Bart Preamp!!!!

[twest45]

I heard it on talkbass.com and i saw it on the preamp diagram that came with it but i didn't know what it was for.  I think others on this site have made the same up grade also.  But i put a Bart 5.2 Preamp in my ibanez about 4 mouths ago and i always wondered why my basses output wasn't "hot" at all.  Come to find out its a gain knob on the preamp and it comes from the factory on the lowest setting.  So i set it about 3/4 full and now my basses output is hot like MTD or something.  To adjust it you need just about the smallest flat head screw driver they sell.  I used one from an eye glass repair kit.  To make the output hotter just turn the screw clock wise.  The little knob is located on the blue box thingy on the preamp module.  Thoses of you that have Bart Preamps in your bass will know what im talking about.  Now i don't think the Mk1 Bart Preamps have this because there're not the real American Barts.  But i could be wrong.

[ddwilkins]

All I did was rewire my pickups from parallel to series, or the other way around, and my volume increased. I'll check on the little screw thingy. Although, I'm not having any volume issues.

[browntree]

I'm guessing this is a midrange select/sweep.  Quite a few brands of preamps have midrange selects.  Emg's have 2/3 pin dip switches.  Most Aguilar have the switching built into the knobs (Aguilars are sooo compact), and I know Bartalini has mid selects.  Fact is, your sound may have gotten more bold depending on where you swept the frequency by turning that knob.  That would be the best bet; from a design standpoint, I can't see why you would need a variable gain on an onboard preamp.  I can see the need for variable resisters for voltage trimming, but I'm guessing that's a frequency select. 

Browntree

And David spake to the chief of the Levites to appoint their brethren to be the singers with instruments of music, psalteries and harps and cymbals, sounding, by lifting up the voice with joy.  I Chronicles 15:16

[CallowHill]

That's actually a common feature on Bart preamps.  It's a gain knob so turning it clockwise will give you a substantial volume boost.  This comes in handy given the fact that the preamp can be adjusted to work well with several different types of pickups.  Some types (brands) of pickups will demand that the gain knob be adjusted lower to eliminate hiss and extra noise.  In situations where the preamp can be bypassed, many players like to adjust the gain trim pot so there's no audible difference in output when the preamp is defeated.
Wiring a pickup in series will create more output, but it also changes the eq curve of the pickup.  Parallel wiring tends to have more of a scooped mid sound while series wiring has a more present midrange. 
It's kind of a quick summary but I hope that helps.

[browntree]

Now that's interesting...

Browntree

And David spake to the chief of the Levites to appoint their brethren to be the singers with instruments of music, psalteries and harps and cymbals, sounding, by lifting up the voice with joy.  I Chronicles 15:16