One thing I noticed in the article was that it said that you could only attenuate what had been added. This was not my experience. When I turned up only attenuation, I got suppression in the pink noise.

@Jeff, thanks for your comments on the clip switch.I'm not sure this was talked about much in the article. I was actually wondering if you might just turn the pre off. I think I will be adding this plug to my latest mix and playing with it.

Jeff Evans
A great Pultec emulation is the full thing eg here: 
http://nomadfactory.com/products/pulsetec/index.html 
In my opinion this is the fulll model with all the bands etc and there is no mystique about it either.  Nor is there any placebo effect.  It is very real.  Even when this is set to a flat response it will make things sound different.

So it's not flat then, is it?

Geoff  you  can  boost and attenuate in the same area and sometimes they don't completely cancel out though. They add to create an overall curve.  I tend not to do that though.  I prefer to select one approach and use it eg attenuation or boost.
 
Karyn,  well yes and no. I bet if you do a frequency response on it while set completely flat, it will be flat but when you switch it in and out over a track or a mix you can hear the difference. (as per the real thing)  It is a bit like the testing I did many years ago on power amps.  eg a transisor amp vs a valve class A amp.  Both will test flat as a ruler but one can sound dull and the other will have beautiful top end.  Hard to explain why.
 
It does not fit every single application though.  Remember it is adding distortion!  I have found in some situations a much more modern great sounding EQ plugin can sound better.  Where it does excel I think is when you want to bring the mid range forward it can do a lovely job of that and also getting rid of the 200-300Hz build-up in a mix it is excellent for that.  It has a nice top end boost thing going on too. Sometimes I just use it one area of the spectrum only as well.  (Switch off the other bands in the Nomad Pultec if you don't need them)
 
I did not mean to diss  David's  use of the word Mystique either.  From an electronics engineers perspective it is just a passive EQ that uses reactive components followed by a gain stage.  It certainaly does have a reputation and from that perspective I guess it has plenty of mystique as to why it sounds the way it does.  (like the class A valve poweramp thing)  I enjoyed David's article and it explains many aspects of it well.

Loved the article!  I recently posted here that I could detect 'color' just by flipping the switch on that Pulse-Tec EQ from Nomad Factory, but perhaps it's just that the dust in my studio is of the fairy variety:)
 
One question asked in the paper had to do with the Pro-Q vs. the Pulse-Tec EQ and another asked why use a Pultec EQ at all.
 
I got the Pulse-Tec for $10, but I didn't try it for quite a while as I was focused on the visual parametric eq's like the ProChannel QuadCurve...I also didn't know how the Pulse-Tec worked.  I did buy a few other eq's before I knew anything about FabFilter and the Pro-Q, but by then I couldn't justify the bucks.
 
The Pulse-Tec EQ does force me to depend on my ears.  I tend to use it as a bus or mix eq with subtle moves.  The same can be said for that Master EQ 432 from IK Multimedia.  I recently watched a YouTube video where the mastering engineer was using outboard gear.  There weren't any visual aids, but there was gain matching....
 
What a fascinating hobby this is.

olemon
What a fascinating hobby this is.

 
Boy you got that right!

fascinating = arm & leg expensive, & maybe a kidney thrown in for good measure.

The WARM is a real nice non-emulation.

I own a few Pultec EQ plugins and use them on most of my mixes. Some of the plugins do sound a little different, however, I like that because my mixes don't get a big buildup of the same coloration.
 
If you were to analyze a analog mixer, you'd find that most of the channels will sound different from each other. For me, that part of the secret sauce, so to speak. I also mix my plugins up a bit to avoid buildup of frequency and coloration.
 
The Pultec EQ plugins aren't for everybody. They seem to be a little harder to understand for a lot of people. Therefore, watching online videos and reading documentation is a must.
 
Thanks for the link on the Pultec documentation. I also own that version of it, therefore, that article could be very helpful, as well.

Great article.  Makes me want to get some fairy dust of my own.  Hello wallet....

I like the Waves Puigtec verson. I found it to be the best eq I have. It makes you use your ears. It isn't an eq for surgical eq'ing for sure. I use fabfilter Pro q2 for that.