Aguilar OBP-3/Lakland 55-02 too quiet

[Texan]

I swapped the Lakland LH3 preamp in my 55-02 for an Aguilar OBP-3 from another bass and the result is VERY quiet. I’ve installed many Aguilar preamps so this is a very familiar operation. I’ve checked all of the solder points and schematic and it’s correct, but it’s considerably quieter than the LH3 and my other basses with Aguilar preamps, I’ve tried 250k and 500k pots in the volume with no difference. Tried volume/volume and volume/blend, no difference. There is no noise when I tap the pots, pre amp various points, it’s just not as loud. Otherwise the pre works exactly as it should, just the output is not there. The pickups are the Lakland/Hansen pickups, not Bartolini. I took the pre out and put it in a bass with DiMarzio P/J pups and the volume is as you’d expect.

Any ideas?

 

[Dr. Turkey]

Just curious have you tried running the pickups without a preamp at all? Have you tried installing both pres in another instrument (as in the same exact ones and not just the same model) and noticed no difference in output? And have you tried a different battery (I imagine you have, just covering all the bases)

 

[Texan]

Just curious have you tried running the pickups without a preamp at all? Have you tried installing both pres in another instrument (as in the same exact ones and not just the same model) and noticed no difference in output? And have you tried a different battery (I imagine you have, just covering all the bases)

I've checked the DCR on the pups, I reinstalled the LH3 and no issues. I put the OBP-3 in another bass and the volume is back. I've swapped batteries, checked continuity. I'm going to try re-installing the OBP-3 back in the Lakland again tonight. Fingers crossed.

 

[Texan]

Reinstalled the obp-3 in the 55-02 and no difference. Still has the volume of a passive bass, have to boost the controls to about 75% to get the normal volume this preamp puts out in other basses. I’m guessing it has to be something with the stock Lakland pickups. I’ve had this OBP-3 hooked up to EMG MM/J configuration, jazzz bass with Dimarzios, and PJ with Dimarzios all with no issue.

 

[Aloe]

well, first there's no thing as 'active bass should be louder than a passive one'. there're some very hot passive basses, as well as pretty tame active.

second, if that's a two pickup bass and you're trying both, they could be out of phase, so double-check this just in case.

third, a pre without a trim pot is a wrong tool for setting even levels of output on all your basses. different pickups have different output level and the pre could have a unity gain, i.e. not make it louder at all. so, if you need to match the output, you either need to boost this bass' output (maybe, a 3-band Nordstrand? it's rather close to OBP-3, but with a trim pot for boosting up to +15dB of additional gain, if I read the specs right) or to trim the rest (to install a trim pot that cuts the volume after the pre is not complicated).