Bearhug FET Compressor

effect pedal project by Jon Patton

Here's the Bearhug FET Compressor effect pedal project from Jon Patton.

This project has been described using terms like compressor, 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
    10u
  • C2
    10u
  • C3
    1u
  • C4
    10n
  • C5
    100p
  • C6
    47u
  • C7
    47u
  • C8
    10u
  • C9
    4u7
  • C10
    47u
  • D1
    1N4001
  • D2
    9V1 ZENER
  • D3
    1N60P
  • D4
    1N60P
  • P1
    1k Comp
  • P2
    10k Volume
  • R1
    10M
  • R2
    2k2
  • R3
    10M
  • R4
    2k7
  • R5
    100k
  • R6
    100k
  • R7
    1k
  • R8
    10M
  • R9
    2k2
  • R10
    1M
  • R11
    47k
  • R12
    47R
  • R13
    1M
  • R14
    10k
  • R15
    1k
  • S1
    SPST
  • T1
    BS170
  • T2
    MPSA18
  • T3
    2N5457
  • U1
    9V

Similar transistors & Potential Alternatives

Can't find an exact match for the recommended transistors 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 21 alternatives for the BS170 mentioned above in the parts list for this project. These suggestions were derived by considering the original component's FETType, CntlChType, Vgs, Vgs(th), Vds, and Id 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. You can also to suit your preferences.

