Single OP Kit

Product status: Planned

This is an add-on for the Otto 8 Passive. It is a DIY-KIT.

With this KIT you can create one of the following:

  • AND with 7 inputs
  • Dual 3 channel mixer
  • Dual AND with 3 inputs
  • Dual OR with 3 inputs
  • OR + AND
  • OR with 7 inputs
  • Quad Inverter
  • Decisions

    First you need to decide what you want to build. The links above contain more details and building instructions for each project.

    You also need to decide if you want protection resistors on the op amp outputs. The TL074 have short circuit protection built-in, BUT it will be very hot when this happens. It is protected against shorts to ground or to the rails. You should not leave it in a shorted state because it will probably break after some time. Shorting to ground or rails is a wrong connection from the beginning, so you should avoid this at all times. In the building instructions you will see “1k or wire”. This is the places where you choose if you want a 1k protection resistor or just a wire for no extra protection.


    This kit is based on four op amps that are coupled like inverting amplifiers.

    All input and output resistors can be connected to one of four “buses” on one side. This makes it possible to build a number of different projects with the same kit.

    In the different project instructions you will see if the component should be connected to bus A, B, C or D. Or if it should be omitted. See the links above.

    R1 – R8 are Connected to the jacks.

    R9 – R12 are connected to GND.

    AO, BO, CO, DO are the outputs from the op amps. There are some extra solderpads where you can connect to these.

    R8 is always connected to DO (output from op-amp D).

    At the bottom of the pcb you will find the power connector, protection diodes and power supply capacitors.

    General tips

    • In some places you will need wires. First try to use the cut legs from already soldered components. Then use legs from unused components in the kit, but don’t cut them so that your component can’t be soldered later…
    • It’s usually best to start with the lowest components and finish with the biggest ones.
    • Don’t rush things. Finalize each soldering and make sure you don’t create any shorts or bad connections.
    • Always test what you have built before you connect it to other stuff.
    • See here how to create the power cable.

    KIT Contents

    • 4 Resistor 1k
    • 14 Resistor 100k
    • 2 Ceramic capacitor 100nF
    • 4 Ceramic capacitor 22pF
    • 2 Electrolytic capacitor 47uF 16V
    • 2 Diode 1N5819 (black)
    • 7 Diode 1N4148 (orange)
    • 1 Quad Operational amplifier TL074
    • 1 Female header 1×15 position
    • 1 Power connector 2×5 pin
    • 1 IDC female connector 2×5 pin
    • 1 IDC female connector 2×8 pin
    • 1 Ribbon cable 10 position, 25cm
    • 1 PCB
    • 1 Sticker sheet
    • Plastic zip bag


    290 SEK

    Technical specifications


    Width: 0 HP
    Depth: 28 mm

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