McIntosh Stereo Amplifier MC501 User Manual

Power Amplifier  
MC501  
Owner’s Manual  
McIntosh Laboratory, Inc. 2 Chambers Street Binghamton, New York 13903-2699 Phone: 607-723-3512 FAX: 607-724-0549  
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Thank You  
Table of Contents  
Your decision to own this McIntosh MC501 Power Ampli-  
fier ranks you at the very top among discriminating music  
listeners. You now have “The Best.” The McIntosh dedica-  
tion 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.  
Safety Instructions ............................................................ 2  
Thank You and Please Take a Moment............................. 3  
Technical Assistance and Customer Service .................... 3  
Table of Contents and General Notes ............................... 3  
Connector Information ..................................................... 4  
Introduction ...................................................................... 4  
Performance Features ....................................................... 4  
Dimensions ....................................................................... 5  
Installation ........................................................................ 6  
Top Panel Connections and Switch .................................. 7  
How to Connect ................................................................ 8  
Front Panel Displays and Controls ................................. 10  
How to Operate............................................................... 11  
Technical Description ..................................................... 12  
Notes ............................................................................... 16  
Specifications ................................................................. 18  
Packing Instruction ......................................................... 19  
Please Take A Moment  
The serial number, purchase date and McIntosh Dealer  
name are important to you for possible insurance claim or  
future service. The spaces below have been provided for  
you to record that information:  
Serial Number:  
Purchase Date:  
Dealer Name:  
Important Information  
Caution: The MC501 Amplifier weight is 91.5 pounds (41.5  
kilograms). It requires two or more persons to  
safely handle when moving the amplifier.  
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 wish addi-  
tional help concerning a suspected problem, you can re-  
ceive technical assistance for all McIntosh products at:  
1. The following Connecting Cable is available from the  
McIntosh Parts Department:  
Power Control Cable Part No. 170-202  
Six foot, 2 conductor shielded, with two 1/8 inch stereo  
mini phone plugs.  
2. For additional connection information, refer to the owners  
manual(s) for any component(s) connected to the MC501.  
3. The MC501 mutes the speaker output for approximately two  
seconds when first turned on.  
McIntosh Laboratory, Inc.  
2 Chambers Street  
Binghamton, New York 13903  
Phone: 607-723-1545  
Fax: 607-723-3636  
4. It is very important that loudspeaker cables of adequate size  
be used, so that there will be no power loss. The size is  
specified in Gauge Numbers or AWG, (American Wire Gauge).  
The smaller the Gauge number, the larger the wire size:  
If your loudspeaker cables are 50 feet (38.1m) or less,  
use at least 14 Gauge.  
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 as-  
sistance on factory repair return procedure, contact the  
McIntosh Service Department at:  
If your loudspeaker cables are 100 feet (76.2m) or less,  
use at least 12 Gauge.  
5. In the event the MC501 over heats, due to improper  
ventilation and/or high ambient temperature, the protection  
circuits will activate. The Power Guard LED will stay ON and  
the audio will be muted. When the MC501 has returned to a  
safe operating temperature, normal operation will resume.  
6. The MC501 incorporates Fully Double Balanced Circuitry. As  
McIntosh Laboratory, Inc.  
2 Chambers Street  
Binghamton, New York 13903  
Phone: 607-723-3515  
Fax: 607-723-1917  
a result, the Loudspeaker  
Negative Connections are above  
chassis ground. Do not combine any connections together,  
ground them or connect with another MC501.  
Copyright 2003 by McIntosh Laboratory, Inc.  
3
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Connector Information  
XLR Connectors  
harsh distorted sound that can also damage your valuable  
Loudspeaker.  
Below is the Pin configuration for the XLR Balanced Input  
and Output Connectors on the MC501. Refer to the dia-  
gram for connection:  
PIN 1: Shield/Ground  
PIN 2: + Input  
PIN 3: - Input  
Patented Sentry Monitor with Thermal Protection  
McIntosh Sentry Monitor power output stage protection  
circuits ensure the MC501 will have a long and trouble free  
operating life. Built-in Thermal Protection Circuits guard  
against overheating.  
