McIntosh MC3500-MKII

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McIntosh Laboratory, Inc. 2 Chambers Street Binghamton, New York 13903-2699 Phone: 607-723-3512 www.mcintoshlabs.com MC3500 Mono Tube Amplifier Owner's Manual 2 Thank You Your decision to own this McIntosh MC3500 Tube Power Amplifier ranks you at the very top among discriminating music listeners. You now have “The Best.” The McIntosh dedication to quality is assurance that you will receive many years of musical enjoyment from this unit. Please take a short time to read the information in this manual. We want you to be as familiar as possible with all the features and functions of your new McIntosh. Please Take A Moment The serial number, purchase date, and McIntosh Dealer name are important to you for possible insurance claims or future service. The spaces below have been provided for you to record that information: Important Safety Information is supplied in a separate document “Important Additional Operation Information Guide ” Serial Number: _______________________________ Purchase Date: _______________________________ Dealer Name: _______________________________ Technical Assistance If at any time you have questions about your McIntosh product, contact your McIntosh Dealer who is familiar with your McIntosh equipment and any other brands that may be part of your system. If you or your Dealer need additional help concerning a suspected problem, you can receive technical assistance for all McIntosh products at: McIntosh Laboratory, Inc. 2 Chambers Street Binghamton, New York 13903 Phone: 607-723-3512 Fax: 607-724-0549 Customer Service If it is determined that your McIntosh product is in need of repair, you can return it to your Dealer. You can also return it to the McIntosh Laboratory Service Department. For assistance on the factory repair return procedure, contact the McIntosh Service Department at: McIntosh Laboratory, Inc. 2 Chambers Street Binghamton, New York 13903 Phone: 607-723-3515 Fax: 607-723-1917 Table of Contents Unpacking the MC3500 ............................................ 4 General Information ................................................. 6 Connector and Cable Information ............................ 6 Introduction ............................................................... 6 Performance Features ............................................... 6 Dimensions ............................................................... 7 Navigating the Rear Panel ........................................ 8 Connection Diagram ................................................. 9 How to Connect Loudspeakers ................................. 10 Navigating the Front Panel ........................................ 12 How to Operate ......................................................... 12 Amplifier Specifications ........................................... 14 General Specifications .............................................. 14 Packing Instructions ................................................. 15 3 IMPORTANT! INSTRUCTIONS FOR REMOVAL OF FOAM INSERT OVER THE VACUUM TUBES PRIOR TO CONNECTING THE A.C. POWER SUPPLY CORD START ON THE NEXT PAGE. 4 Unpacking the MC3500 WARNING: To prevent damage to the MC3500 Vacuum Tubes during shipping, there is a special foam insert surrounding the Vacuum Tubes of the Power Amplifier. The Foam Insert must be removed from the MC3500 before connecting the AC Power Supply Cord to the Power Amplifier. Failure to do so is a Fire Hazard, which could result in damage to the MC3500 and the surrounding environment. Follow these instructions for removal of the packing foam before connecting the AC Power Supply Cord to the MC3500. In order to remove the foam insert surrounding the Vacuum Tubes on the MC3500, it is necessary to temporarily remove the Tube Cover. After the foam insert is removed, the Tube Cover must be reinstalled for proper and safe operation of the MC3500 Power Amplifier. The Tube Cover provides protection from the hazardous voltages inside the MC3500. The MC3500 has no user serviceable parts, including the Vacuum Tubes. If repairs are needed, they must be performed by an authorized McIntosh Service Agency. 