Alto aMictube User manual

Service Manual
www.altoproaudio.com
Version: 1.1
Model: aMICTUBE
STEREO TUBE PREAMP

CONTENTS
1. Specification………………………………………….1
2. Block Diagram………………………….…………… 1
3. Schematic Diagram..…………………………..…….3
4. Printed Circuit Board……………………………….11
5. Wiring Diagram…………………………………..….1
6. Test Procedure………………………………….…… 2
7. Electrical Parts List………………………………… 11
8. Exploded Views………………………………..…….1
9. Notes…………………………………………….……

Input
XLR Impedance 5K Ohm
1/4”High Z 1M Ohm
Connectors NeutrikTM Combo
Output
XLR Balanced 100 Ohm
1/4”Unbalanced 100 Ohm
Panel Controls
Tube Drive 0dB to +40dB
Gain 0dB to +30dB
Phase Reverse
20 dB Pad
+48V Phantom Power
Performance
THD+Noise <0.5%
Signal To Noise >90dB
Power Supply Rejection >98dB
Amplifier Type Dual Servo
Meter
8-Digit LED -24dBu to +18dBu
Physical
Weight 1.05Kg
Dimensions
131(W)X116(D)X44(H)mm(5.16”X4.57”X1.7”)
Chassis Steel
Panel Brushed Aluminum(?LTO®Style)
Power Supply
Type Linear,External
Input 18VAC
Power 14Watts
Transformer External Wall Mount

1234
A B C D
4321
D C B A
1 2 3 4 5 6 X1 X2 X3
2 1 3 4 2 1 3
22 11 33
Block Diagram
U1(INA163)
TUBE-12AX7
2
1 3
2 1 3 4 2 1 3
22 11 33
2
1 3
1 2 3 4 5 6 X1 X2 X3 U2(INA163)
POWERSUPPLY
VOLTAGEREGULATOR AC18V
+12VDC +15VDC
-15VDC
+48VDC
PHANTOM
CH1MICROPHONEINPUT CH2MICROPHONEINPUT
CH1OUTPUT CH2OUTPUT
PHASE PHASE
+ PAD(20dB) + PAD(20dB)