Pin 1  
Pin 3  
Pin 2  
Power Control and Trigger Connectors  
The MC501’s Power Control Outputs provide a 5 volt sig-  
nal. Use a 1/8 inch stereo mini  
phone plug to connect to the  
Power Control  
The McIntosh Power Control Circuit allows for remote  
turn-on of the MC501 Power Amplifier from a McIntosh  
Audio/Video Control Center or Preamplifier. If any addi-  
tional McIntosh Power Amplifiers are part of the system, a  
delayed Power Control Output Trigger is available. This  
delayed trigger reduces the strain on the house’s electrical  
wiring and protection devices.  
Positive  
Power Control Input on other  
McIntosh Components.  
N/C  
Ground  
Introduction  
Now you can take advantage of traditional McIntosh stan-  
dards of excellence in the MC501 Power Amplifier. The  
500 watt high current output will drive any high quality  
Loudspeaker System to its ultimate performance. The  
MC501 reproduction is sonically transparent and abso-  
lutely accurate. The McIntosh Sound is “The Sound of the  
Music Itself.”  
Balanced and Unbalanced Inputs  
Balanced connections guard against induced noise and al-  
low long cable runs without compromising sound quality.  
Illuminated Power Meter  
The Illuminated Power Output Watt Meter on the MC501  
is peak responding, and indicates the true power output of  
the amplifier. The Peak Watt Hold Mode allows the meter  
to temporarily stay at the highest power output and then  
slowly decay. The Front Panel Meter Illumination may be  
switched Off at any time.  
Performance Features  
Power Output  
The MC501 is a Power Amplifier with a capability of 500  
watts into 2, 4 or 8 ohm speakers with less than 0.005%  
distortion.  
Fiber Optic Solid State Front Panel Illumination  
The Illumination of the Front Panel is accomplished by the  
combination of custom designed Fiber Optic Light Diffus-  
ers and Light Emitting Diodes (LEDs). This provides even  
Front Panel Illumination, together with the extra long life  
LEDs.  
Full Balanced Quad-Differential Circuitry  
The MC501 is fully balanced from inputs to outputs. It  
consists of two matched power amplifiers operating in  
push-pull with their outputs combined in a McIntosh  
Autoformer. The double balanced configuration cancels  
virtually all distortion.  
Glass Front Panel and Super Mirror Chassis Finish  
The famous McIntosh Illuminated Glass Front Panel with a  
three dimensional look and the Stainless Steel Chassis with  
Super Mirror Finish ensures the pristine beauty of the  
MC501 will be retained for many years.  
Patented Autoformers  
The McIntosh designed and manufactured Output  
Autoformer provides an ideal match between the amplifier  
output stage and speaker loads of 2, 4 and 8 ohms. The  
Autoformer also provides perfect DC protection for your  
valuable Loudspeaker.  
Patented Power Guard  
The patented McIntosh Power Guard Circuit prevents the  
amplifier from being over driven into clipping, with its  
4
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Connector Information, Introduction, Performance Features and Dimensions  
The following dimensions can assist in determining the  
best location for your MC501. There is additional informa-  
tion on the next page pertaining to installing the MC501  
into cabinets.  
17-1/2"  
44.45cm  
8-13/16"  
22.38cm  
9-  
7
/16"  
23.97cm  
Front View of the MC501  
16-13/16"  
42.70cm  
Rear View of the MC501  
13-1/4"  
33.66cm  
14-1/2"  
36.83cm  
13-5/8"  
34.61cm  
Side View of the MC501  
8-1/8"  
20.64cm  
8-3/16"  
21.11cm  
7/8"  
2.22cm  
9-1/2"  
24.13cm  
1-1/16"  
2.70cm  
5
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Installation  
Installation  
Caution: The MC501 Amplifier weight is 91.5 pounds (41.5  
(40.64 cm) depth behind the front panel. Allow 1-3/16  
kilograms). It requires two or more persons to  
safely handle when moving the amplifier.  
