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Modular UREI 545 and 546
EQ clone and variations project

Schematics and Bill of
Materials for Parametric EQ
project

3 -

Modular parametric EQ project based on UREI 545 and 546

Schematics and Bill of Materials for Parametric EQ project
Schematic and BOM of “Parametric EQ” circuit module

1

2

3
Bandwidth

GND

A

Boos/Cut
C1
100n

B

Band Fr.

6
5
4
3
2
1

A

Header 6X2A

R1 4.7k

GND
P2
6
5
4
3
2
1

R2 390

2
3

A

Header 6X2A

Top and bottom PCBs and overlay of EQ module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Top and bottom PCBs and overlay of 3 adjustable resistors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Top and bottom PCBs and overlay of 2 adjustable resistors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Top and bottom PCBs and overlay of power filters (ver.2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Top and bottom PCBs and overlay of power filters (ver.1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Top and bottom PCBs and TOP overlay of EQ mainboard for UREI 545 clone . . . . . . . . . . . . . . . . . . . . . 18
Top and bottom PCBs and TOP overlay of EQ mainboard for modified 6 band UREI 546 clone . . . . . . 20
Top and bottom PCBs and TOP overlay of EQ mainboard for 4 band UREI 546 clone . . . . . . . . . . . . . . 22

Power supply for Parametric EQ project . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Schematic of power supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Top and bottom PCBs and TOP overlay of power supply for UREI 546 and 546 clone . . . . . . . . . . . . . . 26

R4
4.7k

R3
4.7k

R6

R7
4.7k

2k
C5
100n

GND

U1B

6
B

C3
C(c)

Input

TL074J

4.7k

4.7k R9
U1C
TL074J
9
R10
8
C
10

C4

U1D

13
D

12

14

TL074J

GND

D1 Diode 1N4148

http://custompcb.blogspot.com/
http://diyguitarpa.blogspot.com/

Multiband Section:
Multiband Low: C(a) and C(b)= 160nF ; C(c) = 100nF - 15Hz-200Hz
Multiband Mid: C(a) and C(b)= 16nF ; C(c) = 100nF - 150Hz-2kHz
Multiband High: C(a) and C(b)= 1.6nF ; C(c) = 100nF - 1.5kHz-20kHz

Title
Size

The required mainboard available for 4 band EQ (similar with UREI 546) and for 6 band
EQ just for fun.

2

Description

C

U1: TL074, LM837, LME49740, LT1125, OPA4132, OPA4137,
OPA4134 and the compatible quad versions of these op-amps.

GND

Examples for UREI 545 clone:
Low band: C(a) and C(b)= 100nF ; C(c) = 100nF - 24Hz-310Hz
Mid band: C(a) and C(b)= 13nF ; C(c) = 100nF - 190Hz-2.24kHz
High band: C(a) and C(b)= 2.5nF ; C(c) = 100nF - 960Hz-12.5kHz

This module can adjust the Bandwidth (Q), Frequency, and the
Boost/Cut. The module frequency depend on the value of C(a), C(b),
and C(c). The value of adjustable resistors are available on the
"resistor board" schematic.
Examples:
Low band: C(a) and C(b)= 100nF ; C(c) = 1uF - 30Hz-330Hz
Low-Mid band: C(a) and C(b)= 27nF ; C(c) = 100nF - 110Hz-1.2kHz
High-Mid band: C(a) and C(b)= 8nF ; C(c) = 100nF - 390Hz-4.2kHz
High band: C(a) and C(b)= 2.2nF ; C(c) = 100nF - 1.4kHz-15kHz

For more option, this module useful for UREI 545 clone.

1

B

R5
4.7k

This schematic is the part of UREI 546 or UREI 545 clone. This is the
adjustable EQ module. The required mainboard and the PCB are
available on the web.

C(b)

R11
100k

D

7

GND

Output
C

C(a)

5

R8

Schematics and Bill of Materials for Parametric EQ project . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Printed Circuit Boards for Parametric EQ project . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

U1A
TL074J
1

390

In this option have to change all 4.7k resistors to 5.1k, R2 = 1.6k, R6 = 330,

Schematic and BOM of “Parametric EQ” circuit module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Schematic of “Adjustable resistors” circuit module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Schematic of “Voltage filter” module for ±15...±18V . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Schematic of “Mainboard” for UREI 545 clone EQ project . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
BOM of the “Mainboard” for UREI 545 clone EQ project . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
BOM of the “Mainboard” for UREI 546 clone EQ project . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Schematic of the “Mainboard” for UREI 546 clone EQ project . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

C2

+15V
4

12
11
10
9
8
7

6

W1
Jumper

-15V

English blog and PCB order: http://custompcb.blogspot.com/
Hungarian blog and PCB order: http://diyguitarpa.blogspot.com/
The Youtube Channel • Picasa gallery • Email: gitarfogas@gmail.com

12
11
10
9
8
7

5

11

This project made for cloning (or creating alternatives) of UREI 545 and 546 parametric EQ device with modular system. This is not only a clone, find something new
in the project details. The main circuits are separated to modules, and finally all connected to the one (big) mainboard. The parts of this projects: mainboard, power filters
for less noise, the EQ board, Power Supply, and the board for adjustable resistors.
Because finally all of the modules are connected, lots of headers on the circuits. These
are required for module connections. Look at details on the page of schematics and
notes. PCB-s and more notes, pictures, details about this project are available on the
author’s blog and websites:

P1

4

Footprint

Number

D

Revision

A
Date:
File:
3

Value

EQ Module for Parametric Multiband EQ

10/12/2011
Sheet of
D:\!Works\..\Multiband EQ 1-panel.SchDocDrawn By:
4

Quantit
y

Designator

5

6

Model:Footprint

Capacitor

100n

RAD-0.3

2 C1, C5

Radial Cap, Thru-Hole; 2 Leads; 0.3 in Pin Spacing

Capacitor

C(a)

RAD-0.3

1 C2

Radial Cap, Thru-Hole; 2 Leads; 0.3 in Pin Spacing

Capacitor

C(c)