1 2 3 4 5 6 78
A
B
C
D
8
7654321
D
C
B
A
C64
104P
C65
104P
C66
10U
C67
10U
84
U11C
2068DD
-15V
+15V
TR9
HR
R39
47K5
TR8
HR
R38
47R 1/4W
+15V
C6
103P
LD17
GR
LD18
GR LD19
GR
LD20
GR
7
8
9
P
SW2C
PS-42E85L
7
8
9
P
SW3C
PS-42E85L
1
2
3
SW4A
PS-22E85L
1
2
3
SW5A
PS-22E85L
LD21
RED LD22
RED
4
5
6
P
SW1B
PS-42E85L
(PWRON)
(PHANTOM)
(PAD-CH1)
(PAD-CH2)
(PHASE-CH2)
(PHASE-CH1)
8
914
U9C
LM339
10
11 13
U9D
LM339
1
6
7
U9B
LM339
5
42
U9A
LM339
8
914
U10C
LM339
10
11 13
U10D
LM339
1
6
7
U10B
LM339
5
42
U10A
LM339
LD9
GR
LD10
GR
LD11
GR
LD12
GR
LD13
GR
LD14
GR
LD15
YEL
LD16
RED
TR6
HR
R4
47K5
TR5
HR
R2
100R 1/4W
+15V
R104
100R
R105
200R
R106
402R
R107
806R
R108
1K58
R109
3K24
R110
6K34
R111
8K06
+15V
R103
110R
-15V
8
914
U7C
LM339
10
11 13
U7D
LM339
1
6
7
U7B
LM339
5
42
U7A
LM339
8
914
U8C
LM339
10
11 13
U8D
LM339
1
6
7
U8B
LM339
5
42
U8A
LM339
LD1
GR
LD2
GR
LD3
GR
LD4
GR
LD5
GR
LD6
GR
LD7
YEL
LD8
RED
TR4
HR
R3
47K5
TR3
HR
R1
100R 1/4W
+15V
R95
100R
R96
200R
R97
402R
R98
806R
R99
1K58
R100
3K24
R101
6K34
R102
8K06
R94
110R
-15V+15V
C50
104P
C53
104P
OUTPUT1 OUTPUT2
C1
103P
C2
103P
3
21
U11A
2068DD
R49
47K5
R72
1K00
R17 47K5
C62
1uF
-15V
5
67
U11B
2068DD
D7
DA204K
R50
47K5
R74
1K00
R18 47K5
C63
1uF
-15V
312
U10E
LM339
312
U9E
LM339
312
U8E
LM339
312
U7E
LM339
+15V
-15V
C57
104P
C60
104P
C56
104P
C59
104P
C52
104P
C55
104P
C51
104P
C54
104P
(-24)
(-18)
(-12)
(-6)
(0)
(+6)
(+12)
(+18)
3
2
1
D8
DA204K
D5A
DA204K D6A DA204K
CN8-14
CN9-14
1 2
3 4
5 6
7 8
910
11 12
13 14
15 16
CN8 HEADER8X2
1 2
3 4
5 6
7 8
910
11 12
13 14
15 16
CN9 HEADER8X2
CN8-1 CN8-2
CN8-3 CN8-4
CN8-6
CN8-8
CN8-10
CN8-12
CN8-14
CN8-16
CN8-5
CN8-7
CN8-9
CN8-11
CN8-13
CN8-15
CN9-1
CN9-3
CN9-5
CN9-7
CN9-9
CN9-11
CN9-13
CN9-15
CN9-2
CN9-4
CN9-6
CN9-8
CN9-10
CN9-12
CN9-14
CN9-16
CN8-15
CN8-2
CN8-16
+48V+15V
CN9-15
CN9-2
CN9-16
+48V-15V
1 2 3
SW1A
PS-42E85L
PHANTOM ON (+48V)
PHANTOM OFF
+48V
R5
47K5 CN8-1
7 8 9
P
SW1C
PS-42E85L
+48V
R6
47K5
CN9-1
R19
619R
R33
619R
10
11
12
P
SW2D
PS-42E85L
4
5
6
P
SW2B
PS-42E85L R31
169R
R20
619R
R34
619R
10
11
12
P
SW3D
PS-42E85L
4
5
6
P
SW3B
PS-42E85L R32
169R
CN8-3
CN8-4
CN8-5
CN8-6CN9-6
CN9-5
CN9-4
CN9-3
VR1 A20K
(CH1 INPUT GAIN)
VR2 A20K
(CH2 INPUT GAIN)
CN8-7 CN8-8
CN9-8CN9-7
R64
100R
VR3B
C1K2P
R82
100R
R25
100R
VR3A
C1K2P
R81
100R
CN8-10
CN8-9
CN8-12
CN8-11
R66 100RVR4B C1K2P
R65
100R
R45 100RVR4A C1K2P
R67
100R
CN9-10
CN9-9
CN9-12
CN9-11
4
5
6
P
SW4B
PS-22E85L
( PHASE )
4
5
6
P
SW5B
PS-22E85L
( PHASE )
CN8-10
CN8-14
CN8-13
CN9-10
CN9-14
CN9-13
VCH1-IN
VCH1-OUT
GND
+48V
+12V
VCH2-IN
VCH2-OUT
R121
10K0
R120
10K0
5
19
28
37
46
PT2
GT2
KT2
HT2 HT1 PT1
GT1
KT1
HM
TB1 TUBE-12AX7
1
2
3
4
5
6
7
8
CN4
CON8
R122
10R
R123
4K53
+15V
AMTUBEFP.Sch
Titel
Size
File:
Date: Drawn By: Sheet
RevisionModel No:
7-Mar-2002 C.C.LIN
ALTO Mobile : ALPHAMICtube FRONT PANEL BOARD
11of
ALPHAMICtube VER020307
A3

