Very mysterious noise problem - Can someone help?

[Stelio Kontos]

Hi,

when I'm at rehearsal, I happen to have mysterious noises from my bass rig which sound almost like digital glitches but more broadband, very loud, and yeah, they sound 'wet' like someone was slurping their soup but they are very chopped off and random, too. I can recreate the situation these sounds occur in mostly, but I cannot recreate or control the exact sounds. It's driving me crazy. I'll post more info on my rig now but please note before that recently ALL components have changed one after the other, so this problematic combination is still sort of brand new and I would not notice the noise during the first two or three sessions with this specific equipment.

1. Bass: I have an Epiphone Thunderbird Pro IV converted to passive. Volume-Volume-Tone + kill switch. Original soapbar pickups but electronics all new. I followed the schemes exactly, checked all connections with volt meter and made beautiful, silvery solder joints. The bass is dead silent in terms of unwanted noise with my home practice amp and when recorded direct. The kill switch works absolutely noiseless and nothing is coming through my home rig when I play the muted bass or hit the wood or touch the plugged-in jack.

2. Bass amp: Bugera Veyron Tube, bought 2 months ago. All settings quite noonish and connected to 4 ohm 4x10 cab via speakon cable. No extreme gain, no extreme master volume. Works fine with three different basses directly plugged to it.

3. FX Chain: Bass -> Boss Tuner -> Boss LS-2 -> SEND: Joyo Vintage Drive + Joyo Ultimate Drive :RETURN -> Ls-2 main out to Amp input. A+B mix mode. When engaged, the mixed signal very well equates the clean signal in loudness.
I recorded this setup at home through a small 15 watt combo and direct to my interface to find the noise but it was not there no matter what I did try to provoke it. The pedals are powered from individually isolated ports of a pedal power bank.

The mystery: When I play at rehearsal, the slurping glitchy sound appears bot not when I play the strings, rather in between. Now comes the stupid part: It is even there when I mute my bass with its kill switch. And, I think it has sometimes to do with me moving, or moving or touching the bass. Since the muted bass is totally silent with other amps, this should just not be possible. However, it is never the same length or quality of noise, like with hum or ground issues and so on. It's choppy, glitchy, and sometimes it sounds like an 8 bit sample of a branch saw going through wood when I shake the bass (not touching metal parts!) or walk a few steps. Then sometimes again, it does not occur when I walk around or the shake the bass and I feel relieved. However, it will most likely occur a couple of seconds later when I'm standing still again and am just about to unmute the bass and play on.

How is this interaction even possible with a muted bass and three major components that work perfectly fine when tested in individually? I have a certain suspicion but I'd like to know what you think about all this first.

Any help appreciated. Cheers.

Edit: Oh, since I do not know if it is an issue related to the bass electronics or pickups, the thread might be in the wrong section. Sorry, I did not know in which section it belonged since I do not know where this noise is coming from.

 

[Mike_IronFist]

This sounds like pretty standard interference issues, usually caused by a computer or something electrically similar in the room.

Does the noise you're getting sound anything like this?


Usually there's at least one of three culprits:
1. Poor shielding inside the control cavity
2. Being too close to/directly facing something digital that makes machine noise (a laptop, PC, etc)
3. A ground loop causing noise to be passed into your amp from the ground connection in the wall due to a PC or other electronics plugged into the same power lines.

 

[James Collins]

This sounds like pretty standard interference issues, usually caused by a computer or something electrically similar in the room.

Does the noise you're getting sound anything like this?


Usually there's at least one of three culprits:
1. Poor shielding inside the control cavity
2. Being too close to/directly facing something digital that makes machine noise (a laptop, PC, etc)
3. A ground loop causing noise to be passed into your amp from the ground connection in the wall due to a PC or other electronics plugged into the same power lines.

Phones will make that sound also. You can hold a phone in front of a pickup and hear this exact sound.

 

[Holy Diver]

Phones will make that sound also. You can hold a phone in front of a pickup and hear this exact sound.

