McIntosh C2500 Service Manual

11
12
2
DISPLAY
751456 SCH 2 OF 4
0V
0V
0V
0V
0V
.3V
-.5V
-3.7V
0V
0V
1
1
1
0V
0V
0V
.3V
-.5V
1
0V
0V
LEFT
-3.7V
LEFT
-3.7V
-3.7V
1K
R115
LEFT
METER DRIVER
LEFT METER
RIGHT -
RIGHT +
LEFT -
J22:2
RIGHT
LEFT
47µF
C5
RIGHT
.1µF
C64
1K
R94
47µF
C65
D14
220µF
C69
D6
D7
D11
RIGHT
D10
D9
D13
D12
3
1
2
Q39
METER DRIVER
1K
R114
LEFT
J23:1
J23:2
LEFT +
J22:1
47
R95
D8
3
1
2
Q40
2.21M
R110
2.21M
R111
3
1
2
Q44
3
1
2
Q43
3
1
2
Q45
3
1
2
Q46
RIGHT METER
METER BUFFER
LEFT METER
LOG CONVERTER
METER BUFFER
METER RECTIFIER
.1µF
C71
RIGHT METER
METERS
ON/OFF CONTROL
D5
100K
R99
LOG CONVERTER
1K
R97
2
3
1
8
4
B+
B-
U10:1
.1µF
C67
.1µF
C68
6
5
7
U11:2
D3
100K
R98
1K
R96
.47µF
C72
.1µF
C73
150K
R105
22.1K
R101
.47µF
C70
221
R108
METER RECTIFIER
150K
R103
22.1K
R100
METERS
ON/OFF CONTROL
D4
6
5
7
U12:2
D2
6
5
7
U10:2
221
R109
3
1
2
Q42
2
3
1
8
4
B+
B-
U12:1
3
1
2
Q41
2
3
1
84
B+
B-
U11:1
10K
R116
10K
R117
-5V
10V
10V -5V
-5V
10V
10V
-5V
2.21
R113
15K
R38
D30
2.21
R112
15K
R37
1K
R249
1K
R250
.01µF
C170
.01µF
C169
221K
R251
221K
R252
10V
-5V
R76
R77
(806 ohm)
(806 ohm)
J4:1
J4:2
J4:3
J4:4
R-METER
L-METER
TO AUDIO PCB
CABLE 173081, PIN1-1
GND
GND
L METER
R METER
R-METER
L-METER
J41:1
J41:2
J41:3
J41:4
METER MUTE
100K
R3
100K
R4
15V
-15V
15V
-15V
5k
13
2
CCW
R106
5k
13
2
CCW
R107
10
10
10
10
OPEN
R400

McIntosh C2500 Specifications

General

Total Harmonic Distortion	0.08%
Signal to Noise Ratio	100dB
Rated Output Voltage	2.5V unbalanced, 5V balanced
Maximum Output Voltage	8V unbalanced, 16V balanced
High Level Voltage Gain	15dB
Type	Vacuum Tube Preamplifier
Inputs	6 unbalanced, 2 balanced, 1 phono MC, 1 phono MM
Outputs	3 unbalanced, 2 balanced
Weight	29 lbs (13.2 kg)
Input Impedance	47k ohms
Phono Voltage Gain	40dB (MM), 60dB (MC)
Frequency Response	+0, -0.5dB from 20Hz to 20, 000Hz +0, -3dB from 10Hz to 100, 000Hz