Arcam A28 Schematic
FD100 FD101
FIX100
Dia 3.5mm
Power Supplies
L991CT2_2.2.SCH
PWR_ON
A28 PreAmp
L991CT3_2.2.SCH
FIX101
Dia 3.5mm
1
P101
0V(D)
0V(SIG_2)
0V_FB_R
0V_HF_R
0V_LS_R
-38V_VFD
0V_PREOUT
*PRE_MUTE
0V_D_PRE
TAPE_0
TAPE_1
TAPE_2
VOL_SCLK
0V_SER
VOL_SDATA
VOL_*CS
LISTEN_0
LISTEN_1
LISTEN_2
+15V(A)
+5V(A)
+4.8V_D_PRE
*PRE_RLY
0V(SIG)
0V(SIG_2)
-15V(A)
PRE_OUT_L
PRE_OUT_R
C101
100N
50V
0805
9VRMS
+4.8V(D)
+45V_R
+45V_L
0V(D)
0V_LS_L
0V_HF_L
0V_FB_L
0V(SIG)
0V(PSU)
-45V_L
-45V_R
FIL_1
FIL_2
+15V(A)
+5V(A)
-15V(A)
FIX102
Dia 3.5mm
FIX103
Dia 3.5mm
*PRE_MUTE
0V(D)
TAPE_0
TAPE_1
TAPE_2
VOL_SCLK
0V(SER)
VOL_SDATA
VOL_*CS
LISTEN_0
LISTEN_1
LISTEN_2
FIX104
Dia 3.2mm
9VRMS
+4.8V(D)
+45V_R
+45V_L
0V(D)
0V_LS_L
0V_HF_L
0V_FB_L
0V(SIG)
0V(SIG_2)
0V_FB_R
0V_HF_R
0V_LS_R
-45V_L
-45V_R
-38V_VFD
FIL_1
FIL_2
+15V(A)
+5V(A)
-15V(A)
PreAmp Controls
+15V(A)
+5V(A)
0V(SIG)
0V(SIG_2)
-15V(A)
TAPE_0
TAPE_1
TAPE_2
VOL_SCLK
0V(SER)
VOL_SDATA
LISTEN_0
LISTEN_1
LISTEN_2
0V(D)
*PRE_MUTE
VOL_*CS
Power Supplies
+45V_L
0V_FB_L
-45V_L
0V_HF_L
0V_LS_L
+45V_R
0V_FB_R
-45V_R
0V_HF_R
0V_LS_R
+45V_L
+4.8V(D)
0V(D)
+45V_L
+45V_R
+4.8V(D)
0V(D)
0V(SIG)
-45V_L
-38V_VFD
FIL_1
FIL_2
9VRMS
+45V_L
0V(D)
Power Amp Left
L991CT4_2.2.SCH
PRE_OUT_L
0V_FB_L
Power Amp Right
L991CT5_2.2.SCH
PRE_OUT_R
0V_FB_R
A28/P28Protection & Micros
L991CT6_2.2.SCH
OUTPUT_L
OUTPUT_R
+45V_L
+45V_R
+4.8V(D)
0V(D)
0V(SIG)
-45V_L
-38V_VFD
FIL_1
FIL_2
TAPE_0
TAPE_1
TAPE_2
VOL_SCLK
0V_SER
VOL_SDATA
LISTEN_0
LISTEN_1
LISTEN_2
+4.8V_D_PRE
0V_D_PRE
*PRE_MUTE
VOL_*CS
VIPROT_L
VIPROT_R
9VRMS
REMOTE_P
REMOTE_N
TRIG_IN
VIPROT_L
OUTPUT_L
0V_LS_L
0V_HF_L
VIPROT_R
OUTPUT_R
0V_LS_R
0V_HF_R
0.38Hz_CLK
SPKR2_ON
SPKR1_ON
PWR_ON
+45V_L
-45V_L
+45V_R
-45V_R
*RESET
R100
5R6
2W
CF
L100
2U2
R101
5R6
2W
CF
L101
2U2
RLY100A
Omron
G5PA-2 24VDC
RLY100B
RLY101B
Omron
G5PA-2 24VDC
+45V_L
+4.8V(D)
0V(D)
0V_CHASS
0.38Hz_CLK
*RESET
PRE_OUT_L
0V_PREOUT
PRE_OUT_R
G5PA-2 24VDC
Omron
RLY101A
G5PA-2 24VDC
Omron
REMOTE_P
REMOTE_N
TRIG_IN
P100
P104
A28 Trigger, RC5 & P28 Sig Detect
L991CT7_2.2.SCH
LS100
G P PRECISION
P102
P103
LS101
G P PRECISION
P105
Left Outputs
Right Outputs
QTY DESCRIPTIONPART No. NOTESITEM
ITEM100 1 Blank PCB A28 Power Supply And AmplifierL991PB
ITEM102 1 Earth Lead Assy 75MM - This part is RoHS compliant.8M101
ITEM103 4 13/16 inch O-RingF232
ITEM104 6 Pad Damping 15x6x3MM RubberE827AP
This is the Master Schematic for A28 (L991AY) and P28 PCB
assemblies. Any changes to the schematics in this document must be
reflected in the relevant child documents.