+1. If you keep your phone - especially a smartphone (ie iPhone or Android) - in your right front pocket (or left, if you play lefty), and your shielding isn’t bulletproof, it’ll make the most godawful noise. Ditto keeping it in a rack drawer or on top of your amp. Ideally, you want to keep it in an instrument case or utility case away from the amp while you’re playing. If you absolutely HAVE to have your phone on you, keep it in a back pocket, as far away from your bass’s guts as you can.

 

[DiabolusInMusic]

+1. If you keep your phone - especially a smartphone (ie iPhone or Android) - in your right front pocket (or left, if you play lefty), and your shielding isn’t bulletproof, it’ll make the most godawful noise. Ditto keeping it in a rack drawer or on top of your amp. Ideally, you want to keep it in an instrument case or utility case away from the amp while you’re playing. If you absolutely HAVE to have your phone on you, keep it in a back pocket, as far away from your bass’s guts as you can.

Leaving a phone on your amp will cause similar issues in my experience. I get interference any time I get a text or call. I just leave my phone in a case or jacket.

 

[Stelio Kontos]

Thanks for the replies so far. Unfortunately, the rehearsal space in an old bunker with walls as thick as 1 meter and there is no phone related waves coming in. No connection at all. I do keep the phone away from me and the amp nonetheless all the time, cause I think maybe it could send something out when searching for a connection. My control cavitiy is still factory shielded, that is, a sort of black matte laquer finish on the wood and aluminum foil on the backside of the cover. The noise sounds rather like this (from 16 or so seconds on. The higher pitched examples):



Since my kill switch does send all signal from the pickups to ground with a resistor in between, and since it does not have any bleed in other setups, I think it is not coming from my bass at all. At home, I can hold my mobile with active phone call to the pickups and crank the practice amp. There is total silence when I mute it with the switch. At the rehearsal, there's incontrollable glitches when the bass and fx chain are muted.

Sounds like it is either the amp's class D power section that emits some bullsh*t artefacts, or a faulty preamp tube passing peaks on to the power amp even when there's no incoming signal... What do you think?

I will install some copper foil to the control cavity and change preamp tubes next week. I'll report back if it solved the problem.

 

[Stelio Kontos]

Okay, it was the bass itself. But only noticeable on that one particular amp and with the high gain pedals in the effects loop. The output jack's signal lug touched the side of the hole it was set into. Since this cavity is shielded with conductive paint, some signals went into it. So when I knocked on the wood of the bass or shook the bass I could hear portions of that movements as signal peaks through the amp with gain pedal and tube preamp. Sometimes these peaks were delayed a couple of seconds, which is strange but probably a feedback loop thing. On another amp and without the pedals there was no noise at all. Maybe also had to do with the impedance of that particular setup. Anyways, I installed a long shaft jack socket and eliminated the short circuits. Noise is gone. Thanks for all suggestions.

 

[HappyChillmore]

Thanks for the replies so far. Unfortunately, the rehearsal space in an old bunker with walls as thick as 1 meter and there is no phone related waves coming in. No connection at all. I do keep the phone away from me and the amp nonetheless all the time, cause I think maybe it could send something out when searching for a connection. My control cavitiy is still factory shielded, that is, a sort of black matte laquer finish on the wood and aluminum foil on the backside of the cover. The noise sounds rather like this (from 16 or so seconds on. The higher pitched examples):



Since my kill switch does send all signal from the pickups to ground with a resistor in between, and since it does not have any bleed in other setups, I think it is not coming from my bass at all. At home, I can hold my mobile with active phone call to the pickups and crank the practice amp. There is total silence when I mute it with the switch. At the rehearsal, there's incontrollable glitches when the bass and fx chain are muted.

Sounds like it is either the amp's class D power section that emits some bullsh*t artefacts, or a faulty preamp tube passing peaks on to the power amp even when there's no incoming signal... What do you think?

I will install some copper foil to the control cavity and change preamp tubes next week. I'll report back if it solved the problem.

Yo I’m having the same issue…. Weird. Playing through my fender rumble with headphones, usually when having a six plugged into my phone but seemed to do it even when I unplugged it. Weird part is it only happens out of nowhere like going from 0 to 100 for a few seconds then Totally goes away. I think it’s the bass because I just got it used, which really sucks because it was expensive. But I just saw ur other comment about it being due to electronics touching inside? I’ll have to have a look inside I guess