Aguilar OBP-1 Wiring Diagram: A Comprehensive Guide

The Aguilar OBP-1 preamp is a popular choice for bassists looking to enhance their tone. With its powerful EQ controls and versatile wiring options, the OBP-1 can help you dial in the perfect sound for any genre or playing style. In this article, we’ll take a closer look at the Aguilar OBP-1 wiring diagram and provide a step-by-step guide on how to install it in your bass guitar.

What is the Aguilar OBP-1?

The Aguilar OBP-1 is a preamp designed specifically for bass guitars. It features a 3-band EQ (bass, mid, and treble), as well as a preamp gain control. The OBP-1 is known for its transparent, natural sound and has been used by many professional bassists in a variety of musical settings.

Wiring Diagram

Before we begin, it’s important to understand the Aguilar OBP-1 wiring diagram. Here’s a visual representation of the OBP-1 wiring:

OBP-1 Wiring Diagram
Aguilar Obp-1 Wiring DiagramSource:

As you can see, the OBP-1 has four pots: a volume pot, a balance pot, and two EQ pots (bass and treble). The preamp gain control is located on the circuit board and is not accessible via the pots. The OBP-1 can be wired in a variety of ways, depending on your preferences and the type of bass you have. Here are a few common wiring options:

  • Passive mode: In this mode, the OBP-1 is bypassed and the bass functions as a passive instrument.
  • Active mode: In this mode, the OBP-1 is engaged and provides active EQ and gain controls.
  • Series mode: In this mode, the pickups are connected in series, which can provide a hotter, more compressed tone.
  • Parallel mode: In this mode, the pickups are connected in parallel, which can provide a brighter, more open tone.

Installation Guide

Now that you understand the Aguilar OBP-1 wiring diagram and the different wiring options, it’s time to install the preamp in your bass. Here’s a step-by-step guide:

Step 1: Remove the old electronics

The first step is to remove the old electronics from your bass. This typically involves removing the control plate or pickguard and desoldering the wires connecting the pickups, pots, and output jack. Make sure to take note of how everything was wired before you start removing anything.

Step 2: Install the OBP-1 circuit board

Next, you’ll need to install the OBP-1 circuit board. This involves drilling a hole for the preamp gain control (if your bass doesn’t already have one), and mounting the board somewhere inside the control cavity. The OBP-1 can be powered by either a 9-volt battery or an external power supply, so make sure to connect the power source before mounting the board.

Step 3: Wire the pickups

Once the circuit board is installed, you can start wiring the pickups. Depending on your wiring preferences, you may want to wire the pickups in series, parallel, or a combination of both. Follow the wiring diagram that best suits your needs.

Step 4: Wire the pots and output jack

After the pickups are wired, you can start wiring the pots and output jack. Follow the wiring diagram for your desired wiring option (passive, active, series, or parallel). Make sure to use high-quality wiring and solder everything securely.

Step 5: Test and adjust

Once everything is wired up, it’s time to test your new setup. Plug in your bass and make sure everything is functioning properly. Adjust the EQ controls and gain as needed to dial in your desired tone.


What is the difference between passive and active bass guitars?

A passive bass guitar relies solely on the pickups and tone controls to shape its sound, while an active bass guitar has a built-in preamp that provides additional EQ and gain controls. Active basses tend to have a hotter, more modern sound than passive basses.

Can I install an OBP-1 in any bass guitar?

As long as your bass has enough space in the control cavity to accommodate the OBP-1 circuit board and pots, you should be able to install it. However, some basses may require additional modifications to make the installation work.

What is series/parallel switching?

Series/parallel switching allows you to switch between having your pickups wired in series (for a hotter, more compressed tone) or in parallel (for a brighter, more open tone). Some basses come with this feature built in, while others may require additional wiring modifications to add it.

How do I choose the right wiring option for my bass?

Choosing the right wiring option depends on your personal preferences and the type of music you play. If you’re not sure, experiment with different wiring options to see what works best for your playing style.

How do I adjust the EQ on the OBP-1?

The OBP-1 has three EQ controls (bass, mid, and treble) that can be adjusted using the corresponding potentiometers. Experiment with different EQ settings to find the sound you’re looking for.

How long does the OBP-1 battery last?

The OBP-1 can be powered by a 9-volt battery, which typically lasts for several months of regular use. However, it’s a good idea to replace the battery periodically to avoid any unexpected power failures during a performance.

With these tips and tricks, you can easily install the Aguilar OBP-1 preamp in your bass guitar and start enjoying its powerful EQ controls and versatile wiring options. Remember to experiment with different wiring options and EQ settings to find the sound that works best for you. Happy playing!