The MC501 can be placed upright on a table or shelf,  
standing on its four feet. The  
inches (3.02 cm) in front of the mounting panel for knob  
clearance. Be sure to cut out a ventilation hole in the  
mounting shelf according to the dimensions in the drawing.  
four feet may be removed  
from the bottom of the  
MC501 when it is custom  
installed as outlined below.  
17-1/16"  
43.34cm  
The four feet together with  
the mounting screws should  
be retained for possible fu-  
ture use if the MC501 is re-  
moved from the custom in-  
stallation and used free  
8-5/16"  
21.11cm  
MC501 Front Panel  
Custom Cabinet Cutout  
standing. It also can be cus-  
tom installed in a piece of  
furniture or cabinet of your  
choice. The required panel  
cutout, ventilation cutout and  
unit dimensions are shown.  
Always provide adequate  
ventilation for your MC501.  
Cool operation ensures the  
longest possible operating  
life for any electronic instru-  
Alternate Rear Foot Location  
Cutout Opening  
for Custom Mounting  
6"  
15.24cm  
Cabinet  
Front  
Panel  
Opening  
for Ventilation  
ment. Do not install the  
MC501 directly above a heat  
generating component such  
as a high powered amplifier.  
If all the components are in-  
stalled in a single cabinet, a  
MC501 Side View  
quiet running ventilation fan in Custom Cabinet  
can be a definite asset in  
maintaining all the system  
components at the coolest  
possible operating tempera-  
ture.  
A custom cabinet installa-  
tion should provide the fol-  
lowing minimum spacing di-  
mensions for cool operation.  
Allow at least 6 inches  
Cutout Opening for Ventilation  
Support  
Shelf  
1-1/4"  
3.18cm  
11-1/2"  
29.21cm  
(15.24 cm) above the top, 2  
inches (3.81cm) below the  
bottom and 1 inch (2.54 cm)  
on each side of the amplifier,  
so that airflow is not ob-  
structed. Allow 16 inches  
MC501 Bottom View  
in Custom Cabinet  
14-3/8"  
36.51cm  
Cutout Opening  
for Ventilation  
6
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Top Panel Connections and Switch  
Main Fuse holder,  
refer to information  
on the back panel of  
the MC501 to deter-  
mine the correct fuse  
size and rating  
BALANCED INPUT  
for an audio cable  
from a preamplifier or  
control center audio  
output  
UNBALANCED INPUT  
for an audio cable from a  
preamplifier or control  
center audio output  
POWER CONTROL IN receives  
a turn On/Off Trigger from a  
McIntosh component. POWER  
CONTROL OUT sends a turn On/  
Off Trigger to the next McIntosh  
component  
INPUT MODE  
switch selects  
BALANCED or  
UNBALANCED  
Input  
Connect the MC501  
power cord to a live  
AC outlet. Refer to  
information on the  
back panel to deter-  
mine the correct  
voltage  
OUTPUT Connections  
for 2 ohm loudspeaker  
OUTPUT Connections  
for 8 ohm loudspeaker  
OUTPUT Connections  
for 4 ohm loudspeaker  
Caution: The Loudspeaker  
Negative Connections are above chassis  
ground. Do not combine any connections together, ground  
them or connect with another MC501.  
7
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How to Connect  
Caution: The supplied AC Power Cord should not be  
connected to the Rear Panel of the MC501  
Amplifier until after the Loudspeaker Connections  
have been made and the supplied protective  
Terminal Connections Cover has been installed.  
Failure to observe this could result in Electric  
Shock.  
Banana plug connection:  
Insert the banana plug into the hole at the top of the  
terminal. Tighten the top portion of the terminal post  
and the set screw to secure the banana plug in place.  
Note: The use  
of  
Banana  
1. For Remote Power Control, connect a power control  
cable from the Control Center or Preamplifier Power  
Control Out to the MC501 Power Control In.  
