Possible onboard preamp issue, help please!

[Anthbass]

I have the opportunity to pick up a Tobias Growler (ser# is6130) quite affordably. I am currently renting it to see if I actually want to make the purchase. Here is the issue: the bass (to my ears) sounds great, very clear and crisp, but the output is very low. I have heard that some Bart preamps are notoriously 'soft' in output. Could this be the case here? My other bass, a passive BTB, is far louder at the same amp settings. While volume is not everything, this bass is much quieter in output than either of my other 2 passive basses, which is surprising, as it is an 18 volt active system (I think?). If I flip on the active input switch on my amp, I can barely hear the bass at what should be normal practise volume. I checked the batteries but other than that I have no idea what to look for. Any thoughts or suggestions would be greatly appreciated.

[luknfur]

FWIW:

if it's an older bass the older preamps don't have the boost of current preamps. As long as you can up the amp to desireable output level, I would be a lot more concerned about the tone it puts out than volume. Normal enough for basses to vary considerably in output. An issue swapping onstage to a degree but nothing a volume pedal wouldn't address - or perhaps the flip of a switch. You may find the volumes fairly even with the Bart ran through amp passive and BTB through active. There's no law that says you have to use the active pad for an active bass or passive mode with a passive bass - it's just often necessary to prevent distortion. The Bart pre may also have a gain trim tab you can adjust, a lot of them do.

May also depend on how you have the basses adjusted. If you're heavy on the neck pup with one and weak on the other, you're probably going to get significant volume variation from that alone.

[Rano Bass]

Originally Posted by luknfur

FWIW:
The Bart pre may also have a gain trim tab you can adjust, a lot of them do.

May also depend on how you have the basses adjusted.

+1
Look for a small (often blue) gain trim and try adjusting it, and maybe raise the pickup to see if that helps.

[Anthbass]

Thanks to both ya'll. I did find the gain tab and have been playing with it. I also raised the pickup slightly and the results were both positive. This is a relief, as I am very taken with this bass. If nothing could have been done for the output short of a preamp swap, it would have to go back, due to my limited funds. As it sounds now, it is appearing to be a keeper.
Thanks again.