While my electric bass is connected to a mixer Mackie 402 VLZ4 and I am not touching the bass or just holding in my hands the broom sound is heard in monitors. The feedback stops when I am touching the strings while holding it or not. Is the bass faulty? Is it missing anything? Please, help me guys

 

The noise stops when you touch the strings because you essentially become the ground. What that means is that you might have a problem in your outlet, PC and/or interface. I would start by changing USB ports (try ports that are more distant to the one you're using), then I would move into checking if the outlets are grounded. If the bass cable you're using is low quality that might also contribute to the issue, but if it's a proper 1/4 inch cable for guitar I doubt it has any issues, but trying another cable doesn't hurt.

 

Last edited: Aug 29, 2025 at 5:57 AM

How long has it been doing this? If it’s only started recently, but you’ve had the bass for a long time, it could be a loose connection or part. Electrical issues usually show up right away, so think about what might have changed that made you notice it now.

Also, double-check your cable. It should be a 1/4" TS instrument cable, not a TRS. A quick way to test: pull the plug out one click — that bypasses the ring contact and effectively makes a TRS act like a TS. If the noise changes or goes away, that’s a clue your cable is the issue.

It could be anything, but these two are quick to check.

 

A fun piece of trivia is that you can turn any balanced cable unbalanced just by joining the negative and ground wires in both sides. No need to replace the plug or cable if you can solder. That's how I make RCA to TRS cables.

 

For a minute I thought the bass is making a brooming sound, as if sweeping the floor with a broom. Broom broom.

I think the correct term should be humming or buzzing, no?
"Broom" sounds more like the "Englished" version of the German "brummen" which means just that, humming/buzzing.

I agree with the first two replies though.

 

I have just sat with my old cheap bass and the second-hand mixer I got recently. The sound is buzzing/humming, and not brooming-brooming . I use TS cable but it is not a dedicated for a guitar. The buzzing doesn’t occur with a microphone or a synth connected. The bass has three knobs and is a little bit loose. The mixer is connected to active monitors and not USB.

 

Last edited: Aug 29, 2025 at 7:52 AM

If it was a vacuum, you wouldn't be able to hear it.

 

DI box
Ground Lift: This switch can safely help to break an earth loop, which is often a cause of mains noise getting into a signal path.
https://www.guitarworld.com/lessons/how-to-use-a-di-box-on-bass-guitar

 

Hello @nmkeraj, first, try a different or new 6.3mm jack cable. If that doesn't help:
Millenium DI-E passive DI-Box - 14,90 € www.thomann.de/de/millenium_die_dibox_passiv.htm
You can set the language for your country in the top right corner.

Spoiler: Source: Perplexity KI

The buzzing or humming sound from the bass is likely due to grounding or shielding issues within the instrument, faulty or improper cables, or loose internal components rather than a mixer problem, since microphones and synths do not cause noise on that channel.

Common Causes
Loose or Faulty Wiring: Old or second-hand basses with loose knobs can have broken or disconnected ground wires in the control cavity, especially from the bridge or output jack.
Inadequate Shielding: If the bass isn’t properly shielded (with conductive paint or metal foil in the control cavity), electromagnetic interference from nearby equipment may create buzzing.

Cable Issues: Using a TS cable that isn’t designed for guitars can introduce unwanted noise, especially if the cable or jack is worn or not fitting snugly.

Ground Loops: While more common between multiple powered devices, if all other sources (synth, mic) are clean, the bass likely has internal grounding problems instead.

Troubleshooting Steps
Try a new or dedicated instrument cable specifically for guitars or basses to see if the buzzing improves.

Open the bass’s control cavity and check for loose or disconnected ground wires, especially from the bridge to the electronics.

Make sure all connections are tight (knobs, jack socket) and that the shielding connects to ground.
If the buzzing changes or disappears when touching metal hardware (strings, bridge), this indicates grounding or shielding issues.

Plug the bass directly into the monitors or another amp, bypassing the mixer, to confirm whether the instrument or cable is the source.

Next Steps
Replace or repair loose internal wiring, especially any ground wires or connections.
Consider installing or improving shielding inside the bass’s electronics cavity.
Use a high-quality, shielded instrument cable for bass/guitar.
If uncertain, bring the bass to a technician for inspection and rewiring.
The buzzing is almost certainly due to the bass’s internal electronics, faulty or inappropriate cable, or lack of shielding—rather than the mixer or monitor setup.

 

Last edited: Aug 29, 2025 at 1:20 PM

this could be normal behavior for a single coil pickup.

 

Is it possible to change a pickup into the n-coil one? I suspect the bass to give trouble.

I will check all the cables I have later on.

The mixer was bought for its hi-z feature and it still might need DI

I tried vacuum… devices exploded

 

Instead of replacing the pickup, I'd rather buy a used bass on eBay, or a cheap brand from an online retailer. Harley Benton JB-20 CA Standard Series - €89. Who knows what repairs you might have to deal with? What model do you have? I have a built-in DI on my amp. DI makes a lot of sense and is a good investment. A vacuum cleaner only has a limited lifespan.

 

Any kind of DI and a short TS cable will help for sure. The best you can afford.
However, I would check the bass electronics, too, if it doesn't sound right even without the humming it may be a faulty pickup, or just bad.

 

Sounds like your bass isn't properly grounded. There should be a ground wire going from the underside of the bridge (or from a bridge post if your bass has those) to the back of one of the potentiometers. See if this wire has come loose or is damaged.

