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Where to find a pot for my Ibanez bass?
#3025825 01/26/20 04:17 AM
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I need to replace the treble boost/cut pot in my SRA550, a bass Ibanez has not made in a while. This bass uses an active preamp/eq called the EQB3C. My ohmeter measures it at 56K so I'll guess it's a 50K and probably a linear taper. I've looked at ibanez.com and they sell the entire preamp assembly with all four pots. Ebay does have some pots but they're only specified as "for Ibanez", no other description. They might work but I'd rather see if anyone here can point me to the exact part. Thanks!

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Re: Where to find a pot for my Ibanez bass?
Reezekeys #3025885 01/26/20 06:03 PM
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These guys have everything.

https://www.mouser.com/?utm_source=...ectronics&utm_content=Brand%20Mouser

I would do a search for "Ibanez SRA550 schematic" online, somebody may have done all the heavy lifting for you. Also try adding the word "Forum", sometimes people will be discussing the same problem you have. Yes, it is probably linear but if it is audio taper then it won't adjust in the same way it used to. You could also google "test potentiameter for audo or linear taper" and see if anything simple comes up. You will have to remove the pot to test it and to replace it. You cannot get accurate readings with it being part of the circuit.

If not.

They will need every number off that pot, a sharp photo of the bottom would be helpful. If there is solder covering some of the codes, remove the pot (noting the location for all connections and putting labelled masking tape flags on the wiring) and first use a solder sucker and then a solder wick to remove the solder and get down to the numbers. You may have to gently file away the last layer of solder and the number should be discernable. The complete codes should inform as to the taper.

Yes, it is a PITA. Your other option is to pay a tech and hope they get it right. Cheers, Kuru


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Re: Where to find a pot for my Ibanez bass?
Reezekeys #3025962 01/27/20 01:24 AM
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Thanks, I appreciate the advice. I looked for markings but saw none (I'll try looking again, more closely this time). I'm guessing it's a linear taper as it has a center detent (it's an active eq pot that boosts and cuts, the zero position is in the middle). I'm ready with my Harbor Freight digital caliper if I need to measure the dimensions, then go to Mouser and find a match – but I thought it would be wise to ask here first in case anyone had been down this road before. I don't relish going through a ton of drawings on that site to find the exact pot. I can't imagine I'm the first guy with an Ibanez bass that's needed to replace a single pot! BTW I did look for a schematic of that preamp or bass and could not find one. Worse comes to worse I'll order a few pots and pick the one that fits best – that'll still cost a lot less than buying the entire preamp assembly or bringing the bass to a repair person. I'm no EE but soldering a potentiometer is not a problem for me.

Re: Where to find a pot for my Ibanez bass?
Reezekeys #3025985 01/27/20 02:31 AM
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Originally Posted by Reezekeys
Thanks, I appreciate the advice. I looked for markings but saw none (I'll try looking again, more closely this time). I'm guessing it's a linear taper as it has a center detent (it's an active eq pot that boosts and cuts, the zero position is in the middle). I'm ready with my Harbor Freight digital caliper if I need to measure the dimensions, then go to Mouser and find a match – but I thought it would be wise to ask here first in case anyone had been down this road before. I don't relish going through a ton of drawings on that site to find the exact pot. I can't imagine I'm the first guy with an Ibanez bass that's needed to replace a single pot! BTW I did look for a schematic of that preamp or bass and could not find one. Worse comes to worse I'll order a few pots and pick the one that fits best – that'll still cost a lot less than buying the entire preamp assembly or bringing the bass to a repair person. I'm no EE but soldering a potentiometer is not a problem for me.


Yeah, easy solder job. I would still recommend you mark and remove the wires and then measure the resistance as the circuit it is attached to could change it. You will have to remove them anyway.

I searched ebay for "50k linear potentiometer center detent" and specified USA only for faster shipping. It's not a rare part at all, especially if you include other countries...

https://www.ebay.com/itm/50K-Ohm-Alps-Linear-Taper-Rotary-Potentiometer-Variable-Resistor-Center-Detent/282884742236?hash=item41dd3e9c5c:g:nBwAAOSwcSJa14DC


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Re: Where to find a pot for my Ibanez bass?
Reezekeys #3026017 01/27/20 05:05 AM
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OK looks like it's not 50K. There is one marking on it, "B100K", and after I took it out of the circuit I measured the end-to-end resistance – it's 86.2KΩ. I guess that's a 100K "low tolerance" pot, lol.

I also made a few measurements (all numbers are millimeters) and did a little photo editing. Thanks for checking out what was available on Ebay. Unfortunately the pots you linked to didn't have the right kind of shaft, I need it to be like this one (I think it's referred to as "split" and "serrated").

With these measurements I should be able to find something on Mouser, I think. Thanks again for your assistance!

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Re: Where to find a pot for my Ibanez bass?
Reezekeys #3026033 01/27/20 06:15 AM
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Yeah, 100k is "nominal".