1. Orient the MC3500 so the rear of the Power Amplifier is facing you and remove the Warning Sheet. Refer to figure 1. 2. Remove the four screws and the two Hot Surface Tags located on the top of the Tube Cover by using a #2 Phillips Head Screw Driver. Refer to figure 1. 3. Place the Tube Cover, Hot Surface Tags, and screws in a safe location, as the Tube Cover will be reinstalled. 4. Carefully lift up and remove the Tube Cover from the MC3500. Refer to figure 2. 5. Carefully lift up and remove the Foam Insert from the MC3500, exposing the Vacuum Tubes. Refer to figures 3 and 4. 6. Carefully place the Tube Cover back on the MC3500. 7. Place the Hot Surface Tags in the top corners of the Tube Cover. Secure the Cover to the MC3500 Chassis using the four screws. Refer to figure 5. Note: Save the Foam Insert and Warning Sheet with the MC3500 Shipping Carton for future use. EL509S EL509S EL509S EL509S FUSE PUSH PUSH BALANCED UNBALANCED INPUTS OUTPUTS POWER CONTROL IN OUT M C 3 5 0 0 T U B E A M P L I F I E R McINTOSH LABORATORY, INC., BINGHAMTON, NY HANDCRAFTED IN USA WITH US AND IMPORTED PARTS BALANCED UNBALANCED AUTO OFF INPUT MODE ENABLED DISABLED BALANCED UNBALANCED 120V 50 / 60Hz 6 AMPS T8AL 250V EL509S EL509S EL509S EL509S FUSE PUSH PUSH BALANCED UNBALANCED INPUTS OUTPUTS POWER CONTROL IN OUT M C 3 5 0 0 T U B E A M P L I F I E R McINTOSH LABORATORY, INC., BINGHAMTON, NY HANDCRAFTED IN USA WITH US AND IMPORTED PARTS BALANCED UNBALANCED AUTO OFF INPUT MODE ENABLED DISABLED BALANCED UNBALANCED 120V 50 / 60Hz 6 AMPS T8AL 250V EL509S EL509S EL509S EL509S FUSE PUSH PUSH BALANCED UNBALANCED INPUTS OUTPUTS POWER CONTROL IN OUT M C 3 5 0 0 T U B E A M P L I F I E R McINTOSH LABORATORY, INC., BINGHAMTON, NY HANDCRAFTED IN USA WITH US AND IMPORTED PARTS BALANCED UNBALANCED AUTO OFF INPUT MODE ENABLED DISABLED BALANCED UNBALANCED 120V 50 / 60Hz 6 AMPS T8AL 250V REAR FOAM REMOVAL VENTILLATION ART TOP POWER TRANSFORMER UNITY COUPLED OUTPUT TRANSFORMER YL BR YL WH BL RD BL BL +8 Ω YL +4 Ω RD +2 Ω BK COM POWER 350W FREQUENCY 15-100kHz VI OR VI WH WH MC3500 TUBE POWER AMPLIFIER Precision Performance By DYNAMIC HEADROOM 2.4dB FREQUENCY RESPONSE +0, -0.5d B from 20Hz to 20,000Hz + 0, -3.0d B fro m 10Hz to 70,000Hz A-WEIGHTED SIGNAL TO NOISE RATIO 120dB below rated output TOTAL HARMONIC DISTORTION 0. 3% maximum harmo nic distortion at any level from 250 mW to rated power output INPUT SENSITIVITY 1.9 volts unbalanced 3.8 volts balanced POWER OUTPUT 350 watts into an 8, 4 or 2 ohm load is the minimum sine wave continuous average power output McIntosh Laboratory Inc., Binghamton, New York, U.S.A. BK BK GY VI WH WH RD YL RD BL GR BL OR BK VI GY PRI 1 PRI 2 SEC 1 HIGH VOLTAGE TCO SEC 2 HEATERS TO AVOID A FIRE HAZARD, THE FOAM INSERT OVER THE VACUUM TUBES MUST BE REMOVED PRIOR TO CONNECTING THE AC POWER CORD AND OPERATING THIS PRODUCT. WARNING REFER TO THE OWNER’S MANUAL FOR INSTRUCTIONS. Shipping Foam Hot Surface Tag Metal Tube Cover Warning Sheet Screws Figure 1 Figure 2 Figure 3 Figure 4 5 Ventilation Adequate ventilation extends the trouble-free life of the MC3500. Always allow air to flow through the ventilation