McIntosh C2500 Service Manual

39
40
4
AUDIO
751458 SCH 5 of 5
0V
0V
0V
0V
R
2
1
1
2
0V
0V
0V
0V
221K
R281
221K
R280
0V
0V
0V
PROC LOOP (FROM ) BUFFER
0V
NEGATIVEPOSITIVE
7.5 VOLT REGULATOR
RIGHT BUFFER AM P
LEFT BUFFER AM P
221
R303
221
R301
SW IT C HE D O U TP UT S
267k
R223
267 k
R22 0
22pF
C150
22pF
C148
.1µF
C157
.1µF
C158
22.1k
R239
.01µF
C159
.1µF
C156
22.1k
R236
7.5 VOLT REGULATOR
.1µF
C191
33.2 k
R28 7
33.2 k
R28 6
47µF
C209
221
R302
47µF
C208
47µF
C207
221
R300
47µF
C206
10µF
C143
10µF
C142
22pF
C187
1k
R225
10µF
C154
10µF
C152
1
4
6
7
8
2
3
5
B+
B-
U27
1
4
6
7
8
2
3
5
B+
B-
U26
22µF
C197
23
14
K47
23
14
K45
22µF
C19 4
1k
R224
23
14
K46
23
14
K44
22.1 k
R29 2
1
4
6
7
8
2
3
5
B+
B-
U19
1
4
6
7
8
2
3
5
B+
B-
U17
15V -15V
15V
-15V
15V
-15V
15V
-15V
15V
-15V
15V
-15V
5v1
L
L
R
HDPH
GND
HDPH
9
J2:4
J2:2
J2:1
LEFT
GND
J2:5
TO HEADPHONE
RIGHT
HEADPHONE
AMP
HEADPHONE
0V
0V
0V
NC
R HDPH
L HDPH
AMP
2 3
1 4
K48
2 3
1 4
K49
5v1
5v1
J16:1J16:2J1 6:3J16:4J16:5J1 6:6
J16:7
J16:8
3
FROM CONTROL
J2 1:1
SDATA
VOLCS
VOLCK
5v15v -15v
10
R291
10
R290
.1µF
C203
.1µF
C202
470µF
C201
470µF
C200
15V
-15V
15HP
-15HP
J21:1
J21:2
J21:3
J21:4
J21:5
J21:6
J21:7
J21:8
J21:9
J21:1 0
J21:1 1
J21:1 2
L-MAIN
R-MAIN
L_MAIN+
L_MAIN-
R_MAIN-
R_MAIN+
5V1
TO A UD IO E XP AN SI ON
R_M AIN
L_M AIN
5V
M UTE
R_M AIN +
R_M AIN -
L_M AIN +
L_M AIN -
J4:1
MUTE
OUTPUT2
OUTPUT1
L-MAIN
R-MAIN
HDPH_MUTE
22.1 k
R29 3
22.1 k
R29 4
22.1 k
R29 5
L-MAIN
R-MAIN
LISAUD-L
LISAUD-R
100p F
C144
100p F
C146
100p F
C147
100p F
C145
.1µF
C189
.1µF
C190
.1µF
C188
22pF
C186
J16:9
J16:1 0 J16:1 2 J16:1 1
D36
D37
D38
D39
1
TO
P
3
5
J19:1
2
BOTT
4
6
J18:2
1
3
5
J18:1
2
BOTT
4 6
J19:2
J4:2
J4:3
J4:4
J4:5
J4:6
J4:7
J4:8
J4:9
J4:10
J4:11
J4:12
GND
GND
GND
GND
11
11
11
11
11
11
11
11
11
11
11
11
J2 1:2 J2 1:3 J2 1:4 J2 1:5 J2 1:6 J2 1:7 J2 1:8 J2 1:9
J2 1:1 0 J2 1:1 1 J2 1:1 2
3 3 3 3 3 3 3 3 3 3 3
9
9
9
PROC LOOP (FROM) BUFFER
VOLCK
VOLCS
5V
21
22
24
25
26
27
28
29
30
31
321
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16 17
18
19
20
23
InA
GND
SWCA
OutA
GND
Tone_Tr1a
Tone_Mi1a
Tone_Ba1a
Tone_Ba2a
NC
GND
VDDout
DATA
CLOCK
LATCH ADR0
ADR1
V-
V+
NC
NC
Ba2b
Ba1b
Mi2b
Mi1b
Tr1b
GND
OutB
SWCB
GND
InB
Tone_Mi2a
U24
133668
10µF
C17 5
-7.5V
10µF
C174
-7.5V
.0022 µF
C171
.0022 µF
C179
10µF
C164
10µF
C17 8
1µF
C185
1.65k
R268