Shaft is important so your knobs will fit. Mouser should have something now that you know what you need.
Cheers, Kuru


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Re: Where to find a pot for my Ibanez bass?
Reezekeys #3026125 01/27/20 05:02 PM
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Well, no luck at Mouser. The Bourns PDB181-GTR Series - 17 mm Guitar Potentiometer seems to be a match for mine, but lacks the center detent. I don't see a similar pot with one.

So far I looked at Ebay, Amazon, Allied, Arrow, guitarelectronics.com and a few others.

The basic form factor is not a rare thing. Here's a PDB181-GTR sold at reverb.com, it would be almost identical to mine... if it was 100K and had a center detent!

Re: Where to find a pot for my Ibanez bass?
Reezekeys #3026130 01/27/20 05:18 PM
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Bummer on Mouser not having it. Did you shoot them a line and ask? Maybe they don't list them but can get one for you.

Is the center detent a must have or just a convenience?


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Re: Where to find a pot for my Ibanez bass?
Reezekeys #3026137 01/27/20 05:37 PM
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The center detent is where the EQ is flat, not boosted or cut. That's where I normally keep it. The more I think about it, the more I can see dealing without the detent. I'll just fudge the pot position somewhere in the middle. Thanks for planting that seed!

Re: Where to find a pot for my Ibanez bass?
Reezekeys #3026245 01/28/20 02:22 AM
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Just wanted to tie a bow on this as after hours of clicking around multiple electronics parts sites, I think I have found the part that will work. It's a Bourns pot and it does exist, unfortunately it shows as out of stock everywhere except a site called Hamilton Americas – but I have my doubts as to whether they'll sell me one as I had to fill out my info to "request a quote." Not typical for a business that sells to end users like me.

I'm pretty well spent after spending this much time chasing this stupid part so I'm probably gonna order it from Mouser and wait 16 weeks. That's what they call "lead time" on this piece. All the other major suppliers that had this (Arrow, Digikey, Avnet, and Newark) had the same 0 stock and a minimum order of 450 units! Mouser is the only place that will sell me just one. Needless to say, the shipping is more than the part – by more than 6x! Beggars can't be choosers, I guess.

BTW the exact part number (subject to change if I screwed up on my measurements!) is PDB181-E218K-104B1.

BTW #2 - the Ibanez web site is NO HELP AT ALL. This post is already too long to go into detail, but it was pretty frustrating looking around there.

Re: Where to find a pot for my Ibanez bass?
Reezekeys #3026268 01/28/20 04:45 AM
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Originally Posted by Reezekeys
The center detent is where the EQ is flat, not boosted or cut. That's where I normally keep it. The more I think about it, the more I can see dealing without the detent. I'll just fudge the pot position somewhere in the middle. Thanks for planting that seed!



I read your other post too, sorry about the bummer.

You could mark the end of travel in both directions, put another mark exactly in between those two and call it good. A dot on the knob and one on the bass and you can go "home" every time.
As the I Ching says, "Perseverence Furthers."


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Re: Where to find a pot for my Ibanez bass?
Reezekeys #3026308 01/28/20 01:25 PM
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Just ask Gorrie if you can have one of his old basses. Then send it to me. grin


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Re: Where to find a pot for my Ibanez bass?
Reezekeys #3026634 01/29/20 09:32 PM
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I tried that, for some reason he wasn't that receptive to the idea! smile

In the meantime, a good friend of mine who's a great player as well as a designer & builder of his own basses gave me an idea on how to continue using my bass with the current pot while I wait for the new one. He told me he hates the "split shaft" pots. He suggested breaking off the half that's almost gone (maybe I should mention that this is why I need to replace the pot in the first place!). Then, superglue that half to the other half and get a knob with a setscrew to keep it attached.

Re: Where to find a pot for my Ibanez bass?
Reezekeys #3026641 01/29/20 09:47 PM
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Originally Posted by Reezekeys
I tried that, for some reason he wasn't that receptive to the idea! smile

In the meantime, a good friend of mine who's a great player as well as a designer & builder of his own basses gave me an idea on how to continue using my bass with the current pot while I wait for the new one. He told me he hates the "split shaft" pots. He suggested breaking off the half that's almost gone (maybe I should mention that this is why I need to replace the pot in the first place!). Then, superglue that half to the other half and get a knob with a setscrew to keep it attached.


That should work.
We have one of the best hardware stores in the known Universe here. I'd be inclined to get a longer set screw but that's just me being lazy.


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Re: Where to find a pot for my Ibanez bass?
Reezekeys #3026646 01/29/20 10:05 PM
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Yea, he mentioned I might need something to build up the pot's shaft so the screw has something to grab! (No, this is not a pitch for a porn movie plot, ha ha!).

A longer set screw should work too. Seeing as my next gig playing this bass is March 21, I'm sure I'll have it figured out. My new pot should be on a boat somewhere on the Pacific Ocean then, unless all of China is closed!


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