Dual Concentric 500 K Pot for guitar?????

[guitar199]

I have a crazy modification planned for one of my guitars and would be looking for such a pot (actually, two of them!).

I see Fender pots where one is 500 K and one is 250 K .... apparently their old basses used this one....

What I am wanting to do.....

The "patient" is an Ibanez GAX 30.  I am going to change out the humbuckers for something Alnico/a little warmer......BUT....

I'd also like to have independent controls over the pickups as you do on an LP or SG.
What I am thinking of doing is replacing the single volume and tone control with a pair of dual/concentrics...making the inner control VOLUME and the outer control the tone, for each pickup.

But first I have to get a handle on the pots....   if anyone has seen such .... I would appreciate it.

Bob

[reTrEaD]

Mar 27, 2020 17:31:14 GMT -5 guitar199 said:

But first I have to get a handle on the pots....

Hi guitar199 and to Guitarnuts2.

I don't imagine you'll have any problem finding dual concentric pots. The only questions would be, what value for the upper(outer knob) element, what value for the lower (inner knob) element, and do you want split-shafts for push-on knobs or solid shafts for set-screw knobs, like this:


www.allparts.com/collections/potentiometers/products/ep-4586-cts-500k-500k-concentric-audio-pot


www.allparts.com/products/mk-0137-stacked-concentric-knob-set?pr_prod_strat=copurchase&pr_rec_pid=1986735669305&pr_ref_pid=1986723250233&pr_seq=uniform

[guitar199]

I had looked at Allparts earlier and could not get anything to show up....

I will apparently have to look later as something seems to be wrong with their website.  It's like a connection gets made but never quite completes right.  The actual pages never come in.... just what looks like a list of text links.  If you try following the links that make sense.... you just get another list of links.

But thank you, I will look at these when I can.

Bob 

[frets]

500k/500k
guitarelectronics.com/cts-stacked-dual-concentric-audio-pot-500k-500k/

[guitar199]

Those two links refer to the same CTS pot assembly.

The problem I see with it .....

The pots on the current guitar are not mounted in a pick guard, rather they are similar to a Les Paul (or other single cut style) in that there is just a hole drilled in the wood and the pots are rear loaded through a compartment in the back.   That "hole" is almost exactly 1/4" thick and the threaded bushing on the pots are 3/8" so almost 1/8" sticks out the top and allows for washers and the nut.

The bushing on this pot is exactly 1/4" which means it won't stick out far enough for the nuts to grab the threads... let alone any washers.

I suppose I could either open up the area around the pots and create a small plastic piece "like" a pick guard and screw it to the body, then mount the post to this" OR (the cavity is fair sized) just drill in two more holes and use single element pots and wire it the way I want.   I am hoping not to have to do that IF I can find a stacked dual concentric pot like this with a 3/8" tall bushing area.

I very much appreciate the time you spent in sending me these!!!!  Thanks!

[sumgai]

agent99,


Hi, and to The NutzHouse!

Mar 28, 2020 17:49:57 GMT -5 guitar199 said:

.....
I suppose I could either open up the area around the pots and create a small plastic piece "like" a pick guard and screw it to the body, then mount the post to this"

That would be rather ugly.

OR (the cavity is fair sized) just drill in two more holes and use single element pots and wire it the way I want.   

Bog standard, and not what you want.

I am hoping not to have to do that IF I can find a stacked dual concentric pot like this with a 3/8" tall bushing area.

The only fly in your ointment is the fact that you want two different values in one control, with a long bushing. The original units found in Fender Jazz Basses used, of course, short bushings (1/4" high). But if you're willing to look at things sideways, you could grab one of these:


(Image is a link)


That's a 500/500KOhms unit. But wouldn't you know it, you can also order the same thing in 250/250, at this link:

Same image as above.

Instead of thinking "one pickup = one pair of controls", instead think like "one pot = one function (for example, both Volumes; Neck inner and Bridge outer)".

One thing, though.  These babies have a slightly shorter bushing than 3/8", coming in at 8.75mm.  That's 0.75mm smaller (3/8" = 9.5mm), or about 1/32 of an inch. I can't imagine that this will make it impossible to use in your application.  Additionally, when you view those linked pages, you'll see a suggestion as to knobs made for them.

And to cap it off, they are made by Bourne, one of the top names in the business.  Many here swear by that brand as being the only one they'll ever use.  Sorry, I mistook the brand name, after reading several other potential components that would perhaps fit the bill.  Just got mixed up, that's all.  The ones I linked above are made by Alps, a somewhat decent quality, but be aware that they are "mini" or "dime sized" pots, which gets some folks all up in a tizzy.

HTH



sumgai

[Deleted]

cdn.shopify.com/s/files/1/0127/4508/0889/products/EP-4585-4586-000-w_71711fce-7163-4534-978d-099d2734a751_900x900.jpg

Sorry to go off topic a bit..
Anyone have pdf or size of this pot
High width etc

[guitar199]

Mar 28, 2020 21:12:30 GMT -5 sumgai said:

The only fly in your ointment is the fact that you want two different values in one control, with a long bushing. The original units found in Fender Jazz Basses used, of course, short bushings (1/4" high). But if you're willing to look at things sideways, you could grab one of these:


(Image is a link)


That's a 500/500KOhms unit. But wouldn't you know it, you can also order the same thing in 250/250, at this link:

Same image as above.

