4003 Hi-gain bridge making fuzzy noise

[espidog]

A fellow bass playing friend of mine here in the UK has just bought his first Rick: a 2007 4003. He's only had it a day or so, and he's noticed an apparent fault with the bridge P/U. Here's how he describes it:

"The bridge pickup is noisy. It produces a slight distorted noise which at first made me believe that the amp was faulty, but after processes of elimination I narrowed it down to the pup. I set the controls firstly with the treble rolled off slightly and everything else turned up and the pup selector to central. This hides the noise, but if I use the bridge pup on its own you can hear the fuzz. The bass has a push/pull switch on the treble control and when pulled the noise reduces slightly but does not go away. Any ideas?"

Although virtually new, the bass has had one previous owner. One thought that occurred to me was that said person might have been at the controls with a soldering iron, and there might be a dry solder joint where the pup meets the controls, causing a diode effect. However, this seems a tad unlikely. From my pal's description, it looks like there's some kind of basic fault with the pup itself.

Has anyone else ever experience this phenomenon? All ideas gratefully appreciated!
Cheers,
Ken

[johnallg]

He could just be overdriving the amp input. A sound file would help diagnose.

[espidog]

Ta for the idea, John, but no: he's definitely not overdriving the amp. In fact, he says that the bridge pup sounds quieter and less bass-heavy than the neck pup, even with the 'vintage' cap switched out, and still has the fizzing sound

He's had a look at the wiring and says he can't see any obvious dry joints etc. I've now advised him to do a bit of diagnostic stuff. I've asked him to swap over the hot leads of the two pickups, where they arrive at the selector switch. That way, if the problem is in the pup itself, the fizzing sound will move over to the neck controls. If it's a wiring/pot/switch/capacitor problem, it'll stay on the bridge controls. Soon, I suspect, we'll know the truth.

[johnallg]

Knowing what the pups read on an ohmmeter while he has them unconnected would be good to know also.

[espidog]

Good point, John - thanks. Can you remind me what the typical DCR is for a recent hi-gain bridge pup?

[johnallg]

Both neck and bridge weigh in around 11.4K ohms,

[soundmasterg]

It should be somewhere around 12k to 15k.

It is hard to determine exactly what is being talked about since "fizzing" isn't very descriptive.

Greg

[espidog]

My friend has since described the sound as "rather like an active bass with a dying battery". Apparently it affects all strings and all notes to the same extent. This is what leads me to suspect that the problem may not be in the pickup itself, but in the associated circuitry. I'd expect a pickup flaw to react differently to different strings or frequencies, whereas this sounds to me like it's a distortion of the signal after it has left the pickup.

[rickcrazy]

Maybe cleaning both controls to the treble pickup will do away with the problem?...

[espidog]

Maybe cleaning both controls to the treble pickup will do away with the problem?...

It certainly wouldn't do any harm, although TBH I'd be very surprised if pot track issues were the cause, as the bass is a 2007 model - it's virtually brand new.

Since my last post, my friend has had the wiring and controls examined by a fellow 4003 owner, and he is of the opinion that they have been "messed about with" by the previous owner. He says that some of the solder joints look amateurish.

I'm frustrated as hell over this. I'm an experienced electronics hobbyist, and if my friend could only bring the bass round to my house, I'd go through it with a fine-toothed comb (well... testmeter and soldering iron ) and sort the problem out for him - but he lives over 100 miles away, so all we can do is chew the fat over the phone!

[MrThumb]

Hi all. I thought that it would make sense to register myself as its my bass in question.

After making some phone calls to the previous owner and a repair shop I discovered that the bass has had this fault for a while. The repair guy thought he had fixed it (earth problem) and the old owner was happy. As this was the previous owners 2nd Ric it wasn't used much so he can be forgiven for not realizing that the bass was still ill. That or the swine knowingly sold it me in that state.

When I first tried the bass it seemed that there was a slight fuzz/distortion coming from the speaker. This got me panicking as I thought the amp was dying. But after a long process of elimination I narrowed it down to the bridge pup, neck pup being fine.

I had a friend check the solder/connections, re-soldered some and now they seem fine. But unfortunately I don't have any access to testing equipment.

I have noticed on occasions that this noise stops. I have left the amp on standby for 10 minuets or so and on return all seems to be fine but after a short while the noise slowly returns. Also the level of the 'distortion' changes. I could plug in and the noise is quite bad and on other occasions its not too bad but most of the time its there somewhere. All very confusing.

[espidog]

Hi Paul - welcome to the Rickresource forum!

[MrThumb]

Hi Paul - welcome to the Rickresource forum!

I thank you sir!

[johnallg]

Welcome, Paul. I think it is time for a train ride. Take it to Ken and let him clean pots and connections, check the ground soldering, make sure it is all wired right, and ohm the coil. Since it works right sometimes, I'm wondering if it is just a corrosion problem.

[MrThumb]

Welcome, Paul. I think it is time for a train ride. Take it to Ken and let him clean pots and connections, check the ground soldering, make sure it is all wired right, and ohm the coil. Since it works right sometimes, I'm wondering if it is just a corrosion problem.

I doubt that after the 'last time' Ken would want me anywhere near London!

I'm going to try a friends '05 4003 this afternoon and make a bass for bass comparison. That should give me a good insight as to how it should really sound. I'll let you know how it goes.