check with your ADCOM Dealer to obtain one If the 750 Ground Loop Isolator works only partially or not at all then please read Note 2 to complete the troubleshooting procedure Not
23. truction manual and its i d built tatic ch Section 810 of th warnings for proper operation of the unit against vo tage surges and built up static charges ec ion O he National Electrical Code ANSI NFPA No 70 1984 provides information with Do not place this unit on an unstable cart stand tripod respect to proper grounding of the mast and supporting structure grounding bracket or table The unit may fall causing serious of the lead in wire to an antenna discharge unit size of grounding injury to a child or adult and serious damage to the unit Use only with a cart stand tripod bracket or table recommended by the manufacturer or sold with the unit Any mounting of the device should follow the man a Use No 10 AWG 5 3 mm copper No 8 AWG 8 4 mm aluminum ufacturer s instructions and should use a mounting ac No 17 AWG 1 0 mm copper clad steel or bronze wire or larger as a cessory recommended by the manufacturer ground wire conductors location of antenna discharge unit connection to grounding electrodes and requirements for the grounding electrode Read all the safety and operating instructions before connecting or using b Secure antenna lead in and ground wires to house with stand off this unit insulators spaced from 4 6 feet 1 22 1 83 m apart c Mount antenna discharge unit as close as possible to where lead in Retain this notice and the owner s manual for future reference enters house All warnings on the
24. unit and in its operating instructions should be adhered to d Use jumper wire not smaller than No 6 AWG 13 3 mm copper or the equivalent when a separate antenna grounding electrode is used See NEC All operating and use instructions should be followed Section 810 21 j Do not use this unit near water for example near a bathtub washbowl EXAMPLE OF ANTENNA GROUNDING AS PER NATIONAL ELECTRICAL CODE INSTRUCTIONS kitchen sink laundry tub in a wet basement or near a swimming pool CONTAINED IN ARTICLE 810 RADIO AND TELEVISION EQUIPMENT The unit should be installed so that its location or position does not interfere POWER LINES with its proper ventilation For example it should not be situated on a bed sofa rug or similar surface that may block the ventilation openings or placed in a built in installation such as bookcase or cabinet that may impede the flow of air through its ventilation openings SERVICE ENTRANCE y CONDUCTORS STANDOFF The unit should be situated away from heat sources such as radiators heat PA m INSULATORS b registers stoves or other devices including amplifiers that produce heat The unit should be connected to a power supply outlet only of the voltage MAST and frequency marked on its rear panel n SERVICE ANTENNA The power supply cord should be routed so that it is not likely to be walked ENTRANCE LEAD IN WIRE on or pinched especially near the plug convenience receptacles or where EQUIPMENT the c
25. vsssaceveedetvsccwvecoesveseedusceuuseetensecwebeaeenees 10 Connecting the GEA 7 705 07 reer erento e EOE E ais 11 Caring for your GFA 7705 07 resemson essenin none so 12 Troubleshooting Resolving PrOD SIMS iia na 13 Service InformatioN oooococononoccncccnnoroconorononocoonoroconnconnncnorarconcnnonos 14 SPCCINCATIONS in ciiessccdoewes sekes Seaeureseens riss Ersta Enee Anas sei 15 Introduction Congratulations on your decision to purchase the GFA 7705 07 multi channel power amplifier The GFA 7705 07 integrates very well with any other home theater system such as Dolby ProLogic or Dolby Digital You have made a wise choice that will reward you with exceptionally accurate and musical sound reproduction for years to come To realize the full potential of your new amplifier please read these operating and installation instructions thoroughly before attempting to make any connections to it ADCOM Protection Plan NORTH AMERICA ONLY ADCOM offers the enclosed valuable Limited Warranty Please read the details on the Warranty Card carefully to understand the extent of the protection offered by the Warranty its reasonable limitations and what you should do in order to obtain its benefits Be sure to verify that the serial number printed on the rear panel matches the serial number on the outer carton If any number is altered or missing you should notify us immediately in order to ensure that you have received a genuine ADCOM product wh
26. x 5 to 30VDC Center conductor tip is positive AC Circuit Breaker 3b The 15 Amp AC Breaker protects the electronic circuits of the GFA 7705 07 Normally this breaker will open only if there is an overload or a component failure within the GFA 7705 07 If the Power LED 7 does not glow it may be an indication that the AC Breaker has blown If you are using the 12VDC Triggering feature above it may be possible that there is no trigger voltage present or a problem exists with that connection To determine if the problem is caused by a malfunction in the 12VDC system remove the small plug inserted into the 12VDC Triggering jack Press the front panel power switch to turn off the amp and immediately re press the power switch If the problem is caused by the 12VDC triggering circuit the amp will turn on and the LED will glow DO NOT attempt repair of the 12VDC system If you are not sure or the amplifier displays other symptoms please consult the RESOLVING PROBLEMS section on page 13 AC Power Cord 4 The AC cord provides power to operate all the GFA 7705 07 s circuits The GFA 7705 07 is a very high power amplifier and as such must be directly connected to the wall outlet or an appropriate non current limiting surge protector or AC line conditioner of 20 Amp service capability NOTE As previously described on Page 4 the attached plug is a 20 Amp fitting which in order for the amplifier to deliver its rated power output
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