When generating BOMs for L991AY, ensure that the relevant
components are fitted or not fitted (those with "NF" or "FIT" in the nearby text).
These schematics follow a simple heirarchy scheme. Sheet symbols on the top
sheet represent a child or sub-sheet. Net labels on sub-sheets are local or
specific to that sheet. Ports on the sub-sheets connect to sheet entries on
the parent sheet, where they are connected together.
Primary power nets are denoted by type in parenthesis, e.g. 0V(D).
Secondary nets are denoted by underscores, e.g. 0V_LS_L.
To perform an electrical rule check or synchronise with the PCB, set Net
Identifier Scope to Sheet Symbols/Port Connections.
R104
R105
330R
330R
1W
1W
CF
CF
CON100
1
Q106
2
Q111
3
Q121
4
Q125
5
AMP
CT
CON101
AMP
CT
1
2
3
4
5
GENERAL NOTES
HEADPHONE OUTPUT & MUTE
Q113
Q114
Q115Q118
Q116
Q117
SPKR2_ON
SPKR1_ON
R108 220R
0W25 MF
R109 220R
0W25 MF
R107
100R
1W
CF
(NF ON P28)
R106
100R
1W
CF
D100
1N4003
DO-41
RLY100C
RLY102C
NEC
EB2-5NU
Omron
G5PA-2 24VDC
TR100
BD179
TO-126
R110
220R
0W25
MF
R114
0R0
0W25
MF
Soldered to SKT200
Rubber O-Rings fitted over UPPER HALF of amp supply caps (C228 - C231)
Placed on top of: output relays (RLY100, RLY101), mains relay (RLY200),
output chokes (L100, L101) and preamp mute relay (RLY300)
NF
R102 0R0
0W125 0805
RLY102A
NEC
EB2-5NU
NF
RLY102B
NEC
EB2-5NU
R103 0R0
0W125 0805
D102
BAS16
SOT-323
NCL
NCR
SKT100
CL
2
L
3
R
1
CR
HOSIDEN
HLJ
OUTPUT MUTING
RLY101C
D101
1N4003
DO-41
Omron
G5PA-2 24VDC
TR101
BD179
TO-126
R112
2K2
0W125
0805
R111
220R
0W25
MF
R113
2K2
0W125
0805
ANNOTATION
A28 & P28 Display Circuitry
L991CT8_2.2.SCH
Flexfoil
DRAWING TITLE
A & R Cambridge Ltd.
Pembroke Avenue
Waterbeach
Cambridge CB5 9PB
A28/P28 - Top Level Sheet
Filename:
L991CT1_2.2.SCH
Notes:
A28
Contact Engineer:
Contact Tel: (01223) 203 200Andrew Dutton
MJT 07/04/08 Removed 4-off handbag links (ITEM300, 400, 500, 700) 2.208_E076
MJT 25/03/08 Added rubber damping pads on top of components. 2.108_E069
PK 28/11/07 Correct O ring quantity 2.007_E226
SLRR 12/09/2007 None to this sheet 1.007_E156
PK 20/04/2007 Output devices replaced, seperate emitter resistors added B.007_E068
INITIALS
Printed:
DATE
25-Apr-2008
1 8Sheet of
ECO No. DESCRIPTION OF CHANGE
DRAWING NO.
L991C1
ISSUE
SH200
This EMC can should now not appear
EMC Shield
NF
SKT200
N
E
L
BULGIN
PX0580
1
on any BoM as there is a safety
issue regarding the can shorting to a
live mains track on the top layer.
Consider removing the holes for the
can or perhaps move mains tracks
onto bottom layer for next PCB
revision.
