Actually, for what's it's worth.... The XK1 and XK3C use the exact same leslie sim and VASE III engine. (The XK3 has an inferior leslie sim.) The XK3C has added tweekability for making custom drawbar sets (and a tube) so with some careful editing, it can offer up a few more variations to the overall tone than the XK1 can, but they share all the same guts. The XK1 is still tweekable as well, and a few tweeks definitely help over the stock settings. 

Bonzo, please tell me the magic tweak! I thought I'd been through every option over the past 8 years I've had this thing, but no matter what I do I get a subtle graininess that annoys me.
 
I could have sworn the XK-3 I played sounded better. That, I believe, was called an XK-3C, suggesting possibly newer firmware. Mine's an original XK-1, not the later XK-1C. It does not have, for example, the Color control in the Leslie parameters.

Fleer
FSOSA!

Fleer
FSOSA!

Maybe the name should be shortened to Fleer University. Or just FU for short. 

Bonzo/Beagle: I've done a little background reading on the XK-3c. It does have the same electronic guts as the XK-1c, but it's not the same software that's in my original XK-1.
 
Besides the software, the other major difference between the two is that the XK-3 has a higher-quality keyboard, closer to a vintage Hammond's. Both are made by Fatar in Italy. Mine's not bad but it's a little plastic-y and does not feel like a real B3, although it's still quite a bit more fluid than your typical weighted piano or MIDI controller keyboard. I wouldn't be surprised if it was even possible to swap keyboards between the two, but unfortunately Fatar only sells to OEMs.
 
Apparently, the 3 is also manufactured in Japan, while the XK-1 was made in China.

Hi Bit,
 
I have an XK1 as well with a Vent. (original one.)
 
Through trial and error, I tweeked everything possible that's tweekable in the thing. I don't remember all the changes as I set it up a couple of years ago.
 
When I got the Vent, I first had to arrive at an optimal overdrive setting on it. I found there's a delicate balance to get things right within the XK1, so if you go "all drawbars out to the max", it doesn't red line the Vent. I adjusted the internal XK1 output for starters, as well as the EQ. (You can do this/ save this on any patch I believe.) Of course the internal XK1 leslie is off, but the overdrive is still on. The Vent adds "growl" which the XK1 drive sim is a little weak on. The Vent doesn't have that "sizzle" though, so I use the XK1 overdrive for that in various degrees, depending on what I'm shooting for. I find that works really well. This was part of the "delicate balance" to get it sounding the way I wanted. 
 
I also adjusted all the vibrato/chorus settings to my liking, as the factory defaults weren't exactly what I wanted. They're quite tweekable. Again, depends on what you're shooting for. I also use the reverb on the XK1, which puts the reverb before the leslie, which is correct if you have a real Hammond/leslie setup. You can't get that dopplered (it that a word?) reverb effect any other way.
 
It took awhile to get things the way I wanted. (think ELP - Tarkus as one example.) I played around with different percussion tweeks, key click, you name it. It all affects the output and overdrive of both the XK1 and the Vent. I don't know if there's a "magical" tweek per se, as everyone has their own preferences for a Hammond sound. More like a lot of programming and experimentation to get it the way you want it. 
 
Don't know if any of this helps you, other than to say that it took some time and attention via experimentation to get it right. It can be done though...and as much as I agree that VB3 sounds really good, there's something about the XK1/Vent that sounds a a little more detailed, open and pleasing to me.
 
 
 

BassDaddy

Fleer
FSOSA!

Fleer
FSOSA!

Maybe the name should be shortened to Fleer University. Or just FU for short. 

Who's selling undies now?

I may have to invest in a vent.  I've only had my XK3c for a little over a year (so of course I still have the "new car" syndrome with it anyway!).
 
Bonzo, do you think the tube in the XK3c defines the "growl" that you're having to use the Vent for on the XK1?
 
have either of you (or anyone) used the XK series with a real Leslie?  vintage or even a new one (like the Studio 12)?

I have not had the pleasure of using mine with a real Leslie. However, I did see a Deep Purple tribute band where the organist did just that, running an XK-1 through two stacked 122's just like Jon Lord used to do. It sounded authentic. Of course, the Jon Lord sound is among the easiest to approximate of all the classic Hammond tones even without the Marshall head - just distort it until it sounds like it's on the verge of catching fire.
 
Bonzo, thanks for your observations. Due to this conversation, I've revisited the XK-1's settings. I've been reluctant to make extensive customizations because the battery goes dead so often. But during yesterday's exploration I discovered something new - the Leslie Brake button.
 
All these years I thought it just enabled the Leslie brake. But yesterday I realized that it also significantly changes the tone. It especially improves chords played in the middle to lower end of the keyboard. What classic Leslie characteristic this is trying to emulate beats the heck outa me, though, as I don't remember any tonal difference when I disabled the brake on my old 147.

Most of it is way beyond me but I have enjoyed this thread. Learned a few things too.

Have any of you compared the Vent to the Mini? I play guitar way better than keys, but would want to use it for both. Actually, mostly for "Hammond world" .LOL .... Jim Alfredson's reviews of the various Vents, are very inspiring and the OD aspect is very cool.
Michael