Help Wiring a L2500 with OBP3TK

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Help Wiring a L2500 with OBP3TK

Postby Fanatic » Mon Apr 16, 2018 12:30 pm

Hey guys, can you help me? I'm lost here.

Hi Guys, can you help me please?
I need to wire a G&L 2500.
It has 1 Vol 1 Bass 1 Treble and 3 switches.
Attached is wiring diagram.
https://www.bassesbyleo.com/paul/g&l_bb ... am_omg.jpg

I bought Aguilar OBP3 TK preamp with 3 pots and 1 switch. And two Aguilar humbuckers.
https://docs.google.com/gview?embedded=true&url=https%3A%2F%2Fwww.bestbassgear.com%2Fwiring-diagrams%2Fv-tbstack--msw.pdf
I don’t have stack pots, and I want to wire exactly as the original version. I found that wiring diagram for OBP3 3 knobs and 1 switch
Should I use the original 250k pots or the 50k included in OBP3
Can you help?
Thank you!
Fanatic
 
Posts: 2
Joined: Mon Apr 16, 2018 7:53 am

Re: Help Wiring a L2500 with OBP3TK

Postby Ken Baker » Mon Apr 16, 2018 1:56 pm

This thread moved to The Experimental Bass Association forum by the admin.

Fanatic wrote:Hey guys, can you help me? I'm lost here.

Hi Guys, can you help me please?
I need to wire a G&L 2500.
It has 1 Vol 1 Bass 1 Treble and 3 switches.
Attached is wiring diagram.
https://www.bassesbyleo.com/paul/g&l_bb ... am_omg.jpg

I bought Aguilar OBP3 TK preamp with 3 pots and 1 switch. And two Aguilar humbuckers.
https://docs.google.com/gview?embedded=true&url=https%3A%2F%2Fwww.bestbassgear.com%2Fwiring-diagrams%2Fv-tbstack--msw.pdf
I don’t have stack pots, and I want to wire exactly as the original version. I found that wiring diagram for OBP3 3 knobs and 1 switch
Should I use the original 250k pots or the 50k included in OBP3
Can you help?
Thank you!


This is not a mod for the faint of heart.

The OBP3, in all its iterations, is a 3-band active preamp. This means that it will have fully active EQ with cut/boost on bass, mid, and treble. This is in addition to an upstream passive volume control. If you want to use this preamp in a G&L L series and have its full capabilities available, you'll need to be prepared to give up your current bass & treble controls. You'll also need to have a couple of EQ pots stacked or drill some holes. The OBP3 requires the 50K linear pots that it is supplied with, NOT the 250K treble or 1M bass pots that are in the bass. The only pot that would be retained is the 250K volume control.

I have done this mod (with a mod within the mod) to my L-2500. It provides me with fully active Aguilar EQ when in active mode, passive mode with volume only and the preamp isolated, parallel/SC (outers)/series, and standard pickup select.

This is the circuit used, showing the feed to the OBP3 (blue and green leads, lower-right). The Aguilar circuit you show should work, though you may need to hardwire the mid select (I used 300Hz). The cavity will be VERY crowded, so using two batteries for 18V will be tough. I run mine on 9V. The difference between 9 and 18 volts is headroom, but 9V works quite well. Be sure to carefully read the description on the drawing.

Click the image for a PDF version.

Image

Here's what it looks like.

Image

If you don't want single coil you'll need to modify the original circuit. Not particularly difficult, but that's where you are. I don't have a circuit here for that. BTW - that L-2000 circuit you linked is for an older bass, probably early 90s or earlier and is unlikely to be what you have in your bass. If you do have an older bass AND it has a control plate rather than a cavity in the back, this mod may not be doable due to lack of space under the control plate.

Have fun!

Ken...
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Re: Help Wiring a L2500 with OBP3TK

Postby Fanatic » Tue Apr 17, 2018 7:05 am

Ken,
Thanks for your help.

I will do 9v, and I will add a stack post.
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Posts: 2
Joined: Mon Apr 16, 2018 7:53 am


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