1 2 3 4 5 6 78
A
B
C
D
8
7654321
D
C
B
A
9
4
5
6
11 3
121014
18
U1
INA163
R47
2K21 C22
10U
R21
20K0
R22
20K0 ZD4
H2
ZD3
H2
ZD2
H2
ZD1
H2
C11
47/63VZ
C12
47/63VZ
3
21
U6A
2068DD
C35
104P
C36
104P
R13
402R
R15
1M00
C9
104P
R35
51R1
C30
104P
C31
104P C23 10U
C20
10U
C21
10U
-15V
+15V
C18
220P
1. H2 = Zener Diode MMSZ5242BT1NOTE: 2. LOW BUMP ON
3. LOW BUMP OFF C9,C12,C39,C42=104P R21,R32=4K99 R73,R28=200K C9,C39,R21,R66 =0R OMIT:C12,C42,R28,R32,R73,R77
R27
10R0
R28
10R0
9
4
5
6
11 3
121014
18
U2
INA163
R48
2K21 C24
10U
R23
20K0
R24
20K0 ZD8
H2
ZD7
H2
ZD6
H2
ZD5
H2
C13
47/63VZ
C14
47/63VZ
C32
104P
C33
104P C25 10U
-15V
+15V
C19
220P
R29
10R0
R30
10R0
PS:H2=MMSZ5242
411
U3E
TL074CD
-15V
+15V
5
67
U6B
2068DD
R14
402R
R16
1M00
C10
104P
R36
51R1
3
21
U4A
TL074CD
R55 10K0
R56
10K0
R63
1K00 R61
10K0
84
U6C
2068DD
C58
104P
C61
104P
C71
10U
C72
10U -15V
+15V
HR=MMBT3906LT1 / 2SA1036K(R)
CH1-INX3
CH1-INX2
CH1-INT
CH1-INTS
CH2-INTS
CH2-INT
CH2-INX2
CH2-INX3
CH1-OUT
C46
100P
R62
100R
R26
301K
R70
301R
C15
0.47U
C40
0.47U
R44
1M00
R71
301R
10
98
U3C
TL074CD
12
13 14
U3D
TL074CD
R42
1M00
C45
100P
R83
100R
R68
301K
R76
1M00
C41
0.47U
C17
0.47U
R43
1M00
5
67
U3B
TL074CD
3
21
U3A
TL074CD
R41
1M00
C8
104P
5
67
U4B
TL074CD
C48
0R
R73R85
C47
R86
0R
LOW BUMP
1
2
3
4
5
6
7
8
CN3
CON8
10
98
U4C
TL074CD
R53 10K0
R52
10K0
R57
1K00
R54
10K0
CH2-OUT
C16
100P
R37
100R
R69
301K R51
301R
C43
0.47U
C42
0.47U
R78
1M00
R84
301R
10
98
U5C
TL074CD
12
13 14
U5D
TL074CD
R75
1M00
C26
100P
R40
100R
R46
301K
R80
1M00
C44
0.47U
C7
0.47U
R77
1M00
5
67
U5B
TL074CD
3
21
U5A
TL074CD
R79
1M00
C27
104P
12
13 14
U4D
TL074CD
C29
0R
R59R58
C28
R60
0R
LOW BUMP
+48V+12V
1
2
3
4
5
6
X3
X2 X1
J1
COMB-XLR
S
SS
R
RS
T
TS
CH1-INPUT
R7
169R1/4W
R9 6K81
R10 6K81
C3
100/63V
1
2
3
4
5
6
X3
X2 X1
J2
COMB-XLR
S
SS
R
RS
T
TS
CH2-INPUT
R11 6K81
R12 6K81
C4
100/63V
R8
169R1/4W
1
2
3
4
5
6
7
CN5
7P-2.0
+48V
GND
+15V
-15V
CH1-OUT
CH2-OUT
C49
104P
C5
104P
C34
10U
C38
10U
411
U4E
TL074CD
-15V
+15V C68
104P
C69
104P
C37
10U
C39
10U
411
U5E
TL074CD
-15V
+15V
1 2
3 4
5 6
7 8
910
11 12
13 14
15 16
CN1 HEADER8X2
1 2
3 4
5 6
7 8
910
11 12
13 14
15 16
CN2 HEADER8X2
CN1-1 CN1-2
CN1-3 CN1-4
CN1-6
CN1-8
CN1-10
CN1-12
CN1-14
CN1-16
CN1-5
CN1-7
CN1-9
CN1-11
CN1-13
CN1-15
CN2-1
CN2-3
CN2-5
CN2-7
CN2-9
CN2-11
CN2-13
CN2-15
CN2-2
CN2-4
CN2-6
CN2-8
CN2-10
CN2-12
CN2-14
CN2-16
CN1-1
CN1-3
CN1-4
CN1-5
CN1-7
CN1-9
CN1-11
CN1-13
CN1-15
CN1-2
CN1-6
CN1-8
CN1-10
CN1-12
CN1-14
CN1-16
+48V+15V
CN2-1
CN2-3
CN2-5
CN2-7
CN2-9
CN2-11
CN2-13 CN2-15
CN2-2
CN2-4
CN2-6
CN2-8
CN2-10
CN2-12
CN2-14
CN2-16
+48V-15V
FrontPanel
AMtubeFP.sch
CN1-10
CN2-10
R0
0R
+12V
C78
47U
C79
47U
AMTUBEMN.Sch
Titel
Size
File:
Date: Drawn By: Sheet
RevisionModel No:
7-Mar-2002 C.C.LIN
ALTO Mobile : ALPHAMICtube MAIN BOARD
11of
ALPHAMICtube VER020225
A3

