Used Bongo: Preamp Question

[Addni]

I recently bought myself a Bongo 5 (H/S), went around the local music stores and tried every interesting bass I could find, walked out with a Bongo 5 (used)

Loving the way it feels and sound, but something has been getting on my nervers. I am noticing a hint of overdriven sound from my amp (that I never noticed before) It's not much but more than acceptable to me.

I put fresh batteries (Duracell Procell) when I got it so it shouldn't be that. I first tought it was my cabinet saying "no more" (Ampeg PF210) but today I borrowed a new one (Ampeg STV410HE) and the problem persisted. I then thought it was my amp and tried another in the same rehersal space.

I've tried cutting the low end off, both on my bass and amp to avoid the distortion. My amp is far from clipping and I notice this even at lower volumes. Turning down the output volume of the bass helps a bit, but does not get rid of the problem. I tried 2 amps, 3 cabs and headphones at various levels and EQ's, but always noticing the problem. I noticed if I turned up the Mid-EQ I got a lot of distortion if I went fully upp (both amps, and I was not running them hot or peaking the input)

Is there a possibility that something in the preamp is somehow overloading or it has a bad component? I opened up the back of the electronics compartment I noticed two adjustable resistors (like these

) and started thinking if previous owner might have tampered with them?

In a previous attempt to fix the problem I lowered both pickups a bit.

I'm going back to the rehearsal space tonight with fresh batteries and my other bass to do more extensive tests.(will also bring my computer for DI into my audio interface to completely rule out amps) Will report if I come to any conclusion

 

[bovinehost]

Something is not right there, I think.

Everyone else, hold your thoughts, let me do some talking to someone who will know and I'll answer ASAP.

 

[jlepre]

EBMM Customer Service is you first call.

 

[Oldtoe]

I know Jack is furiously investigating the problem, but take a small screwdriver and gently pull the flat contactors at the bottom of both battery compartments up slightly to ensure that they are making good contact with the batteries. Over time, the batteries can gradually flatten those out to where they sometimes aren't making solid contact.

You could also try some incense, should you feel so inclined. Wards off the electronics goblins.

 

[bovinehost]

Dudley G (who designed the Bongo electronics) says that those trim pots are not factory equipment. This is very much what I thought, since I've never seen anything like that before (I have some Bongos).

So what you have there is a modified Bongo. There's no way to tell from looking at it what has been done. I might try returning that bad boy if it was sold to you as a stock instrument. Because it ain't.

Jack

 

[Addni]

Interesting, maybe I'm not remembering correctly about those trim pots. Will open it up tomorrow and post pictures.

 

[Oldtoe]

Dudley G (who designed the Bongo electronics) says that those trim pots are not factory equipment. This is very much what I thought, since I've never seen anything like that before (I have some Bongos).

So what you have there is a modified Bongo. There's no way to tell from looking at it what has been done. I might try returning that bad boy if it was sold to you as a stock instrument. Because it ain't.

Jack

Or, you know...that.

 

[Golem]

`

You CAN tell something from the pix. See the printing on
the circuit board ? By design, that spot was for a 5K ohm
resistor ... which somebody removed and replaced, with
a trim pot. For starters, I'd put meter across the pot and
check on whether its range even offers 5K.

Trim pots have a much narrower adjustment range than
regular user control pots. Frinstintz, if that pot only runs
from 1.5K to 3K, how you gonna dial it even close to 5K ?

Znot awlass mysterioes as it first might seem Darge
can prolly reconnize the function of that resistor by it's
location and the printing on the board. Value is known,
as is its name: "R47".