holes on the bottom of the amplifier and a means for the warm air to escape at the top. Refer to figure 6. Allow at least 19 inches (48.3cm) above the top; 6 inches (15.2cm) for the Front, Rear and Sides; allow 7/8 inch (2.2cm) below the Power Amplifier so airflow is not obstructed. HEAT TAG SCREW Screw Hot Surface Tag POWER TRANSFORMER UNITY COUPLED OUTPUT TRANSFORMER YL BR YL WH BL RD BL BL +8 Ω YL +4 Ω RD +2 Ω BK COM POWER 350W FREQUENCY 15-100kHz VI OR VI WH WH MC3500 TUBE POWER AMPLIFIER Precision Performance By DYNAMIC HEADROOM 2.4dB FREQUENCY RESPONSE +0, -0.5d B from 20Hz to 20,000Hz +0, -3.0d B fro m 10Hz to 70,000Hz A-WEIGHTED SIGNAL TO NOISE RATIO 120dB below rated output TOTAL HARMONIC DISTORTION 0. 3% maximum harmonic distortion at any level from 250 mW to rated power output INPUT SENSITIVITY 1.9 volts unbalanced 3.8 volts balanced POWER OUTPUT 350 watts into an 8, 4 or 2 ohm load is the minimum sine wave continuous average power output McIntosh Laboratory Inc., Binghamton, New York, U.S.A. BK BK GY VI WH WH RD YL RD BL GR BL OR BK VI GY PRI 1 PRI 2 SEC 1 HIGH VOLTAGE TCO SEC 2 HEATERS Metal Tube Cover FUSE PUSH PUSH BALANCED UNBALANCED INPUTS OUTPUTS POWER CONTROL IN OUT M C 3 5 0 0 T U B E A M P L I F I E R McINTOSH LABORATORY, INC., BINGHAMTON, NY HANDCRAFTED IN USA WITH US AND IMPORTED PARTS BALANCED UNBALANCED AUTO OFF INPUT MODE ENABLED DISABLED BALANCED UNBALANCED 120V 50 / 60Hz 6 AMPS T8AL 250V Cool Air Warm Air REAR VIEW VENTILLATION Figure 5 Figure 6 6 General Information 1. For additional connection information, refer to the documentation included with any component(s) connected to the MC3500. 2. Apply AC Power to the MC3500 and other components only after all the system components are connected together. Failure to do so may cause a malfunction of system operations as the Microprocessor’s Circuitry inside the components is active when AC Power is applied. 3. When discarding the unit, comply with local rules or regulations. Batteries should never be thrown away or incinerated but disposed of in accordance with the local regulations concerning battery disposal. 4. For additional information on the MC3500 and other McIntosh Products, please visit the McIntosh Website at www.mcintoshlabs.com. Connector and Cable Information XLR Connectors Below is the Pin configuration for the XLR Balanced Input Connectors on the MC3500. Refer to the diagram for connection: PIN 1: Shield/Ground PIN 2: + Output PIN 3: - Output Power Control Connector The Power Control Input Jack receives Power On/Off Signals when a component is connected. The Power Control Output will in turn provide a +12 volt Output Signal with a current up to 25 mA. An additional connection is for controlling the illumination of the MC3500 Power Meter when connected to a compatible McIntosh Preamplifier or A/V Control Center Power Control Output. A 3.5mm stereo mini phone plug is used for these connections. Output Terminal Connector When cables with spade lugs are used for Loudspeaker Connection, the spade lugs need an opening of at least 3/10 inch (7.6mm) PIN 1 PIN 2 PIN 3 Power Control Illumination Control Ground 3/10 of an inch (7.6millimeters) Introduction Now you can take advantage of traditional McIntosh standards of excellence in the MC3500 Tube Power Amplifier. The 350 watt power output will drive any high quality Loudspeaker System. The MC3500 repro - duction is sonically transparent and absolutely accu - rate. The McIntosh Sound is “The Sound of the Music Itself.” Performance Features Power Output The MC3500 is a Tube Power Amplifier with a capability of 350 watts into 2-, 4-, or 8-ohm Loudspeakers with less than 