McIntosh C2500 Service Manual

51
52
6
DIGITAL AUDIO 751120 SCH 3 of 3
1.82K
R9
10uF
C36
10uF
C22
475
R27
.0022uF
C10
.1uF
C37
22.1K
R30
100uH
L2
133757 TI PCM1795DB
12
13
10
7
8
5
2
3
17
16
19
22
21
24
27
26
9
11
14
1
4
6
20
18
15
28
25
23
MC
MDO
VDD
M\S\
DGND
SCL
PDATA
ZEROR
MSEL
IREF
MDI
R\S\T\
ZEROL
BCK
VCC2R
AGND3R
IOUTR+
AGND1
VCOMR
VCOML
AGND2
IOUTL+
IOUTL-
AGND3L
IOUTR-
VCC1
VCC2L
LRCK
U6
2
3
1
-
+
8 4
B+
B-
U8:1
-15V-OP
15V-OP
-15V-OP
-14.5V-OP
2
3
1
-
+
8
4
B+
B-
U4:1
6
5
7
-
+
U4:2
1000pF
C3
475
R4
15V-OP
-14.5V-OP
220uF
C7
100uH
L3
22.1
R16
22.1
R18
22.1R1
9
22.1
R22
22.1
R25
22.1
R26
47.5KR28
.1uF
C16
.1uF
C5
.1uF
C9
.1uF
C26
.1uF
C27
10K
R23
1000pFC13
6
5
7
-
+
U8:2
1K
R24
.0022uF
C15
2.21K
R32
.1uF
C40
1.82K
R14
1.5K
R6
330pF
C4
1.5K
R17
475
R20
1000pFC23
1.5K
R8
1.5K
R13
3
1
2
Q3
1K
R37
3
1
2
Q6
1K
R40
22.1K
R41
3
1
2
Q4
1.82K
R61
.0022uF
C35
6
5
7
-
+
U10:2
-14.5V-OP
15V-OP
1000pFC33
475
R57
-14.5V-OP
15V-OP
1000pF
C41
1K
R55
1.82K
R65
1.5K
R59
330pF
C34
1.5K
R68
475
R69
1.5K
R60
1.5K
R64
10uF
C28
475
R53
22.1K
R54
2
3
1
-
+
84
B+
B-
U10:1
2.21K
R51
1000pFC29
.0022uF
C30
330pF
C38
330pF
C12
2
3
1
-
+
84
B+
B-
U9:1
6
5
7
-
+
U9:2
22.1
R67
22.1
R63
DA-L
DA-R
10K
R38
10uF
C39
10uF
C6
10uF
C8
47uF
C11
47uF
C14
SP3
SP2
332
R5
332
R21
332
R58
332
R70
1.82K
R62
1.82K
R66
1.82K
R15
1.82K
R10
RST
4
2
1
3
Vcc
GND
5
U2
PLRCK
PBCK
SYS-CLK
22.1
R7
DA AUDIO MUTE
L6
.1uF
C69
PDATA
22.1
R79
3.3V
5VD
TO
AUDIO
PCB
J10:1
J10:3
DA-L
DA-R
J3:12
J3:10
ADDR-1
ADDR-0
SCL
SDA
-15V
15V
-15.4V
DA RESET/
SDA
SCL
GND
2
E/D
1
OUT
3
VDD
4
Y5
10uFC 105
.1uF
C104
3.24V
100K
R174
1 2
L14
OPEN
R173
SYS-CLK
J10:5
J10:7
0
R176
4
4
4
4
5VD
5VD
CONV UNLOCKED
Unlocked
Good Signal
Unmuted
Muted
L L = H
L H = L
H L = L
H H = L
Unmuted
Muted
Unmuted
Muted
LED4
22.1K
R181
47.5K
R182
ON = Audio Out
DA Run
DA Reset
OPENR186
OPEN
R187
3.24V
3.24V
0V
1.65V
0V
0V
0V
0V
0V
0V
0V
0V
-2.75V
-2.75V
-2.75V
-2.75V
-1.38V
-1.38V
0V
-1.38V
-1.38V
0V 0V
0V
0V
0V
0V
0V
0V
4.5V
5V
5.1V
.77V
.77V
0V
0V
0V
0V
J3:6
J3:8

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