Newly installed active preamp too loud

[klt79]

Hi all! I recently completed my first attempt at bass modification. I installed a Belcat preamp, from eBay, on my SX jazz bass. It's a 2 band preamp with volume and blend control. All the controls work the way they're supposed to but the volume is way too loud, even if plugged into the "bright" input of my preamp. The EQ pots are 25k and the volume pot is B500k.

[klt79]

Will changing the pot value lower my volume?

[Greyfin10]

Do you have tiny trim pots on the preamp itself? A lot of these systems have a sort of "master" volume on the circuit board itself.

Edit: Looked at their website and... not particularly forthcoming with documentation

[dug dog]

As an example, this pic shows the trim pot in my Ibanez ATK. Yours may have something similar.

[parsons]

It may just be way too hot of a signal depending on your pickups. I put a Seymour Duncan MM pickup in my ATK and even with the trimpot pictured above turned all the way down, it was still clipping the input of every amp I own with the amps input gain turned low.

[darkstorm]

Is the signal causing your amp to clip? If not, just lower its voliume and be happy that your bass now puts out a signal that lets you play amp at louder volumes then you could before. When you want that extra. Some amps however do have a problem with high output basses. I avoid those myself. Lol.

Also make sure your not maxing tha bass and treble pots volume level. Those are generally kept within about 1/4 turn of flat. Plus or minus or at flat that is.

[klt79]

I'll check if there is a trim pot on the preamp - it has some sort of covering.

Thanks for all the responses.

[klt79]

just checkEd, it does not have a trim pot. Any suggestions?

[FunkMetalBass]

Originally Posted by klt79

just checkEd, it does not have a trim pot. Any suggestions?

You can install a trimpot in the bass to use as a second volume knob, except it will be a set-and-forget.

[klt79]

How do I do that?
Do I put it infront of the volume pot?

Thanks!

[wcriley]

Can't you just turn the volume pot down some?

[SGD Lutherie]

Originally Posted by klt79

All the controls work the way they're supposed to but the volume is way too loud, even if plugged into the "bright" input of my preamp. The EQ pots are 25k and the volume pot is B500k.

I'm not sure how plugging into the bright input would do anything but make it brighter.

What kind of amp is this? Does it have an active input? Can't you reduce the gain on your amp?

I used to use an active bass that put out a line level signal. I could plug it right into a power amp. I had no problems using it with any regular bass amp, with the exception of an Eden I tried, which clipped a little.

[dmusic148]

If its just too much to deal with comfortably, you could add a resistor to the output(at the Jack) or even add a trimpot there. It would change the tone a little, but maybe not in a bad way.

[dmusic148]

Originally Posted by klt79

How do I do that?
Do I put it infront of the volume pot?

Thanks!

No, put it between the preamp and output Jack. This way you can trim the finished signal just before it leaves your bass.

[klt79]

SGD: I sold the preamp... the "bright" input supposedly had a 8 dB pad, or something like that.

dmusic148: I will try installing the trim pot. What value should I use? There's 1k, 100k, & 1M available at the local radioshack.

[SGD Lutherie]

Originally Posted by klt79

dmusic148: I will try installing the trim pot. What value should I use? There's 1k, 100k, & 1M available at the local radioshack.

100k

[klt79]

how do i connect the trim pot between the preamp and TRS output jack? Do I use all three leads of the trim pot? or do i wire the 2nd and 3rd together like I would a normal volume pot?

Thanks!

[FunkMetalBass]

Originally Posted by klt79

do i wire the 2nd and 3rd together like I would a normal volume pot?

Thanks!

That's exactly what you want to do. After all, the trimpot is just a volume pot that you're putting in the bass.

[klt79]

Just want to verify this with you guys.before I do it.

I connect the ground to the 2nd & 3rd terminals of the trim pot to tip of output jack. I connect the hot signal from the preamp to 1st terminal then to sleeve. Leaving the ring connected to positive terminal of battery?

Not even sure if im using the correct terms here but im assuming whats connected to the tip is the ground...

Thanks for all the help!

[mrridgely]

can this preamp be run on 9 or 18v? Which voltage are you running?