RAD-0.3

1 C3

Radial Cap, Thru-Hole; 2 Leads; 0.3 in Pin Spacing

Capacitor

C(b)

RAD-0.3

1 C4

High Conductance Fast Diode

DO-35

1 D1

Radial Cap, Thru-Hole; 2 Leads; 0.3 in Pin Spacing
Diode, Axial; Body 3.8 x 1.9 mm (LxDia. max), Lead
Dia. 0.53 mm (max)

Header, 6-Pin, Dual row

HDR2X6_CEN

Resistor

4.7k

AXIAL-0.4

2 P1, P2
Connector; Header; 6x2 Position
R1, R3, R4, R5, R7, R9,
7 R10
Axial Device, Thru-Hole; 2 Leads; 0.4 in Pin Spacing

Resistor

390

AXIAL-0.4

2 R2, R6

Axial Device, Thru-Hole; 2 Leads; 0.4 in Pin Spacing

Resistor

2k

AXIAL-0.4

1 R8

Axial Device, Thru-Hole; 2 Leads; 0.4 in Pin Spacing

Resistor
Low-Noise JFET-Input
Operational Amplifier

100k

AXIAL-0.4

1 R11

Axial Device, Thru-Hole; 2 Leads; 0.4 in Pin Spacing

J014

1 U1

DIP; 14 Leads; Row Spacing 7.62 mm; Pitch 2.54 mm

RAD-0.2

1 W1

Radial Cap, Thru-Hole; 2 Leads; 0.2 in Pin Spacing

Jumper Wire

Document last modified and saved: 12 October 2011 6:07 PM

Modular parametric EQ project based on UREI 545 and 546

- 4

5 -

Schematic and BOM for the module of Parametric EQ project
Schematic of “Adjustable resistors” circuit module
1

2

3

5

P5

R (Band frequency)
A

4
1
2
3
4
5
6

P1
Pot stereo

Schematic and BOM for the module of Parametric EQ project.
Schematic of “Voltage filter” module for ±15...±18V

6
1

R (Bandwidth - Q)

7
8
9
10
11
12

Modular parametric EQ project based on UREI 545 and 546

2

3

4

5

6

A

A

A

P2
Pot stereo

P1
1
2
3
4
5
6

B

Header 6X2A

GND

C1
47uF 60V

7
8
9
10
11
12

R1

BC560C
Q1

C4
10uF C5
10uF

C3
100nF

12K

C8
47nF

GND
GND

GND

C2
100nF

BC550C
Q2
R2
12K

C6
47nF

47uF 60V
C7

B

GND

Header 6X2A
C

C
Title

P3

R (Boost/Cut)

1
2
3
4
5
6

P4
Pot stereo

B

This schematic is the part ofparametric EQ
projects. These projects are clones ofUREI
545 and 546 EQ-s. The value ofadjusteble
resistors are depending on the function ofEQ
module. This module required the mainboard
made for UREI545 or 546 clones.

7
8
9
10
11
12

http://custompcb.blogspot.com/
http://diyguitarpa.blogspot.com/

B

Description
Polarized Capacitor (Radial)

Value
47uF 60V

C

Date:
File:

3

Footprint
Elco 6mm, 1 mil
pins

Revision

10/11/2011
D:\!Works\..\PowerFilter.SchDoc
4

Quantit
y

Sheet of
Drawn By:
5

Designator

D
6

Model:Footprint

2 C1, C7

Capacitor

100nF

RAD-0.3

2 C2, C3

Polarized Capacitor (Radial)

10uF

Cap, Tantal, 1mil

2 C4, C5

Capacitor

47nF

RAD-0.3

2 C6, C8

Capacitor; 2 Leads

HDR2X6_CEN

1 P1

Header, 6-Pin, Dual row

Resistor values for UREI545 clone:
- Low cut and high cut: 50k stereo (P4)
- Bandwidth (Q): 10k mono (P2)
- Frequency: 10k stereo (P1)
- Boost/Cut: 10k mono (P4)

C

2

Number

A

This schematic is the partof preamps and EQ projects. This module filtering the symmatrical (+-) power for
circuits. PCB and another modules, mainboards are available.

1

Resistor values for UREI546 clone:
- Low cut and high cut: 55k stereo (P4)
- Bandwidth (Q): 10k mono (P2)
- Frequency: 55k stereo (P1)
- Boost/Cut: 10k mono (P4)

Header 6X2A

D

Size

Power filter module

Capacitor; 2 Leads

Transistor PNP Silicon

BC560C

29-04

1 Q1

Transistor NPN Silicon

BC550C

29-04

1 Q2

Connector; Header; 6x2 Position
TO, Flat Index; 3 In-Line, Axial Leads; Body Dia.
4.8mm; Leads 0.48 x 0.5 mm (max)
TO, Flat Index; 3 In-Line, Axial Leads; Body Dia.
4.8mm; Leads 0.48 x 0.5 mm (max)

Resistor

12K

AXIAL-0.4

2 R1, R2

Resistor; 2 Leads

For both:
Output module gain: 5k mono (P4)

http://custompcb.blogspot.com/
http://diyguitarpa.blogspot.com/
Title

Potmeter module for parametric EQ project

Size
D

Revision
D

A
Date:
File:
1
Description

Resistor

Resistor
Header, 6-Pin, Dual row
Resistor

Number
10/12/2011
D:\!Works\..\Pots.SchDoc
2
Value
R (Band
frequency)
R
(Bandwidth Q)

Sheet of
Drawn By:

3
Footprint
Pots Plastic
Stereo

4
Quantit
y

6
Model:Footprint

1 P1

Pots Plastic
Stereo

1 P2

HDR2X6_CEN

2 P3, P5

R (Boost/Cut)Pots Plastic Stereo

Designator

5

1 P4

Connector; Header; 6x2 Position

Notes

The 3th module required for the EQ mainboard is the power filter circuit. I like to use this simple
circuit to filter the problems of power. These circuits have to be connected to the headers P26-P29,
and P33-36 on the PCB of 546 clone mainboard. 8 (ot the PCB-V4 6) modules required for better
power and less noise, but if you think this is not important, you can wire pin 8 to pin 10 and pin
7 to pin 12 to ignore these circuits and boards.
We have two versions of power filter PCB. No difference between schematics, the one of them is
landscape, the another one is portrait orientation.
Document last modified and saved: 12 October 2011 6:07 PM

Modular parametric EQ project based on UREI 545 and 546

- 6

7 -

Modular parametric EQ project based on UREI 545 and 546

Schematic for the module of Parametric EQ project
Schematic of “Mainboard” for UREI 545 clone EQ project
2

3
P1

7
8
9
10
11
12

Bandwidth

12
11
10
9
8
7

P4
Header 6X2A

1
2
3
4
5
6

Low cut Fr.