0.3% distortion. Unity Coupled Circuitry The MC3500 Power Amplifier uses the famous McIntosh Patented Unity Coupled Circuit which provides low distortion, extended frequency response and cool operating output tubes. Multifilar Wound Output Transformer The MC3500 Output Transformer Windings are part of the Unity Coupled Circuitry. There are three trifilar wound primaries, one for the cathodes, one for the plates, and one for the screens. The secondary winding is wound together with the primary windings. This provides very close primary to secondary coupling. The result is flat frequency response and wide power bandwidth. Balanced and Unbalanced Input Balanced connections guard against induced noise and allow long cable runs without compromising sound quality. Sentry Monitor Tube Protection Sentry Monitor provides protection for the MC3500 by monitoring Output. In the event of a large imped - ance mismatch, a short circuit at the Output Terminals, or Tube failure, Sentry Monitor will activate to prevent potentially destructive levels of current from flowing. Vacuum Tube Sockets Small Signal Vacuum Tubes Sockets have Ceramic Base construction with gold plated contacts, providing protection from atmospheric contamination. Output Tube Sockets include Air-Pipe cooling at their bases for long term operation. Amplifier Gold Plated Connectors Gold Plated Input Jacks and Output Binding Posts provide trouble free connections. Special Power Supply A very large core Power Transformer and large filter capacitors ensure stable operation. Power Guard Screen Grid Sensor (SGS) Power Guard Screen Grid Sensor™ (SGS) helps prevent premature Vacuum Tube failure by monitoring the screen grid current in the EL509S output Vacuum Tubes. If the current becomes too high, a circuit in Power Guard SGS™ is activated which then dynami - cally attenuates the input signal in real time to keep the Vacuum Tubes operating at safe levels. The right amber LED will flash when Power Guard SGS is engaged in protecting the Vacuum Tubes. 7 EL509S EL509S EL509S EL509S FUSE PUSH PUSH BALANCED UNBALANCED INPUTS OUTPUTS POWER CONTROL IN OUT M C 3 5 0 0 T U B E A M P L I F I E R McINTOSH LABORATORY, INC., BINGHAMTON, NY HANDCRAFTED IN USA WITH US AND IMPORTED PARTS BALANCED UNBALANCED AUTO OFF INPUT MODE ENABLED DISABLED BALANCED UNBALANCED 120V 50 / 60Hz 6 AMPS T8AL 250V DIMENSION PAGE Dimensions 18" 45.7cm 11 -5/16 " 28.7cm 11- 13/16 " 30cm 19 -3/16 " 48.7cm 1 -7/8 " 4.8cm 16 -5/8 " 42.2cm 17 -1/2 " 44.5cm 16 -1/4 " 41.3cm Front View Side View Rear View 9/16 " 1.4cm 11 -1/4 " 28.6cm EL509S EL509S EL509S EL509S WATTS HOLD LIGHTS OFF REMOTE OFF ON POWER METER POWER GUARD SGS WARMUP WATTS HOLD LIGHTS OFF REMOTE OFF ON POWER METER POWER GUARD SGS WARMUP 8 Navigating the Rear Panel MC3500 REAR WITHOUT CAGE EL509S EL509S EL509S EL509S FUSE PUSH PUSH BALANCED UNBALANCED INPUTS OUTPUTS POWER CONTROL IN OUT M C 3 5 0 0 T U B E A M P L I F I E R McINTOSH LABORATORY, INC., BINGHAMTON, NY HANDCRAFTED IN USA WITH US AND IMPORTED PARTS BALANCED UNBALANCED AUTO OFF INPUT MODE ENABLED DISABLED BALANCED UNBALANCED 120V 50 / 60Hz 6 AMPS T8AL 250V 1 2 3 4 5 6 7 8 9 10 11 1. Balanced Input: Connect an XLR connector cable (see Page 6) from an external output device into this port to amplify a Balanced signal. 2. Unbalanced Input: Connect an RCA connector cable from an external output device into this port to amplify an Unbalanced signal. 3. Balanced Output: This port produces a signal from the Balanced Input using an XLR connector cable (see Page 6) 4. Unbalanced Output: This port produces a signal from the Unbalanced Input using an RCA connector cable. 