C200
3N3
250V
CER
C201
3N3
250V
CER
EARTH
NEUTRAL
LIVE
C209
115V 230V
220N
275V
PP X2
2A22B
1A11B
SW200
18-000-0019
FS201
T2.5A
S506
FHLDR201
20mm HLDR
FS200
T2.5A
S506
FHLDR200
20mm HLDR
MAINS WIRING AND AUXILIARY SUPPLY
TX200
FIX200
Dia 3.2mm
RLY200A
Omron
G2R-24-5VDC
C202
3N3
250V
CER
RLY200B
Omron
G2R-24-5VDC
C203
3N3
250V
CER
1
1
115V
2
3 7
115V
4
PCB Mount Frame
7A9311
3
2
1
1
1
9V
9V
CON201
WAGO
256
BLUE
DK GREY
ORANGE
GREEN
CON202
WAGO
256
CON203
GREEN
WAGO
256
5
6
8
FS202
T500mA
R452
C221
100N
100V
MKS2
L916TX
(CHASSIS-MOUNTED)
BLUE
BLUE
115V ac
BLACK
ORANGE
115V ac
GREEN
GREEN/YELLOW
Interwinding Screen
WHITE
BLACK
GREY
WHITE
3.2Vac
WHITE
ORANGE
16Vac
BLUE
16Vac
ORANGE
DBR203
3BDF01M
C225
1000UF
25V
YK
HS201A
SW50-2
8.8C/W
CON204
DK GREY
WAGO
256
REG201
LM317T
TO-220
BLUE
LT GREY
GREY
D214
BAS16
SOT-323
ADJ
R217
680R
0W125
0805
1
2
3
4
ITEM203 1 Clip For SW Profile HeatsinkF006
+4.8V(D)
R218
220R
0W25
MF
R219
22R
0W125
0805
0V(D)
0V(D)
C205
470N
100V
MKS2
PCB Traces to route as shown here
C206
470N
100V
MKS2
C226
1000UF
10V
YK
9VRMS
+4.8V(D)
POWER AMP SUPPLIES
SP200
DBR200
GBU8D
DBR201
GBU8D
SP201
C228
3,300UF
63V
USR
C230
3,300UF
63V
USR
PWR_ON
C229
3,300UF
63V
USR
C231
3,300UF
63V
USR
R216
2K2
0W125
0805
P202
+4.8V(D)
0V(D)
RLY200C
Omron
G2R-24-5VDC
TR202
FMMT497
SOT-23
R221 0R0
P203
0W125 0805
SP202
D215
BAS16
SOT-323
0V(SIG)
0V(D)
0V_FB_R
0V_LS_L
0V_LS_R
0V_HF_R
0V_HF_L
0V_FB_L
+45V_R
+45V_L
0V(SIG)
0V(D)
0V_FB_R
0V_LS_L
0V_LS_R
0V_HF_R
0V_HF_L
0V(PSU)
0V_FB_L
-45V_L
-45V_R
ANNOTATION
CON200
ORANGE
BLUE
ORANGE
WAGO 256
ANALOGUE OP-AMP SUPPLIES
FS203
T2A
R452
C204
470N
100V
FS204
T2A
R452
MKS2
1
2
3
C211
100N
50V
0805
C210
100N
50V
0805
D200
1N4003
DO-41
D202
1N4003
DO-41
(NF ON P28)
D201
1N4003
DO-41
D203
1N4003
DO-41
R204
0R0
0W125
0805
R205
0R0
0W125
0805
C215
1000UF
35V
YK
C216
1000UF
35V
YK
C214
100N
50V
0805
C213
100N
50V
0805
HS200A
6043PB
23C/W
HS202A
6043PB
23C/W
D210
BAS16
SOT-323
REG200
LM317T
ADJ
TO-220
C217
100UF
25V
RX
C218
100UF
25V
RX
REG202
LM337T
ADJ
TO-220
D211
BAS16
SOT-323
P200
P201
R207
100R
0W125
0805
R208
100R
0W125
0805
R213
2K2
0W125
0805
R214
2K2
0W125
0805
R209
100R
0W125
0805
R210
100R
0W125
0805
D212
BAS16
SOT-323
D213
BAS16
SOT-323
C207
22UF
20V
OSCON
C208
22UF
20V
OSCON
R206
10R
0W125
0805
C224
1000UF
25V
YK
R215
2K2
0W125
0805
DZ200
BZX84C
5V6
SOT-23
TR200
BC849B
SOT-23
SP203
P204
C219
100UF
25V
YK
0V(SIG_2)
+15V(A)
+5V(A)
+4.6V to +5.3V
C220
100UF
25V
YK
0V(SIG)
Track by pre-out to pwr-in
0V(SIG_2)
For preamp bulk decoupling
-15V(A)
CON205
WAGO
256
2
GREY
1
GREY
DRAWING TITLE
A & R Cambridge Ltd.
