Simple Guide on How To Wire An Aguilar OBP-2 Preamp

Last week we had a video guide for installing copper shielding in your bass control cavity. Today we are back with a new video guide taking you step-by-step through the process of wiring an Aguilar OBP-2 Preamp.

If you’ve got any questions or are in need of assistance don’t hesitate to drop us an email at sales@bestbassgear.com or comment on the post or video.

The particular bass this preamp is going into is a P-bass, so it is a two knob configuration: a volume and a bass treble stack.

Tools You Will Need:


Step 1 – Stripping Wires



Before starting anything else you want to take your preamp and strip the insulation back from your wires. This will help you make a quality connection. You want to strip about half an inch of insulation from the red and black wires. Strip about an 1/8” of insulation from the rest of the wires.

Now braid together the three wires for the bass and then the three wires for the treble control. For this configuration on a P-Bass we are using a stacked bass and treble, so we twist all those together giving us a clean look for the installation.


Step 2 – Tinning the Contacts and Wires



Working with the pots and the jack can be difficult, so you may find it easier to first rig up a piece of cardboard to hold everything securely.

Next you need to tin all your contacts. This means all three on a standard pot, or in our example, all six on a stacked pot. Just touch your soldering iron to the lug for a few seconds to heat the contact. Then touch your solder wire to the lug. You do not want the iron to melt the solder, the hot lug itself should melt the solder.

Do this for all your contacts, and then for each individual wire. Just a small amount of solder on each will give you a much better connection when you go to wire it.

Step 3 – Wiring the Treble Control



Now you can start wiring the treble control first. All of our preamps at Best Bass Gear come with wiring instructions. Consulting them for our Aguilar OBP-2, we see the configuration for wiring the Treble control is, from left to right: white, yellow, purple/white.

Wiring those to the three lugs closest to you on a stacked bass and treble pot will make the very top knob control the treble.

Since all of our lugs and wires are already tinned, we do not need any more solder. Simply touch your iron to the lug for a moment, and then push the wire through the hot solder. Hold it there for a few seconds to let it cool.

A lot of people are afraid to do this because they think they are going to be destroying these components. But it’s very easy to solder two pots. You should really only be heating it up for a few seconds and, unlike finer circuit boards, they are very heat resistant.

Step 4 – Wiring the Bass Control



Next you are going to move to the three knobs farthest from you and wire the bass. This will make the bottom knob control the bass.

Once again consulting our directions, we see the bass colors go: brown, gray, and purple. Repeat the steps from above – heating the lug, pushing the correct wire through the hot solder, and hoding it until it cools – and you’ll have wired your stacked bass and treble pot.

Step 5 – Wiring the Volume Pot



Now move over to your volume pot.

The leftmost lug on the volume pot is for the ground. Measure out a black wire that is will reach from the pot to the jack and strip off about ¾” of insulation from the end. Tin the tip of the black wire. The three lugs on the volume pot should already be tinned from Step 2.

You want to solder that black wire to the leftmost lug.

The middle lug is going to connect to the hot lead from the pickup. Solder a black wire, again with the insulation stripped off the end and the tip tinned, to that middle lug. This will make the eventually installation easier. You will be able to solder the pickup lead to that wire instead of the soldering it directly to the middle lug.

The process will be slightly more complicated if you have 2 volumes, or a volume and a blend in a two pickup scenario, but all the soldering principles are the same.

Step 6 – Wiring the Jack



Now you can move on wiring the jack. Your 9-volt battery clip will have both a black and a red lead. You want to connect the red lead to the red wire coming from the preamp. Make sure you have a nice solid mechanical connection, and then solder that connection. Slide shrink tubing over the connection to protect it from shorting out.

Then you take the black lead coming from that battery clip and put a wider piece of heat shrink tubing on it. Take your soldering iron and go to the lug that is directly across from the shorter of the two prongs. Solder the black wire to the lug, and your battery is wired.

Now look at the middle lug on the jack. It should be the one that does not connect to either of the prongs. This is for the ground.

You’ll need a small piece of black wire – just a few inches – that has the insulation stripped at the end, and the tip tinned. Take the black wire coming from your volume pot, and the black wire coming from the preamp, and attach them to your short piece of black wire. This is for connecting to your bridge ground during installation. It makes sure your entire system will be connected to your bridge and to your strings, preventing any humming.

Solder all the grounds to that one lug. And then again use a piece of shrink tubing over that connection.

Now you have one more lug on the jack. This is for the green wire on the Aguilar OBP-2. One last time we put on a piece of shrink tubing on that wire and solder it to the lug.

Step 7 – Heat Shrink Tubing



Do a bench test to make sure everything is working properly. When you are satisfied with everything, go back and use a heat gun (or use your soldering iron) on each of the heat shrink tubes. This will cover all your connections nicely; making sure you won’t get any short circuiting.

Your preamp is now fully wired and ready to install in your bass.

Step 8 – Pre-Installation


The first step in installation is connecting the hot lead from your pickup to the wire coming from the volume pot. Then connect the ground wire from your pickup to the back of the volume pot.

Next connect the wire from your bridge to the wire going to your jack.

Now simply plug a 9-volt battery in to your clip and your installation is complete.

Please note! We have a video coming soon of how to actually  install the prewired preamp into your bass. If you are unsure about how to install it in your bass, please wait for the video and article to be released.

4 thoughts on “Simple Guide on How To Wire An Aguilar OBP-2 Preamp

  1. I’m in the process of fniixg my son’s beloved Black and Decker Weed Wacker. I found one broken wire last night and re-soldered it. This gave me juice to all of the dead points I had previously found, but the thing still isn’t working. After that I gave it up for the night, but will give it another go tonight. It’s worth the bit of work, because he really loves helping me around the yard!Funny coincidence here, this is my son Cole’s weed wacker, and his twin brother’s name is Carter!

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