Bartolini preamp stopped working

[funkymonk13]

I recently got this bass, have had it for a bit over a month. It has a bartolini 3band eq, with two 9v batteries. I changed the batteries when I got it and everything was working fine. I started to get a bit of hiss and then it suddenly crapped out on me unexpectedly yesterday.

the bass has sound but there’s a hiss.
the volume is really scratchy and basically kicks in at 6-7. The pickup blend sorta works I think. Then the active electronics are doing nothing.

Any clues as what could be the problem? I changed the batteries again just to make sure it wasn’t that. All the solder joints look alright to me but there’s a lot more wires than I’m used to so can’t tell what it is.
Any insights would be greatly appreciated!

 

[Razman]

Can you identify the preamps in there? Should be some stickers on them indicating what they are. Also, what bass make/model do you have?

Bartolini is also very helpful - I'd suggest reaching out to them once you have all this info and they can provide any additional troubleshooting steps. My guess is this: replace the pots first, and if there are still problems, refer to them for next steps (replacing the preamp if one of those units are bad).

FWIW, Guitar Fuel "Tone Monster" preamps on ebay are a great, less expensive option!

Raz

 

[funkymonk13]

Can you identify the preamps in there? Should be some stickers on them indicating what they are. Also, what bass make/model do you have?

Bartolini is also very helpful - I'd suggest reaching out to them once you have all this info and they can provide any additional troubleshooting steps. My guess is this: replace the pots first, and if there are still problems, refer to them for next steps (replacing the preamp if one of those units are bad).

FWIW, Guitar Fuel "Tone Monster" preamps on ebay are a great, less expensive option!

Raz

hey! Thanks for the reply. I can make out on the label bartolini nstmb-18. Although I can’t find any info on that model.

the bass is a modulus quantum 6 from 1996. It’s a bit crazy cus 3 days ago everything was working great

Damn. I was hoping it would be a simple fix. Don’t wanna have to redo the wiring on these myself. Do preamps go bad?

 

[Razman]

hey! Thanks for the reply. I can make out on the label bartolini nstmb-18. Although I can’t find any info on that model.

the bass is a modulus quantum 6 from 1996. It’s a bit crazy cus 3 days ago everything was working great

Damn. I was hoping it would be a simple fix. Don’t wanna have to redo the wiring on these myself. Do preamps go bad?

The NTMB series has been around for a long time - great systems. I had two basses with preamps that went bad and they were both cheap - a Douglas and a Wolf. I replaced them with Tone Monsters and have been fine since.

I'd start with blasting the pots with DeOxit and see what happens. If they are still dead, check the wiring for continuity (power). Maybe the jack is to blame. Hard to believe a Bart system just up and died but you never know. It has some age but that has never deterred me from buying an older, active bass.

What is your control layout? Looks like vol/blend/mid/bass & treble stacked. I don't see a switch for midrange freq's.

 

[funkymonk13]

Thanks so much, I’m gonna try the contact cleaner.

Yea you got the control layout right, no midswitch. I was a little confused that there’s two little preamp boxes in there.
It’s a little daunting cus it’s a lot more wires in there than I’m used to. Was trying to pinpoint what it could be. There’s sound at least, so was thinking it was maybe one bad contact

 

[--Vissinger --]

These aren't rechargeable batteries are they?

 

[JuanB]

Make sure the bare grounding wire isn’t touching anything it shouldn’t be. I’m assuming the bubble wrap is your battery case and it’s placed in the cavity? Could push things around where you don’t want it. Also, check to make sure the jack contacts aren’t touching anything including the degraded shielding in the cavity. Do this before blasting pots. And only use a very small amount of Deoxit if it comes to that.

 

[JuanB]

What is going on here?

 

[ShadowGroover]

That's an old NTMB 2-module unit. Do yourself a favor and by Bartolini's newer 1 module unit. It's available in a simple prewired drop-in configuration. Then you'll be good to go for another 27 years.