Pembroke Avenue
Waterbeach
Cambridge CB5 9PB
R203
2R2
0W33
FU
A28/P28 Power Supplies
Filename:
Notes:
Contact Engineer:
VFD SUPPLY
(NF ON P28
C222
100N
50V
0805
L991CT2_2.2.SCH
A28
C212
0V(D)
22UF
2 8Sheet of
63V
YK
DRAWING NO.
-38V_VFD
FIL_1
FIL_2
ISSUE
L991C2
R211
100R
0805
0W125
MN 25/04/08 No changes to this sheet 2.308_E088
MJT 07/04/08 None to this sheet 2.208_E076
MJT 25/03/08 C217, C218 changed series for voicing 2.108_E069
PK 28/11/07 None to this sheet 2.007_E226
PK 12/09/2007 R211 changed to 100R to reduce voltage drop to VFD supply 1.007_E156
INITIALS
Printed:
DATE
25-Apr-2008
Contact Tel: (01223) 203 200Andrew Dutton
ECO No. DESCRIPTION OF CHANGE
0V_LS_L
DZ406
BZX84C
3V9
SOT-23
+45V_L
ANNOTATION
VIPROT_L
OUTPUT_L
0V_LS_L
0V_HF_L
-45V_L
->
R405
47R
0W125
0805
C417
100N
50V
0805
C416
470P
100V
FKP2
DZ405
BZX84C
15V
SOT-23
C420
100N
50V
0805
P401
3
2
Q403
84
Q409
TR408
FMMT497
SOT-23
IC400A
TL072CD
SO-8
TR404
FMMT597
SOT-23
R400
22K
0W125
0805
C410
100UF
25V
RX
0V_HF_L
DZ404
BZX84C
15V
SOT-23
0V_FB_L
INPUT FILTER V TO I AMP
PRE_OUT_L
P415
SHEET 3
0V_FB_L
DZ402
BZX84C
3V9
SOT-23
DZ403
BZX84C
3V9
SOT-23
0V_HF_L
R410
100R
0W125
0805
C419
100N
50V
0805
C414
100UF
25V
RX
R402
22K
0W125
0805
0V_HF_L
0V_FB_L
TR400
BC859B
SOT-23
1
0V_FB_L
D400
BAS16
SOT-323
NF
C400
P402
47P
100V
0805
R443
4K7
0W125
0805
0V_FB_L 0V_FB_L
R445
22R
0W25
MF
R446
22R
0W25
MF
NF
C401
P433
47P
100V
0805
PNP CURRENT MIRROR
NF
R409
1K0
0W125
0805
INTEGRATING DC SERVO
C422
470N
100V
MKS2
7
IC400B
TL072CD
SO-8
NF
R451 18K
0W25 MF
R447
820R
0W25
MF
R448
820R
0W25
MF
NF
R412
1K0
0W125
0805
NPN CURRENT MIRROR
P454
R407
47R
0W125
0805
TR416
BC849B
SOT-23
D404
BAS16
SOT-323
R404
22K
0W125
0805
R415
220R
0W25
MF
R406
47R
0W125
0805
P408
TR401
BC859B
SOT-23
P409
P440
R437
5K6
0W125
0805
P459
P407
0V_FB_L
REF400
LM431AIM3
SOT-23
R433
22R
0W125
0805
P442
P458
R408
47R
0W125
0805
TR402
FMMT597
SOT-23
NF
R419
470K
0W125
0805
TR412B
ZDT6758
SM-8
PRE DRIVER BIAS
& TEMP. COMP.
