Double Bass electronics problem... no sound??

[Bassforyourface]

hey everyone, i posted this in the palatino megathread originally but realized i might be able to get some help from some none-palatino players too...

i bought the bass new a couple years ago and it worked great, then maybe a year ago this problem occurred so i haven't been playing it, but it's really about time i got it working again.

so anyways here's what's happening...
if i plug headphones into the headphone jack i can hear the bass through the headphones as always.

BUT when i plug into an amp there is NO SOUND from ANY of the strings (i've checked the volumes, amps, cables etc).

what's even weirder to me is that if i tap on the piezo with the bass plugged into an amp, it makes a thumping sound like i would expect; there's just NO sound from the strings.

i was under the impression that a piezo uses a crystal to take the vibration from the strings through the bridge and amplify it (correct me if i'm wrong). so if it amplifies the tap of my finger, why not the vibration of the strings???

ANY help would be greatly appreciated.

thanks,
Luke

 

[Francois Blais]

Where's the piezo?

If you tap on the bridge, do you get tones out of the amp?

 

[Bassforyourface]

the piezo is in a rectangular bar type thing under the bridge, and no when i tap on the bridge it doesn't come through the amp. i'm almost begining to think the piezo broke in the spots that sit under the feet of the bridge and it's only the middle that is uncovered that still works. is that possible?

 

[Bassforyourface]

but in that case ('the sides of the piezo are broken and the middle isn't') the headphone jack shouldn't be producing normal sounds and what not.

i really am going crazy not because it's broken but because all this just seems impossible.

the headphones working show that the piezo works.
the tapping through the amp shows that the piezo works. and the jack works.

is it possible that the jack or some wiring in between would allow thumps through but not notes????

 

[bassbob]

The pickup wires come out of the middle and go into the cavity inside the body. The weak spot in the pickup is the middle where the wires come out. It may be that tapping on the pickup corrects a short in the wiring. Tapping on the bridge may not have enough force to correct the short if that is the problem. The bridge should transmit the string vibrations to the pickup and give you the sound through the amp.

The quality control or lack thereof is a problem with the Palatino as many folks in this thread know by now. I'd check the wiring going the volume and tone pots. ( Go back to some of my old posts and you'll see a picture schematic of the wiring diagram and my vain attempt to make it work. )

If I was you I'd rip out the junk electronics in the cavity and start over with a rev solo or K and K pickup paired with a good preamp. Good luck.

 

[Bassforyourface]

thanks bassbob! i'll mess around some and let you know how it comes out.