[zurn]

Hey everyone.

I replaced a bad bridge volume pot on my LP. It's a CTS 500k audio taper.

This one
https://www.toneemporium.com/product-page/cts-long-3-4-split-shaft-500k-potentiometer

For some reason when I turn it completely off, there's still some volume from the pickup?

Also, the volume doesn't drop gradually as I turn it, it drops from 10 to around 6 and then pretty much nothing changes for 5 to 0.

Any ideas?

 

[zurn]

Found the problem, I forgot to solder that empty tab to the cover.

All good now. Only problem is that the new pot doesn't feel like the other ones. It's much easier to turn. Ahh well, at least it works lol.

 

[BMW-KTM]

Actually I have always found Gibson pots to sound not very linear.
I don't mean mathematically linear but linear sounding to the ear.
Epiphone pots are about the same in that respect.
PRS branded pots have their own custom taper that makes them sound more linear to the ear.
I put them in my Les Paul and they made a noticeable improvement in functionality in my opinion.
They're not cheap though.
A set of four will run you over $100.
In my opinion it was worth it.
Rolling off felt so much more natural.

 

[mhammer]

Almost 20 years ago, my buddy RG Keen wrote and posted this piece on his GEOFEX site. It explains pot taper and also shows how to customize the taper of a pot. The Secret Life of Pots

 

[bigboki]

Almost 20 years ago, my buddy RG Keen wrote and posted this piece on his GEOFEX site. It explains pot taper and also shows how to customize the taper of a pot. The Secret Life of Pots

for me that link does not work (via HTTPS), however via HTTP it works
The Secret Life of Pots

 

[mhammer]

Thanks for the correction.

 

[laristotle]

I got the price knocked down on a Firebird because of the same problem.
It was hard to find at first because everything looked fine visually and even when tugging at the wires.
It's when I started poking with a stick that I found it.
A blob of solder on the volume ground lug, but not adhered to the casing.
After testing to verify, one of the tone pots was not functioning.
Opened it up and found that the cap wire was not soldered to the lug.
Just floating in the hole.

So much for QA at the plant.

 

[mhammer]

Unlike older guitars with "classic" CTS pots, budget pots on newer guitars tend to have aluminum back covers. These do not take solder readily, and sometimes not at all. I generally scrape the back of a pot with an X-acto blade to try and make it a little more receptive to solder, but getting a secure joint is not always an easy task. Also note that, while a ferrous back cover makes for a greater likelihood of a true solder joint, because it conducts and dissipates heat efficiently, soldering a ground connection to the back cover requires a higher-heat iron, and is one of the few instances where use of a soldering gun with a guitar is warranted.

Can it be judged visually? Somewhat, depends on the shape of the "blob". If it slopes out from the wire to the pot chassis, that can be a fairly reliable sign f a secure joint. If it is a "blob", then it might be a decent joint...or it might not.

Depending on where you live (and where products are manufactured) tarnish, via exposure to air, can form more quickly. Plenty of times, I pull a component from the parts drawer - switch, chip, transistor, resistor, capacitor, pot - and find that I need to "shine up" the leads/lugs/pins on it with a knife blade to be able to get a solder joint I feel I can trust. It's just too damn easy for many solder joints to look like they're legit, when they only have the superficial characteristics of continuity.

 

[High/Deaf]

I've said it before and I'll say it again. Cranking up the temperature on a soldering iron with a tiny tip is not the best way to solder on to large surfaces, like the back of a pot. A large tip, even at the same lower temp, works better. It's all about thermal mass and thermal transfer.

The spade tip on the left is significantly larger than the little pencil tip on the right (sorry about the focus, but I think you can make it out).

It takes longer to heat up, because of the mass, but flows heat to larger objects much more quickly as well. Here are some pot backs I soldered a while ago. No blobs, only smooth solder joints. These were done in around a second, so no damage to the component either. The lugs were soldered with the small-tipped iron on the right.

There's a reason why the hot air in a stove doesn't burn your hand, but the hot grill will. They are both at the same temperature. Thermal mass.

 

[BMW-KTM]

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