High Output Preamp for First Watt SIT-3?

You have a poorly-matched speaker/amp combination. Either sell the .7's and get a higher sensitivity speaker like, say, Altec Valencia's. Or sell the SIT-3 and buy a high-power amp like a Crown XLS1002 (400 wpc/4ohms). The Mytech is fine connected to any amp - no need for a separate preamp!

While the speaker and amplifier are individually good products, as a pairing they aren’t compatible IMO. The assessment of roberjerman is on the mark. If I were in this situation I’d keep the First Watt S.I.T-3 and purchase a more suitable speaker for it (higher sensitivity with an easier to drive speaker impedance load). This amplifier delivers less than 20 watts into a 4 ohm load. The maggies (83 db sensitivity) need more than this to perform at their best. Yet if matched with an appropriate speaker according to owner feedback the S.I,T.-3 will sing will superb sound quality.

Murphbass which do you cherish more, your Maggie’s or the S.I.T,-3? I believe that your amplifier is the better of the two products and offers more sonic performance potential upside ultimately. I readily acknowledge that this is simply my humble opinion. In summary I don’t believe this is exclusively a "gain" issue.
Charles

With the appropriate speakers, the SIT3 is sublime. I’m sorry but the Magnepan speakers are not the right pairing. Everything said by the others is right on. Maggies need a lot more power to sing. The SIT3 may be difficult to replace in the future so I vote for a new, highly efficient speaker to mate with it.

 I have Avantgarde Duo XD which are 107db efficient. With a resistor across the terminals to bring down the resistance that the amp sees (the SIT3 prefers to see 4-8 ohms), its been a revelation. A wonderfully engaging amp. Keep it and get new speakers.

I would suggest any of the Zu Audio speakers or Klipsch Foute III's.

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.