 

[LoveThatBass]

I do know that preamps will hiss when battery voltage is low. A dirty or oxidized jack could lower the voltage through sufficient oxidation. Get some Deoxit5 off Amazon or other sources. Spray the Jack’s contacts and insert and remove a 1/4” plug several times to help wipe the contacts clean. Also it will be helpful to spray the inside of the pots through the slits in the body of the pot where the wire lugs enter and then rotate the pot fully both directions several times. A Voltmeter/Ohmeter would be helpful but cleaning with Deoxit might help you. If the Jack is determined to be the culprit then I would personally change or have it changed whenever possible.

Having said this, what the post above stated about getting the new “Single” Module which encompassed both circuits in one body along with the wired pots is true if one can afford it. I just put one in my 5 string bass and absolutely love it! The first one I installed years ago I just bought the module and sourced the pots etc and wired myself then I changed a year ago to and Audere 4 band preamp and stupidly threw the old stuff away and after 6 months was not happy but older now and didn’t want to do all the work associated with wiring switches and pots so I bought complete unit. I am very happy with the tone now.

 

[funkymonk13]

Thanks for the replies guys. Gonna get a few of the suggestions and see what happens. The preamps aren’t as expensive as I thought, it’s more the wiring is a pain for me to do myself. Not the best at soldering and there’s a lot going on

These aren't rechargeable batteries are they?

They are not

Make sure the bare grounding wire isn’t touching anything it shouldn’t be. I’m assuming the bubble wrap is your battery case and it’s placed in the cavity? Could push things around where you don’t want it. Also, check to make sure the jack contacts aren’t touching anything including the degraded shielding in the cavity. Do this before blasting pots. And only use a very small amount of Deoxit if it comes to that.

I’ll check out the grounding wire. Yea the bubble wrap was to at least keep the batteries tight and from moving

View attachment 5080048
What is going on here?

Not too sure, I think some grounding wires. Gotta open it again

That's an old NTMB 2-module unit. Do yourself a favor and by Bartolini's newer 1 module unit. It's available in a simple prewired drop-in configuration. Then you'll be good to go for another 27 years.

Might have to go that route

I do know that preamps will hiss when battery voltage is low. A dirty or oxidized jack could lower the voltage through sufficient oxidation. Get some Deoxit5 off Amazon or other sources. Spray the Jack’s contacts and insert and remove a 1/4” plug several times to help wipe the contacts clean. Also it will be helpful to spray the inside of the pots through the slits in the body of the pot where the wire lugs enter and then rotate the pot fully both directions several times. A Voltmeter/Ohmeter would be helpful but cleaning with Deoxit might help you. If the Jack is determined to be the culprit then I would personally change or have it changed whenever possible.

Having said this, what the post above stated about getting the new “Single” Module which encompassed both circuits in one body along with the wired pots is true if one can afford it. I just put one in my 5 string bass and absolutely love it! The first one I installed years ago I just bought the module and sourced the pots etc and wired myself then I changed a year ago to and Audere 4 band preamp and stupidly threw the old stuff away and after 6 months was not happy but older now and didn’t want to do all the work associated with wiring switches and pots so I bought complete unit. I am very happy with the tone now.

Right on. I’ll check the jack before cleaning

 

[Thegreatzambini]

I recently got this bass, have had it for a bit over a month. It has a bartolini 3band eq, with two 9v batteries. I changed the batteries when I got it and everything was working fine. I started to get a bit of hiss and then it suddenly crapped out on me unexpectedly yesterday.

the bass has sound but there’s a hiss.
the volume is really scratchy and basically kicks in at 6-7. The pickup blend sorta works I think. Then the active electronics are doing nothing.