1

GND

4

6
5
4
3
2
1

P2

Bandwidth

Low band Fr.

12
11
10
9
8
7

GND

Header 6X2A

5

Mid band Fr.

6
5
4
3
2
1

6
P3

Bandwidth

Header 6X2A

12
11
10
9
8
7

High band Fr.

6
5
4
3
2
1

Header 6X2A

GND

R1

2
1

3

C4
150n

R5 1.6k

U2A

2
3

TL074J

330
R21

H3

GND GND

1

A

100n

R6
5.1k

B

R36
5.1k

7

R31
5.1k

H4

U2C

8

C

10

P7

C9

5.1k R27

9

TL074J

R39

13

P5

D

12

TL074J
14
U2D

GND

U3A
TL074J
1

GND GND

R8
5.1k

R32
2k

6
5
4
3
2
1

R25
5.1k

13n

R9 1.6k
U3B

6
B

TL074J

C7
100n

R33
5.1k

C10
13n

5.1k R28
U3C
TL074J
8
C

9
10

U3D

13
D

12

R40

P6

14

TL074J

GND

100n

1.6n

2
1

5.1k

TL074J

U6B

6
B

5

R63
5.1k

9

R57
5.1k

13
D

12

TL074J

P11

7
8
9
10
11
12

C49

1.6n

4

R56
100k
R60
910

GND

R74
100k

TL074J

GND

14
Bandwidth

GND

P8
Header 6X2A

12
11
10
9
8
7

6
5
4
3
2
1

D5
Diode 1N4148

R61
43k

D6

GND

R72
910

R73
10k

Multiband Fr.

R49
51k

220k

R64
10k

P10
Header 6X2A

C37
10u

GND
P15
Pot Trimmer
47k

GND

W1

C24
10u

D

R38
5.1k

TL074J

GND

+15V Stage4

Q5
2N3370

3
R65
10M

GND

+15V Stage6
-15V Stage6

Jumper

GND

220

P9

12
11
10
9
8
7

P13
Header 6X2A

GND

R71

GND

P12
Header 6X2A

C
GND

6
5
4
3
2
1

+15V Stage5

-15V Stage5

P14
Header 6X2A

Output Gain
Header 6X2A

Header 6X2A

P16
Header 6X2A

GND

+15V Stage1
-15V Stage1

1

GND

H11

3

GND GND

+15V Stage2
-15V Stage2

Low band: C(a) and C(b)= 100nF ; C(c) = 100nF - 24Hz-310Hz
Mid band: C(a) and C(b)= 13nF ; C(c) = 100nF - 190Hz-2.24kHz
High band: C(a) and C(b)= 2.5nF ; C(c) = 100nF - 960Hz-12.5kHz

P17
Header 6X2A

7
8
9
10
11
12

This EQ can adjust the bandwidth (Q), Frequency, and the Boost/Cut.

GND

Multiband Section:
Multiband Low: C(a) and C(b)= 160nF ; C(c) = 100nF - 15Hz-200Hz
Multiband Mid: C(a) and C(b)= 16nF ; C(c) = 100nF - 150Hz-2kHz
Multiband High: C(a) and C(b)= 1.6nF ; C(c) = 100nF - 1.5kHz-20kHz
Ux: TL074, LM837, LME49740, LT1125, OPA4132, OPA4137, OPA4134 and the dual versions of these op-amps.

2

P18
Header 6X2A

1
2
3
4
5
6

2

This schematic is the part of UREI 545 clone. This is the mainboard. The required additional potmeter-modules, power filter moadules and the PCB are available.

7
8
9
10
11
12

R59
1K

GND

1
2
3
4
5
6

R58
1K

3

D

B

R50
5.1k

GND

Diode 1N4148

C36
10n

1

A

GND

U6D

8

C

12

TL074J

14

-15V Stage3

R46
2.2k

TL072P
C23
R51
100n

D4

4.7n
C34

Diode 1N4148

5.1k R66
U6C

10

1
2
3
4
5
6

16n

R47
220k

Diode 1N4148

C30 1uF

GND

R70
5.1k

U4D

13

8

H6

U5A

3

D3

6
5
4
3
2
1

C

160n

C45

Diode 1N4148

7

B

5

1
2

12
11
10
9
8
7

R69 C46
2k 100n

6

2

R43
100k

Diode 1N4148
D2

U5B
TL072P

High cut Fr.

330

7

C38

TL074J

11

R62

D1

7
8
9
10
11
12

R54

C

1
2
3
4
5
6

1

A

U4C

-15V Stage4

7
8
9
10
11
12

C20

4

3

C11
2.5n

5.1k R29

9

1
2
3
4
5
6

16n

5.1k

1.6k

R35
5.1k

2

C18

1

H10

U6A

7

TL074J

1

H9

8

160n

1

2

H8

1

2

C13

2

2

B

GND

R41
100k

+15V Stage3

Output

R48

R55

U4B

6

GND

5.1k

H7

2.5n

GND

R42

Multiband

R10
5.1k

5

10

Header 6X2A

B

R14
5.1k

R26
5.1k
C8

A

C3

R20
1K

GND GND

TL074J

Header 6X2A

100k

GND

R34
2k

6
5
4
3
2
1

1

A

330
R23

12
11
10
9
8
7

U4A

2
3

R37
5.1k

7

GND

Header 6X2A

100k

R13
5.1k

5

R22

12
11
10
9
8
7

A

3

TL074J

100n

2

330

GND

R30
2k 100n

6
5
4
3
2
1

R7 1.6k

U2B

6
5

R24
5.1k
C6

12
11
10
9
8
7

R12
5.1k

R19
1K

4

4

U1A
TL072P
1

5.1k

7
8
9
10
11
12

1

A

R4

C2

R18
1K

1
2
3
4
5
6

2

2

GND

4

1

C5

7

B

5

R11
910

R17
1K

5.1k

7
8
9
10
11
12

330n

U1B
TL072P

R3

C1

1
2
3
4
5
6

6

R16
1K

11

In

H2

R15
1K

5.1k
8

H1

2

R2

GND

4

910

1

11

2

11

A

GND

-15V

1

+15V

H12

Title
GND

UREI 545 Clone Mainboard

Size
http://custompcb.blogspot.com/
http://diyguitarpa.blogspot.com/

1

D

2

3

4

5

Number

Revision

Tabloid
Date:
File:

10/11/2011
Sheet of
D:\!Works\..\UREI545-EQ Pots PF-Panels.SchDoc
Drawn By:
6

Document last modified and saved: 12 October 2011 6:07 PM

Modular parametric EQ project based on UREI 545 and 546

- 8

9 -

BOM for the module of Parametric EQ project
BOM of the “Mainboard” for UREI 545 clone EQ project

Description

Value

Footprint

Capacitor

100n

RAD-0.3

Capacitor

13n

RAD-0.3

2 C2, C10

Radial Cap, Thru-Hole; 2 Leads; 0.3 in Pin Spacing

Capacitor

2.5n

RAD-0.3

2 C3, C11

Radial Cap, Thru-Hole; 2 Leads; 0.3 in Pin Spacing

Capacitor

150n

RAD-0.3

1 C4

Radial Cap, Thru-Hole; 2 Leads; 0.3 in Pin Spacing

Capacitor

330n

RAD-0.3

1 C5

Radial Cap, Thru-Hole; 2 Leads; 0.3 in Pin Spacing

Capacitor

160n

RAD-0.3

2 C13, C38

Radial Cap, Thru-Hole; 2 Leads; 0.3 in Pin Spacing

Capacitor

16n

RAD-0.3

2 C18, C45

Radial Cap, Thru-Hole; 2 Leads; 0.3 in Pin Spacing
Radial Cap, Thru-Hole; 2 Leads; 0.3 in Pin Spacing

Capacitor

1.6n

RAD-0.3

2 C20, C49

Polarized Capacitor (Radial)

10u

Cap, Tantal, 1mil

2 C24, C37

Polarized Capacitor (Radial)

1uF

Cap, Tantal, 1mil

1 C30

Capacitor

4.7n

RAD-0.3

1 C34

Capacitor

10n

RAD-0.3

1 C36

High Conductance Fast Diode

DO-35
Panel Connector
2 input Small
Panel Connector
3 input Small

Header, 6-Pin, Dual row

HDR2X6_CEN

Resistor
N-Channel JFET (General
Purpose Amplifier)

47k

Resistor

910

Description

2 H11, H12
P1, P2, P3, P4, P5, P6,
P7, P8, P9, P10, P11,
P12, P13, P14, P16,
17 P17, P18
1 P15

TO-18

1 Q5

Footprint

Model:Footprint

RAD-0.3

1 C1

Radial Cap, Thru-Hole; 2 Leads; 0.3 in Pin Spacing

Capacitor

330n

RAD-0.3

1 C2

Radial Cap, Thru-Hole; 2 Leads; 0.3 in Pin Spacing
Radial Cap, Thru-Hole; 2 Leads; 0.3 in Pin Spacing

Capacitor

100n

RAD-0.3

1 C3

Polarized Capacitor (Radial)

10u

Cap, Tantal, 1mil

2 C4, C8

Polarized Capacitor (Radial)

1uF

Cap, Tantal, 1mil

1 C5

Capacitor

4.7n

RAD-0.3

1 C6

Radial Cap, Thru-Hole; 2 Leads; 0.3 in Pin Spacing

Capacitor

10n

RAD-0.3

1 C7

DO-35

1 D1

Radial Cap, Thru-Hole; 2 Leads; 0.3 in Pin Spacing
Diode, Axial; Body 3.8 x 1.9 mm (LxDia. max), Lead
Dia. 0.53 mm (max)

High Conductance Fast Diode

Panel Connector
2 input Small
Panel Connector
3 input Small

3 pin, 2 mil connector
Header, 6-Pin, Dual row

Can; 3 Leads; Pin Circle Dia. 2.54 mm; Lead Dia. 0.48
mm (max)

Designator

150n

Radial Cap, Thru-Hole; 2 Leads; 0.3 in Pin Spacing

Connector; Header; 6x2 Position

Quantit
y

Capacitor

HDR2X6_CEN

H1, H2, H3, H4, H5, H6,
11 H7, H8, H9, H10, H11
2 pin, 2 mil connector
2 H12, H13
P1, P2, P3, P4, P5, P6,
P7, P8, P9, P10, P11,
P12, P13, P14, P15,
P16, P17, P18, P19,
P20, P21, P22, P23,
P24, P25, P26, P27,
P28, P29, P31, P32,
35 P33, P34, P35, P36

pot trimmer big

1 P30

TO-18

1 Q1

3 pin, 2 mil connector

Connector; Header; 6x2 Position

Resistor
N-Channel JFET (General
Purpose Amplifier)

47k

Resistor

910

AXIAL-0.4

4 R1, R2, R10, R12

Axial Device, Thru-Hole; 2 Leads; 0.4 in Pin Spacing

Resistor

100k

AXIAL-0.4

2 R3, R9

Axial Device, Thru-Hole; 2 Leads; 0.4 in Pin Spacing

Resistor

2.2k

AXIAL-0.4

1 R4

Axial Device, Thru-Hole; 2 Leads; 0.4 in Pin Spacing

Resistor

220k

AXIAL-0.4

2 R5, R8

Axial Device, Thru-Hole; 2 Leads; 0.4 in Pin Spacing

Resistor

51k

AXIAL-0.4

1 R6

Axial Device, Thru-Hole; 2 Leads; 0.4 in Pin Spacing

Resistor

5.1k

AXIAL-0.4

1 R7

Axial Device, Thru-Hole; 2 Leads; 0.4 in Pin Spacing

Resistor

43k

AXIAL-0.4

1 R11

Axial Device, Thru-Hole; 2 Leads; 0.4 in Pin Spacing

Can; 3 Leads; Pin Circle Dia. 2.54 mm; Lead Dia. 0.48
mm (max)

