A3 Overdrive

effect pedal project by Ampeg

Here's the A3 Overdrive effect pedal project from Ampeg.

This project has been described using terms like ampeg, overdrive, stripboard, and vero and is reportedly verified, meaning many hobbyists have already completed this project and verify that the instructions are without issue.

Beyond the specs and details found on this page, you'll want to check out these stripboard resources too.

Project Resources

Parts List

  • C1
    1u
  • C2
    47n
  • C3
    1u
  • C4
    100u
  • C5
    47u
  • C6
    1u
  • C7
    1u
  • C8
    47n
  • C9
    10n
  • C10
    1n
  • C11
    4n7
  • D1
    1N4148
  • D2
    1N4148
  • D3
    1N4148
  • D4
    1N5817
  • P1
    1M Drive
  • P2
    100k Tone
  • P3
    50k Level
  • Q1
    JRC4558
  • R1
    33k
  • R2
    4k7
  • R3
    10k
  • R4
    470k
  • R5
    1M
  • R6
    1k
  • R7
    10k
  • R8
    100k
  • R9
    33k
  • R10
    10k
  • R11
    10k
  • R12
    10k
  • R13
    1k
  • R14
    4k7
  • R15
    10k
  • R16
    220k
  • R17
    1M
  • R18
    4k7
  • T1
    2N3904
  • T2
    2N3904
  • U1
    9V

Similar transistors & Potential Alternatives

Can't find an exact match for the recommended transistor in this project within your stash? Or maybe you just feel like experimenting. Use these tables below to get started finding a suitable or otherwise interesting transistor substitution.

There may be 65 alternatives for the 2N3904 mentioned above in the parts list for this project. These suggestions were derived by considering the original component's hFE, Pol, Ic, Vcb, and Vce values and finding comparables in our database. These alternatives are suggestions for further exploration (fun!) and have not been tested in the context of this project. The first 25 alternatives are shown below in alphabetical order by partnumber. See the to suit your preferences.

