Treble tone control related buzz - any ideas?

[EdLib-3]

Hi all,

 

I have recently acquired a curious problem with my Ibanez bass; according to this article it is a shielding, (not grounding) issue:

 

https://www.notreble.com/buzz/2015/04/15/solving-bass-hum-problems-grounding-vs-shielding/

 

I have checked the leads and the combo amp, and used a different bass with the same setup in order to eliminate the possible causes; and it is the bass with the buzz problem. The bass in question has a high and low 2 band active EQ; when I boost the high tone control there is a pretty load buzzing when the volume knob is also turned up. It only occurs when I boost the high knob and causes a buzz and sometimes crackle which stops when I put my hand on the strings; when I tap the machine heads on the bass lightly with my finger tips there is also a crackle noise at the point of contact. Has anyone else had this type of problem? If so any ideas on what aspect of the shielding needs to be sorted in order to solve this?

 

Cheers,

 

Ed

[John Cribbin]

Have you tried a fresh battery?

 

I like to eliminate the easy stuff before to much head scratching happens! 

[EdLib-3]

22 hours ago, John Cribbin said:

Have you tried a fresh battery?

 

I like to eliminate the easy stuff before to much head scratching happens! 

Just tried the bass with a new battery but it made no difference unfortunately. The buzz with treble control all the way up is pretty loud as usual and the crackle noise when I tap the tuners is still there. Anyone had a similar situation where the buzz is brought on my having certain tone knobs up on full?? I'm happy to be provide any additional detail that may assist.

Edited August 31, 2021 by EdLib-3

[rmorris]

1 hour ago, EdLib-3 said:

Just tried the bass with a new battery but it made no difference unfortunately. The buzz with treble control all the way up is pretty loud as usual and the crackle noise when I tap the tuners is still there. Anyone had a similar situation where the buzz is brought on my having certain tone knobs up on full?? I'm happy to be provide any additional detail that may assist.

Having Tone Control Open or boosting treble (in the bass guitar sense) usually emphasises buzz.

It's not unusual to get a transient when you go from not being in contact with the grounded metalwork to being in contact. The machine heads may have a surface finish that doesn't give a great connection when touched and the partial intermittency can give a problem.

I have a similar thing on a bass where I have some coated strings and the contact is variable and results in transients / crackles.

The problem does imply that there may be a screening issue where you are acting as an antennae for noise and the bass isn't adequately screened.  What screening is there in the control / pickup cavities ?

[EdLib-3]

21 hours ago, rmorris said:

Having Tone Control Open or boosting treble (in the bass guitar sense) usually emphasises buzz.

It's not unusual to get a transient when you go from not being in contact with the grounded metalwork to being in contact. The machine heads may have a surface finish that doesn't give a great connection when touched and the partial intermittency can give a problem.

I have a similar thing on a bass where I have some coated strings and the contact is variable and results in transients / crackles.

The problem does imply that there may be a screening issue where you are acting as an antennae for noise and the bass isn't adequately screened.  What screening is there in the control / pickup cavities ?

 

Thanks - the tuners are regular chrome Gotoh tuners nothing atypical in the finish. There is definitely something askew shielding wise here; if you could hear the buzz and crackle, you'd agree with me. Plus the bass doesn't sounds that good with the treble backed most of the way off so it needs sorting. Here is what we're working with regard to the control cavities:

 

 

Is this normal looking for the control cavity? I don't want to mess with the pickups so I haven't removed them to check out the pickup cavities - plus I don't really know what I'm looking for; I've read that you really need a multimeter to find the specific cause of this type of problem . I think I'm going to have to grit my teeth and get this bass to my local guitar repairer. Hope it's not too expensive.🤪

Edited September 1, 2021 by EdLib-3
Additional info

[rmorris]

8 minutes ago, EdLib-3 said:

 

Thanks - the tuners are regular chrome Gotoh tuners nothing atypical in the finish. There is definitely something askew shielding wise here; if you could hear the buzz and crackle, you'd agree with me. Here is what we're working with regard to the control cavities:

 

 

Is this normal looking for the control cavity? I don't want to mess with the pickups so I haven't removed them to check out the pickup cavities - plus I don't really know what I'm looking for. I think I'm going to have to grit my teeth and get to my local guitar repairer. Hope it's not too expensive.🤪

 

Mmmm..looks like metallic Alu screening on the control plate with conductive paint to interface to that - but not clear if that has continuity to 'Ground'. And lots of cavity looks to be unscreened.

I see you might be in / near Brighton ? As am I.

Will PM but tomorrow as getting late here now.

[John Cribbin]

OK, something was bugging me with the symptoms.

 

The only way the tuners could get in the audio chain are if they are in the circuit via the ground wire from the bridge, or possibly some weird signal getting into the pickups.

 

From your photo, I don't like that jack socket one little bit, I don't think Ibanez did that work. Normally, the cable would be clamped to the long leg of the socket with the two lugs being bent over. The lugs look like they may have been bent open to remove the cable. The long leg looks twisted and possibly shorting on one of the other lugs. I'd straighten that leg and make sure nothing is touching. Being polite, that type of socket is junk and well known for failure. Maybe someone had a previous problem and poked about?

 

Just in case there is a weird pickup issue, you could use the blend to use one pickup at a time and see if that removes the buzz.

 

[EdLib-3]

Thanks for the help @rmorrisand @John Cribbin- most appreciated. Using the pick up blend to either favour the P pickups or the J pickup still gives you the same buzz and crackle when touching the machine heads. One particular wire looks pretty unhealthy on a closer inspection. Looks almost chewed through as well as bent at an severe angle:

 

 

[EdLib-3]

So could be the jack and lugs...I will email a couple of local repairers to try and get a rough quote. Really useful to have a better idea of the possible issue(s). Here's the control layout for the front with skillfully added calligraphy 😉:

[EdLib-3]

It was a problem with the pickups - now all sorted 👍