McIntosh C8AC Service Manual

2
1. Unless otherwise noted, all voltages indicated on the
schematics are measured under the following conditions:
a. AC input at rated voltage marked on rear panel.
b. All voltages are +/-10% with respect to ground. A
high impedance (10 megaohm) voltmeter must be used.
2. Unlessotherwisespecied:
a. Resistor values are in ohms.
b. Capacitor values are microfarads (uF).
c. Inductor values are in microhenries (uH)
3. On PC board drawings, Square pad indicates:
a. Polarized Capacitors - Positive
b. Diodes - Cathode
c. Others - Pin 1
4. WARNING
Parts marked with the symbol have critical
characteristics. Use only replacement parts recom-
mended by the manufacturer.
NOTES
PERFORMANCE SPECIFICATIONS
Power Output Stereo
Minimum sine wave continuous average power output per
channel, both channels operating is:
75 watts into 4 ohm loads
75 watts into 8 ohm loads
75 watts into 16 ohm loads
Power Output Mono (Parallel)
Minimum sine wave continuous average power output is:
150 watts into 2 ohm load
150 watts into 4 ohm load
150 watts into 8 ohm load
Output Load Impedance
4, 8 or 16 ohms (Stereo Mode)
2, 4 or 8 ohms (Mono Mode)
Rated Power Band
20Hz to 20,000Hz
Total Harmonic Distortion
0.5% maximum harmonic distortion at any power level from
250 milliwatts to rated power, 20Hz to 20,000Hz
Frequency Response
+0, -0.5dB from 20Hz to 20,000Hz
+0, -3.0dB from 10Hz to 100,000Hz
Input Sensitivity (for rated output)
1.7 Volts Unbalanced
3.4 Volts Balanced
Signal To Noise Ratio (A-Weighted)
105dB below rated output
Intermodulation Distortion
0.5% 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.
Wide Band Damping Factor
Greater than 22
Input Impedance
47,000 ohms Unbalanced
20,000 ohms Balanced
Tube Compliment
3 - 12AX7A Input and Phase Inverter
4-12AT7VoltageAmplierandDriver
4 - KT88/6550 Power Output
Power Requirements
Field AC Voltage conversion of the MC275 is not possible.
TheMC275isfactoryconguredforoneofthefollowingAC
Voltages:
100V ~ 50/60Hz at 4.4 Amps
110V ~ 50/60Hz at 3.6 Amps
120V ~ 50/60Hz at 3.6 Amps
220V ~ 50/60Hz at 2.0 Amps
230V ~ 50/60Hz at 1.8 Amps
240V ~ 50/60Hz at 1.8 Amps
Standby: Less than 0.3 watts
Note: Refer to the right side panel of the MC275 for the cor-
rect voltage.
Overall Dimensions
Width is 21-1/2 inches (54.6cm) including Cables
Height is 8-1/2 inches (21.6cm) including feet
Depth is 12 inches (30.5cm)
Weight
67 pounds (30.5 kg) net, 75 pounds (34.1 kg) in shipping
carton
Shipping Carton Dimensions
Width is 22 inches (55.9cm)
Height is 14 inches (35.6cm)
Depth is 16-3/4 inches (42.6cm)

McIntosh C8AC Specifications

General

Brand	McIntosh
Model	C8AC
Category	Amplifier
Language	English