2. Connect cables from the Unbalanced Output of a McIn-  
tosh Preamplifier or Control Center to the MC501  
Unbalanced Input.  
Note: An optional hookup is to use balanced cables.  
3. Prepare the Loudspeaker Hookup Cables that attach to  
the MC501 Power Amplifier by choosing one of the  
methods below:  
Plugs is  
for use in  
the  
United  
States  
and Canada only.  
4. Connect the Loudspeaker hookup cables to the output  
terminals that match the impedance of the Loudspeak-  
er, being careful to observe the correct polarities. Out-  
put impedance connections of 2 ohms, 4 ohms and 8  
ohms are provided. If the Loudspeaker’s impedance is  
in-between the available connections, use the nearest  
lower impedance connection.  
Bare wire cable ends:  
Carefully remove sufficient insulation from the cable  
ends, refer to figures 1,  
2 & 3. If the cable is  
stranded, carefully twist  
the strands together as  
tightly as possible.  
Note: If desired, the twisted ends can be tinned with  
solder to keep the strands together, or attach spade  
lug and/or banana connector.  
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.  
5. Attach the supplied Terminal Connections Cover with  
the three Mounting Screws (6-32 x 1/4 inch Phillips  
Head) to the Rear Panel of the MC501 Amplifier. Refer  
to figure 9.  
Note: There are two openings on the cover allowing for  
the Loudspeakers Cable to exit the MC501.  
6. Connect the MC501 power cord to an active AC outlet.  
Spade lug or prepared wire connection:  
Insert the spade lug connector or prepared section of  
the cable end into the terminal side access hole, and  
tighten the terminal cap until the cable is firmly  
clamped into the terminal so the wires cannot slip out.  
Refer to figures 4, 5 & 6.  
Terminal  
Connections  
Cover  
Cable Openings  
Cover Mounting  
Screw Locations  
Cover Mounting  
Screw Location  
Figure 9  
8
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How to Connect  
McIntosh MX134 A/V Control Center  
MC501 Top Rear View  
To AC Outlet  
4 ohm  
Loudspeaker  
Caution: The Loudspeaker  
Negative Connections are above chassis  
ground. Do not combine any connections together, ground  
them or connect with another MC501.  
9
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Front Panel Displays and Controls  
METER indicates  
the Power Output  
of the amplifier  
POWER GUARD LED  
lights when the amplifier  
POWER GUARD circuit  
activates  
Remote On  
Indicator lights  
when the am-  
plifier is in the  
Remote Turn-  
On Mode  
POWER Switch Turns  
AC power On/Off, or  
On/Remote  
METER Switch selects  
the display modes of the  
Power Output Meter  
10  
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How to Operate  
How to Operate  
Power On  
peaks are reached, the meter pointer will very  
slowly return to its rest position or lower  
power level. The decay rate is approximately  
6dB per minute.  
Note: The MC501 Power Output Meter  
indicates the actual wattage delivered to  
the Loudspeakers by responding to the  
combination of current and voltage  
output.  
To have the MC501 automatically turn On or Off when a  
control center turns on or off,  
rotate the power switch to the  
remote position. For manual  
operation, rotate the power  
switch to the On or Off position  
as desired. Refer to figure 10.  
Note: There must be a power  
control connection  
Input Mode Switch  
between the MC501 and  
the McIntosh Control  
Center, in order for the remote power turn-on to  
function.  
Figure 10  
The Input Mode Switch, which is located on the Top Rear  
Panel of the MC501, allows selection of either the Bal-  
anced or Unbalanced Input.  
Refer to figure 13.  
Meter Selection  
Rotate the meter mode switch to select the meter operation  
mode you desire. Refer to figures 11 and 12.  
Lights Off - Meter lights are  
turned off and  
Figure 13  
the meter will  
continue to indi-  
cate the power  
output.  
Watts- The meter re-  
spond to all the  
musical informa-  
tion being pro-  
duced by the am-  
Figure 11  
plifier. They indicate to an accuracy of at least  
95% of the power output with only a single  
cycle of a 2000Hz tone burst.  
