Static/electrical popping sound from my active bass

[Osiris]

Hi y'all, I'm new to these parts so please forgive me if this topic has already been discussed at length.

My Ibanez SR500 has recently developed a regular static/electrical popping sound - sorry for being a bit vague but I'm not sure how else to describe it???
The noise it makes is a quick 'pop' or burst of static that lasts a fraction of a second and is no louder that the output from the bass itself.
It does it every few minutes or so regardless of whether the bass is being played or is sat on a stand with the volume control fully open - which suggests to me that it is not a loose connection or a fault of that nature. I've systematically checked all the obvious things like a duff battery, dodgy cables etc. and have eliminated all the other components in my rig to be sure that it is definitely the bass that's the problem. The bass is fitted with a pair of Bartolini MK 1 pickups and a Bartolini MK 1 3 band eq.

I recently took it in to my local repair man who thought it was a faulty battery clip (which made sense in light of the intermittent nature of the fault). The clip was replaced and the jack socket was also replaced just to be sure. This has helped reduce the regularity of the popping but the bass still does it from time to time.

My guess is that it's a fault on the eq circuit, not that I'm an expert on these things!!!

Anyone has this, or a similar problem before? If so if anyone can shed any light on the matter it's be greatly appreciated.

[geilerbass]

I did experience a similar thing with my Ibanez in one rehearsal, but haven't experienced it since. Could be a battery clip thing, since my Ibanez has the same type of battery compartment as the SR500.

Anyone have any ideas?

[EBS_freak]

Two things I would certainly look at is the ground and if there are any capacitors in the circuit... thats another thing I would look at.

The circuit may be so minute troubleshooting may be difficult... is the circuit exposed at all or is it sunk in epoxy??

Anyway, as for the ground take the bridge off and look for the grounding cable. Remove cable and replace with new copper cable... may be worth a shot.

These gremlins are always the worst to find.

[Osiris]

Thanks for the suggestions guys.

I'll whip the bridge off and check the ground cable.
By the ground do you mean the earthing cable??? If so, my understanding was that all this did was to help eliminate a general electrical hum, but as I said I'm no expert and will believe almost anything I'm told!!!

The circuit is not epoxy coated but it is covered with a sticky backed peice of high density foam (ala blue Peter). I'm reluctant to try and peel this off in case it does more damage than good..... What componants I can make out though are very tiny indeed so as you say trouble shooting could be a real ball ache.

To be sure it is the preamp that's at fault, is it possible to rewire the bass to bypass the cicuit and run it as a passive instrument?
Could it equally be a duff pickup that's behind the problem?

I have been half heartedly toying with the idea of whipping the guts out of the bass and converting it to a passive model anyway (maybe lob in a pair of SD quater pounder jazz pups) but I'd like to know what the faulty componant is to be able to sell the 'working' parts with a clear conscience!! Don't get me wrong, the Bartolini pups and eq are amazing, very clean, clear and defined - it's just that I prefer the warmth and tone of passive pups so this fault could perhaps force the issue.

My thoughts aside, anyone else have any wisdom to shed on this problem please?

[EBS_freak]

Ground cable - yeah, earthing cable. Same thing. It will be seated under the bridge at some point... as a matter of course, replace it with copper cable as it's likely to be better than the stuff that is already in there.

The circuit looks like it is all mini components = pain.

You can rewire the instrument - the simplest being connecting the pickup(s) to the output jack. I don't think that will be the problem though. Pickups giving up and displaying that sort of behaviour is very rare. They usually just die or go microphonic.

Be aware that jazz pickups are noisy. It's the nature of single coils. Barts are amongst the quiet, but no bass is 100% silent in all conditions.

Just a thought, have you tried your bass in different amps - or running your amp without the bass plugged in..? It could be a cap in your amp that is on the way out.



[quote name='Osiris' post='218239' date='Jun 13 2008, 12:26 PM']Thanks for the suggestions guys.

I'll whip the bridge off and check the ground cable.
By the ground do you mean the earthing cable??? If so, my understanding was that all this did was to help eliminate a general electrical hum, but as I said I'm no expert and will believe almost anything I'm told!!!

The circuit is not epoxy coated but it is covered with a sticky backed peice of high density foam (ala blue Peter). I'm reluctant to try and peel this off in case it does more damage than good..... What componants I can make out though are very tiny indeed so as you say trouble shooting could be a real ball ache.

To be sure it is the preamp that's at fault, is it possible to rewire the bass to bypass the cicuit and run it as a passive instrument?
Could it equally be a duff pickup that's behind the problem?

I have been half heartedly toying with the idea of whipping the guts out of the bass and converting it to a passive model anyway (maybe lob in a pair of SD quater pounder jazz pups) but I'd like to know what the faulty componant is to be able to sell the 'working' parts with a clear conscience!! Don't get me wrong, the Bartolini pups and eq are amazing, very clean, clear and defined - it's just that I prefer the warmth and tone of passive pups so this fault could perhaps force the issue.

My thoughts aside, anyone else have any wisdom to shed on this problem please?[/quote]

[Osiris]

I've tried the bass through several different amps, my gigging rig, my bedroom amp and even the guitarists amp in a rehersal - it is definetly the bass that's the problem.

Noisy jazz pups are not really a major issue, I don't do much recording and when I do I usually use my Ibanez SR1000 Presige which also has Bartolini pups in, though these are the 'custom' models and tonally are more to my tastses being inherantley darker and warmer in tone. I use the SR500 for mostly live work as it's easy and comfortable to play and it didn't cost a stupid amount of money which is great as our rhythm guitarist is Mr Bump - so no tears as and when he decides to barge into me or it on a regulat basis!!!

Still not decided what to do with it as yet, I'll probably keep 'running' it for a while and monitor the issue. At the minute it's not too bad and is aceptable to live and gig with (unlike my misses!) But if the problem comes back again it might be surgery time......

My current band looks like it's about to enter a state of atrophy so getting the SR500 sorted may slip down the prioity list until I get a new project sorted. Hey ho.

[muzzer]

Hi Osiris, sounds to me like it may be a component on your pre-amp starting to go faulty, maybe one of the op-amps.
Though you saying that replacing the battery clip and the jack has improved things suggests it might be a bad or "dry" solder joint and the disturbance of wiring etc. when these were replaced has changed the way the fault appears.
Not sure what type of pre-amp the SR500 has, but my EDC705 has a pre that looks like this:



(this is the track layout, but you get the idea )

Your's is probably similar, it uses a couple of TL062 dual op-amps which I have seen causing "random noise" sort of problems and is the most likely cause after bad connections or intermittent control pots. You could try gently tapping/prodding the various components to see if this re-creates the problem.

Bypassing the pre-amp worth a try I suppose but, as EBS-freak said it's pretty unlikely to be pickup related.

If the worst comes to the worst, replacing the two op-amps on the board would be fairly simple and the chips are pretty cheap if you can find someone willing to do it (assuming you can't yourself).

Good luck.