Active Bass Preamp Problem

[funky8884]

Hi everyone ,

 

I am currently stuck - I changed my Barrel Jack for a " like for like " switchcraft brand and now have the dreaded battery drain.

I put a brand new battery in and within a week it was dead

I have since bought another jack as I thought it was the problem but I have the same issue as I am getting a voltage across the jack without a lead in place

I have a Bartollini NTMB+3 https://bartolini.net/wp-content/uploads/Docs/NTMB_Wiring.pdf

I have tested the jack on the bench with a lead and it opens and closes the circuit as it should

As soon as I solder the jack into the bass I have 9v between the + of the battery and the - of the jack without a lead inside the jack ?

The preamp sounds fine and works as it should 

I have  jack with contact cleaner but no luck

Does anyone have any experience with this or know the next item to test ?

thanks 

[Woodinblack]

I had a a problem with a bass I just recently rewired which had a barrel jack. When I bought it I looked and thought, oh right, it has 3 terminals, that is a good one. I think it was labeled as switchcraft. Anyway, turned out that the socket wasn't a stereo one, it just for some reason had two shield terminals, which was of no use.

In the end I got a stereo barrel connector which was good, but not as good looking. But it was for my wrongo, so not so much of an issue.

So when you say it is fine on the bench, you get the sheild and mid terminal open circuit until you put a plug in, but that doesn't work in the bass?

[funky8884]

17 hours ago, Woodinblack said:

I had a a problem with a bass I just recently rewired which had a barrel jack. When I bought it I looked and thought, oh right, it has 3 terminals, that is a good one. I think it was labeled as switchcraft. Anyway, turned out that the socket wasn't a stereo one, it just for some reason had two shield terminals, which was of no use.

In the end I got a stereo barrel connector which was good, but not as good looking. But it was for my wrongo, so not so much of an issue.

So when you say it is fine on the bench, you get the sheild and mid terminal open circuit until you put a plug in, but that doesn't work in the bass?

Hi Wood

Yes to the Barrel Jack Test,

I had a loose wire in the 9v snap connector and I have ordered a new one and inspected all the wires, so hopefully this will sort it

[Woodinblack]

55 minutes ago, funky8884 said:

Yes to the Barrel Jack Test,

I had a loose wire in the 9v snap connector and I have ordered a new one and inspected all the wires, so hopefully this will sort it

A loose wire in the 9v connector won't drain your battery though

[funky8884]

True, 

Replacing the dodgy connector with a rigid one and new wires will eliminate any chance of a closed circuit in the connector. It was a cheap connector and after inspecting the wiring it was the only thing that was suspect 

Not sure what else can cause a closed circuit

 

[John Cribbin]

Have a close look at the terminals when the socket is in situ.

Is there anything touching that could cause a short?

 

[funky8884]

I found the + wire to have an exposed core close to the battery cavity area,

I tested for continuity between the outside of the battery casing and + and - circuits but nothing 

The snap connector is on order so hopefully early next week I can plug in 

[Woodinblack]

Still won't cause a drain (but a good idea to replace it). Unless you haven't wired the switching part of the plug the right way, the drain has to be caused by the plug being on without a lead in it. If it works fine on the bench, then try it when it is in the body of the guitar, maybe the pressure of it being in causes it to short out by being squashed?