What preamp creates the largest soundstage?

I have always loved a large soundstage.  I have a small listening room (10x10) and have mini-monitors, driven by a tube amp.  I have played a lot with speaker placement, room acoustics, listening position to create a large soundstage.  I have rolled tubes on the amp and made dramatic improvements. (I have purposely left details on the brands of tubes, amp and speakers out, because I don’t want side comments to distract from my question)

i have a digital source into a solid state naim preamp.  I home demo’ed a well reviewed preamp, and was surprised at how much the soundstage shrunk, both side to side and top downward.  It was deeper, and did have much of the tube magic, but I could not live without the big soundstage.  

so my question is, does anyone have experience with a preamp that produces a big soundstage?  I am looking for recommendations on what to demo next. While I lean toward tubes, I am open to solid state.  I am okay either new or used, and could spend in the 5k range, but would be happy to spend less.  Also comments on specific brands (i.e. xyz is known to have great soundstage in all their preamps) as opposed to models, are welcome.

and I will be the first to admit that perhaps the very large soundstage is not “accurate”to real music, but boy is it seductive and I love it and can’t live without it.

Hmm... since there's no way to recommend a pre-amp without knowing the power amp (synergy is crucial!) you're not going to get very good information.

Or you can pick any good preamp and hope for the best.
Audiojan- okay, the amp is the Primaluna HP in stereo mode, four EL34s per channel.   While I assume the matching Primaluna preamp would give good synergy, I have not heard that the Primaluna preamps are anything special.
I’ve had at least a dozen preamps over the years.    Graaf is one name that has never sounded anything but extremely wide open providing the rest of the components are of similiar caliber 
+1 phantom reco - also dehavilland ultra verve III - I am big fan of the 6SN7 vacuum tube for both soundstaging and dynamics.
To many to list start with VAC.
Batman1971- Never heard of graaf.   I see they are an Italian company, but can’t tell much more.  Are they readily available in US?

phantom_av-  it has been years since I have listened to Atma-sphere.  I will check into them.  Per their website, the preamps do not appear to have a remote, which is important to me.

i have also been wondering how the old school tube companies- Conrad johnson and audio research, might do.  Been too long since I have listened to either of these....
CAT SL-1, Audio Research Ref5 & 6, Aesthetix Rhea & Rhea Signature, any Shindo Lab.

Prima Luna Dialogue is not a bad preamp, just not in the same league as the ones above.
I think that audiolab means the Aesthetix Calypso. The Rhea is a phono preamp.
Check out Linear Tube Audio,Decware,and Aric Audio.Each of those small companies offer excellent products.At present  I have a LTA microZ2 and it presents a wide and deep soundstage.
phantom_av-  it has been years since I have listened to Atma-sphere.  I will check into them.  Per their website, the preamps do not appear to have a remote, which is important to me.
A remote is available for both the MP-1 and MP-3.
“...does anyone have experience with a preamp that produces a big soundstage?”

I think most preamps in the $5K USD price range, especially if used, will throw a reasonably believable soundstage. Based on my experience having had a few different preamps, tube or SS, in my system, the difference is mostly in “how” the soundstage is rendered between the speakers. Some preamps have a more forward presentation with the vocals more into the room vs. others that are more recessed. And some have a wide stage but very flat. Your best bet is to try a couple, both tube and SS and see which has the sound quality you like when paired with your amplifier and speakers. If going the tube route, check the output impedance specs to make sure it mates well with your amplifier.
Atmosphere- is the mp-3 balanced only for input and output? Can I use RCAs?
Jtcf- I am big fan of the LTA in general, but that is the preamp I home demoed and the soundstage was disappointing, much smaller compared to my naim solid state.  Otherwise, I would have bought it, and would not be on this quest.  However, I did not roll the tubes.  Don’t know if I would have had the same opinion if I had time to try different tubes........  certainly rolling the 12au7s on my amp has made a huge difference.
Kalali-  I think you make a lot of sense.  Once you have strong candidates, it is probably a “how” the soundstage is rendered.  And perhaps once one is willing to spend (what to me is) a reasonable amount of money, most of the candidates are pretty strong.   
@meiatflask it's good you demoed it.System synergy is everything.In my set-up the soundstage became wider  and deeper instantaneously.I did experience some weird sonics the second day but turned out I had a bad cable.Best of luck in your search!It can become frustrating auditioning and returning.
I have a CJ Classic 2 SE pre-amp and I love it man. Good luck, and buy used ;)
OP: There are a lot of preamps that will create a nice 3-D soundstage. I prefer tube preamps as active devices for doing this, such as an Audible Illusions Modulus preamp. But I’ve had dB Systems active transistor preamps do a great job with creating a nice 3-D soundstage. And my Teo Audio Liquid Pre passive preamp does an admirable job as well. The bottom line is that a lot of preamp designs will serve you well in this regard.
I own the Schiit Saga, only 349,00  Has a single tube: stepped attenuators, can run passive too. I’m very happy with mine running into a Linn LK140. With a 15 day restock policy you are not locked in,,except for small restock fee. I’m a professional musician,I know live sound for 50 years, The Saga May surprise you. Also I’d be interested in knowing what interconnects you use. In my experience interconnects play a big part in “soundstage “. I can hear the groans now LOL.  I roll my own and have spent many 100’s hours listening to wire. I also really like Franks Signal cable silver Ic,s and silver speaker wire. If we’re discussing soundstage or clarity wire unfortunately remains the weakest link. IMHO.