4 R1, R11, R60, R72
R2, R3, R4, R6, R8,
R10, R12, R13, R14,
R24, R25, R26, R27,
R28, R29, R31, R33,
R35, R36, R37, R38,
R42, R48, R50, R54,
29 R57, R63, R66, R70

Axial Device, Thru-Hole; 2 Leads; 0.4 in Pin Spacing

Axial Device, Thru-Hole; 2 Leads; 0.4 in Pin Spacing

Resistor

10k

AXIAL-0.4

2 R13, R16

Axial Device, Thru-Hole; 2 Leads; 0.4 in Pin Spacing

Axial Device, Thru-Hole; 2 Leads; 0.4 in Pin Spacing

Resistor

10M

AXIAL-0.4

1 R14

Axial Device, Thru-Hole; 2 Leads; 0.4 in Pin Spacing

Axial Device, Thru-Hole; 2 Leads; 0.4 in Pin Spacing

220

AXIAL-0.4

1 R15

Axial Device, Thru-Hole; 2 Leads; 0.4 in Pin Spacing

dip-8

2 U1, U2

DIP; 8 Leads; Row Spacing 7.62 mm; Pitch 2.54 mm

RAD-0.2

1 W1

Radial Cap, Thru-Hole; 2 Leads; 0.2 in Pin Spacing

Resistor

5.1k

AXIAL-0.4

Resistor

1.6k

AXIAL-0.4

Resistor

1K

AXIAL-0.4

4 R5, R7, R9, R55
R15, R16, R17, R18,
8 R19, R20, R58, R59

Resistor

330

AXIAL-0.4

4 R21, R22, R23, R62

Axial Device, Thru-Hole; 2 Leads; 0.4 in Pin Spacing

Resistor
Low-Noise JFET-Input
Operational Amplifier

Resistor

2k

AXIAL-0.4

Axial Device, Thru-Hole; 2 Leads; 0.4 in Pin Spacing

Jumper Wire

Resistor

100k

AXIAL-0.4

4 R30, R32, R34, R69
R39, R40, R41, R43,
6 R56, R74

Resistor

2.2k

AXIAL-0.4

1 R46

Axial Device, Thru-Hole; 2 Leads; 0.4 in Pin Spacing

Resistor

220k

AXIAL-0.4

2 R47, R51

Axial Device, Thru-Hole; 2 Leads; 0.4 in Pin Spacing

Resistor

51k

AXIAL-0.4

1 R49

Axial Device, Thru-Hole; 2 Leads; 0.4 in Pin Spacing

Resistor

43k

AXIAL-0.4

1 R61

Axial Device, Thru-Hole; 2 Leads; 0.4 in Pin Spacing

Resistor

10k

AXIAL-0.4

2 R64, R73

Axial Device, Thru-Hole; 2 Leads; 0.4 in Pin Spacing

Resistor

10M

AXIAL-0.4

1 R65

Axial Device, Thru-Hole; 2 Leads; 0.4 in Pin Spacing

Resistor
Low-Noise JFET-Input
Operational Amplifier
Low-Noise JFET-Input
Operational Amplifier

220

AXIAL-0.4

1 R71

Axial Device, Thru-Hole; 2 Leads; 0.4 in Pin Spacing

dip-8

2 U1, U5

DIP; 8 Leads; Row Spacing 7.62 mm; Pitch 2.54 mm

J014

4 U2, U3, U4, U6

DIP; 14 Leads; Row Spacing 7.62 mm; Pitch 2.54 mm

RAD-0.2

1 W1

Radial Cap, Thru-Hole; 2 Leads; 0.2 in Pin Spacing

Jumper Wire

Value

Radial Cap, Thru-Hole; 2 Leads; 0.3 in Pin Spacing
Diode, Axial; Body 3.8 x 1.9 mm (LxDia. max), Lead
6 D1, D2, D3, D4, D5, D6 Dia. 0.53 mm (max)
H1, H2, H3, H4, H6, H7,
9 H8, H9, H10
2 pin, 2 mil connector

pot trimmer big

AXIAL-0.4

BOM for the module of Parametric EQ project
BOM of the “Mainboard” for UREI 546 clone EQ project

Quantit
y

Designator
Model:Footprint
C1, C6, C7, C8, C9, C23,
7 C46
Radial Cap, Thru-Hole; 2 Leads; 0.3 in Pin Spacing

Modular parametric EQ project based on UREI 545 and 546

Axial Device, Thru-Hole; 2 Leads; 0.4 in Pin Spacing

Document last modified and saved: 12 October 2011 6:07 PM

Modular parametric EQ project based on UREI 545 and 546

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11 -

Modular parametric EQ project based on UREI 545 and 546

Schematic for the module of Parametric EQ project
Schematic of the “Mainboard” for UREI 546 clone EQ project

1

2

Notes

This “mainboard” have large amount
of “headers” (connectors) because the
smallest modules connected and collected to this board.

3

P1

4

P2

1
2
3
4
5
6

7
8
9
10
11
12

1
2
3
4
5
6

5

P3

7
8
9
10
11
12

6

P4

1
2
3
4
5
6

7
8
9
10
11
12

1
2
3
4
5
6

P5

7
8
9
10
11
12

P6

1
2
3
4
5
6

7
8
9
10
11
12

1
2
3
4
5
6

7
8
9
10
11
12

Header 6X2A

Header 6X2A

Header 6X2A

Header 6X2A

Header 6X2A

Header 6X2A

P7

P8

P9

P10

P11

P12

1
2
3
4
5
6

P13
Header 6X2A

1
2
3
4
5
6

7
8
9
10
11
12

A

Low cut Fr.