5. Power Control Out: Sends an On/Off signal to a connected McIntosh component via a 3.5mm cable (see Page 6). 6. Power Control In: Receives an On/Off signal from a connected McIntosh component via a 3.5mm cable (see Page 6). 7. Input Mode Switch: Switch to toggle between Balanced and Unbalanced Inputs. 8. Auto Off: Switch to Enable/Disable Auto Off function. 9. Main Power: Connect to a power outlet using the included power cable to supply power to the MC3500. 10. Fuse Holder: Houses the fuse to power the unit. 11. Loudspeaker Terminal Posts: Connect loudspeakers using speaker cable (see Page 10). 9 MC3500 REAR WITHOUT CAGE EL509S EL509S EL509S EL509S FUSE PUSH PUSH BALANCED UNBALANCED INPUTS OUTPUTS POWER CONTROL IN OUT M C 3 5 0 0 T U B E A M P L I F I E R McINTOSH LABORATORY, INC., BINGHAMTON, NY HANDCRAFTED IN USA WITH US AND IMPORTED PARTS BALANCED UNBALANCED AUTO OFF INPUT MODE ENABLED DISABLED BALANCED UNBALANCED 120V 50 / 60Hz 6 AMPS T8AL 250V + To AC Power Outlet - Connection Legend: AC Power Cable: Loudspeaker Cable: Power Control Cable: Audio Signal Cable: Connection Diagram Loudspeaker Preamplifier MC3500 10 How to Connect Loudspeakers For the best performance and safety, it is important to always match the impedance of the Loudspeaker to the Power Amplifier connections. When connecting the Loudspeaker Hookup Cables to the MC3500 Power Amplifier Output Terminals please follow the steps below: 1. Rotate the top of the Output Terminal Post counterclockwise until an opening appears. Refer to figures A and B. 2. Insert the Loudspeaker hookup cable into the Output Terminal Post opening or the cable spade lug around the center post of the Output Terminal. Refer to figure C. 3. Rotate the top of the Output Terminal Post clockwise until it is finger tight. Refer to figure D. 4. Place the supplied McIntosh Wrench over the top of the Output Terminal and rotate it one quarter of a turn (90°) to secure the Loudspeaker Cable Connection. Do not over tighten. Refer to figure E. Figure A Opening Figure B Figure C Figure D Figure E WARNING: Do not connect the AC Power Cord to the MC3500 Rear Panel until after the Loudspeaker Connections are made. Failure to observe this could result in Electric Shock. The connection instructions below, together with the MC3500 Connection Diagram located on Page 9 is an example of a typical audio system. Your system may vary from this; however, the actual components would Figure 1 Figure 2 Figure 3 Loudspeaker Cable Distance vs Wire Gauge Guide Loudspeaker Impedance 25 feet (7.62 meters) or less 50 feet (15.24 meters) or less 100 feet (30.48 meters) or less 2 Ohms 12AWG 10AWG 8AWG 4 Ohms 14AWG 12AWG 10AWG 8 Ohms 16AWG 14AWG 12AWG 3. Prepare the Loudspeaker Hookup Cable for attachment to the MC3500 Power Amplifier: Bare wire cable ends: Carefully remove sufficient insulation from the cable ends, refer to figures 1, 2, and 3. If the cable is stranded, carefully twist the strands together as tightly as possible. Notes: 1. If desired, the twisted ends can be tinned with solder to keep the strands together. 2. The prepared bare wire cable ends may be inserted into spade lug connectors. 3. Banana plugs are for use in the United States and Canada only. Banana Plugs are for use in the United States and Canada only: 4. Attach the previously prepared bare wire cable ends into the banana plugs and secure the connections. Refer to figure F. 5. Rotate the top of the Output Terminal Post clockwise until it is finger tight. Refer to figure G. Then using the McIntosh Wrench, rotate the top of the Figure F Figure G be connected in a similar manner. For additional infor - mation, refer to “Connector and Cable Information” on Page 6. 