Hold - The meter pointer is locked to the highest  
power peak in a sequence of peaks. It is elec-  
tronically held to this power level until a  
Figure 12  
higher power peak passes through the ampli-  
fier. The meter pointer will then rise to the  
newer higher indication. If no further power  
11  
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Technical Description  
McIntosh Laboratory, the company who introduced the  
world’s first amplifier that could be called “High Fidelity”,  
has done it again. The McIntosh engineering staff has cre-  
20Hz to 20,000Hz. Typical performance at mid frequencies  
is less than 0.002%. The true distortion readings on the  
MC501 are so low, it takes special measuring techniques to  
ated a power amplifier without compromise, using the most make accurate readings. The MC501 can deliver the best  
advanced McIntosh circuit design concepts.  
possible performance from any type of high quality Loud-  
speaker System.  
Creating an amplifier with this level of performance did  
not come easily. Many months of design, testing and mea-  
A continuous average power output rating of 500 watts  
and with an output current of greater than 100 amperes,  
makes this not only the most advanced, but also one of the  
most powerful amplifiers McIntosh has ever manufactured. suring were required. Extensive controlled listening tests,  
The distortion limits for the MC501 are no more than  
0.005% at rated power output for all frequencies from  
the ultimate form of measuring, were made before the final  
design was accepted.  
Inside View of the MC501  
12  
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Technical Description  
Design Philosophy  
The output signals of the two balanced circuits are  
coupled together in the unique McIntosh MC501 Output  
Autoformer. It provides low distortion power transfer at  
frequencies from below 20Hz to well beyond 20,000Hz  
with optimum impedance points of two ohms, four ohms  
and eight ohms. The unequaled expertise of McIntosh in  
the design and manufacturing of autoformers is legendary  
in the high fidelity industry.  
The design philosophy incorporated in the MC501 in-  
volved several different techniques, all based on sound sci-  
entific logic. Every stage of voltage or current amplifica-  
tion must be as linear as possible prior to the use of nega-  
tive feedback. McIntosh engineers know how to properly  
design negative feedback circuits so they contribute to the  
extremely low distortion performance expected from a  
McIntosh amplifier. The typical McIntosh owner would  
never accept the approximately 100 times higher distortion  
of many non-feedback designs.  
The high efficiency circuit design of the MC501 con-  
tributes to low operating temperatures. More than 1,045  
square inches of heat sink area keep the MC501 operating  
Double Balanced Push-Pull design is used from input to safely with convection cooling. No fans are needed.  
output. Each half of the amplifier contains complimentary  
balanced circuitry. The resulting double balanced configu-  
ration cancels even order distortion. Refer to figure 14.  
All transistors are selected to have nearly constant cur-  
rent gain over the entire current range they must cover.  
Output transistors in particular, have matched uniform cur-  
rent gain, high current bandwidth product and large active  
region safe operating area. An automatic tracking bias sys-  
tem completely eliminates any trace of crossover distor-  
tion. Precision metal film resistors and low dielectric ab-  
sorption film capacitors are used in all critical circuit loca-  
tions.  
Autoformers  
All solid state power amplifier output circuits work best  
into what is called an optimum load. This optimum load  
may vary considerably from what a loudspeaker requires.  
In the case of more than one loudspeaker connected in par-  
allel, the load to the power amplifier may drop to two ohms  
or even less. A power amplifier connected to a load that is  
lower than optimum, causes more output current to flow,  
which results in extra heat being generated in the power  
output stage. This increase in temperature will result in a  
reduced life expectancy for the amplifier.  
Block Diagram  
of the  
Amplifier and Meter Circuitry  
Figure 14  
13  
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The special Balanced Winding Autoformer creates an  
ideal match between the power amplifier output stage and  
the loudspeaker. A McIntosh amplifier with an Autoformer  
can be used to safely drive multiple speakers without re-  
ducing the life expectancy of the power amplifier. Refer to  
figure 15.  