A
7
8
9
10
11
12

1
2
3
4
5
6

7
8
9
10
11
12

1
2
3
4
5
6

7
8
9
10
11
12

1
2
3
4
5
6

7
8
9
10
11
12

1
2
3
4
5
6

7
8
9
10
11
12

1
2
3
4
5
6

7
8
9
10
11
12

Header 6X2A

Header 6X2A

Header 6X2A

Header 6X2A

Header 6X2A

Header 6X2A

P14

P15

P16

P17

P18

P19

R1

2

910

1

8

In

6

330n

C1
150n

2
3

A

Header 6X2A

7
8
9
10
11
12

Header 6X2A

GND

1
2
3
4
5
6

7
8
9
10
11
12

1
2
3
4
5
6

Header 6X2A

GND

7
8
9
10
11
12

1
2
3
4
5
6

Header 6X2A

GND

7
8
9
10
11
12

Header 6X2A

GND

1
2
3
4
5
6

7
8
9
10
11
12

Header 6X2A

GND

GND

Header 6X2A

H6

1
2
3
4
5
6

Header 6X2A

P23

7
8
9
10
11
12

1
2
3
4
5
6

Header 6X2A

-15V Stage 8

P24

7
8
9
10
11
12

1
2
3
4
5
6

Header 6X2A

1
2
3
4
5
6

Header 6X2A

H7

H8

P25

7
8
9
10
11
12

H9

+15v Stage 8

B

H10

+15V Stage5

Diode Bus

7
8
9
10
11
12

Header 6X2A
2

2

-15V Stage 7

P22

7
8
9
10
11
12

1

1
2
3
4
5
6

2

H5

7
8
9
10
11
12

1

P21

1
2
3
4
5
6

1

P20

H4

2

H3

1

1

GND

1
2
3
4
5
6

2

B

2

R2
910

7
8
9
10
11
12

1

1

7

1

2

5

C2

U1B
TL072P

2

1

H2

B

U1A
TL072P
1

4

2

1
2
3
4
5
6

GND

H1

P29
Header 6X2A

R12
910

1
2
3
4
5
6

7
8
9
10
11
12

10n

GND
R13
10k

GND

P32
Header 6X2A

12
11
10
9
8
7

6
5
4
3
2
1

R16
10k
High cut Fr.

GND
D1
Diode 1N4148

R11
43k

C7

R7
5.1k

7
8
9
10
11
12

R10
910

220k

GND

C4
10u

C8
10u

GND
P30
Pot Trimmer
47k

GND

W1
Jumper

GND

Q1
2N3370

3
R14
10M

P28
Header 6X2A

GND

C

+15V Stage6
-15V Stage6

R15

GND
P31

12
11
10
9
8
7

P27
Header 6X2A

1
2
3
4
5
6

GND

R6
51k

GND

220

GND
6
5
4
3
2
1

7
8
9
10
11
12

+15V Stage 7

100n

R9
100k

-15V Stage5

TL072P
C3
R8

P33
Header 6X2A

1
2
3
4
5
6

C5 1uF
4.7n
C6

-15V Stage3

7
8
9
10
11
12

R5
220k

1

A

1
2
3
4
5
6

3

7
8
9
10
11
12

7

B

+15V Stage3
R4
2.2k

P34
Header 6X2A

1
2
3
4
5
6

2

4

5

U2B
TL072P

H11

U2A

2

6

1

-15V Stage4

1

8

GND

C

2

R3
100k

1
2
3
4
5
6

7
8
9
10
11
12

+15V Stage4
Output

P26
Header 6X2A

Output Gain
Header 6X2A

GND

+15V Stage1
-15V Stage1

1
H12

D

P35
Header 6X2A

1
2
3
4
5
6

Examples:
Low band: C(a) and C(b)= 100nF ; C(c) = 1uF - 30Hz-330Hz
Low-Mid band: C(a) and C(b)= 27nF ; C(c) = 100nF - 110Hz-1.2kHz
High-Mid band: C(a) and C(b)= 8nF ; C(c) = 100nF - 390Hz-4.2kHz
High band: C(a) and C(b)= 2.2nF ; C(c) = 100nF - 1.4kHz-15kHz

7
8
9
10
11
12

2

+15V Stage2
-15V Stage2

P36
Header 6X2A

1
2
3
4
5
6

This EQ with additional EQ module can adjust the bandwidth (Q), Frequency, and the Boost/Cut.

7
8
9
10
11
12

This schematic is the part of EQ circuit based on UREI 546 clone. This is the mainboard. The required additional potmeter-modules, EQ modules, power filter modules and the PCB are available.

3

GND

GND
D

This module have 6 several EQ cards, but working with 4....6 modules depending on the required bands.

3

GND

2

-15V

1

+15V

H13

Title
GND

Size
http://custompcb.blogspot.com/
http://diyguitarpa.blogspot.com/

1

UREI 546 Clone Mainboard

2

3

4

5

Number

Revision

Tabloid
Date:
File:

10/11/2011
Sheet of
D:\!Works\..\UREI546-based MB-EQ.SchDoc
Drawn By:

The required most important modules are the EQ module. This panel
have to be connected to the headers
P14...P25. This is 12 connectors, but 6
modules only, because 1 EQ module
have 2 headers, look at the PCB of
EQ module.
Under these modules (on the PCB)
have 6 connectors for adjustable resistors. For the EQ modules required 3
resistors/module, adjusting the bandwidth, the frequency, and the cut/
boost, from P1 to P12. And required 3
smallest resistor modules with only one
header for low cut filter P13, high cut
filter P32, and to adjust the output
gain P31. Visit the PCB board about
adjustable resistors.
The 3th module required for this board
is the power filter board. I like to use
this simple circuit to filter the problem of
power. These circuits have to be connected to the headers P26-P29, and
P33-36. These are 8 modules for better
power and less noise, but if you think
this is not important, you can wire
pin 8 to pin 10 and pin 7 to pin 12 to
ignore these circuits and boards.
Finally in this schematic have connectors for 6 parametric EQ bands instead
of 4 (like in the original UREI 546). This
is just for fun, you can ignore the last 2
band and boards, but you can build 6
bands parametric EQ instead if 4 just
for fun.

