Electro Harmonix BASS MICRO SYNTHESIZER Schematics
R26
820
1
A3A
RC4558
3
7.5K
10K
10K
0.47
6
C3
C2
C1
RC4558
R1
D2 1N914
D11N914
TANT.
RC4558
0.0022
0.022
0.1
PRE-
AMP
4
68K
8
R5
GAIN
-V
13K
R3
+V
6
2
10K
C5
+V
0.0018
R15
3.3M
R14
R16 27K
100K
+V
4
-V
2
SQUELCH
R12
-V
R11
R13
15K
FULL WAVE RECTIFIER
R10
C4
3
7
A2B
5
R9
33K
R8
3.3K
700 HZ LOW PASS FILTER
R7
2.2K
1
1
A2A
8
3
2
R2
4.7K
C12
7
A3B
5
R6
100K LIN
GUITAR
R4
470
C13
0.47
TANT.
RC4558
D7
D6
D5
D4
0.082
R27
R28
OCTAVE
100K LIN
1N914
1N914
-V
1N914
1N914
4.7K
R29
4
1
A7A
RC4558
STOP DETECTOR
4
-V
C11
A4A
R24
5
27K
TRIGGER
TANT.
1.0
1
2
1K
7
6
C10
22K
2.2K
3.3K
560
R31
100K LIN
RC4558
3
R25
RC4558
0.1
C9
1.0
C8
2.2
C7
-V
2
22K
R23
4.7
R30
8
47K
TANT.
A6A
4
8.2K
4
LOG AMP
A4B
R22
R21
SMOOTHING FILTER
R20
R19
R18
NORMALLY LOW
PULSES HIGH
8
R33
330
3
R32
2.2K
+V
-V
+V
D3 1N914
A5B
5
1
3
2
C6
1.0
AT END OF
NOTE
+V
-V
390K
SQUELCH
SMALL SIGNAL
DETECTOR
A5A
8
3
7
RC4558
6
RC4558
8
A7B
RC4558
5
+V
R44
1
RC4558
4
R43
1K
2
R42
820K
R41
PEAK FOLLOWER
+V
7
7
6
ATTACK DETECTOR
R45
330K
-V
-V
220
A6B
SQUARE WAVE
MODULATOR
NORMALLY -8V
PULSES HIGH ON
ATTACK
470
D10
D8 1N914
R39
120K
C16
4.7
5
6
7
Q1
6 HIGH ON SILENCE
1N914
D11
1N914
D9 1N914
R40
0 TO -7V DEPENDING
ON SIGNAL
R38
22K
RC4558
2N5087
A8
+V
REVISION: 12/12/78
DESIGNED BY: D.COCKERELL
ELECTRO HARMONIX
ELECTRO HARMONIX BASS MICRO SYNTHESIZER
A DRAWN BY: FABIAN P. HARTERY 1
Date: September 28, 1996 Sheet 1 of 3
Size Document Number REV
Title
TO VCF (A10)
5
6.8K
TO ADAPTIVE SCHMITT TRIGGER
TO VCA SWEEP GENERATOR
TO SUB-OCTAVE TRACK & HOLD MODULATOR (A18) & OUTPUT
2436
1
5
R37
13K
R36
100K LIN
SQUARE WAVE
6 5 1
8
CA3094
(or EH1040)
7
3
2
R35
4
10K
TO VCF SWEEP GENERATOR
7
-V
SQUARE WAVE SHAPER
J1/INPUT
1/4" PHONEJACK
R17
2.7K
SQUARE WAVE SHAPER
C14
R34
2.7K
1.0
C15
0.047
* ALL CAPACITOR VALUES IN MICROFARADS
Q2
2N4302
CA3094
(OR EH1040)
7
R57
27K
1
CD4013
Q
6
S
D
5
A17B
CD4013
1
0
R
Q
12
8
+V
C17
0.0033
8
3
CLK
3
11
CLK
C23
C22 0.0033
6 5 1
2
R58
2
9
13
+V
+V
+V
HOLD MODULATOR
SUB-OCTAVE TRACK &
1
A17A
-V
R53
47K
1
A15A
RC4558
4
-V
3
2
TANT.
C19
4.7
R49
220
R48
10K
D13
1N914
7
A15B
RC4558
D12
1N914
5
6
ADAPTIVE SCHMIDT TRIGGER
R47
3.3K
R46
3.3K
3
SUB-OCTAVE
R61
100K LIN
1.0
A18
4
470
R55
Q
4
R
-V
D
8
S
Q
A16B
RC4558
C20
A16A
8
R50
6.8K
C24
10K
-V
7
-V
0.082
-V
10K
R64
R74
100K LIN
SWEEP RATE
R73
2.2K
+V
D17
1N5235
D16
1N914
U9A
RC4558
8
+V
3
R66
STOP FREQUENCY
R65
R70
22M
6.8V
1
2
3.3K
100K LIN
R63
R62
12K
27K
R60
-V
R59
470
47K
R56
C21
3.9K
R54
6
4.7
R52
RC4558
0.1
-V
S-R FLIP FLOP
& DIVIDE BY TWO
SPECIAL NOTE: PIN 14 IS CONNECTED TO
THE POWER SUPPLY GROUND AND PIN 7 IS
CONNECTED TO THE -V SUPPLY.
47K
7
5
TANT.
220
R51
10K
D15
1N914
D14
1N914
1
4
3
2
C18
0.1
-V
-V
-V
R67
-V
R79
-V
-V
R69
R68
820
R84
R83
3.3K
A12
CA3094
R80
3.3K
4
A11
CA3094
R75
3.3K
A10
CA3094
12K
+V
+V
1K
4
-V
8.2K
6 5 1
4
2
/EH1040
47K
R81
8.2K
6 5 1
8
3
2
/EH1040
R77
R76
8.2K
6 5 1
4
2
/EH1040
A13
7
R71
680K
Q3
2N5087
-V
8
C27
7
0.0033
3
R82
1K
C26
7
0.0033
1K
R78
47K
8
C25
7
0.0033
3
2
C28
D18
6 5 1
8
1N5235
4
3
2
CA3094
(OR EH1040)
1K
R72
R105
R95
4.7K
R93
3.3K
START FREQUENCY
R92
100K LIN
+V
+V
100K LIN
RESONANCE
R86
R87 330K
+V
4
10
TANT.
6.8V
-V
+V
1
1K
R94
820
47K
R85
R88 47K
R89 4.7K
5
-V
C29
1.0
47K
R96
3
A14
7
6
1
8
R104
S1
FOOTSWITCH
J2/OUTPUT
-V
1/4" PHONEJACK
R90
R91
TANT.
R97
2
5
1K
1K
470
1K
+V
4
R98
47K
CA3094
(OR EH1040)
-V
VCA
Q4
47
R99
2N5088
R100
22K
2N5088
Q5
Q6
2N5088
R102
6
REVISION: 12/12/78
DESIGNED BY: D.COCKERELL
ELECTRO HARMONIX
ELECTRO HARMONIX BASS MICRO SYNTHESIZER
Title
DELAY
R101
100K LIN
ATTACK
D19
1N914
10
C30
TANT.
820
R103
8.2K
-V
B DRAWN BY: FABIAN P. HARTERY 1
Date: September 28, 1996 Sheet 2 of 3
Size Document Number REV
* ALL CAPACITOR VALUES IN MICROFARADS
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