LIII Music Man Bridge Pickup Issue

[Phrankenstrat]

I've having an issue with my LIII bridge pickup. It has the new Music Man pickups. It sounds great. The problem is, about 45 minutes to an hour into the first set, the pickup drops volume. I mean it is super quiet. Pos 2 and 3 then sound identical (like the middle pickup). The pickup never cuts out, it just loses 75-80% of its volume. But at a gig, that's unusable. Twice I have sent it back to Music Man. They cannot see an issue. I sent sound samples of the phenomenon but they can't reproduce it. The last time they said they replaced the battery housing as there was some sort of intermittent short with it. I got it back about 3 weeks ago thinking this time it was fixed. Same exact thing.

I can't imagine there is anything wrong with the pickup itself. If the guitar "rests' for a couple of hours, the volume of the bridge pickup returns to normal. Again, only for about 45 minutes to an hour. Then we start all over. It's almost like a car that overheats. You let it "cool " down and it will run again but then overheats. I just don't get it. In 40 years of playing guitar, I've never experienced anything like this. I have an earlier LIII with the Transition pickups but it is fine (I did have to replace the battery compartment). I've had guitars with active electronics and they never showed these symptoms.

Has this happened to anyone else? Any suggestions? This is one of the best sounding guitars I've ever had and probably the best feeling. But this volume drop issue is killing me. Open to suggestions.

 

[racerx]

That’s really bizarre and sorry it’s happening even after sending it back a few times. Have you tried neutral equipment for an extended period of time? Strictly for troubleshooting purposes - maybe there’s some flakey edge case issue with your particular setup and that guitar. Wouldn’t even know where to begin but I’d start there and start isolating as many variables as possible.

 

[DrKev]

Having worked as a guitar tech in customer service for a large music store, I can tell you that intermittent issues are the ones that drive everybody crazy. If an issue can't be reliably reproduced they are all but impossible to diagnose and fix, other than guessing at some minor preventative measures which may not always be possible. The instrument will of course be returned with a note that says "we can't find anything wrong" because it's the truth. And we simply cannot spend hours with a single instrument waiting for a fault to appear, or not. So this is the kind of thing that you must be able to give step-by-step instructions to reproduce. But if we know it happens after, say, 45 minutes every time, we'll plug it in and do other things while we wait.

Also remember that many times customers get irate insisting that they have problem X which customer service can't find, later turns out to be problem Y. It happens a lot more often that intermittent issues that really are what the customer says.

You have to spend time with the guitar and a single cable right into the amp. In fact, take the amp out of the equation, just go straight into an audio interface or mini amp or multi effects unit, something you were NOT using on stage. Eliminate all other possibilities from the signal chain and start there. You have to reproduce the issues many times and take notes. How long you play for before the issue occurs. What is the max and minimum time to reproducing the problem? If you unplug from the instrument and re-plug what happens? Try it with different brand cables. Can you reproduce it leaving it plugged in but not playing it (e.g. leaving it on a stand). When it happens, does it spontaneously resolve? Can you make it go away and what do you do to make it do so? Every time somebody was able to give me hints like this, I could reproduce it and a solution would be clear.

 

[Phrankenstrat]

It happens with every interface I have. Plugged directly in an amp, into my Focusrite, using any cable, using wireless. The ONLY thing I haven't tried is just leaving it plugged in on a stand. I can certainly give that a try. Once the volume drops, there is nothing that I can do that makes it come back. Only time. If I leave it sit for a few hours, it will work as it is designed to.

I will typically learn new songs just plugged into a Laney battery powered Lionheart. I can play it roughly an hour. I've been doing my own guitar work for the last 25 or 30 years. Have never seen or heard anything like this. The only unfamiliar portion is of course the preamp which admittedly, I know nothing about.

As I stated earlier, it's like something gets overheated and crosses its threshold of functionality. Once it has time to "cool down" ( I have no other way to word this) it returns to normal until such time as it "heats up" again. I love the preamp with the silent circuit and I love the boost, which incidentally I thought was just a gimmick when I bought my first LIII.

I totally get the EBMM technician's point of view. If you can't replicate a problem, you can't fix it, just like a car mechanic. I was hoping someone would have experienced the same type of issue. At this point, it seems the best course of action would be to pull everything and put passive pickups in the guitar.

PS. - I forgot to say, at one point EBMM sent me a new bridge pickup to install. It exhibited the same behavior.

 

[DrKev]

I would agree with your heating up theory, except there is nothing heating up. Something in a tube amp, sure, that would be a 100% good call, often a cracked solder joint that once it warms up it expands and whatever it's connecting to craps out. But in a guitar there is no heating. Your body heats it more than the generated current will and that's not enough to do anything to anything.

I'm sorry I can't be of more help.

 

[jayjayjay]

I would agree with your heating up theory, except there is nothing heating up.

Putting on my technician's hat (I studied computer science and electrical engineering in school), I have to disagree. Even low voltage electronics can heat up if asked to dissipate too much current. I have personally fried transistors - as in, it let out the magic smoke - using a 9 volt battery by miswiring. If a component is faulty - say a current-limiting resistor or capacitor is shorted - that could absolutely cause other components to overheat.