 

Well, I have checked the cables. I have got a few. Surprisingly some were worse. Today the buzzing is quieter but it’s still there. Touching the strings silences the buzzing. But touching the mixer itself makes it quieter as well. When But the worst scenario is when I disconnect the cable from the guitar being still connected to the mixer. The bloody buzzing is loud. Buzzing disappears after connecting to a synth. The monitors and the mixer are connected to the same mains. But if I use different sockets there no difference about the buzzing.

Now there is the time for disassembling the guitar and checking its wiring.

 

Last edited: Aug 29, 2025 at 9:16 PM

Spoiler: Source: Grok KI

It sounds like you're dealing with a frustrating ground loop or interference issue in your guitar setup. Based on your description, here’s a breakdown of the symptoms and some steps to troubleshoot the issue, particularly since you’re planning to disassemble the guitar to check its wiring:

Key Observations:

1. Buzzing is quieter when touching the strings: This suggests the guitar’s grounding is partially working. When you touch the strings, your body acts as a ground, reducing the noise.
2. Touching the mixer reduces buzzing: This indicates the mixer might also be part of the grounding issue or picking up interference.
3. Buzzing gets loud when the cable is connected to the mixer but disconnected from the guitar: This points to the cable or mixer input picking up electromagnetic interference (EMI) or radio frequency interference (RFI) when not grounded by the guitar.
4. No buzzing when connected to a synth: The synth likely has better shielding or grounding, which eliminates the noise.
5. Same mains power for monitors and mixer, no change with different sockets: This rules out a simple power-related ground loop between devices, but the issue could still be within the guitar or cable.

Steps to Check Guitar Wiring:
Since you’re ready to disassemble the guitar, here’s what to focus on:

1. Inspect the Grounding:
   • Bridge/String Ground: Ensure the bridge or tremolo system is properly grounded. There should be a wire connecting the bridge (or a metal part in contact with the strings) to the guitar’s ground (usually the back of a pot or the ground lug of the output jack). If this wire is loose, corroded, or disconnected, it can cause buzzing.
   • Control Cavity Grounding: Check that all metal components (pots, switches, and output jack) are properly grounded to a common point. Look for loose or broken solder joints.
   • Shielding: Verify if the guitar’s control cavity and pickguard are shielded (e.g., with copper tape or conductive paint). Poor shielding can allow EMI to enter the circuit, causing buzzing.
2. Check Pickup Wiring:
   • Inspect the wiring to the pickups. Loose or frayed wires, especially the ground wires, can introduce noise.
   • If you have single-coil pickups, they’re more prone to picking up interference compared to humbuckers. Consider testing with a humbucker-equipped guitar if available to compare.
   • Ensure the pickup selector switch and pots are clean and secure. Dirty or loose connections can cause noise.
3. Output Jack:
   • Check the output jack for loose connections or corrosion. A faulty jack can cause intermittent grounding issues.
   • Test the continuity of the ground and signal wires using a multimeter to ensure there’s no break in the circuit.
4. Test the Cable:
   • Since the buzzing is loud when the cable is connected to the mixer but not the guitar, the cable might be picking up interference. Test with a high-quality, shielded instrument cable. Low-quality cables with poor shielding can act like antennas for EMI/RFI.
   • If you have a cable tester, use it to check for continuity and shorts in the cable.
5. Mixer and Input Check:
   • The fact that touching the mixer reduces buzzing suggests it might not be properly grounded or is picking up interference. Test the mixer with another instrument (like the synth) to confirm it’s not the issue.
   • Try a different input channel on the mixer to rule out a faulty input.
   • If the mixer has a ground lift switch, experiment with it (though this is more common in pro audio interfaces).

Additional Troubleshooting Tips:

• Test with a Different Guitar: If you have another guitar, plug it into the same setup (same cable, mixer, and monitors). If the buzzing persists, the issue is likely external (mixer, cable, or environment). If it stops, the problem is within the guitar.
• Isolate EMI Sources: Move the guitar and setup away from potential sources of interference (fluorescent lights, Wi-Fi routers, computers, or phone chargers). These can induce buzzing, especially with poorly shielded guitars.
• Try a DI Box: If the issue persists after checking the guitar, use a direct injection (DI) box with a ground lift between the guitar and mixer. This can break ground loops and reduce noise.
• Battery-Powered Test: If possible, power the mixer with a battery-powered source (like a portable interface) to rule out mains-related interference.

Next Steps After Checking Wiring:
If the guitar’s wiring checks out (all grounds are secure, shielding is intact, and no loose connections), the issue might be external:

• Replace the Cable: Invest in a high-quality, shielded instrument cable if you suspect the current one is faulty.
• Mixer Grounding: If the mixer itself seems to be part of the issue, check its power supply and grounding. You might need to consult the mixer’s manual or contact the manufacturer.
• Environmental Check: If the buzzing persists, try the setup in a different location (e.g., another room or building) to rule out local EMI.

If You Need Visuals or Further Help:

• If you want a diagram of typical guitar wiring to guide your inspection, let me know your guitar type (e.g., Strat, Les Paul, etc.), and I can describe a standard wiring setup or suggest where to look.
• If you’re comfortable uploading a photo of the guitar’s control cavity (once opened), I can analyze it for obvious issues like loose wires or missing shielding.
• If you want to track down specific EMI sources, I can suggest ways to test for interference in your environment.

Let me know how the guitar wiring check goes or if you need specific guidance for the disassembly process!

 

"Now there is the time for disassembling the guitar and checking its wiring."
Take a good look at the solderpoints , (the dull - not shiny) resolder those.

 

but before it was good without DI box ! i hate such stuff eh eh