Hey walterw

**line6man** · #1 08-30-2009, 11:46 AM

Ok, I just tried the linear taper volume pot.
You're absolutely right, totally smooth roll off!
I think you have been right about this all along.

But there is one problem...
It rolls smoothly from full down toward the end of the rotation, then it just abruptly mutes.

Is it just the pot I have, or is that typical of a linear volume?

I did this on my other bass, because I had a linear taper pot lying around.

My main bass is with my luthier right now being routed to fit the new electronics upgrades I have planned.
If I can get this linear taper to not abruptly cut off, I'm going to put linear volumes on my main bass when I wire it up.

walterw · #2 08-30-2009, 01:36 PM

hmm, i haven't noticed that before. is this an active bass? what size pot did you use?

i personally like 500k linear volumes on vintage fender-type basses, and haven't noticed it being anything other than even.

...ok, i just went and pulled out my P-bass (passive, fralin pickup) and plugged it into the johnson j-station that's hooked through my computer to my stereo for at-home noodling; on a clean setting, it sweeps perfectly evenly from "off" to "full".

**line6man** · #3 08-30-2009, 02:17 PM

Nope, it's a passive bass with one volume and one tone:
http://www.flickr.com/photos/jrkdesi...7616932207171/

I spent some time just hitting a chord and fiddling with the volume control while it rang out.
There is definitely an abrupt mute toward the end.
Another thing I noticed is that rolling down the volume really seems to pull out the treble.
I know that passive volumes by nature pull out the treble when you turn them down, but it seems more pronounced with the linear.
This might be because an audio taper has the big drop from "10" to "8"-ish where most of the treble is cut, then it's fairly smooth, but the linear taper is drawing out that roll off from "10" down to like "5".

I might record a soundclip of the volume control sweep later today so you can hear it.

**line6man** · #4 08-30-2009, 03:16 PM

Ok, my first ever YouTube upload...

http://www.youtube.com/watch?v=LmSuk-PLbRE

Here is a soundclip. It really doesn't seem to come out as much being recorded, but you can still hear the drop off in volume toward the end of the rotation.

walterw · #5 08-30-2009, 04:23 PM

yeah, that does sound like it's dropping off at the bottom, there.

again, what resistance pot? and what are you plugging it into? (and forgive me, but are you sure it's a linear pot?)

is the pickup attached to the input lug or the center lug of the pot?

**line6man** · #6 08-30-2009, 04:46 PM

Quote:

Originally Posted by walterw

yeah, that does sound like it's dropping of at the bottom, there.

again, what resistance pot? and what are you plugging it into? (and forgive me, but are you sure it's a linear pot?)

is the pickup attached to the input lug or the center lug of the pot?

500K
Yes, it's a linear. I've tested it a while back on the ohm meter.

Plugged into a Line6 Bass PODxt Live, on a bypassed setting, into a direct box to my FirePod, recording into SONAR 6.
Everything is pretty much totally flat, no EQ, compression or anything.

Yeah, I always wire my volumes with the center terminal as an input and the first terminal as an output.

walterw · #7 08-30-2009, 07:30 PM

Quote:

Originally Posted by line6man

Yeah, I always wire my volumes with the center terminal as an input and the first terminal as an output.

aha!

that's for jazz basses, where you have to do that to keep one volume from shutting off both pickups.

for single volume instruments, you should wire the pickup to the first terminal and use the middle one for the output.

i'll bet this fixes both problems (volume & treble loss).

**line6man** · #8 08-30-2009, 08:39 PM

Quote:

Originally Posted by walterw

aha!

that's for jazz basses, where you have to do that to keep one volume from shutting off both pickups.

for single volume instruments, you should wire the pickup to the first terminal and use the middle one for the output.

i'll bet this fixes both problems (volume & treble loss).

Ok, I just switched the connections.
Damn, your absolutely right! Totally smooth taper.
I'm changing my "Log. versus linear" stance to linear now!

I never knew it made any difference to use the first and second terminals interchangeably? When dealing with two or more volumes, the output has to be the outer terminal to avoid shorting the output, but I never knew it mattered when dealing with a single volume instrument?

Ok, that presents a problem for me then...
I am going to be wiring my main bass up with two volumes plus a three way switch.
I can use the switch to solo either pickup without adding extra resistance from the unused pot which would darker my tone, but I would still be able to have a different volume setting for each pickup when I select them, and be able to blend them together in different proportions when combined.
My main plan for the bass is to use each pickup by itself, and since I am going with traditional P and J pickups rather than a matched output set that would compromise the soloed tone of either pickup, the output of the P pickup is going to overpower the J, so I will probably want it at a lower volume.
This is why I am going with the rather unorthodox setup of a pickup selector switch in addition to separate volumes.

The switch is going to cause the bass to toggle between being a single volume and a two volume configuration, depending on whether the pickups are soloed or combined...

So what should i be doing then?

Worst case scenario, I would wire each volume with the first terminal as an input and the second as an output, then configure the middle position of the pickup selector switch as a killswitch.
That would allow me to keep my separate volume settings when switching between the pickups, but I would lose the ability to combine the pickups.

walterw · #9 08-30-2009, 08:51 PM

sweet, linear volume FTW!

i would go with the gibson guitar scheme, where the two pickups each go to the input lugs of their volume pots for the best tone and taper, and then get fed to the switch.

in the middle, you can still blend and balance them, all the way down until you turn one all the way off, which will then kill everything.

**line6man** · #10 08-30-2009, 09:09 PM

Quote:

Originally Posted by walterw

sweet, linear volume FTW!

i would go with the gibson guitar scheme, where the two pickups each go to the input lugs of their volume pots for the best tone and taper, and then get fed to the switch.

in the middle, you can still blend and balance them, all the way down until you turn one all the way off, which will then kill everything.

Like I said, I never even knew about this until today, so I'm a little slow catching on here,
Wouldn't that cause a drop in volume to both pickups when either volume is rolled down?

Basically the middle terminals are connecting together and the third terminals are connecting together, so we have two resistors in parallel between the output and ground.

As we decrease the resistance on one resistor, the total resistance from the output to ground would also decrease, as both resistors are in parallel, and it would provide a more direct path along the other resistor as well.

However, the resistance from the input to the output (first to second terminals) should remain the same regardless of the other pots setting, as the first terminals are not linked in parallel.

walterw · #11 08-30-2009, 10:13 PM

that sounds logical, but you're missing something, because that's not what happens.

i can't off the top of my head think of what that something is, but i know as a guitar player that a standard technique for gibson les paul players is to turn up both pickups, put the switch in the middle, and roll one or the other volume down a little to change the balance between them.

this works fine, and with no overall volume loss, right up until one volume is all the way off, at which point the guitar goes silent unless the switch is thrown to the other pickup.

**line6man** · #12 08-30-2009, 11:16 PM

Quote:

Originally Posted by walterw

that sounds logical, but you're missing something, because that's not what happens.

i can't off the top of my head think of what that something is, but i know as a guitar player that a standard technique for gibson les paul players is to turn up both pickups, put the switch in the middle, and roll one or the other volume down a little to change the balance between them.

this works fine, and with no overall volume loss, right up until one volume is all the way off, at which point the guitar goes silent unless the switch is thrown to the other pickup.

Well, I'm going to guess that just like the linear vs. log taper volume thing, this is another instance where the practice differs greatly from the theory.

I guess that I can easily try both ways of wiring the pots without needing to switch any components out.