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I am having a great time with this instrument! It's my first 6 string bass and it has opened up a whole new way of playing for me.

Just recently, I was setting up to play a church gig and noticed I had considerably less bass volume coming from my amp. I shut everything down and powered up and the problem went away. Then, at another gig it did the same thing. Rather than shutting down, I moved the instrument cable to see if it was damaged and nothing changed. So I started rotating the volume knobs then the tone knobs. When I rotated the bass tone knob the volume returned instantly.

So am I thinking properly - is it possible that this pot (which has a center detent) has dead spot and the pot needs to be replaced? (the bass is about 6 years old and I have no clue who owned it before or how it was taken care of) If I need to replace the pot, I was thinking of replacing all three tone pots with ones that don't have a center detent, since I adjust tone by listening not by looking. The pots are B50K ohms. Any suggestions on this situation?

Looking forward to your replys.

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Hi Lee.

This instrument has active electronics. Without doing further research, I' wouldn't be too eager to begin replacing pots with anything except exact spec/value pots. The 'tone pots' you refer to are actually active tone controls that both boosts & cuts frequencies at the designated EQ centers. Hence, the center detent where they're effectively 'out of the circuit'. Conventional tone controls only 'cut' frequencies and replacing the existing pots with 'conventional' pots is not a good idea.

The first thing I'd do is remove the circuit board from the instrument and spray clean all the pots with Deoxit. At the same time, inspect the circuit board pads for cold solder joints and check the pads on the pots to see if they've become intermittent or broken. This is a VERY common ssue and is almost always remedied by re-flowing the connection.

There's one other thing that could have caused this issue. Being active tone controls, they are more akin to frequency "gain" controls. IF the bass tone control was turned to 'full cut', the overall gain of the lowest frequencies was nearly non existent. In other words, it was working fine, the gain was just cut to the point where it mimicked a faulty pot.

BTW: That's an exquisite bass. Those mid/high end Ibanez basses are (IMO) some of the best basses being produced.

Let me know if any of that info helps, OK?

Best of luck,

Paul (-:

Hello again Paul,

I'm not familiar with Deoxit. Where should I look to get some? I'm not sure of what you mean by the pads on the pots-is that the solder connect on the outside of the pot? I'd like to get more knowledgable about electronics than I am. Any recommendations as to literature available?

Thanks again for your help.

Lee

Lee,

Paul's on the money with this.  The SR506 has a bass boost/bass cut control - not a standard tone control.  Turn it down past the center detent and the bass thump and volume goes away.   I have enclose the circuit diagram so as to define the controls.

Rusty.

Paul's good on this, as usual:  it's a bass boost/cut control and it has a lot of authority -  turn it down and it'll kill the volume stone dead along with the thump factor.  I've enclose a wiring schematic to impress the locals! - but it's just to map the controls for you and note, that when they get bit feeble or start distorting when you dig-in, replace the battery with a good alkaline or lithium - the Kmart specials won't cut it.

Rusty.

Sorry lee, the broadband is down for the count at the moment - my schematic attachments didn't get through the ether/link to you - so, trust me for the time being with the narrative.  I tried.

Rusty

Hi Rusty,

It's apparant I need to get more education in electronics. I found a wiring diagram for the sr506 on Ibanez.com. It shows the connections- the parts list is listed separately elsewhere on the site. Any suggested reading? -Lee

Hi Lee, HNY,

The subject of active basses is a comprehensive one - there are many different ways that the manufacturers and makers arrange their controls and assign roles and sensitivity to these controls - not to mention the odd multifunction switch or two as well.  These days  I have to look up anything that is not a P-Bass to work out what's going on with each instrument.

I have a background in electronics and repair and short of dud pots, crap output jacks and re-flowing cold joints I opine that there is very little economic repair that can be done to most of the actives that go dead.   Not to say it can't be done, and I know that I have colleagues on this forum who are very good at hunting down electric/electronic faults but the active modules are generally cheaper to replace than to troubleshoot and order spares, repair etc. 