2N3904
more info
Cc
4
pF
ft
300
MHz
hFE
40
β
Ic
0.2
A
Pc
0.31
W
Pol
NPN
Tj
135
°C
TranMat
Si
Vcb
60
V
Vce
40
V
Veb
6
V
2N697
more info
Cc
35
pF
ft
50
MHz
hFE
40
β
Ic
0.5
A
Pc
0.6
W
Pol
NPN
Tj
175
°C
TranMat
Si
Vcb
60
V
Vce
40
V
Veb
5
V
2N730
more info
Cc
35
pF
ft
40
MHz
hFE
40
β
Ic
1
A
Pc
0.5
W
Pol
NPN
Tj
200
°C
TranMat
Si
Vcb
60
V
Vce
40
V
Veb
5
V
2N2221AX
more info
Cc
8
pF
ft
250
MHz
hFE
40
β
Ic
0.8
A
Pc
1.8
W
Pol
NPN
Tj
175
°C
TranMat
Si
Vcb
60
V
Vce
40
V
Veb
5
V
2N2396
more info
Cc
30
pF
ft
40
MHz
hFE
40
β
Ic
0.3
A
Pc
0.45
W
Pol
NPN
Tj
200
°C
TranMat
Si
Vcb
60
V
Vce
40
V
Veb
5
V
2N2853
more info
Cc
125
pF
ft
30
MHz
hFE
40
β
Ic
3
A
Pc
0.85
W
Pol
NPN
Tj
200
°C
TranMat
Si
Vcb
60
V
Vce
40
V
2N2853-1
more info
Cc
125
pF
ft
30
MHz
hFE
40
β
Ic
3
A
Pc
0.85
W
Pol
NPN
Tj
200
°C
TranMat
Si
Vcb
60
V
Vce
40
V
2N2853-2
more info
Cc
125
pF
ft
30
MHz
hFE
40
β
Ic
3
A
Pc
0.85
W
Pol
NPN
Tj
200
°C
TranMat
Si
Vcb
60
V
Vce
40
V
2N2853-3
more info
Cc
125
pF
ft
30
MHz
hFE
40
β
Ic
3
A
Pc
0.85
W
Pol
NPN
Tj
200
°C
TranMat
Si
Vcb
60
V
Vce
40
V
2N2855
more info
Cc
125
pF
ft
30
MHz
hFE
40
β
Ic
3
A
Pc
0.85
W
Pol
NPN
Tj
200
°C
TranMat
Si
Vcb
60
V
Vce
40
V
2N2855-1
more info
Cc
125
pF
ft
30
MHz
hFE
40
β
Ic
3
A
Pc
0.85
W
Pol
NPN
Tj
200
°C
TranMat
Si
Vcb
60
V
Vce
40
V
2N2855-2
more info
Cc
125
pF
ft
30
MHz
hFE
40
β
Ic
3
A
Pc
0.85
W
Pol
NPN
Tj
200
°C
TranMat
Si
Vcb
60
V
Vce
40
V
2N2855-3
more info
Cc
125
pF
ft
30
MHz
hFE
40
β
Ic
3
A
Pc
0.85
W
Pol
NPN
Tj
200
°C
TranMat
Si
Vcb
60
V
Vce
40
V
2N2868
more info
Cc
20
pF
ft
50
MHz
hFE
40
β
Ic
1
A
Pc
0.8
W
Pol
NPN
Tj
200
°C
TranMat
Si
Vcb
60
V
Vce
40
V
Veb
7
V
2N2909
more info
Cc
20
pF
ft
50
MHz
hFE
40
β
Ic
1
A
Pc
0.4
W
Pol
NPN
Tj
200
°C
TranMat
Si
Vcb
60
V
Vce
40
V
2N3506A
more info
Cc
40
pF
hFE
40
β
Ic
3
A
Pc
5
W
Pol
NPN
Tj
200
°C
TranMat
Si
Vcb
60
V
Vce
40
V
Veb
5
V
2N3506AL
more info
Cc
40
pF
hFE
40
β
Ic
3
A
Pc
5
W
Pol
NPN
Tj
200
°C
TranMat
Si
Vcb
60
V
Vce
40
V
Veb
5
V
2N3506L
more info
Cc
40
pF
ft
60
MHz
hFE
40
β
Ic
3
A
Pc
1
W
Pol
NPN
Tj
100
°C
TranMat
Si
Vcb
60
V
Vce
40
V
Veb
5
V
2N3597
more info
Cc
700
pF
ft
30
MHz
hFE
40
β
Ic
20
A
Pc
100
W
Pol
NPN
Tj
200
°C
TranMat
Si
Vcb
60
V
Vce
40
V
2N5527
more info
ft
200
MHz
hFE
40
β
Ic
5
A
Pc
5
W
Pol
NPN
Tj
200
°C
TranMat
Si
Vcb
60
V
Vce
40
V
Veb
3
V
2N5528
more info
ft
200
MHz
hFE
40
β
Ic
10
A
Pc
35
W
Pol
NPN
Tj
200
°C
TranMat
Si
Vcb
60
V
Vce
40
V
Veb
4
V
2N5529
more info
ft
200
MHz
hFE
40
β
Ic
10
A
Pc
35
W
Pol
NPN
Tj
200
°C
TranMat
Si
Vcb
60
V
Vce
40
V
Veb
3
V
2N5530
more info
ft
200
MHz
hFE
40
β
Ic
10
A
Pc
35
W
Pol
NPN
Tj
200
°C
TranMat
Si
Vcb
60
V
Vce
40
V
Veb
3
V
2N6412
more info
Cc
50
pF
ft
50
MHz
hFE
40
β
Ic
4
A
Pc
15
W
Pol
NPN
Tj
150
°C
TranMat
Si
Vcb
60
V
Vce
40
V
Veb
6
V
2SC189
more info
Cc
15
pF
ft
75
MHz
hFE
40
β
Ic
0.5
A
Pc
0.6
W
Pol
NPN
Tj
175
°C
TranMat
Si
Vcb
60
V
Vce
40
V
Veb
5
V