6

Document last modified and saved: 12 October 2011 6:07 PM

Modular parametric EQ project based on UREI 545 and 546

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13 -

Modular parametric EQ project based on UREI 545 and 546

PCB for the module of Parametric EQ project
Top and bottom PCBs and overlay of EQ module

TOP LAYER

BOTTOM LAYER

PCB OVERLAY

OVERLAY ON TOP LAYER

Printed Circuit Boards
for Parametric EQ
project
U1

C2

R9 R11

R5

C1

R2

R10

R3

C5

12
6

P1

7
1

7
1

12
6

P2

D1

R6

R5

R1

R4

12
6

R10

R7 R8

R1

R4
W1

C3

R6

P2

C1

W1

R2
R3

C5

7
1

D1

12
6

R7 R8

C2

C4

C4
C3

U1

P1

7
1

R9 R11

Document last modified and saved: 12 October 2011 6:07 PM

Modular parametric EQ project based on UREI 545 and 546

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15 -

PCB for the module of Parametric EQ project
Top and bottom PCBs and overlay of 3 adjustable resistors

Modular parametric EQ project based on UREI 545 and 546

PCB for the module of Parametric EQ project
Top and bottom PCBs and overlay of 2 adjustable resistors
Notes

BOTTOM LAYER

TOP LAYER
BOTTOM LAYER

TOP LAYER

I made 2 versions
of PCB for adjustable resistors, because one of these
made for max. 2
(or 1 only) mono
and stereo adjustable resistors (for
high cut and low
cut filters, and for
output gain), the
another one is
made for max. 3
(or 2 or 1) resistors (adjust Freq.,
Boost, and Q features of EQ). The
bigger’s have 2
connectors,
the
smallest for 2 resistors have 1 connector only. Make
sure the board
direction is correct
before you finish it.

P2

P2

PCB OVERLAY
PCB OVERLAY
P2

P5

12
6

12
6

P3

7 12
1
6

7
1

7 12
1
6

P5

7
1

12
6

P3

P1

7
1

P4

P1

12
6

P4

OVERLAY ON TOP LAYER

P1

OVERLAY ON TOP LAYER

P1

P5

7
1

P2

P5

Document last modified and saved: 12 October 2011 6:07 PM

Modular parametric EQ project based on UREI 545 and 546

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17 -

PCB for the module of Parametric EQ project
Top and bottom PCBs and overlay of power filters (ver.1)

TOP LAYER

BOTTOM LAYER

PCB for the module of Parametric EQ project
Top and bottom PCBs and overlay of power filters (ver.2)

Modular parametric EQ project based on UREI 545 and 546

TOP LAYER

Notes
We have two versions of power filter PCB. No
difference between schematics, the one of them is
landscape, the another one is portrait.

BOTTOM LAYER
OVERLAY ON TOP LAYER

C8

C4

3
1

C7
Q2

C6 C2

R2

P1
12
6

PCB OVERLAY

12
6

Q1
C1

R1

C4

C8

C3

C3 C8

12
6

3
1

C6

R1

P1
7
1

C5

C2

7
1

R2

C1

Q1
C1

3
1

R2

Q2
C7

C6

P1
7
1

C4

3
1

3
1

R2

C1

R1

C6 C2

3
1

C3

R1

3
1

C2

Q1

C7
Q2

3
1

Q1
Q2
C7

C5

C5

C5

C4

PCB OVERLAY

C3 C8

P1
7
1

12
6

OVERLAY ON TOP LAYER
Document last modified and saved: 12 October 2011 6:07 PM

Modular parametric EQ project based on UREI 545 and 546

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Modular parametric EQ project based on UREI 545 and 546

PCB for the V.2 mainboard of Parametric EQ project
Top and bottom PCBs and TOP overlay of EQ mainboard for
UREI 545 clone
H12

H1

H2

H4

Q5

R51

2
3

R49

P15

U5

W1

C37

R8

R7

R65

R22

R6

R27 R21

D6 D5 D4

R33 R3

U2

R12 R39

C10
R2

R5
R28 R32

R30

R18

R16

C4

R17

R20

R15

R9

R34
R35

H7

R48R62 C13
H10

C45

R29

R23

H8

C18

C8

C7
R4

U1

R66R69 C20

U6

R57

C2

C5
R1 R11

R41 R38

U4

C34

R72

R40
R36

R24

TOP LAYER

R26

U3

C9

H6

R54 R70

C11

R10

R61

C3

R42
C46

R19

PCB TOP OVERLAY

C6

R14

R13 R25

R43

D2 D1

D3

C1

R31

R73

C23

C30

R37

R64

R60 R56

R47 R46 C36

R50

1

C24

H11

H3

R55

C38

H9

R63
C49

R74

R71 R59 R58

H12

H1

H2

H4

Q5

R60 R56

R47 R46 C36

R50

1

C24

H11

H3

2
3

R49

P15

U5

W1

C37

R8

R7

R65

R22

C30

R37

C1

R31

R27 R21

D6 D5 D4

R33 R3

U2

R12 R39

C10
R5
R28 R32
C9

BOTTOM LAYER

R30
R24

U1

C11

R10
R41 R38

U4

C4

R15

R54 R70

H6

U6

C18

R18
R20

R17

R29

R9

R34

R23

C45
C3

R42
C46

R35

R19

R55

C38

R63
R74

R71 R59 R58

H8

H7

R48R62 C13

C7
R4

C34

R66R69 C20

C8
R57

C2

R16

C23
R43

R72

R40
R36

C5
R1 R11

R26

U3

C6

R14

R13 R25

R61

C49

H10

H9

TOP OVERLAY ON TOP LAYER

R2

D2 D1

D3

R6

R73

R64

R51

Document last modified and saved: 12 October 2011 6:07 PM

Modular parametric EQ project based on UREI 545 and 546

PCB TOP OVERLAY
H5
W1

R1 R16P30

R15 R13 R14 R12

H3

H2

Q1

D1

3

PCB for the V.3 mainboard of Parametric EQ project
Top and bottom PCBs and TOP overlay of EQ mainboard for
modified 6 band UREI 546 clone

