Replacement pot for Ernie Ball Jr passive vol pedal

[Om_Audio]

I can't stand the non linear sweep. There is a jump when you approach toe down. There is a small switch which smoothes it out a little but still drives me nuts. Contacted them they only offer replacement parts. Any suggestions for replacement pot that would allow smooth and linear volume sweep?
Thx
C

[midwayfair]

http://www.smallbearelec.com/servlet/Detail?no=1154

E-mail Steve at Smallbear and ask him what the taper is.

Before you spend any money, though, swap your input and output plugs (plug your guitar into the output).

[Om_Audio]

Thanks much, will check with Steve at SB. Hopefully it is not the same taper as what is already in mine.
That is really strange you can reverse things and it still works! I noticed the volume had more of a bump at very beginning.
I guess in reality it starts to make sense the way they did it as I don't want a jump at the beginning either- so if you smooth the start, you have to put the rest of the sweep somewhere thus the bulge at the end.
Hmm, without a chip and different type of sensor I'm not sure how you could stretch the volume sweep out farther but with the same throw of the pedal. Maybe optical sensor and a chip or something where it could read not just 360 degrees but is measuring using steps. That original device to measure the speed of light comes to mind- the eyeball would be the sensor, and some sort of circuitry to read the pulses and adjust the vol.

http://www.smallbearelec.com/servlet/Detail?no=1154

E-mail Steve at Smallbear and ask him what the taper is.

Before you spend any money, though, swap your input and output plugs (plug your guitar into the output).

[midwayfair]

If you want a perfect taper throughout a pot's travel, you need to make it, and that gets complicated with the way the string is set up. Audio, linear, and reverse audio tapers all have issues at one point in their travel. I believe Gusmarkov has a graph for an ideal volume taper. It's also the taper I and some other forumites have used in some Cavedweller feedback pot mods, that might come up on a search.

Morley makes an optical volume pedal. It dulls the highs, but some people like that. Knopfler used one in early Dire Straights; it's a big part of the smoother sound of his strat on stuff like "Lions."

[Om_Audio]

Thanks. I had a Morely power boost/wah and I sold it, just too big. Didn't seem to suck tone. Was too big though!
http://www.madbeanpedals.com/forum/index.php?topic=4030.0

Maybe this could be simplified and shrunk to a wah pedal size.
C

PS- just watched a Knopfler doc, was interesting. Cool guy.

[Om_Audio]

Steve said it is same spec as OEM and hard to replace as they have some special brass long shat.
C

[joegagan]

if you look at the graph for log ( audio ), you see a slight flattening at the high end. but it continues to rise even through the final 5%. the 'hump' you are hearing is this quick flattening of this curve in reverse. you even mention it does the reverse when the leads are swapped.

i tested a 2011 EB VP jr, but with 25k ( active?). the pot was linear. i assume they chose linear to avoid the problem you are experiencing with the 250k version.

[joegagan]

let me add, i do not know that the 250k is log taper. it might be the way the string acts at the end of travel, or something else. seems logical ot me that EB would stick to linear throughout the range, all i know for sure is that the 25k 2011 model was linear.

EB mentions on their website that tapers have changed as they have used 3 different pot suppliers over recent years.

[Om_Audio]

Oh, great info, thanks. Mine is passive. Will look into this further. I need linear!
C