Figure 16  
Protection Circuits  
The MC501 incorporates a version of the McIntosh Sentry  
Monitor Output Transistor Protection Circuit. Refer to Fig-  
ure 17. There is absolutely no compromise in sonic perfor-  
mance with this  
Figure 15  
There is absolutely no performance limitation with an  
circuit, and it en-  
Autoformer. Its frequency response exceeds that of the out- sures safe opera-  
put circuit itself, and extends well beyond the audible tion of the ampli-  
range. Its distortion level is so low it is virtually impossible fier under even the  
to measure. most extreme oper-  
In the rare event of a power amplifier output circuit fail- ating conditions.  
ure, the McIntosh Autoformer provides absolute protection  
from possible damage to your valuable loudspeakers. The  
unequaled expertise of McIntosh in the design and manu-  
facturing of Autoformers is legendary in the high fidelity  
industry. McIntosh engineers know how to do it right.  
The different types  
of protection cir-  
cuits incorporated  
in the MC501 in-  
sure a long and  
safe operating life.  
This is just one of  
Figure 17  
Power Output Meter  
The McIntosh MC501 has a Output Watt Meter that re-  
sponds 95% full scale to a single cycle tone burst at 2kHz.  
Refer to figure 16. Voltage and current output are electroni-  
cally measured, multiplied and fed to a special circuit that  
accelerates the pointer movement in the upward direction.  
When the pointer reaches its peak it pauses only long  
enough for the human eye to perceive its position, then  
drops. It is almost 10 times faster than a professional VU  
meter.  
the many characteristics of McIntosh Power Amplifiers  
that make them world famous.  
The MC501 also includes the unique patented McIntosh  
Power Guard circuit.  
Input Test Signal  
Power Guard eliminates  
the possibility of ever  
overdriving the amplifier  
into clipping. Refer to  
figures 18, 19 and 20. An  
overdriven amplifier can  
A front panel switch is provided to change the meter to  
the Watts Hold Mode of operation. This allows fast upward produce both audible and  
movement of the pointer but greatly increases Hold Time at inaudible distortion levels  
the peak of its travel. The highest power output of the  
source material is thus recorded.  
exceeding 40%. The au-  
dible distortion is un-  
pleasant to hear, but the  
inaudible ultrasonic dis-  
tortion is also undesir-  
Figure 18  
14  
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Technical Description, con’t  
Without Power Guard  
able, since it can damage  
valuable loudspeaker sys-  
tem tweeters. You will  
never experience the  
produce distortion free output well above its rated power  
due to the McIntosh philosophy of conservative design.  
Power Supply Circuits  
harsh and damaging dis-  
tortion due to clipping.  
The Power Guard cir-  
cuit is a waveform com-  
parator, monitoring both  
the input and output  
waveforms. Under nor-  
mal operating conditions,  
there are no differences  
between the shape of  
To compliment the fully balanced design of the MC501 in-  
corporates a high voltage power supply. Refer to figure 21.  
High power amplifiers draw high current from the AC  
power line. Therefore, it is important that they plug directly  
into the wall outlet.  
Also, most owners desire that there be one power  
switch for the whole audio system. The MC501 is equipped  
with a circuit that provides remote Power Control from the  
McIntosh Preamplifier or Control Center. When the Pream-  
plifier or Control Center is switched On, a digital “1”  
(+5V) signal operates the power relay in the MC501. The  
MC501 also has a remote Power Control Out Jack. The  
Power Control signal from this jack is delayed by a fraction  
of a second so that the turn on power surge of the next  
power amplifier occurs at a later time. This helps prevent  
power circuit overload that could trip circuit breakers or  
blow fuses, a very important feature in a high power Home  
Theater System employing many MC501 Power Amplifi-  
ers.  
The MC501 can provide greater than 100 amperes peak  
output current to drive uneven speaker loads. Some poor  
speaker designs have input impedance that dip to 1 or 2  
ohms at various frequencies and the MC501 has the output  
current reserve to drive them. It can deliver over 500 Watts  
Output on tone bursts. The MC501 has huge main filter ca-  
pacitors that guarantee an excellent signal to noise ratio  
and the energy storage necessary for the wide dynamic  
range that “Digital Audio” demands.  