1 2 3 4
A
B
C
D
4
321
D
C
B
A
R25
20K0
R79
20K0
C40
47P
R67
20K0
R77
20K0 R80
10K0
C41
47P
R40
100R
R41
100R
2
1
3
22
11
33
J4
LJB0661
R87
100K
R90
100K
C44
47/50VNP
C45
47/50VNP
R86
100K
R68
6K81
C46
47/50VNP
2
1
3
4
J3
BAL-MALE
12
13 14
U4D
TL074CD
3
21
U4A
TL074CD
10
98
U4C
TL074CD
R37
100R
R45
51R1
-15V
+15V
C34
104P
C37
104P
C26
10U
C27
10U
411
U4E
TL074CD
C38
104P
C39
104P
C28
10U
C29
10U -15V
411
U5E
TL074CD
+48V
R26
20K0 R81 20K0
C42
47P
R69
20K0
R78
20K0 R82
10K0
C43
47P
R43
100R
R44
100R
2
1
3
22
11
33
J6
LJB0661
R89
100K
R91
100K
C47
47/50VNP
C48
47/50VNP
R88
100K
R70
6K81
C49
47/50VNP
2
1
3
4
J5
BAL-MALE
12
13 14
U5D
TL074CD
3
21
U5A
TL074CD
10
98
U5C
TL074CD
R42
100R
R46
51R1
1
2
3
4
5
6
7
CN4
7P-2.0 +15V
-15V
CH1-OUT
CH2-OUT
C8
100/63V
D3
1N4004
D4
1N4004
R83
10K
R92
150R
C68
M104P
C7
100/63V
U13
LM7815CT
U14
LM7915CT
D1
1N4004
D2
1N4004
C66
47/25VZ
C70
M104P
C64
2200/25V
C67
47/25VZ
C65
1000/25V
C69
M104P
+15V
C5
100/63V C17
100/63V
-15V
ZD9
1N5261B
TR7
TIP122
(47V)
+48V
J7
ACIN
(AC 18V)
CH1-OUTPUT CH2-OUTPUT
C73
100/63V
U15
LM7812CT
C74
47/25VZ C75
M104P
+12V
+12V
C76
47/50VNP C77 47/50VNP
AMTUBEPU.Sch
Titel
Size
File:
Date: Drawn By: Sheet
RevisionModel No:
7-Mar-2002 C.C.LIN
ALTO Mobile : ALPHAMICtube REAR BOARD
11of
ALPHAMICtube VER020225
A3

