Although it seems this thread is drying up a bit....I have some late to the party stuff to add.
I have an update for my post above. I went ahead with the SA-31 and have had it here for a week. I posted a quick write-up on the "Amp recommendations for LCD-2" thread, but I'll share it here as well. Short version is this is a great amp. Get one if you can!
Aaaaand.. my copy and paste for your reading enjoyment:
I have had the Audio-GD SA-31 here for a week, using the DACmini CX (1ohm) > SA-31 > LCD-2.2. I am pretty satisfied with this setup. The DACmini/LCD-2 combo is supposedly nearly a perfect match (from what I've read from several on here) so I was not really expecting to get any kind of improvement. My expectations were low. Before you read on, be aware that I have not used any other amps with the LCD so I don't have any comparisons with the names that always pop up on this thread. Just my portable amp, Leckerton UHA 6S-MKII, and the DACmini all-in-one.
With the DACmini feeding the LCD, the sound is really good. However I couldn't help but feel that I wanted to try an amp with some more wattage behind it to see if I could bring a bit more out of the LCD. Direct out of the DACmini, my issue is wishing for a bit more bass presence. And I also feel the sound of the combo is the best when the headphones are driven at a bit higher volume, and when you go just a bit past that I can feel the amp section is straining just a bit. Bass gets a bit looser, highs a little more harsh. (very very minor amounts) So my sweet spot with that setup is just near the cusp of pushing the amp sections ability. Probably a little room for improvement.
The Audio-GD SA-31 puts out 10 watts @ 40 ohm (so what is that at the LCD's 50 ohm?) I don't know. Maybe 9 watts? Plenty, anyway. Diamond differential design. There are 3 adjustable "warmth" settings that can be set with internal jumpers. "0", "Warm 1" and "Warm 2". This amp, while having the description of "musical flavor" and "warmth settings"...well, don't let that fool you into thinking it will be a muddy mess with the LCD. Quite the opposite.
This amp pumps out gobs of clear goodness and the warmth seems to be affecting harmonics and space more so than primary notes. Compared to direct out of the DACmini, it is actually cleaner and more detailed. Adding the jumpers to the "warm 1" setting gives more depth to the space and a wonderful lifelike sensation while not affecting the clarity whatsoever. I hate to use this term, buuuuuttt..."3D" works here. That's the difference. "warm 2" is just on the cusp of affecting details a bit. Bass/ headspace gets bigger and deeper...still perfectly suitable for the LCD. I settled on "warm 1" for now. Best of both worlds. I have read on some posts describing the Audio-GD amps darkness or warmth as "Kingwa dark". Whatever that guy is doing, he is doing it right. My biggest fear was that this amp would be too dark or warm for the LCD. Not an issue.
Drawbacks? I wish it had a volume knob rather than buttons. But it was a design choice for sound quality reasons. Also, I need to now invest in some good RCA interconnects, since it's not one box anymore . (I'm using kind of cruddy ones now) Also the blue display lights are way too bright, but a touch of window tint fixed that. My wife says it's ugly. But she says that about everything audio related.
Anyway, just initial impressions. This amp gives you all juice you need for the LCD-2 without breaking a sweat. The real surprise here is the added warmth and soundstage without affecting clarity at all. This reminds me of some of my favorite gear, Heir Audio 8.A and the LCD-2. They can be warm, and fun, but serving up details as well. Speaking of which, the amp has no issue driving sensitive custom IEM's as well. Switch it to low gain and you're good. The DACmini is just too strong for my Heir 4.A's (the 8.A's are okay). I had to run the DACMini to my UHA amp to use it with the 4.A's. I can plug those right into the SA-31 and get good results.
Is it worth adding a $500 amp to the DACmini for the improvement? well that's up to you. Everybody has done stupider things! ha ha. I really would love to be able to try some other amps in this price range or some of the other gear discussed on this thread to see how the SA-31 compares.