Crackling noise on Fender Marcus Miller

[tevitag]

An intermittent crackling noise is coming out of my Fender MM, it seems to be happening more frequently. It's not the instrument lead because I have plugged a few leads in including my best one which I gig with, and the same thing happens. The noise happens even when the bass is perfectly still with no movement on the jack etc. which is why I also don't think it's the jack. The same leads are used on other guitars and no prob.

I am certain it has something to do with the preamp or the preamp switch, because when I cut the toggle switch to passive, there is no noise. A friend suggested it might be interference to the preamp when it is active, from a fridge or similar. But I have had the bass a while now so why would that just happen now?

Can anyone give me a tip on how to test the preamp and wiring between jack, preamp (model FMEQ 080097) etc with a multimeter? Comparing the wiring with a Marcus Miller IV wiring diagram - it visually seems fine, with everything in place and nothing loose.

Many thanks
Dave G

 

[DiabolusInMusic]

I am sure you tested this since you seem really competent, but did you try a new battery?

 

[tevitag]

Battery all good, fairly new and still reading green on battery tester.

 

[RobbieK]

There's no real set rules or measurements for intermittent crackles unfortunately. It usually means there's a frayed wire, a dry solder joint, a dodgey switch or battery clip. It could also be the jack, as the preamp relies on an earth contact here.

 

[tevitag]

I will check all of these again RobbieK, thanks

 

[qbury]

When I owned a MM it had a peculiar crackle when I touched the pick guard. Your issue seems to happen when your not touching the bass. My issue was resolved by using copper tape in the control and pickup cavities. Not much paint was used in the cavities from the factory. It might be worth a try.