AMTUBEFP Top Layer AMTUBEFP Top Solder Mask
AMTUBEFP Bottom Layer
AMTUBEFP Bottom Solder Mask
AMTUBEFP Top Scilkscreen
AMTUBEFP Drill Drawing
---------------------------------------------------------------------------
NCDrill File Report For: AMTUBEFP.PCB 9-May-2002 16:26:29
---------------------------------------------------------------------------
Layer Pair : TopLayer to BottomLayer
ASCII File : NCDrillOutput.TXT
EIA File : NCDrillOutput.DRL
Tool Hole Size Hole Count Plated Tool Travel
---------------------------------------------------------------------------
T1 24mil (0.6096mm) 72 29.54 Inch (750.27 mm)
T2 31mil (0.7874mm) 140 30.14 Inch (765.64 mm)
T3 39mil (0.9906mm) 28 14.01 Inch (355.84 mm)
T4 79mil (2.0066mm) 4 9.78 Inch (248.33 mm)
T5 83mil (2.1082mm) 9 6.04 Inch (153.35 mm)
T6 87mil (2.2098mm) 4 10.82 Inch (274.86 mm)
---------------------------------------------------------------------------
Totals 257 100.33 Inch (2548.29 mm)
Total Processing Time : 00:00:00

AMTUBEMN Top Layer
AMTUBEMN Top Solder Mask
AMTUBEMN Bottom Layer
AMTUBEMN Bottom Solder Mask

AMTUBEMN Top Scilkscreen
AMTUBEMN Drill Drawing
---------------------------------------------------------------------------
NCDrill File Report For: AMTUBEMN.PCB 9-May-2002 18:22:27
---------------------------------------------------------------------------
Layer Pair : TopLayer to BottomLayer
ASCII File : NCDrillOutput.TXT
EIA File : NCDrillOutput.DRL
Tool Hole Size Hole Count Plated Tool Travel
---------------------------------------------------------------------------
T1 24mil (0.6096mm) 58 26.73 Inch (678.84 mm)
T2 31mil (0.7874mm) 44 20.77 Inch (527.61 mm)
T3 35mil (0.889mm) 32 11.01 Inch (279.53 mm)
T4 39mil (0.9906mm) 15 13.68 Inch (347.41 mm)
T5 47mil (1.1938mm) 20 9.43 Inch (239.45 mm)
T6 138mil (3.5052mm) 2 8.74 Inch (221.92 mm)
T7 83mil (2.1082mm) 4 NPTH 6.86 Inch (174.24 mm)
T8 138mil (3.5052mm) 2 NPTH 15.44 Inch (392.11 mm)
---------------------------------------------------------------------------
Totals 177 112.64 Inch (2861.12 mm)
Total Processing Time : 00:00:01

AMTUBEPU Top Layer
AMTUBEPU Top Solder Mask
AMTUBEPU Bottom Layer
AMTUBEPU Bottom Solder Mask

---------------------------------------------------------------------------
NCDrill File Report For: AMTUBEPU.PCB 9-Mar-2002 18:30:07
---------------------------------------------------------------------------
Layer Pair : TopLayer to BottomLayer
ASCII File : NCDrillOutput.TXT
EIA File : NCDrillOutput.DRL
Tool Hole Size Hole Count Plated Tool Travel
---------------------------------------------------------------------------
T1 24mil (0.6096mm) 1 6.10 Inch (155.01 mm)
T2 28mil (0.7112mm) 14 10.41 Inch (264.49 mm)
T3 31mil (0.7874mm) 57 20.11 Inch (510.86 mm)
T4 39mil (0.9906mm) 29 14.11 Inch (358.42 mm)
T5 47mil (1.1938mm) 4 10.33 Inch (262.28 mm)
T6 59mil (1.4986mm) 12 12.09 Inch (307.05 mm)
T7 63mil (1.6002mm) 4 10.41 Inch (264.44 mm)
T8 110mil (2.794mm) 2 9.26 Inch (235.31 mm)
T9 126mil (3.2004mm) 1 9.77 Inch (248.28 mm)
T10 71mil (1.8034mm) 4 NPTH 10.90 Inch (276.85 mm)
---------------------------------------------------------------------------
Totals 128 113.50 Inch (2883.01 mm)
Total Processing Time : 00:00:01
AMTUBEPU Top Scilkscreen
AMTUBEPU Drill Drawing

PCB:AMTUBEFP

PCB:AMTUBEMN

PCB:AMTUBEPU

Test Procedures(aMICTUBE)
Required Equipment
Audio Precision System 2 with APWin software
100MHz oscilloscope connected to APS2 Analyzer Signal Monitor output (Ch. A and Ch. B)
Connection Mode
Use Audio Precision System 2 analog unbalanced (XLR) inputs/output