1.65k
R274
1µF
C183
-7.5V
+7.5V
TONECS
VOLCK
100µF
C184
-7.5V
SDATA
.22µF
C165
.22µF
C181
2.21k
R258
2.21k
R275
15V
-15V
VOLUME CONTROL
21
22
24
25
26
27
28
29
30
31
321
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16 17
18
19
20
23
Z/C REFL
L_REF
L+
L_REF
L-
L_REF
OUTL
DCCAP_R
OUTR
R_REF
R-
R_REF
R+
R_REF
Z/C REFR D_VDD
DATA
CLOCK
LATCH
D_REF
V+
INR
V+
V-
INL
V-
D_CAP
ADR2
ADR1
ADR0
Z/C
DCCAP_L
U23
133779
3
2
1
8 4
B+
B-
U18 :1
5
6
7
U18:2
-15V
15V
1KR244
1K
R245
10K
R246
1K
R269
1K
R259
220p F
C182
.1µF
C11
.1µF
C180
47pFC15 1
47pF
C149
0
0
0
0
10µF
C212
100µF
C21 3
100µF
C172
100µF
C163
100µF
C162
SDATA
L-MAIN
R-MAIN
22.1k
R289
22.1k
R28 8
3
1
2
Q52
3
1
2
Q51
3
1
2
Q50
3
1
2
Q49
47
R169
47
R164
10
R168
10
R167
0V
0V
0V
0V
2.21k
R297
2.21k
R299
2.21k
R78
2.21k
R77
470p F
C198
470p F
C199
10k
R171
47
R165
.022µF
C217
.022µF
C21 9
47
R170
10k
R166
2
3
1
8
4
B+
B-
U28 :1
6
5
7
U28:2
-15HP
-15HP
15HP
15HP
.1µF
C20 5
.1µF
C20 4
4.75k
R306
4.75k
R305
4.75k
R16 3
4.75k
R30 4
10
R93
10
R161
15HP
-15HP
10µF
C155
10µF
C15 3
J20:1
J20:2
J20:5
J20:4
Tip-Left
Ring-Right
GND
Cable 173167, 1-1 Pinout.
-7.5V+7.5V
100µF
C21
100µF
C20
475
R79
1.21K
R80
15V
475
R81
1.21K
R82
-15V
IN(TAB) OUT
ADJ
1
2 3
U29
IN OUT(TAB)
ADJ
1
23
U7
GND
J20:3
Lef t
Right
Right
Lef t
Lef
t
Right
Lef t
Right
2C
2C
GND
GND
GND
2C
J46:6
J46:9
J46:7
J46:8
J46:10
J46:1
J46:11
2C
2C J6:10
GND
J16:8
J46:2
J46:5
J46:3
J46:4
T U B E P C B
15V
-15V
4.75K
R184
4.75K
R185
.47µF
C111
D43
D48
2.21M
R18 6
3.32K
R18 9
3.32K
R191
3
1
2
Q53
2
3
1
84
B+
B-
U30:1
6
5
7
U30:2
.47µF
C220
6.81K
R190
AUDIO DETECTOR
15V -15V
.1µF
C22 1
.1µF
C22 2
To ne C S o n J 12
To Display PCB for M eter L/R signal
J41:1
J41:2
J41:3
J41:4
R-MAIN
L-MAIN
TO DISPLAY PCB
CABLE 173183, PIN1-1
GND
GND
L METER
R METER
J4:1
J4:2
J4:3
J4:4
10
10
10
10
OPE N
R500
TUBE LED
2B J14:3
J46:12
TUBE-LED
Lef t
Lef t
GND
GND
GND
+ 6 d B
10K
R307
OPE N
C166
100p F
C168
3
1
2
Q54
3
1
2
Q55
3
1
2
Q56
3
1
2
Q57
470µF
C21 6
10µF
C19 5
470µF
C218
10µF
C196
10µF
C22 8
10µF
C22 9
4
2
1
3
Vcc
GND
5
U31
100K
R410
AUD DET
3.3VBU2
3.3VBU2
Add Pwr On Attn, for tube DC mute??
1.21K
R411
1.21K
R412
Remove resistors
TONE CONTROL
D45
D46
D47
D50
4.75K
R413
D44
+7.5V
4.75K
R41 4
D49
-7.5V
332
R41 5
332
R416
TO
P

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