Any clues as what could be the problem? I changed the batteries again just to make sure it wasn’t that. All the solder joints look alright to me but there’s a lot more wires than I’m used to so can’t tell what it is.
Any insights would be greatly appreciated!View attachment 5079761

Unfortunately, I can’t diagnose what exactly went wrong, but I can tell you that is one of the older Bartolini pres as it’s got the two modules… and it’s a used pre so Lord knows what the previous guy did

 

[ahc]

If you do spray your pots use VERY LITTLE Deoxit D5. Too much will eat the pots.

 

[rojo412]

So I won't sugarcoat my disdain for Bart preamps to anyone. Personally, I can't stand them for their sound.
But that said, one thing I've never found an issue with them on was reliability. They make a solid product. And like any encapsulated preamp like that, if you're having issues with it working, it's mostly due to battery clips, potentiometers, jacks, switches, or wires going to any of those.
The preamp unit itself should be fully functional, it just may require being redone from scratch for absolute best results.

All that said, I wholeheartedly recommend putting in a Nordy 3B preamp and being much happier with the sound and function.

 

[Thegreatzambini]

So I won't sugarcoat my disdain for Bart preamps to anyone. Personally, I can't stand them for their sound.
But that said, one thing I've never found an issue with them on was reliability. They make a solid product. And like any encapsulated preamp like that, if you're having issues with it working, it's mostly due to battery clips, potentiometers, jacks, switches, or wires going to any of those.
The preamp unit itself should be fully functional, it just may require being redone from scratch for absolute best results.

All that said, I wholeheartedly recommend putting in a Nordy 3B preamp and being much happier with the sound and function.

Your opinion is noted however, you may want to contact some high-end bass manufacturers, and let them know they are tone deaf and the Bart preamps they put in their basses sound bad. It seems to be a trend as of late on this forum of giving backhanded compliments after a negative remark, which is exactly what you did in this case.

 

[JMarkD]

I had a similar experience with my 2000 Q-5 Modulus. I don't know if it had the exact same preamp module that you have but it turned out that a certain design from that era seemed to have a service life of about twenty years. It had an unusual circuit that had a switch that went bad eventually. Bartolini discontinued it but was willing to custom build a replacement. I opted for a new circuit which is what current Modulus basses are using. Not saying that has happened here, but your experience sounds similar and the time frame is about right. As others have noted, the newer modules are smaller and you can get them in a prewired harness, I believe.

 

[mustBmtd]

There is a new preamp replacement for that model. Which the preamp you now have in the bass was used back when they called it the Burbank Era design by Mike Tobias what he used in some of the original Tobias Signature basses. The replacement is now called the Bartolini HR-TCT 5.4AP.

 

[kgbeast]

Preamps like this usually have nothing in them but one dual channel opamp, probably mc33178 which can go dead if you put batteries wrong way around. But it simply will have a very low output if any output at all. Well there are couple of electrolytic caps that can dry out but that usually takes half a century. I would think that the pots went bad. If you physically interacted with pots, like tightening the nut or something like that, it can definitely compromise the contact between the solder lug and the resistor element. This can easily produce scratchy sound and strange reaction to adjustments.

 

[iplay5strings]

So that is an NS-TMB, which is

View attachment 5080048
What is going on here?

The NSTMB circuit differs from the NTMB stuff in that it uses a +9-9 switching power supply. There should be a pair of wires coming out of the main module that do not attach to anything and have shrink wrap over them. Those are not supposed to see ground or touch each other. It is possible that the switching power supply failed as the NS stuff was (unfortunately) notorious for reliability issues. Here's a diagram of a later (but similar) NS3TMB setup.

The color coding may be different, but the wire paths should be the same for you to double your setup.

 

[funkymonk13]

Hey guys, thanks again for all the input.

Took your suggestions, started with looking at replacing the jack which didnt solve the issue. Hit up costumer service at bartolini and they got back to me right away. Suggested a few things but they did say that it was possible that the preamp failed. I was probably gonna sell the bass, so def wanted a solid solution. Wound up finding a prewired NTMB preamp for $180 all in so just went with that. I hate soldering and even then It was pretty easy to install. The bass is sounding great. Thanks again everyone!