1. For Remote Power Control, connect a power control cable from the Audio Preamplifier Power Control Main Output Jack to the Power Amplifier POWER CONTROL IN Jack. 2. Connect XLR cables from the Balanced Main Output connector of the Audio Preamplifier to the Power Amplifier Balanced INPUTS. Place the INPUT Switch in the Balanced Position. Note: An optional hookup is to use unbalanced cable and place the INPUT MODE Switch in the Unbalanced Position. This McIntosh MC3500 Power Amplifier is designed for Loudspeakers with an impedance of 2 ohms, 4 ohms, or 8 ohms. Connect a single Loudspeaker only to the Output Terminals. When connecting Loudspeakers to the MC3500 it is very important to use cables of adequate size, so there is little to no power loss in the cables. The size is specified in AWG (American Wire Gauge). The smaller the Gauge number, the larger the wire size: Note: The impedance of a Loudspeaker actually varies as the Loudspeaker reproduces different frequencies. As a result, the nominal impedance rating of the Loudspeaker (usually measured at a midrange frequency) might not always agree with the impedance of the Loudspeaker at low frequencies where the greatest amount of power is required. Contact the Loudspeaker Manufacturer for additional information about the actual impedance of the Loudspeaker before connecting it to the McIntosh MC3500. 11 tighten the terminal cap until the cable is firmly clamped into the terminals so the lugs or wire cannot slip out. Do not over tighten. Refer to figures 4, 5, and figure E. If the Loudspeaker’s impedance is in-between the available connections, use the nearest lower imped - ance connection. WARNING: Loudspeaker terminals are hazardous live and present a risk of electric shock. For additional instruction on making Loudspeaker Connections contact your McIntosh Dealer or McIntosh Technical Support. 9. For a Stereo system, repeat steps 2-8 for the other channel. 10. Connect the MC3500 Power Cord to an active AC outlet. Figure F Figure H Output Terminal one quarter of a turn (90°). Do not over tighten. Refer to figure E. 6. Referring to figure H, connect the Loudspeaker hookup cables with banana plugs into the hole at the top of the MC3500 Negative (-) and Positive (+) Output Terminals. The Positive Terminals are indentified as 2Ω (ohms), 4Ω (ohms) or 8Ω (ohms) connection to match the impedance of the Loudspeaker, being careful to observe the correct polarities. If the Loudspeaker’s impedance is in-between the available connections, use the nearest lower imped - ance connection. WARNING : Loudspeaker Terminals are hazardous live and present a risk of electric shock. For additional instruction on making Loudspeaker Connections, contact your McIntosh Dealer or McIntosh Technical Support. 7. Connect the MC3500 Power Cord to an active AC outlet. Spade Lug or Wire Connections: 8. Connect the Loudspeaker hookup cables to the MC3500 Negative Output Terminal (-) and Positive Output (+) Terminal indentified as 2Ω (ohms), 4Ω (ohms) or 8Ω (ohms) connection to match the impedance of the Loudspeaker, being careful to observe the correct polarities. Insert the spade lug connector or prepared section of the cable end into the terminal side access hole, and Figure 4 Figure 5 12 Navigating the Front Panel How to Operate Power Control The POWER CONTROL is located on the Front Panel of the MC3500. Set the Control to the REMOTE Position. Refer to figure 10. The MC3500 Power Amplifier will turn ON or OFF as the Preamplifier it is connected to (via the Power Control Connection) turns On or Off . For manual operation, place the POWER CONTROL to the ON Position as desired. The LED