C220
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 recomĀmended by the manufacturer.
2
REAR PANEL
SECTION LOCATIONS
TOP VIEW WITH COVER REMOVED
C220
3