Instead of thinking "one pickup = one pair of controls", instead think like "one pot = one function (for example, both Volumes; Neck inner and Bridge outer)".

One thing, though.  These babies have a slightly shorter bushing than 3/8", coming in at 8.75mm.  That's 0.03mm smaller (3/8" = 9.5mm), but I can't imagine that this will make it impossible to use in your application.  Additionally, when you view those linked pages, you'll see a suggestion as to knobs made for them.

And to cap it off, they are made by Bourne, one of the top names in the business. Many here swear by that brand as being the only one they'll ever use. Sorry, I mistook the brand name, after reading several other potential components that would perhaps fit the bill. Just got mixed up, that's all. The ones I linked above are made by Alps, a somewhat decent quality, but be aware that they are "mini" or "dime sized" pots, which gets some folks all up in a tizzy.

HTH



sumgai

Thanks!
I went back and read my original post and I believe that, in my lack of clarity, I misled you!
I actually am looking for a dual 500k.   I only mentioned the Fender 500K/250K because it was all I could find ....but neglected to ever say that it wasn't what I wanted.....or even what I WAS looking for!!!!!

But this suggestion seemed to really fit the need.   Looking at the busing length......  I simply can't believe that .775 mm would cause a problem.   At less than a mm I would take a dremel and shave off a tiny bit on the inside of the hole on the compartment side to make up for it.  This is not a touring guitar.... just a club gigging guitar... so that would be fine for me!  I even see that, in keeping with the guitar's original color scheme, they have black stacked knobs as well.

You may have just saved the day and I thank you!!!!

Oh, and I will give some thought to your suggestion as well  (front stack both volumes, rear stack both tones).  It may indeed make more sense. 

So again.....many thanks!!!
Bob

[sumgai]

Bob,


The way you describe it as "just a club guitar", that sounds to me like it's not meant to be kept in pristine shape, ready for resale at maximum value. Well, if that's the case, just don't use the washer under the nut, and you're home free.

HTH





sumgai

[reTrEaD]

Mar 28, 2020 21:12:30 GMT -5 sumgai said:

And to cap it off, they are made by Bourne, one of the top names in the business.  Many here swear by that brand as being the only one they'll ever use.

That would be nice ... except that they aren't Bourns. They're Alps which is an acceptable brand but nothing write home about.

Also they're small-element pots (sometimes referred to as dime-sized). I tend to shy away from those unless the amount of real estate below the pickguard is an issue.

If there's enough length on the threaded bushing that these will work without any butchery, they may indeed be a solution. But I wouldn't hard-sell them.

[JohnH]

Mar 31, 2020 13:38:57 GMT -5 reTrEaD said:

That would be nice ... except that they aren't Bourns. They're Alps which is an acceptable brand but nothing write home about.

That would depend on whether ones 85 year-old mother is an electronics nerd who still reads handwritten letters because she never understood Facetime:

"My Dearest Mother,

I am so excited about the new potentiometers that I received today from Digikey!….

...your loving son"

[sumgai]

Mar 31, 2020 13:38:57 GMT -5 reTrEaD said:

Mar 28, 2020 21:12:30 GMT -5 sumgai said:

And to cap it off, they are made by Bourne, one of the top names in the business.  Many here swear by that brand as being the only one they'll ever use.

That would be nice ... except that they aren't Bourns. They're Alps which is an acceptable brand but nothing write home about.

Corrected. Thanks, 'TrEaD.

But I wouldn't hard-sell them.

No hard sell was intended in the making of that post.

But some folks just grab the first thing off the shelf that seems to fit the need. I consider it courteous to let others know that I'm not personally flogging a POS.






sumgai

[guitar199]

Man...... I didn't check for a few days...... I missed some stuff!!!!!!  


I'm thinking about those pots but may well do a little more looking around.  I would indeed like it a  little better if I could find larger sized pots to fill the bill.  Don't know why but I'd feel a bit better with them.  I do appreciate all the replies!

Bob

[curtwash2]

Hello, I wanted a dual concentric CTS pot that was ALSO no load. I ended up buying 2 single CTS no load pots of the values I wanted and then took the available regular concentric pot that was physically the right size apart. Then I replaced the wafers with the correct carbon pads for the impedance and the no load functions. Since they were from the same CTS family just carefully unbending the small tabs that held the 3 pots together was very doable. Being careful to put them back together after using wafers from the two single no load pots and bend the tabs the correct amount, and even the physical feel was good as new. Be careful though. I do remember I had to pay attention to the shaft sizes. I even have 2 single pots left over that are not the impedance they say on the back but I remember using one to fix a guitar I ended up giving away.

[guitar199]

That is a good idea!   I have already "given up" and bought a pair of Alpha stacked that will "do the job" and they just arrived today.

but this makes me think that I may do the same thing..... and, assuming I am successful, swap them in down the road.  I would really rather have  the beefier pots.  

Thanks for this!

[guitar199]

Just thought I would come back and show the "finished product".   It is everything I wanted from this work!!!!

When you look at the pic, the original only had single knobs because it had a single volume and single tone control.  Now, the leading control is volume for each pickup and the other is tone for each pickup.  Upper knobs are neck pickup, lower knobs are bridge.   The switch is "Switchcraft" brand and man it feels better than the original!!!!  And to my ears, it sounds wonderful.  All the tonal color that I had in mind.





 


 


 

[guitar199]

Second photo, dead center.... I caught that unsoldered tab on the switch when I soldered the guitar ground and pickups in!