W Taper?

[thetrend77]

What is it?

[slimtriggers]

I think they're reverse log for the 1st half of the rotation, and log for the second half of the rotation.  Midpoint of the rotation is 50% resistance, similar to a linear taper.  Kind of like a platypus or something. 

[thetrend77]

Ah ok, thanks. I was looking at pots on PPP and I saw W taper and had no idea what that was lol

[slimtriggers]

They're used for the tone pot in a Tubescreamer usually.  If you didn't already know that

[mgwhit]

I thought 'W' taper was log/audio taper for the first half of the rotation and then another log/audio taper for the second half of the rotation.  If you visualize the two log tapers connected at the midpoint you can see the 'W'.  Half-log, half-antilog is 'S' taper.

I was totally wrong.  [See below.]

[calciferspit]

I thought 'W' taper was log/audio taper for the first half of the rotation and then another log/audio taper for the second half of the rotation.  If you visualize the two log tapers connected at the midpoint you can see the 'W'.  Half-log, half-antilog is 'S' taper.

this +1

[slimtriggers]

I thought 'W' taper was log/audio taper for the first half of the rotation and then another log/audio taper for the second half of the rotation.  If you visualize the two log tapers connected at the midpoint you can see the 'W'.  Half-log, half-antilog is 'S' taper.

This makes way more sense than what I thought it was.  I learned something.  Thank you

[jkokura]

You're right, it would seem that way, but there's no difference between a W and an S taper as far as the actual part is concerned. I've measured the W taper pots, it works like the S would work.

After all, a Linear designation is B, Log is A, and anti-Log is C... None of them look like their tapers...

Jacob

[mgwhit]

After I ran my big mouth I decided to actually confirm it with a W20K pot and my DMM...and of course my 10-yr-old cheapie DMM has given up the ghost. :p

[mgwhit]

My sincerest apologies to slimtriggers.  If I would have actually looked at his diagram (or tested before I posted) I wouldn't have run my stupid mouth and said something totally incorrect here.  W taper is in fact log-antilog (i.e. log/audio for the first half of the taper and antilog/reverse audio for the second half). 

I picked up a new DMM today and here's what I got off of a W20K alpha pot from Mammoth:

7:00: 0R
9:00: 0.7K
10:30: 1.5K
12:00: 10K
1:30: 18.6K
3:00: 19.9K
4:00: 20.1K

Actually looks like it's the opposite of the G/W/S taper shown in the diagram, so I'm still a bit confused.

[jkokura]

It's not that big a deal Matt, we all make mistakes and I'm always a culprit for speaking (typing?) before knowing.

It looks like yours is A for the first half, and then C for the second half to me, so that makes me think you measured it backwards from the way it's show on the graph. Perhaps if you measure in relation to the other lug (if you measured from 1, switch to 3) you'll see what I mean.

Also, throw a BIG knob on the pot while you measure. Then you'll be able to actually make more delicate adjustments. My recommendation is to clip the leads right onto the two lugs you're measuring, and then turn the knob smoothly and watch the meter. The resistance "should" come up quickly, then even out for a while, before finishing out quickly again.

Jacob

[gtr2]

That BIG knob tip is actually a great idea for builds that are sensitive to small increments of potentiometer movement.  Thats probably why I like the big knob on my reverb.  Funny how we sometimes overlook the simple stuff 

Josh