BS170
more info
CntlChType
N
channel
FETType
MOSFET
Id
0.5
A
Pd
0.83
W
Rds
50
Ω
Tj
150
°C
Vds
60
V
Vgs
20
V
Vgs(th)
3
V
2SK3124
more info
CntlChType
N
channel
FETType
MOSFET
Id
0.5
A
Pd
10
W
Rds
230
Ω
Tj
150
°C
Vds
400
V
Vgs
20
V
Vgs(th)
3
V
Cd
10
pF
tr
35
ns
AP01N40J
more info
CntlChType
N
channel
FETType
MOSFET
Id
0.5
A
Pd
17.4
W
Rds
160
Ω
Tj
150
°C
Vds
400
V
Vgs
20
V
Vgs(th)
3
V
Cd
11
pF
tr
12
ns
BS170D26Z
more info
CntlChType
N
channel
FETType
MOSFET
Id
0.5
A
Pd
0.83
W
Rds
50
Ω
Tj
150
°C
Vds
60
V
Vgs
20
V
Vgs(th)
3
V
Cd
17
pF
BS170D27Z
more info
CntlChType
N
channel
FETType
MOSFET
Id
0.5
A
Pd
0.83
W
Rds
50
Ω
Tj
150
°C
Vds
60
V
Vgs
20
V
Vgs(th)
3
V
Cd
17
pF
BS170D74Z
more info
CntlChType
N
channel
FETType
MOSFET
Id
0.5
A
Pd
0.83
W
Rds
50
Ω
Tj
150
°C
Vds
60
V
Vgs
20
V
Vgs(th)
3
V
Cd
17
pF
BS170D75Z
more info
CntlChType
N
channel
FETType
MOSFET
Id
0.5
A
Pd
0.83
W
Rds
50
Ω
Tj
150
°C
Vds
60
V
Vgs
20
V
Vgs(th)
3
V
Cd
17
pF
BS170G
more info
CntlChType
N
channel
FETType
MOSFET
Id
0.5
A
Pd
0.35
W
Rds
50
Ω
Tj
150
°C
Vds
60
V
Vgs
20
V
Vgs(th)
3
V
BS170L34Z
more info
CntlChType
N
channel
FETType
MOSFET
Id
0.5
A
Pd
0.83
W
Rds
50
Ω
Tj
150
°C
Vds
60
V
Vgs
20
V
Vgs(th)
3
V
Cd
17
pF
BS170RL1G
more info
CntlChType
N
channel
FETType
MOSFET
Id
0.5
A
Pd
0.35
W
Rds
50
Ω
Tj
150
°C
Vds
60
V
Vgs
20
V
Vgs(th)
3
V
BS170RLRA
more info
CntlChType
N
channel
FETType
MOSFET
Id
0.5
A
Pd
0.35
W
Rds
50
Ω
Tj
150
°C
Vds
60
V
Vgs
20
V
Vgs(th)
3
V
BS170RLRAG
more info
CntlChType
N
channel
FETType
MOSFET
Id
0.5
A
Pd
0.35
W
Rds
50
Ω
Tj
150
°C
Vds
60
V
Vgs
20
V
Vgs(th)
3
V
BS170RLRMG
more info
CntlChType
N
channel
FETType
MOSFET
Id
0.5
A
Pd
0.35
W
Rds
50
Ω
Tj
150
°C
Vds
60
V
Vgs
20
V
Vgs(th)
3
V
BS170RLRP
more info
CntlChType
N
channel
FETType
MOSFET
Id
0.5
A
Pd
0.35
W
Rds
50
Ω
Tj
150
°C
Vds
60
V
Vgs
20
V
Vgs(th)
3
V
BS170RLRPG
more info
CntlChType
N
channel
FETType
MOSFET
Id
0.5
A
Pd
0.35
W
Rds
50
Ω
Tj
150
°C
Vds
60
V
Vgs
20
V
Vgs(th)
3
V
BS170ZL1G
more info
CntlChType
N
channel
FETType
MOSFET
Id
0.5
A
Pd
0.35
W
Rds
50
Ω
Tj
150
°C
Vds
60
V
Vgs
20
V
Vgs(th)
3
V
CHT170GP
more info
CntlChType
N
channel
FETType
MOSFET
Id
0.5
A
Pd
0.3
W
Rds
50
Ω
Tj
150
°C
Vds
60
V
Vgs
20
V
Vgs(th)
3
V
Cd
11
pF
CS7000
more info
CntlChType
N
channel
FETType
MOSFET
Id
0.5
A
Pd
0.4
W
Rds
50
Ω
Tj
150
°C
Vds
60
V
Vgs
20
V
Vgs(th)
3
V
MMBF170
more info
CntlChType
N
channel
FETType
MOSFET
Id
0.5
A
Pd
0.3
W
Rds
50
Ω
Tj
150
°C
Vds
60
V
Vgs
20
V
Vgs(th)
3
V
NVBF170L
more info
CntlChType
N
channel
FETType
MOSFET
Id
0.5
A
Pd
0.225
W
Rds
50
Ω
Tj
150
°C
Vds
60
V
Vgs
20
V
Vgs(th)
3
V
RDR005N25
more info
CntlChType
N
channel
FETType
MOSFET
Id
0.5
A
Pd
1
W
Rds
8.8
Ω
Tj
150
°C
Vds
250
V
Vgs
20
V
Vgs(th)
3
V
Cd
10
pF
tr
10
ns
Qg
3.5
Nc

There may be 2 alternatives for the MPSA18 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. You can also to suit your preferences.

MPSA18
more info
ft
100
MHz
hFE
800
β
Ic
0.1
A
Pc
0.31
W
Pol
NPN
Tj
150
°C
TranMat
Si
Vcb
45
V
Vce
45
V
BD675BPL
more info
ft
260
MHz
hFE
800
β
Ic
4
A
Pc
40
W
Pol
NPN
Tj
150
°C
TranMat
Si
Vcb
45
V
Vce
45
V
Veb
5
V

There may be 2 alternatives for the 2N5457 mentioned above in the parts list for this project. These suggestions were derived by considering the original component's FETType, CntlChType, Vgs, Vds, and Id 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. You can also to suit your preferences.

2N5457
more info
CntlChType
N
channel
FETType
JFET
Id
0.005
A
Pd
0.625
W
Tj
150
°C
Vds
25
V
Vgs
2.5
V
2N5953
more info
CntlChType
N
channel
FETType
JFET
Id
0.005
A
Pd
0.36
W
Tj
150
°C
Vds
30
V
Vgs
2.5
V