Ibanez SR1000 Prestige - dead pre-amp?

[Osiris]

I have an Ibanez RS1000 Prestige that my good lady bought it for me as an engagement present in around 2006.

After about a year or so, the output has been temperamental or intermittent - if you move any of the controls (volume, pickup balance, stacked bass and treble and a stacked parametric mid) there's lots of static type noise and more often than not, the output cuts right out. It's been to a couple of luthiers/repair men over the years with mixed results, but the long and short of it is that it's still unreliable. It has also had copious amounts of switch cleaner squirted into the pots on numerous occasions too.

Much as I'm tempted to burn it, this was an engagement present and one can only grow ones pips back a finite number of times ....

So, would I be right in thinking that the pre-amp is at fault here? (The pickups are Bartolini 'custom' soapbars but I have no idea what the stock pre-amp is).

In terms of getting the bass up and running again, can I get away with just having the pots replaced?
Or am I looking at a new pre-amp?
Is there any reason why I couldn't just rip the current electrics out and go passive? Or do the Barts' need a pre?

Any help greatly appreciated.

Edited May 5, 2015 by Osiris

[icastle]

If its a crackling then that indicates a bad connection somewhere in the vicinity of a movable part.

First up, check for dry joints and loose wires.

Second job would be to eliminate the jack socket from the equation.
SRs all use barrel sockets and they have been known to fail regardless of manufacturer.

Squirting switch cleaner into pots will clear out any debris, but if the track on the pot is damaged or the wiper has become worn, no amount of switch cleaner is going to fix that.

If the first and second steps don't fix the problem, then I'd be inclined to identify the worst pot and change it.

If that pot then starts behaving itself, then change the rest of them.

IIRC the barts used in the SR series have to be powered, so changing to a passive setup would be awkward and would achieve nothing if the pots are faulty anyway.

HTH

EDIT: 9v 'flying' battery connectors all have one thing in common, they're all sh*t, so try wiggling the wires and see if that makes a difference as well.

[Osiris]

Thanks for the information.

I've just given the cable a heavy handed wobble about in the jack socket and the signal was fine, no crackling, static or other nasty noises so I'm as sure as I can be that that's not the problem. Unless there's a more scientific way to check?

The pots on the other hand are a different story. The volume and pan are OK, just OK. A bit noisy in operation but when left untouched for a few seconds seem settle down.

The 2 stacked eq controls are noisy and each cuts the signal when touched. These, I'm sure are the culprits.


I don't have time to whip the plate off the back of the bass right now as I'm off to rehearsal in a minute but I'll take a look tomorrow to see if it's feasible to replace the pots.

If they can't, and you think the Barts need a pre-amp, then I'm going to have to replace the stock model.

[Osiris]

Forgot to add, the battery box has fixed terminals at one end, not a floating clip so I think we can cross that off the list too.

[icastle]

My gut reaction is to aim at the noisiest pots first.

Check to make sure there's no loose wiring there and swap it out if necessary.

You don’t generally get crackling noises after moving a mechanical item (i.e. a pot) without a mechanical fault (i.e. a duff track or intermittent connection).

[Osiris]

Having looked inside the cavity earlier, the 2 stacked eq pots each have their own mini circuit board with what looks to be 6 closely packed solder points for each pot.
So with my limited soldering skills, swapping the pots out isn't as straight forward a task as it might initially seem.

Factor in the fact that the bass has already been to a couple of different people to fix and has had a fair amount of money chucked at it (one so-called reputable luthier had it for 6 months, bodged it, tried to palm me off with some half arsed excuse and charged me £80 for the pleasure ) I'm really looking to get this sorted for once and for all.
Needless to say I don't really have much faith in the electronics that are currently in it so although I thought changing the pots could have been a possible cheap fix, it's not a simple as I first thought. And although it may have resolved the issue, it may have been another potential bodge too if it's a fault on the circuit board! I'd rather spend a bit more money on it and know that it's going to work.

Now that a couple of other factors have been eliminated from the list of likely causes, I'm trying to figure out if changing the pre-amp will solve the issue?
I think that it will, but I'm no expert on these things. Do you agree with it being the right thing to do?

[PlungerModerno]

As simple / silly as it sounds - I'd try turning the noisy pots back and forth 100+ times to see if that lessens the symptoms - often pots just need plenty of use to clear up noisiness. Unfortunately the stack type are sometimes trickier to clean.

In general - unless there's clear signs of damage or loose wires - if electrics are noisy, my first move is to roll those pots back and forth a whole bunch of times... after checking they are turning internally, not the whole pot with wires whipping around and snapping off in the control cavity .

[Osiris]

[quote name='PlungerModerno' timestamp='1430956249' post='2766368']
As simple / silly as it sounds - I'd try turning the noisy pots back and forth 100+ times to see if that lessens the symptoms - often pots just need plenty of use to clear up noisiness. Unfortunately the stack type are sometimes trickier to clean.

In general - unless there's clear signs of damage or loose wires - if electrics are noisy, my first move is to roll those pots back and forth a whole bunch of times... after checking they are turning internally, not the whole pot with wires whipping around and snapping off in the control cavity .
[/quote]

Thanks for the suggestion, but alas, I've already done it many times. It certainly helps in the short term (we're talking minutes rather than days or weeks) but it no way 'fixes' the issue. For example, the last time I gigged it 2 or 3 years ago, the stage was booming so I tried backing the low end off a bit but it killed the output all together - I'd rolled the pots back and forth several times during soundcheck and it seemed to be OK. Fortunately I had another bass to swap over.

[Osiris]

The pots certainly seem secure enough on the bass body, the casing doesn't move when they're turned and you can clearly see the spindle rotating when the stacked pots are turned.

[tauzero]

It could be the pots, it could also be a leaky capacitor allowing DC into the audio circuitry.

You could do a reasonably cheap replacement with an Artec SE3P-A giving you the same number and function of controls - [url="http://www.axesrus.co.uk/SE3PA-3-band-EQ-system-p/se3p-a.htm"]http://www.axesrus.co.uk/SE3PA-3-band-EQ-system-p/se3p-a.htm[/url] has them at £36.

[Osiris]

[quote name='tauzero' timestamp='1431420869' post='2771003']
It could be the pots, it could also be a leaky capacitor allowing DC into the audio circuitry.

You could do a reasonably cheap replacement with an Artec SE3P-A giving you the same number and function of controls - [url="http://www.axesrus.co.uk/SE3PA-3-band-EQ-system-p/se3p-a.htm"]http://www.axesrus.c...em-p/se3p-a.htm[/url] has them at £36.
[/quote]

Thanks for the input, tauzero, but I took a punt on a 2 band Glockenklang pre-amp at the weekend. My 2 Sandbergs use them and they are great sounding, very natural and organic tone.
It certainly wasn't as cheap and cheerful as the Artec, but having already spent a fair bit of money on trying to get the bass back in order I thought it wise to get something that I know will do what I want it to.
At least by replacing the whole circuit it will (hopefully) eliminate all and any duff parts on the old one, whatever the cause of the problems, and the bass will finally be back up to earning its keep.