High Output Preamp for First Watt SIT-3?

To keep distortion down though and yet still make reasonable power, I'd be looking at an 8 ohm speaker rather than 4 ohms.

I wasn't aware that distortion could be a function of a speaker's impedance.  Or, at least, I assumed a lower impedance speaker driven by a solid state amp wouldn't stress the amp as much as a higher impedance speaker playing at a similar SPL.  Tube amps, I'm guessing, could be a different story? 

What's the theory behind lower distortion from higher impedance loads?

Thanks for all of your input. I purchased the SIT-3 first because I was intrigued by early reviews and wanted to purchase one before the limited supply ran out.  I've always wanted planar speakers and was aware of the low sensitivity of the Maggies as well as the low wattage of the First Watt.  So, yes, a mismatch guided by two separate thoughts. 

I wouldn't have gone down this road if not for a few factors:  Herb Reichert sang the praises of this specific combination, saying the SIT-3 made him appreciate the .7s 'a lot more' and called them 'beguiling' in this context.  Steve Guttenberg used the term 'magical,' I believe.

The Maggies are 4 ohm, the SIT-3 puts out 30 watts/4 ohms.  I was concerned and asked my Maggie dealer if I could demo the speakers with my amp.  They wouldn't accept my request (because it would be too much of a hassle to connect/reconnect) and mentioned that since the .7s are a special order, I was unable to return them in the event that I did not like them in my system/room.  So, I demoed them with a lower wattage amp that sounded anemic at times.  Yes, I bought the amp with this knowledge!  But, honestly, they sound great together.  Not knowing why, I can guess that it is the high current capability of the SIT-3. 

I am thinking of temporarily using one of my pro power amps to hear the Maggies properly powered.  I have limited space in my listening room but will consider a high sensitivity pair of dynamics.  Avantgarde is a bit out of my price range.  I am curious about SET amps as well and have been looking at speakers that work well with them. 

If anyone has read this far, I appreciate the input and take your advice.  But, if there is anyone out there with this or a similar combination of components, perhaps they could weigh in with additional feedback.  Like I mentioned, I'm at the cusp of where I want to be.  Many hotter LPs and digital files sound fantastic.  I can coax a bit more streaming a lower level file with Fidelia or my UAD interface.  
Additional high sensitivity speaker recommendations in that $4k and under price range (used is fine) are greatly welcomed. 

Al- I appreciate you running calculations on my setup. The cartridge is a MOFI Mastertracker. 3mv output. That's substantial, no?

https://www.mofielectronics.com/mastertracker-cartridge
I was curious if the amp was seeing the full potential input signal (and therefore outputting a full 30 watts). 

Last night I listened to the Speakers Corner issue of Aretha Franklin's 'Live at Fillmore West.'  It was very/too loud when the Mytek was maxed out.  However, my listening tastes are varied.  I listen to classical chamber and solo works, acoustic jazz (50s-60s and up), rock, new grass, reggae, pre war blues, Grateful Dead, electronica, post punk and more.  A rock album with limited dynamic range mastered in a normal to hot range is great on my system.  Many classical pieces don't fare as well with this setup.
I have always expected to have at least two setups to cover various genres and listening needs.  Planar speakers have a midrange, imaging and other qualities that I don't think I'll find in dynamics.  But, I don't think planars will 'rock' like dynamics will.

Without going into my life story and why my listening room is (temporarily) limited (11 x 13, I believe), I do have to settle on one system for now until my situation changes. 

My local dealer carries McIntosh, Klipsch and Primaluna.  My tastes are toward a more euphonic presentation.  I would love to hear what the Maggies sound like with a robust power amp, but I imagine a solid state amp such as the often paired Bryston would leave me cold.  Same for Wyred4Sound and Class D.  Maybe a tube preamp would mitigate that.  If Nelson Pass's other (higher power) amps are anything at all like the SIT-3, I'd like to hear them.  But, I'm guessing the SIT-3 is unique, the First Watt stuff underpowered, and do I want to heat up my room with an XA, nevermind the expense? 

I know I was the one who started the thread asking about high gain preamps, but I don't like the idea of fixing a problem based on my other mismatched components.  It seems like a better idea to find a synergistic combination.  Your responses have shown me the light.

