Issues wiring up a volume pot

[kcducttaper]

So, I kinda feel stupid, but I just can't get this one figured out. After putting in all new electrics on my bass, my volume wasn't working right. This evening, I took the blend pot out of the equation, so now, I'm running one passive pickup through one audio taper 500k volume knob and straight to my output jack. Even with this setup, the volume goes from 0% to 100% in the first eigth turn of the volume knob. I tried another 500k pot with the same result. I've got it wired up with the TRS tip going to the middle, the pickup hot on one side and the TRS sleeve (ground) on the other. It might be worth noting that I've also put down a layer of copper tape in there for RF shielding and hooked that up to my TRS sleeve to ground it as well. The weird thing is, if I swap the pickup and sleeve wires around on the volume pot, it's nice and linear - but with the knob is turning the wrong way. Any pro tips 'cause I'm dumbfounded just by one knob...

 

[Matei]

A pic with the wiring and a pic with the schematics you are trying to wire would do I suppose, BUT it sounds to me that you wired it mirrored... Check with a multimeter how the pot varies the resistance when you turn it around

Check this link out, it gives a crash course on what is going on
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And just for the reference, it looks like in the case of log pots (audio taper) there are left and right hand pots.

The linear one can, of course, be reversed (mirrored) without any noticeable effect. But the log ones change the slope (not an expert here, just what I've picked up from the Internet)
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[kcducttaper]

It totally sounds like I've got a lefty pot, but I've tested the same pot that I pulled out which was working correctly for the previous 11 years... Thanks for the linky! I'll be sure to check it out here in the next couple days when I get a chance.

 

[ctmullins]

Try connecting the pickup hot to the center lug of the pot, and the jack to the outside lug (reverse of what you have now).

 

[kcducttaper]

Here's my testing setup. I've verified with a voltmeter that the black is ground (sleeve), the red is tip, and white is my neck pickup's hot wire. In this configuration, the volume is nice and linear, but backwards - meaning the volume increases as I turn the pot counterclockwise. I'm using this pot.

 

[kcducttaper]

I just buttoned up a used Ibanez sr505 (little brother to my 755 with the same stock electronics) and its volume knob seems to only come into play in the last 10% as well. Maybe my 755 was that way all along and I never noticed...? I've ordered another pot just to be sure.

 

[kcducttaper]

I just received my Dimarzio 250k pot and guess what? Same thing! When hooked up 'correctly', the volume is all in the last ~10% of travel, but it's nice and linear (to my ear) when hooked up backwards! What gives? Do I need to order a lefty push/pull pot for my very normal righty bass?

 

[ctmullins]

Try connecting the pickup hot to the center lug of the pot, and the jack to the outside lug (reverse of what you have now).

Did you try that?

 

[kcducttaper]

Did you try that?

Yep. That's actually what I've got in the picture, but it's made no difference. I've tried every combination I can think of and I can consistently get a smooth volume turning the pot backwards, but never forwards.

I just don't get it. There's literally nothing hooked up other than one pickup's hot wire straight to the pot and the pickup ground going to the sleeve along with the rest of the grounds (shielding, bridge grounding, etc)....

 

[ctmullins]

Ok. Couldn’t see your picture.

 

[kcducttaper]

Anybody have any thoughts at all? Stabs in the dark are welcome! What would happen if my pickups were wired up backwards from the factory? I guess I could try the other pickup to see if it behaves the same.....