Ernie Ball as expression pedal for TomeFactor : logarithm curve ?

[Grorom]

Hi,

I’m using a Ernie Ball 6180 vp jr 250K as a volume pedale, in which I replace the pot for a linear 22k.

My problem is that the curve of the pedal seems to be understood as a logarithm curve… is there a way to correct this in the TimeFactor ?

Or may I recieve a log pot ?

 

Best,

Grorom

[nickrose]

A volume pedal will usually have a log pot – using a linear one will work, but may not give the correct response. You might want to change it back.

 

 

[Grorom]

oh, ok ! So the stompbox is prepared for log pots ?

(changing it back to the original 250k is not so much better, because the TimeFactor will only see the half the the pedal’s journey)

Thanks for the answer !!!

[nickrose]

The stompbox doesn't care (as long as the pot is around 25k).

You may care, if the pedal response is wrong. It may vary from effect to effect, depending if you are trying to control a linear function or a log function.

I would suggest that you not worry too much, and see how it works in your situation.

 

 

[Grorom]

Hi nickrose, thanks for answering !

I’m trying to control the feedbacks and filter of the two delays, so the percentage of the expression pedal is shown on the TimeFactor. My little problem is that this percentage shows (as I hear too) :

the curve of the linear 22kΩ pot of my Ernie Ball Jr is making a log modification of the feedbacks and filter.

If I change the pot for a 22kΩ log one, will I have a linear understanding by the stompbox ?

Or a log² ?

[nickrose]

If your linear pot is giving you a log response, and you want a linear response, you will need an anti-log pot. These are not common – they are usually found as part of a stereo balance control, with a log/antilog dual pot.

My suspicion is that you are overthinking things – try what you have, and you will find it fine in a little time.  The control laws for the controls are not documented – my guess is that some are log, and some are linear. It depends on what you are trying to do.

 

[Grorom]

I’ve bought the TimeFactor in 2011, using it nearly every day since, with the Ernie Ball Jr 250k as expression pedal, then replacing the pot for 22kΩ linear one in 2013… so, trust me I’ve tested what I have !!

I’ve taken some measures of the pot, it is a linear one, now I’m sure of it.

I’ve also understood that what is called a “logarythm pot” acts following an exponential curve.

And this is how the TimeFactor react with a linear pot :

So I finaly understand that if I put a Log pot in my ErnieBall, I will have a correct linear response of the stompbox !

Here is where I need to connect a R1 resistor about 4kΩ or 5kΩ to have something that could be like a log 22k pot :

 

(see the attachment to understand more clearly what I would like to get !)

[Grorom]

I’ve find a 25k log pot and put it in my expression pedal, the TimeFactor now show a linear curve !!!

[Author]

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