McIntosh C-220 Service manual

C220

TUBE PREAMPLIFIER

SERIAL NO. WS1001 And Above

CONTENTS

Performance Specifications ........................................ 2

Notes ......................................................................... 2

Rear Panel .................................................................. 3

Section Location ........................................................ 3

Block Diagram ...................................................... 5 - 6

Interconnection Diagram ...................................... 7 - 8

Main Schematic and PCB ................................... 9 - 18

SERVICE MANUAL

Seri al Num be r W S1 0 01 And A bo ve

Display Schematic and PCB .............................. 19 - 24

Balanced/Data Sch and PCB .............................. 25 - 30

Pushbutton Sch and PCB .................................. 31 - 32

Headphone Sch and PCB ................................. 33 - 34

Parts List ............................................................ 37 - 43

Repacking Instructions ............................................. 45

PERFORMANCE SPECIFICATIONS

Frequency Response

+0, -0.5dB from 20Hz to 20,000Hz

Total Harmonic Distortion

0.08% from 20Hz to 20,000Hz

Main Output

2.5V for rated input

Maximum Voltage Output

8V RMS Unbalanced, 16V RMS Balanced

Sensitivity (for rated output)

High Level, 450mV unbalanced, 900mV balanced Phono, 4.5mV

Signal To Noise Ratio (A-Weighted)

High Level, 90dB below rated output Phono, 80dB below 10mV input

Input Impedance

High Level, 22K ohms Phono, 47K ohms; 65pF

Maximum Input Signal

High Level, 5V Unbalanced, 10V Balanced Phono, 50mV (@ 1,000Hz)

Headphone Output Impedance

16 ohms to 250 ohms

Tube Compliment

Phono Circuitry: 2 - 12AX7A High Level Circuitry: 2 - 12AX7A

Power Requirements

100 Volts, 50/60Hz at 75 watts 110 Volts, 50/60Hz at 75 watts 120 Volts, 50/60Hz at 75 watts 220 Volts, 50/60Hz at 75 watts 230 Volts, 50/60Hz at 75 watts 240 Volts, 50/60Hz at 75 watts

Note: Refer to the rear panel of the C220 for the correct voltage.

Overall Dimensions

Width is 17-1/2 inches (44.45cm) Height is 6 inches (15.24cm) including feet Depth is 18 inches (45.72cm) including the Front Panel, Knobs and Cables

Weight

21.1 pounds (9.59 kg) net, 37.5 pounds (17.05 kg) in shipping carton

Output Impedance

250 ohms

Voltage Gain

High Level to Tape Output: 0dB High Level to Main Output: 15dB Phono to Main Output: 55dB

NOTES

1. The heavy notes on the schematic denote the primary

signal path.

2. Unless otherwise noted, all voltages indicated on the schematics are measured under the following conditions: a. AC input at 120 volts, 50/60Hz. b. All voltages are +/-10% with respect to ground. A

high impedance (10 megaohm) voltmeter must be used.

3. Unless otherwise specified: a. Resistor values are in ohms. b. Capacitor values are microfarads (uF). c. Inductor values are in microhenries (uH).

Shipping Carton Dimensions

Width is 26-1/2 inches (67.3cm) Depth is 24-1/4 inches (62.2cm) Height is 11-3/4 inches (29.9cm)

4. On PC board drawings, Square pad indicates: a. Polarized Capacitors - Positive b. Diodes - Cathode c. Others - Pin 1

5. WARNING Parts marked with the symbol have critical characteristics. Use only replacement parts recommended by the manufacturer.