I think I'll listen to the sentiment of most of the contributors to this thread and build around the better of the two variables:  my amp.  I like the idea of having a high efficiency speaker on hand when I add an SET amp. Since it's hard to demo most of what's out there, I really appreciate everyone's recommendations.  I can sell or store the Maggies, but ultimately I'll be looking at 3.7s or higher when I have more space.  I have tube guitar amps from the 40s (!) through the 70s that sit unused in the attic.  I'm a bit of a hoarder.  Hoping to fund my system through trading rather than collecting pieces that aren't listened to. 

Mglik-
Great info.  Quads have always been on the 'list.'  There's a lengthy thread on the Hoffman forums about which amps make them 'sing' that I bookmarked yesterday but have yet to read.  Does 'sand' refer to silicon and transistors, the graininess of solid state or something else?

I was a working musician until the coronavirus cleared my calendar.  Fortunately, I'm also an essential worker.  The Maggies don't reproduce the lowest octave(s), but in some sense, it is the truest representation of acoustic and electric bass I've heard.  My audiophile friends tease me about being a bassist yet not getting the support from my system. 

Greg-  I was hoping to hear from someone with the .7s and SIT-3.  Encouraging to know that you are liking that setup with a good preamp to match.  Similar room, too!

Thanks for adding to the thread, @eugene81 .  That's useful information.  I suspect that most of my listening centers around 85db, or at least that's were it sat on the day I checked.  I listen in a nearfield position because of the size of my room and so that I may mitigate some of the room's acoustic problems.  Of course, much of it is highly dynamic classical or jazz, so I'm getting up to adjust my preamp frequently.

Thanks to advice from @mglik , I purchased a used but low hours/refurbished Audible Illusions M3B.  I can't overstate the difference between my Mytek Brooklyn Bridge connected directly to the SIT-3 and the new arrangement.  Hard to say the objective sound of the M3B because my only reference point is my previous setup.  Perhaps a bit darker sounding?  The tubes do impart their magic.  I find myself turning the system up a little louder than previously when playing vinyl to reach the sweet spot- and the separation/clarity of instruments.  Streaming never requires the gain controls above noonish, but I can get close to the extent of the knobs' travel when playing quieter records.  Overall, a great improvement.

Still, a Linear Tube Audio microZOTL is on my list for the future.  I went with the M3B because the price was right, and the phono stage is good.  When I make the move to a MC cartridge, I will weigh purchasing the gold phono card vs a whole new preamp. 

@eugene81 I'm glad you mentioned the Bel Canto Ref 500S, because that unit and the mono block 600M were enticing.  I think the one you had actually delivers more current than the monoblocks, and Maggies seem to be current hungry.  But, I guess I can scratch those off my list! 

Thanks for the recommendation of the XA25.  I purchased the SIT-3 first because I was motivated by the limited supply (initially only 250?).  As a collector of all things music, I rarely sell back instruments/amps, etc.  The SIT-3 is special, and even if I temporarily take it out of the system, it was my first high end audio piece and will probably be with me forever.  I will consider the XA25.  If I change anything, or add options, it would probably be a high wattage amp.  I know conventional wisdom is Bryston with Maggies, but I think I need a more engaging/magical/euphonic amp.  So, that hunt continues, but I should reiterate that I'm pretty happy with where I'm at, thanks to advice received here. 

I took a power amp from my live bass guitar rig-  a QSC CX302- as an experiment.  It's 325 watts/channel @ 4 ohms- 10 times the power.  The fan was so ridiculously loud that it was laughable.  It was nice having more power on hand, but upon switching back to the SIT-3 after a few weeks, it was no contest.  I may not have the best tonal memory when switching pieces in and out, so quantifying differences is difficult.  Upon its return to my system, the SIT-3 thrilled me from note one, and it pulled me into the music, compelling me to listen for hours longer than I anticipated.  One lesson for me is that I will hear a clear audible difference between gear, sometimes showing distaste when it is outside what I'm familiar with.  It is through subsequent, in depth listening that I can truly value the swapped gear.  The first hours of the M3B were such a shock that I was unable to discern if I liked it! 

Thanks for all the input- you guys are the best!  I'm realizing much like life, this is a journey rather than an ultimate destination.  I'm geeking out on Quad 57s (haven't seen much anecdotal regarding the SIT-3 and Quads) and to a slightly lesser degree, Spatial Audio.  Most importantly, having fun and deriving much satisfaction from listening.