21 -

2

- 20

1

C7 R11 R10 R3

H12

H13

C8

C2 C1 R2 U1

C6

H11

R8 R6 R7

R9

C4

C5

R5 R4 U2

C3

H1
H6

H4

H8

H9

H7

H10

TOP LAYER
TOP OVERLAY ON TOP LAYER
R1 R16P30

R15 R13 R14 R12

H3

H2

Q1

D1

3

W1

1

H5

2

Modular parametric EQ project based on UREI 545 and 546

C7 R11 R10 R3

H12

H13

C8

C2 C1 R2 U1

H11

C6

R8 R6 R7

R9

C4

C5

R5 R4 U2

C3

H1
H4

H6

H9

H8

H7

H10

BOTTOM LAYER
Document last modified and saved: 12 October 2011 6:07 PM

Modular parametric EQ project based on UREI 545 and 546

- 22

23 -

PCB for the V.4 mainboard of Parametric EQ project
Top and bottom PCBs and TOP overlay of EQ mainboard for
4 band UREI 546 clone

Modular parametric EQ project based on UREI 545 and 546

PCB TOP OVERLAY
H1

H2

R16R9 R8 R6 R7

W1

H5

H3

R4
R5

H11

Q1
1

C3

P30

H13

H12

R15 R13R14R12

D1

U2

C7

R11R10 R3

3
2

H4

C8

H8

C4

H7

C5

H10

U1

TOP LAYER

C6 R1

C1 C2

R2

Notes

TOP OVERLAY ON TOP LAYER
H1

H2

R16R9 R8 R6 R7

W1

P30

BOTTOM LAYER

U1

C6 R1

C1 C2

R2

H3

H5

R4
R5

H11

Q1
1

C3
H4

H13

H12

R15 R13R14R12

D1

U2

3
2

C4

H8

C8

H7

C5

C7

R11R10 R3

This is the 3th variations of
UREI mainboards (but the
version number is 4 because
the first is not published).

H10

This mainboard have no
more than 4 bands (instead
of 6), Low, Low-mid, Highmid, and High. This 4 bands
are same than the bands of
original UREI 546 EQ. This
mainboard have 8 connectors for 4 adjustable bands
with 3 potentiometers required for 1 band, and one
potentiometer required for
low cut, high cut, and output
gain circuits. The benefit of
this board the smaller size,
and lower final costs.
Document last modified and saved: 12 October 2011 6:07 PM

Modular parametric EQ project based on UREI 545 and 546

- 24

25 -

Modular parametric EQ project based on UREI 545 and 546

Schematic and BOM for the module of Parametric EQ project
Schematic of power supply

4

A

3

R1

15V AC - 1

D1

C1
2200u

KBL04

C6
47n

3

B

10 1W

5

LM317BT
U1
IN

OUT
ADJ

6

A

2
+15V Out

+15V In
C2
2200u

C4
100n

D2
16V Zener

C3
47u

C5
100n

C7
47n

1

2

B

2

1

EQ project

3

1

for Parametric

2

GND
15V AC - 2

H1

C8
47n

C9
47n

3

GND
2200u
C11

C10
2200u

R2

-15V In

D3
16V Zener

100n
C13

10 1W

H2

C12
47u

C14
100n
-15V Out

1

Power supply

1

C

ADJ
IN
OUT

2

C

3

U2
LM337BT

Title

Power supply

Size
D
http://custompcb.blogspot.com/
http://diyguitarpa.blogspot.com/

1

Description

2

Value

Number

D

Date:
File:

3

10/12/2011
D:\!Works\..\Power supply.SchDoc
4

Quantit
y

Revision

A

Designator

Sheet of
Drawn By:

5

6

Polarized Capacitor (Radial)

2200u

Polarized Capacitor (Radial)

47u

Footprint
ELCO 22 MM 4
MIL
Elco 12 mm, 2 mil
pins

Model:Footprint

Capacitor

100n

RAD-0.3

4 C4, C5, C13, C14

Radial Cap, Thru-Hole; 2 Leads; 0.3 in Pin Spacing

Capacitor

47n

Radial Cap, Thru-Hole; 2 Leads; 0.3 in Pin Spacing

4 C1, C2, C10, C11
2 C3, C12

RAD-0.3

4 C6, C7, C8, C9

Full Wave Diode Bridge

Bridge hor.

1 D1

Zener Diode

DIODE-0.7
panel connector 3
input big

2 D2, D3
2 H1, H2

3 pin, 3 mil connector

AXIAL-0.4

2 R1, R2

221A-04

1 U1

Axial Device, Thru-Hole; 2 Leads; 0.4 in Pin Spacing
TO, Thru-Hole, Vertical, Heatsink Mounted; 3 In-Line
Leads; Pitch 2.54 mm

3-Terminal Adjustable Negative Voltage Regulator221A-04

1 U2

TO, Thru-Hole, Vertical, Heatsink Mounted; 3 In-Line Leads; Pitch 2

Resistor
3-Terminal Adjustable Positive
Voltage Regulator

10 1W

Diode, Thru-Hole; 2 Leads; 0.7 in Pin Spacing

Document last modified and saved: 12 October 2011 6:07 PM

Modular parametric EQ project based on UREI 545 and 546

- 26

27 -

Modular parametric EQ project based on UREI 545 and 546

PCB for the power supply of Parametric EQ project
Top and bottom PCBs and TOP overlay of power supply for
UREI 546 and 546 clone
TOP LAYER

PCB OVERLAY
H1

D1

U1

R1

1 2 3
C5

C9
C1

C8

C2

C6

U2
1 2 3
C14

D2
C12

R2
C7

C4

D3

C10

C11
C3

H2

C13

OVERLAY ON TOP LAYER
BOTTOM LAYER
H1

D1

U1

R1

1 2 3
C5

C9
C1

C8

C2

C6

1 2 3
C14

D2
C12

R2
C4

U2

C7

C10

D3
C11
C3

H2

C13

Document last modified and saved: 12 October 2011 6:07 PM


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