TR414A
ZDT758
SM-8
TR411
FMMT497
SOT-23
TR417
BC849B
SOT-23
P404
R418
1K0
0W125
0805
P405
123
R440 4K7
0W125 0805
R403 10K
0W125 0805
R439
22K
0W125
0805
C415
100UF
25V
YK
P438
C402
100P
100V
0805
P439
C403
100P
100V
0805
R460
330R
0W125
0805
R413
1K0
0W125
0805
R417
1K0
0W125
0805
R420
1M0
0W125
0805
6
D409
P420
5
BAV99
SOT-23
NF
R458 18K
R416
220R
0W25
MF
0W25 MF
C406
10N
100V
0805
CON400
HARWIN
M20-973
*
P456
R449
820R
0W25
MF
R450
820R
0W25
MF
~1.6V
0V_FB_L
0V_FB_L
C411
100UF
25V
YK
NF
R421
470K
0W125
0805
0V_FB_L
C404
10N
100V
0805
C407
10N
100V
0805
BOOTSTRAPBOOTSTRAP
PRE DRIVER
TR407
FMMT497
SOT-23
C423
100UF
100V
YK
R452
1K0
1W
CF
R453
1K0
1W
CF
C424
100UF
100V
YK
TR405
FMMT597
SOT-23
PRE DRIVER
P410
P444
R422
100R
0W125
0805
R427
100R
0W125
0805
D405
1N4003
DO-41
C425
10UF
50V
YK
D408
1N4003
DO-41
TR412A
ZDT6758
SM-8
P411
R431
22R
0W125
0805
R423
220R
0W25
MF
R455
0R22
RV400
D401
BAS16
SOT-323
BIAS MEASURE BIAS
ADJUST
C405
10N
100V
0805
R428
220R
0W25
MF
R434
22R
0W125
0805
P400
TR414B
ZDT758
SM-8
220R
LIN
3W
SPRX
R461
0R22
3W
SPRX
C408
22UF
63V
YK
0V_HF_L
DZ400
22V
BZX84C
SOT-23
P403
OUTPUT STAGE V-I PROTECTION
R438
10K
0W125
TR413
STD03N
STD
TR415
STD03P
STD
R454
100K
0W125
0805
R411
1K0
0W125
0805
R414
1K0
0W125
0805
CON401
HARWIN
M20-973
1
2
R456
330R
0W125
0805
R457
330R
0W125
0805
P427
P449
R424
100R
0W125
0805
R429
100R
0W125
0805
0805
R432
150R
0W125
0805
C412
100UF
25V
YK
C413
100UF
25V
YK
R435
150R
0W125
0805
R441
10K
0W125
0805
R425
100R
0W125
0805
R430
100R
0W125
0805
P429
P451
V-I PROTECTION
P406
DZ401
22V
BZX84C
SOT-23
0V_HF_L
C409
22UF
63V
YK
D402
BAS16
SOT-323
P430
TR409
FMMT497
SOT-23
TR406
FMMT597
SOT-23
P452
D403
BAS16
SOT-323
R426
100R
0W125
0805
D406
1N4003
DO-41
D407
1N4003
DO-41
P431
P413
R436
1K0
0W125
0805
R442
4K7
0W125
0805
P432
TR410
FMMT497
SOT-23
0V_HF_L
0V_HF_L
TR403
FMMT597
SOT-23
P414
R401
10K
0W125
0805
R444
10K
0W125
0805
R459
5R6
2W
CF
ZOBEL NETWORK
C427
100N
100V
MKS2
VI PROTECT
SIGNAL TO MICRO
C426
10UF
50V
YK
OUT_L
C421
100N
50V
0805
ITEM400 0 Con Jumper Socket 0.1IN Gold Blue - This part is RoHS compliant.8K004
Not Fitted. See note above
* - Default jumper setting is NOT FITTED.
Fit jumper on pins:
2 & 3 to increase bias voltage;
1 & 2 to increase bias voltage even more.
DRAWING TITLE
A & R Cambridge Ltd.
Pembroke Avenue
Waterbeach
Cambridge CB5 9PB
A28/P28 - Power Amp Left
Filename:
L991CT4_2.2.SCH
Notes:
A28
Contact Engineer:
MN 25/04/08 No changes to this sheet 2.308_E088
MJT 07/04/08 Removed handbag link ITEM400 2.208_E076
MJT 25/03/08 C410, C414 changed. R410 now 100R. Corrected jumper notes. 2.108_E069
PK 28/11/07 R432,435 now 150R. R436 now 1k0 2.007_E226
SLRR 12/09/2007 Emitter resistors value change, output device footprint change 1.007_E156
INITIALS
Printed:
DATE
25-Apr-2008
4 8Sheet of
DRAWING NO.
L991C4
Contact Tel: (01223) 203 200Andrew Dutton
ECO No. DESCRIPTION OF CHANGE
ISSUE
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