I'm not sure going past what the manufacturers offer in their support section (and it was the same schematic from the excellent Ibanez Bass support tab that I was trying to get across the link) is really useful if you are not going to go towards repairs in this area. But, I do enjoy having my brain strained occasionally by reading up on 'lectrickty and other such unfathomable topics!

Rusty.

Lee,

Rusty speaks the truth about troubleshooting any electronic problem with the active circuits.  A modern manufacturing 'given' is that electronics are meant to be replaced vs. repaired.  It's cheaper (more cost effective) for the manufacturer AND the user to simply pull & replace a circuit board than it is to spend 2-3 bench hours diagnosing and fixing the issue.  Add to that the number of surface mount (SMT) board level components used today and it adds up to a nightmare for even experienced 'old school' technicians. SMT workstations cost an arm & a leg and are required for expert SMT repair.

It's been my experience that active basses seem to be "the big thing" these days.  It's also been my experience that the awful instructions that come with most active instruments give the new owner pathetically little with which to work. 90% of the active basses that come in with 'problems' are fixed with either : a new battery or: showing the owner how to use the active controls. A few need PCB's and the rest are "mystery issues from Mars".

You can think of the active circuit in the bass for what it is: a preamp for the pickups with boost & cut tone controls.  Adjust it as you would the front end (pre-amp section) of an amp head. A common error many players make is to max out the active controls and then their rig distorts.  They're always surprised that the gain overload from their active instrument is the cause.

Folks (especially guitarists) are just getting used to the tremendous amounts of gain available from modern systems and its unpleasant side effects if not used judiciously. Electric players are gain crazy nowadays.  We'll have to wait for the pendulum to swing back closer to center before most of their problems disappear just by dialing back the gain.  I mean, how much more gain do you need than a '60 LP Special into a ProCo Rat into a 1972 100 watt Marshall? (now THAT'S TONE)  But I editorialize.

I think the best path you can take is: sit down with your bass, your amp, a pen & paper.  Play around with the controls and make notes as to what effect they have.  Once you begin to better understand their function & effect, I think you'll be amazed at how quickly you'll be able to dial in your ideal sound. Then...write those settings down because your knobs will get moved. Having a template to restore your settings is invaluable.

I urge active users to start with all tone controls 'flat' and gain at unity (1:1).  Set your amp for a sound as close to what you want as you can get and then use the tone & gain controls to "tweak" the sound to perfection. Also remember that active tone controls DO NOT require the degree of rotation that passive controls do. A 'little bit' of an increase or decrease will yield a dramatic difference.

So, just play around with your rig.  You'll have it figured out in no time & then the fun can start (:

Best regards,

Paul

Lee , this is a common problem in asian electric guitars , the tone or vol pot rotates to a point where one of the solder tabs shorts to the metalic shielding paint . I could be wrong but I see it all the time , when you go to adjust the pot , it moves a tiny bit and comes back on . The answer is to remove the knob , tighten pot in good position , and re-fit knob . Hope thats it.

Hi Len, it makes sense. I'll check it out. Thanks for the reply! -Lee

Those are just regular blend pots, also called stereo pots. Any quality electronics store should carry them. No matter how the electronics work, these are still just regular blend pots or, if you want, your stereo's left/right balance pot.

I never liked the Soundgear series, first of all the headstock is tiny, I have worked on two 5-string SR series Ibanezes that had the wing on the bass side of the headstock broken off. If it has Bartollini pickups or whatever they are called I'm not fond of that either. Very skinny body and a wide neck too.

Anyway, check everything, the cavity looks like spaghetti once with all the wires and a PCB but it's not that hard to understand, just take your time. Ibanez is notorious for bad jack sockets, I do at least 10 or 15 per year I have more of these in stock than regular Switchcrafts. They are nothing what they look. If you are getting any pops while moving the plug, this is the perfect time to replace the jack too.

Howdy Tadej, thank-you for your reply! I'll open the cavity up again, now that I have more info of what to look for.

-Lee

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