indicator located on the Front Panel is illuminated when the MC3500 is connected to an active AC Outlet. When the MC3500 is first switched On, there is a Warmup period of time during which no sound will be heard and the WARMUP LED will illuminate. During this period, the Power Output Meter needle will gradually rise to show the warmup percentage. After the needle reaches 100%, the MC3500 will begin playing sound, the WARMUP LED will switch off, and the needle will return to displaying the appropri - ate Output based on the Meter Control Knob position (see below). Meter Control The Meter Control Knob changes how the Power Output Meter behaves. If the Knob is set to WATTS, the Meter will continuously respond to and display the current Output of the MC3500. Refer to figure 11. If the Knob is set to HOLD, the Meter will display the highest peak Output in a series of peaks, until a greater peak is read. If no greater peak is read, the Meter will begin to lower at a rate of approximate 6dB per minute. Figure 11 WATTS HOLD LIGHTS OFF REMOTE OFF ON POWER METER POWER GUARD SGS WARMUP D E C I B E L S 2 0 10 0 8 0 6 0 P E R C E N T 4 0 MC3500 FRONT VIEW 1 2 3 4 5 1. Power Output Meter: Displays power output level in Watts and Decibels. 2. Meter Control Knob: Select between the different Output Meter functions (see next page). 3. Warmup LED: Illuminates to indicate when Warmup state is active (see next page). 4. Standby LED: Illuminates whenever the MC3500 is connected to a live AC outlet. Flashes whenever Sentry Monitor has activated (see next page). 5. Power Guard LED: Illuminates to indicate when Power Guard is active. 6. Power Knob: Turn MC3500 On/Off, or set to REMOTE position to have it be turned On/Off automatically by a Preamplifier (see next page). 6 REMOTE OFF ON POWER Figure 10 13 Sentry Monitor Reset Sentry Monitor provides protection for the MC3500 by monitoring Output. In the event of a large impedance mismatch, a short circuit at the Output Terminals, or Tube failure, Sentry Monitor will activate to prevent potentially destructive levels of current from flowing. When Sentry Monitor is activated, the MC3500 will power off, and the Standby LED will flash. To reset the Sentry Monitor Protection Circuitry, turn the Power Control Knob to OFF. (See “Power Control” on previous page). Then, turn the Power Control Knob to ON. If Sentry Monitor continues to engage, the problem must be fixed before continuing. Check that wires connected to the Output Terminals and the Loudspeaker Terminals are not shorted. If those connections are fine, and the Impedance of the Loudspeakers is close to the value of the connected Output terminals, the issue may be a defective tube. When the MC3500 doesn’t return to Normal Operation after the Power Switch has been switched back ON, then place the Power Switch in the OFF position and disconnect the AC Power Cord from the MC3500. Then contact your McIntosh Dealer for repair of the Power Amplifier. While the Knob is set to either WATTS or HOLD, the Power Output Meter light will be powered On/Off by a Preamplifier or A/V Control Center connected by a Power Control Cable if that unit has Power Control capabilities. If the Knob is set to LIGHTS OFF, the Power Output Meter light will be permanently off, and the Meter will respond as if the Knob was set to WATTS. Input Switch The Input Mode Switch, which is located on the Rear Panel of the MC3500, allows selection of either the Balanced or Unbalanced Input. Refer to figure 12. Auto Off Switch The MC3500 incorporates Power Save Circuitry to automatically place the MC3500 into the power saving Standby Mode approximately 30 minutes after there has