ER-PROTO-01

Features

• Eurorack Prototyping card set
• 6 HP wide (30mm) front panel
• 3U tall
• Three card set
  • Board interconnect headers duplicated on headers
  • 30mm wide front panel
  • 28mm wide panel and daughtercards
• 6 POTS
  • Marked as RV1-RV5
  • Series resistors on pot wiper
  • All 3 pot pins brought to top header
• 4 Jacks
  • Marked as J1-J4
  • Tip/sleeve brought to header near middle/bottom
• Pots on top, jacks on bottom of card
  • Easier to adjust pots without bumping into pots
  • Pots more often accessed than jacks
• Large prototyping area
  • 58 nodes with 3 holes per node (29 per "side")
• +12V, -12V down board edges
• 5V/GND down center of card
• Bussed connections horizontally
• Front Panel with generic labels
  • Cover with White on Black P-Touch labels

Connectors

• J1-J4 are front panel connectors

Inter-card Connectors

Pots

• J5 on the Controls card and J5 on the I/O card
• Pot connections
  • POTx-1 is fully CW connects to wiper
  • POTx-2 is wiper
  • POTX-3 is fully CCW connects to wiper

• To make pot into voltage control
  • POTx-1 (CW) = +5V
  • POTx-13CCW = GND
  • Wire RV1-1 to RV3-1 to RV5-1 on controls card
  • Wire RV1-3 to RV3-3 to RV5-3 on controls card
  • Wire RV2-1 to RV4-1 to RV6-1 on controls card
  • Wire RV2-3 to RV4-3 to RV6-3 on controls card

Jacks

• J6 on the controls card and J37 on the I/O card

Daughtercard Connectors

J5, J37 - POT connectione

J6 - Eurorack Power

• J6 on the I/O card
  • Eurorack power
  • 2x5 IDC
  • GATE, CV not connected

J10 - Jacks connections on Controls card

J38 - Jacks connections

Examples

Arduino NANO MOZZI

NANO Pinout

Controls

• 6 Pots
  • RV1 = Analog 7
  • RV2 - Analog 4
  • RV3 - Analog 6
  • RV4 - Analog 3
  • RV5 - Analog 5
  • RV6 - Analog 2
• 2 CV Input Jacks
  • J1 = Analog 0
  • J2 = Analog 1
• 1 Output Jack
  • J4 = MOZZI HI DEF Audio

Audio Out Schematic

CV In Schematic

• ANA0 in example

Parts

• 3D view

• Top parts view

• Bottom parts view

• With NANO

• CAD placement

Wires

NET: ANA0, A1-19, (C7-1, D1-2, D3-1, R9-2)
NET: ANA1, A1-20, (C8-1, D2-2, D4-1, R10-2)
NET: ANA2, A1-21, J37-3
NET: ANA3, A1-22, J37-6
NET: ANA4, A1-23, J37-9
NET: ANA5, A1-24, J37-12
NET: ANA6, A1-25, J37-15
NET: ANA7, A1-26, J37-18
NET: J1-T, J38-1, (R7-1, R9-1)
NET: J2-T, J38-5, (R10-1, R8-1)
NET: J4-T, J38-7, (C10-1, R14-2)
NET: GND1, J37-7
NET: GND2, J38-6
NET: GND3, A1-4
NET: GND4, A1-29
NET: +5VD, A1-27, J37-11
NET: L5V, J37-14, J37-8
NET: LGND, J37-16, J37-4

Parts List

Find	Qty	Ref Des	Part Number
1	2	R7, R8	100K
2	2	R9, R10	10K
3	2	R11, R14	3.9K
4	2	R12, R13	1M
5	4	D1-D4	BAT41
6	8	C1-C8	0.1uF
7	1	C9	4.7nF
8	1	C10	10nF
9	1	J5	HEADER, 2X10
10	1	J6	HEADER, 2X8
11	1	J10	HEADER, 1x8
12	1	A1	Arduino_Nano_v3

Software

• PROTO01_POTS_CHECK.ino - Dump pots/input jacks to screen

CV4 - 4 Control Voltages

• Pot controlled CV generator
  • Useful for testing VCOs, etc
• (4) Buffered Outputs
• 4 Pots
  • RV1-RV4 used
  • RV5, RV6 not used
• 4 Jacks
  • RV1 controls J1, etc
• Output voltage Levels are assignable via jumpers
  • +5V/GND
  • +12V/-12V
  • +12V/GND

Opamp Choices

• 8 pin Opamps
  • MCP6002, 5V max
  • MCP6232, 5V max
  • LM358, 3-36V

3D PCB Layout

• Board soldermask is actually black, but shown in green for contrast

• Details

Schematic

Opamp buffers

• Voltage selection headers

Output jacks

• Jack grounds connected on Controls card (3 jumpers)
• Single ground connection on daughtercard (1 jumper)

Pots on Controls card

• Connections of CW and CCW
  • RV1 goes to RV2
  • RV3 goes to RV4

Slew Rate Controller

• Dintree D107-Slew
  • Schematic

The D107 is a very simple dual slew rate limiter. It can be used for portamento effects or to smooth out a stepped voltage from a sequencer, or for general audio or CV smoothing. Each channel contains a buffer with 100K input impedance suitable for pitch CVs. The slew pot affects the charging of a large capacitor connected to a second amplifier. The second amp provides buffering for output to isolate the output jack from the actual slewing function.

Specifications:

Dual slew rate limiter
Control range of 0-10s (approx.)
Power: +12V @ 5mA, -12V @ 5mA

Video