Based on what the OP said, I'd lay money there's a faulty component somewhere in the preamp, and when it's on, it's slowly heating up (or causing something to slowly heat) until it causes the failure. The fact that it happens after an hour or so points to something heating up over time as it's used.

I'd also lay money that just swapping out the preamp module would fix the problem.

 

[Phrankenstrat]

@DrKev, normally I would agree with you 100%. However, once a battery gets in the mix there is power involved. And once power is involved, there is chance if something is faulty, it can heat up. While the pickups themselves are passive, the preamp is not. I'm just shooting in the dark here looking for any answers. I greatly appreciate your input. All ideas can help. Just out of curiosity, are the pickups the only thing that changed on the LIII models? If the preamp is the same, maybe I can take both guitars to my more electrical minded buddies to see if they can take some comparison readings.

Again, thank you very much for your input.

 

[Phrankenstrat]

@jayjayjay I am in agreement. Unfortunately, Music Man does not agree so I'm kind of stuck. I have two LIII's. One with Transitions and one with the EBMM pickups. I guess if I get adventurous, I could swap the preamps in the guitars to see if the situation still occurs. While I'm decent with soldering and such, I have no idea about these preamps. These are definitely not like EMG's. But I whole heartedly believe you are on the right track.

 

[jayjayjay]

@jayjayjay I am in agreement. Unfortunately, Music Man does not agree so I'm kind of stuck. I have two LIII's. One with Transitions and one with the EBMM pickups. I guess if I get adventurous, I could swap the preamps in the guitars to see if the situation still occurs. While I'm decent with soldering and such, I have no idea about these preamps. These are definitely not like EMG's. But I whole heartedly believe you are on the right track.

If the preamp is like what I've seen in other instruments, it probably uses surface mount components. Those are near impossible to troubleshoot or work on without specialized soldering tools, like a hot air pencil and solder paste. I've soldered my fair share of through-hole components onto PCBs, but it's frighteningly easy to ruin an SMD board without the right setup and experience.

Would MM just swap you a preamp board if you took out the old one and sent it to them?

 

[TripHazard]

With what has been described, I would have swapped the PCB module as my first port of call after the battery box had been ruled out.

 

[Phrankenstrat]

I will have a word with Billy about swapping out the preamp this coming week. Your collective input has led me to the same conclusion. I will offer to send my preamp to them first before they ship me another one.

I have two LIII's, one with Transitions and one with EBMM pickups. Does anyone know if the preamps are the same and swappable in these two guitars? I wouldn't know why they would change them but you never know.

 

[Steve Nukather]

Gut it and wire it passive. Active circuitry has no place in guitars.

 

[beej]

You're sure it's not the battery? On the older battery boxes, it was possible for the battery to make intermittent contact with the terminals (over time they'd bend a bit, and not all 9V batteries are the same size). An easy fix was using a cardboard shim at the foot of the battery to make sure it was fully inserted.

Btw- when you say it's the bridge pickup ... do the other pickups go quiet as well? If you have an issue with the preamp, it should be affecting all pickup positions.

 

[Phrankenstrat]

Gut it and wire it passive. Active circuitry has no place in guitars.

Nah, I actually love the preamp. I dread playing my other guitars live because they don't have the push/push boost. At first I saw it as a gimmick bot once I started using it, every guitar should have one.

You're sure it's not the battery? On the older battery boxes, it was possible for the battery to make intermittent contact with the terminals (over time they'd bend a bit, and not all 9V batteries are the same size). An easy fix was using a cardboard shim at the foot of the battery to make sure it was fully inserted.

Btw- when you say it's the bridge pickup ... do the other pickups go quiet as well? If you have an issue with the preamp, it should be affecting all pickup positions.

I've spoken with Billy at Ernie Ball. First, I can't say enough about what a great guy he is. Very responsive and cares about their product. He had some discussions with the technicians and they are going to send me a new preamp. I replaced the battery box on my LIII with Transition pickups so I'm aware of that issue.
The guitar has been shipped back to EBMM twice now. We're pretty sure it's not a battery issue. It is only the bridge pickup that does it. It's an HSS guitar. When the bridge drops in volume, you also lose all the quackiness in position 4. It sounds pretty much like the middle pickup alone. They tend to think as I do that something heats up in the preamp and causes the volume drop. When it cools down sufficiently, things go back to normal until the next hour or so of playing.
I will swap out the preamps and ship them the old one so they can analyze what is going on and hopefully identify the issue.

 

[TripHazard]

Keep us posted - be good to get to the bottom of it and we can all log it in our collective data banks for if any of us ever experience it.

 

[beej]

Billy is awesome- no doubt about that

That's really odd that it's just the bridge pickup- the pickups are wired to the lever, not the preamp directly. I would suspect it's something in the pickup itself, not the preamp. That said, I'm certainly not going to second guess EBMM- they'd know best.

Well good luck with it- that does suck!

 

[Phrankenstrat]

A pickup swap has already happened. It didn't make any difference. I would have thought just as you were thinking that it's something with the pickup.

 

[beej]

Man, what a mystery. Please let us know how it works out.

 

[Phrankenstrat]

Looking forward to what they say myself.