Figure 19  
these waveforms. If an amplifier channel is overdriven,  
there will be a difference between the two signal wave-  
forms. When the difference exceeds 0.3% (equivalent to  
0.3% harmonic distor-  
With Power Guard  
tion), the Power Guard  
activates the PG light and  
a dynamic electronic at-  
tenuator at the amplifier  
input reduces the input  
volume just enough to  
prevent any further in-  
crease in distortion. The  
Power Guard circuit acts  
so fast that there are ab-  
solutely no audible side  
effects and the sonic pu-  
rity of the music repro-  
Figure 20  
duction is perfectly pre-  
served. The MC501 Power Amplifier with Power Guard is  
not limited to just the rated power output, but will actually  
Block Diagram  
of the  
Power Supply  
Figure 21  
15  
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16  
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Notes  
17  
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Specifications  
Specifications  
Power Output  
Power Requirements  
Minimum sine wave continuous average power output is:  
500 watts into 2 ohm load  
500 watts into 4 ohm load  
100 Volts, 50/60Hz at 8.0 amps  
110 Volts, 50/60Hz at 7.2 amps  
120 Volts, 50/60Hz at 6.6 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  
500 watts into 8 ohm load  
Rated Power Band  
20Hz to 20,000Hz  
Note: Refer to the rear panel of the MC501 for the correct  
voltage.  
Total Harmonic Distortion  
Maximum Total Harmonic Distortion at any power  
level from 250 milliwatts to rated power output is:  
0.005% for 2, 4 or 8 ohm load  
Overall Dimensions  
Front Panel: 17-1/2 inches (44.45cm) wide, 8-13/16 inches  
(22.38cm) high. Depth is 14-13/16 inches (37.62cm) in-  
cluding the Front Panel and Knobs  
Dynamic Headroom  
1.8dB  
Weight  
91.5 pounds (41.6 kg) net, 105.5 pounds (48 kg) in ship-  
ping carton  
Frequency Response  
+0, -0.25dB from 20Hz to 20,000Hz  
+0, -3dB from 10Hz to 100,000Hz  
Sensitivity  
2.1 Volts Unbalanced Input  
4.2 Volts Balanced Input  
A-Weighted Signal To Noise Ratio  
97dB (124dB below rated output) Unbalanced and Bal-  
anced  
Intermodulation Distortion  
Maximum Intermodulation Distortion if instanta-  
neous peak output does not exceed twice the rated  
output, for any combination of frequencies from  
20Hz to 20,000Hz is:  
0.005% for 2, 4 or 8 ohm load  
Input Impedance  
10,000 ohms Unbalanced Inputs  
20,000 ohms Balanced Inputs  
Wide Band Damping Factor  
100 @ 8ohms  
18  
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Packing Instructions  
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 plastic feet are at-  
tached to the bottom of the equipment. Three #10 x 2-1/2  
inch screws and washers must be used to fasten the unit  
securely to the bottom pad and shipping skid. This will en-  
sure the proper equipment location on the bottom pad. Fail-  
ure to do this will result in shipping damage.  
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 Labo-  
ratory. Please see the Part List for the correct part numbers.  
Quantity Part Number  
Description  
Shipping carton only  
Foam end cap  
1
2
034158  
034250  
1
1
1
1
1
034198  
034199  
034188  
034037  
033699  
Inner carton top  
Inner carton bottom  
Foam pad  
Inner carton pad  
Shipping skid  
7
4
2
3
3
017218  
100159  
104083  
101204  
104033  
Plastic foot  
#10-32 x 3/4” Machine screw  
#10 x 7/16” Flat washer  
#10 x 2-1/2” Wood screw  
#10 x 1-3/4” Flat washer  
19  
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McIntosh Laboratory, Inc.  
2 Chambers Street  
Binghamton, NY 13903  
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 Part No. 040856  
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