been an absence of an audio input signal. When there is a Power Control Connection between the MC3500 and a Preamplifier with Power Save Circuitry, the AUTO OFF Switch is bypassed (located on the Rear Panel of the MC3500). Refer to figure 13. In the event there is no Power Control Connection and the Power Save Circuitry is activating inappropriately relative to your specific use of the MC3500, place the AUTO OFF Switch in the DISABLED position. If the Power Save Circuitry has switched Power to the MC3500 OFF, place the POWER in the OFF Position and then in the ON position to reset the circuitry. Figure 12 BALANCED UNBALANCED INPUT MODE ENABLED DISABLED Figure 13 AUTO OFF 14 Amplifier Specifications Power Output 350 watts into 2 ohm load 350 watts into 4 ohm load 350 watts into 8 ohm load Rated Power Band 20Hz to 20,000Hz Dynamic Headroom 2.4dB Wide Band Damping Factor Greater than 25 Frequency Response +0, -0.5dB from 20Hz to 20,000Hz +0, -3.0dB from 10Hz to 70,000Hz Total Harmonic Distortion 0.3% maximum harmonic distortion at any power level from 250 milliwatts to rated power, 20Hz to 20,000Hz Intermodulation Distortion 0.3% maximum, if the instantaneous peak power output does not exceed twice the rated power output for any combination of frequencies from 20Hz to 20,000Hz Signal To Noise Ratio (A Weighted) 120dB below rated output Input Sensitivity (for rated output) 3.8 Volts Balanced 1.9 Volts Unbalanced VoltageGain 29dB, 8 Ohms 26dB, 4 Ohms 23dB, 2 Ohms Input Impedance 22,000 ohms Balanced 22,000 ohms Unbalanced General Specifications Power Control Input 5-15VDC, less than 1mA Power Control Output 12VDC, 25mA (Delayed 0.2 seconds from power on) Power Requirements 100 Volts ~ 50/60Hz at 7.2 Amps 110 Volts ~ 50/60Hz at 6.0 Amps 120 Volts ~ 50/60Hz at 6.0 Amps 127 Volts ~ 50/60Hz at 6.0 Amps 220 Volts ~ 50/60Hz at 3.3 Amps 230 Volts ~ 50/60Hz at 3.3 Amps 240 Volts ~ 50/60Hz at 3.3 Amps Standby, less than 0.5 watt Refer to the rear panel of the MC3500 for the correct voltage. Overall Dimensions Depth is 21-5/8 inches (54.9cm) Width is 18 inches (45.7cm) Height is 11-13/16 inches (30cm) Weight 121 pounds (54.9kg) net 147 pounds (66.7kg) in shipping carton Shipping Carton Dimensions Depth is 31 inches (78.7cm) Width is 28 inches (71.1cm) Height is 17-1/4 inches (43.8cm) 15 MC3500 PACK ART B Packing Instructions In the event it is necessary to repack the equipment for shipment, the equipment must be packed exactly as shown below. It is very important that the four feet are attached to the bottom of the equipment. This will ensure the proper equipment location on the bottom foam pad. Failure to do this will result in shipping damage. To protect the tubes during shipment, the Foam Insert removed from the MC3500 needs to be re-inserted. Follow the unpacking instructions on pages 4-5 in the reverse order . Use the original shipping carton and interior parts only if they are all in good serviceable condition. If a shipping carton or any of the interior part(s) are needed, please call or write Customer Service Department of McIntosh Laboratory, refer to page 2. Please see the Part List for the correct part numbers. Quantity Part Number Description 1 034105 Shipping Carton Top 1 034104 Shipping Carton Bottom 1 034680 Tube Foam Insert 2 034679 Pad Top/Bottom 3 034678 Foam Ring 1 241109 Warning Sheet 1 033739 Poly Bag WARNING SHEET & TUBE FOAM The continuous improvement of its products is the policy of McIntosh Laboratory Incorporated who reserve the right to improve design without notice. Printed in the U.S.A. McIntosh Laboratory, Inc. 2 Chambers Street Binghamton, NY 13903 www.mcintoshlabs.com McIntosh Part No. 24113800