1590B · 2 knobs

E.P.3.0

Based on the Maestro Echoplex EP-3 Preamp· 6 other boards clone it

From the vendor

The E.P.3.0 is our take on the Echoplex EP-3 Pre-Amp.

Designed to emulate the bypass mode of the EP-3, it’s a nice easy build for a cool pre-amp, small parts count but def a keeper.

Controls:

• Volume – This ones a little weird, it maxes at around 2 o’clock with tonal changes after this – it’s not broken..its how it is…and it just works!

• Fat (On/Off/On) goes from early EP3 models to new and also a third position for thicker.

The schematic is in the vendor's build document, page 1. Open the build document. No KiCad fragment has been drawn for this circuit yet.

Ref	Value	Normalized	Type
Resistors 10
R1	100K	100k	0.25 Watt Resistor
R8	100K	100k	0.25 Watt Resistor
R9	100K	100k	0.25 Watt Resistor
R2	1M	1M	0.25 Watt Resistor
R4	1M	1M	0.25 Watt Resistor
R5	1M	1M	0.25 Watt Resistor
R3	3K3	3.3k	0.25 Watt Resistor
R6	20K	20k	0.25 Watt Resistor
R7	220K	220k	0.25 Watt Resistor
R10	1K	1k	0.25 Watt Resistor
Capacitors 5
C3	22nF	22n	Cap-Box
C5	22nF	22n	Cap-Box
C2	220pF	220p	Cap-Ceramic
C4	100nF	100n	Cap-Box
C7	10nF	10n	Cap-Box
Diodes 6
D1	1N5817	1N5817	Standard Diode
D2	1N5817	1N5817	Standard Diode
D3	1N5817	1N5817	Standard Diode
D4	1N5817	1N5817	Standard Diode
D5	1N5817	1N5817	Standard Diode
D6	1N4748A	1N4748A / 22V	Standard Diode
Transistors 1
Q1	2N5457	2N5457	Transistor-TO-92 Inline Wide
ICs 1
U1	7660SEPA / 7660 / MAX1044 - Use jumper if 7660 or MAX1044	7660S / 7660 / TC1044	IC-DIP-8
Potentiometers 2
BIAS1	50K	50k	Trim-Pot-6mm
LEVEL	A500K	A500k	Potentiometer Alpha just holes
Switches 1
ON/OFF/ON	SW_SPDT	SW_SPDT	SPDT-Switch-Holes
Other 3
CP1	A	A	TestPoint-Oval
CP2	B	B	TestPoint-Oval
TP1	Board-Connector-4-board-connector	BOARD-CONNECTOR-4-BOARD-CONNECTOR	TH-SolderPad-Medium-4