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Pot doesnt have enough thread.

W

Whippet

Aug 30, 2014
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#1
hey guys, my B50K pot doesn't have enough thread (it has gotten stripped down) for the hex nut to clamp it down tight enough from the top of the body.

I figure I can either get a new B50K pot or shave some part of the inside cavity so that the pot can settle itself deeper.

M questions are.

1. If I get a pot other than B50K, (100k, 250k,500K, 1 meg) and have a tech install it, will this affect the sound?

2. Are all pots essentially made equal in terms of quality?

I ask this because the B50K is rather hard to get in a solid shaft where I live.

3. Also if I can't get a new B50K, is there any other way to clamp down the pot, outside of shaving or changing the pot?

Thank you for all information and advice in advance.



​
 
#3
saabfender said:
Don't carve up your guitar.

1. Depends.

2. No. Amazon delivers everywhere. That's where I buy mine.

3. No.
Click to expand...

Thanks for the reply.

I can get the 50k pots in Japan but the quality is iffy.... supposedly its from Alpha electronics, the same one that's installed in the bass.

I guess I'll just have to get 5 or 6 and see which one is the best.
 
#5
Turnaround said:
You need 50K pots not any of the other values. The pot is part of an active circuit, so you can’t substitute other values the way you can with passive systems.

You can get some here:

[Invalid or Expired Link Removed]
Click to expand...

thanks for the information. Good to know that the only one I can use is a 50K.

I will look into getting the one you provided in the link.

Solid vs Split. Is there any difference in the quality or tolerance? Mine has a solid shaft and I am going to assume that some knobs only fit a solid or split.

There are solid shaft b linear pots in the store link you gave me, but 50K is not available, sadly. I think I read somewhere that the solid 50Ks were being killed off by Alpha.

Thank you once again for the precious information.
 
#6
I’ll probably get raked over the coals for this but... if your existing pot is solid shaft that means the knob has a set screw? You can use a knurled, split shaft pot to replace it if you have to. Granted, it’s not the ideal solution but if that’s all you can get...

If you go that route, when you install the knob line up the set screw with the split in the shaft so it isn’t smashing the two parts of the shaft when you tighten the screw down. Alternatively, you could cut a small piece of wood or metal that slides in the space between the two parts of the shaft to keep them from getting crushed together by the set screw.
 
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#7
Whippet said:
thanks for the information. Good to know that the only one I can use is a 50K.

I will look into getting the one you provided in the link.

Solid vs Split. Is there any difference in the quality or tolerance? Mine has a solid shaft and I am going to assume that some knobs only fit a solid or split.

There are solid shaft b linear pots in the store link you gave me, but 50K is not available, sadly. I think I read somewhere that the solid 50Ks were being killed off by Alpha.

Thank you once again for the precious information.
Click to expand...
Stick with a solid shaft, less to worry about in terms of aligning the set screw.

Split vs solid has no impact on tone, it is just the attachment point for the knob.

Also, did you buy your bass used? Or have you done work on it? The second task, after replacing the pot, is to figure out why it got stripped. You don’t need to tighten them to the point of stripping, that is pretty extreme.
 
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#8
Matt Liebenau said:
I’ll probably get raked over the coals for this but... if your existing pot is solid shaft that means the knob has a set screw? You can use a knurled, split shaft pot to replace it if you have to. Granted, it’s not the ideal solution but if that’s all you can get...

If you go that route, when you install the knob line up the set screw with the split in the shaft so it isn’t smashing the two parts of the shaft when you tighten the screw down. Alternatively, you could cut a small piece of wood or metal that slides in the space between the two parts of the shaft to keep them from getting crushed together by the set screw.
Click to expand...

Just ordered 7 of the B50K solid shaft by Alpha. One of them has to be within tolerance of at least 20%.

On top of the Alpha, I ordered 10, B50K solid shaft by some god knows what company. .28 cents a piece. Almost laughable price. One of these 17 must work.

Anyway thanks for the information. Will stick to the solid shaft to avoid even more complications.
 
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#9
mbasile said:
Stick with a solid shaft, less to worry about in terms of aligning the set screw.

Split vs solid has no impact on tone, it is just the attachment point for the knob.

Also, did you buy your bass used? Or have you done work on it? The second task, after replacing the pot, is to figure out why it got stripped. You don’t need to tighten them to the point of stripping, that is pretty extreme.
Click to expand...

Got the bass, brand new. It's an Alleva The problem is that I can't send it back since I am overseas.

The thread above the body is probably a little less than the thickness of a credit card. So just a little torque in a wrong way kills the first thread. All I need to do to screw it up is, mess up this first thread.

This makes it impossible to torque it down too much from the beginning.

I think the flat nut just didn't seat itself properly from the moment it got screwed on. Other than this first thread, the rest of the thread is fine. Works properly, which is why it was tempting to just carve out a little bit of the cavity to compensate for the lack of thread and just tighten the nut.

Anyway thanks for the information. All I need is more upkeep, so I stuck with what you guys rec'd.
 
#14
Matt Liebenau said:
I’ll probably get raked over the coals for this but... if your existing pot is solid shaft that means the knob has a set screw? You can use a knurled, split shaft pot to replace it if you have to. Granted, it’s not the ideal solution but if that’s all you can get...

If you go that route, when you install the knob line up the set screw with the split in the shaft so it isn’t smashing the two parts of the shaft when you tighten the screw down. Alternatively, you could cut a small piece of wood or metal that slides in the space between the two parts of the shaft to keep them from getting crushed together by the set screw.
Click to expand...
+1 on filling the split.
Some pots with metal split shafts break easily. Be very careful.
There is no inherent quality difference due to the shaft material used. I have seen cheap pots with metal shafts and quality pots with non metallic shafts.
The sleeve is a good idea too, just be sure of the fit.
 
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#17
Whippet said:
Just ordered 7 of the B50K solid shaft by Alpha. One of them has to be within tolerance of at least 20%.

On top of the Alpha, I ordered 10, B50K solid shaft by some god knows what company. .28 cents a piece. Almost laughable price. One of these 17 must work.

Anyway thanks for the information. Will stick to the solid shaft to avoid even more complications.
Click to expand...

There is no need to order all those pots! No one cares if it's within 20% of spec, blah, blah, blah...it's a control in a bass guitar, not part of a space launch or an MRI machine...sheesh!!!
 
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