And the final pics. Fans came out purple on the SLR, but they're still blue

. I couldn't get the wiring as clean as I had hoped, but I'm pretty happy with it.
That's a Focusrite 18i20 in the picture. It's going to be my "AVR replacement". 99% of my content comes from my HTPC, so I see no need in using an AVR anymore, especially now that I have the amp. Plus there's tons of great tools (JRiver, Dirac) that can be used on the PC for EQ, room correction, etc.
Gain Mod: So with the amps unmodified and no input plugged into them (no signal), I did get more hiss/noise floor than I had hoped from the CD/Waveguide on my Pure 10's. One of the main reasons I went with these Hypex amps was because there was a documented method to lower the gain (and potentially the noise floor as well), so I went ahead and removed the r3 resistor on one of the boards to compare. I found that removing the r3 resistor lowered the noise floor quite a bit, whether I had no input signal or the 18i20 connected and turned on. I meant to take some measurements with my umik-1, to visually show how much less hiss was produced between a modded and unmodded board, but of course I forgot. I also found that with the gain reduction, I still has PLENTY of headroom with the voltage coming out of the 18i20. So I went ahead and modded all boards. Going from HTPC -> Focusrite -> Hypex amp, in a very quite room (projector turned off, and no appliances running in the house...pretty dang quite) I had to be within 3 feet of the Pure 10's to hear any hiss. I tried really hard to identify hiss from my listening position (7-8 feet) but I was unable to. Sooo I'm very pleased in this regard. The gain mod was the correct move for my purposes.
Performance: I know there's guys wanting to know how the amp ended up sounding, but I think it's nearly 100% subjective, as is most audio related items. I just spent $2k and like 50-60 man hours building this thing, I'm pretty sure my brain wants this thing to sound amazing lol. So as unbiased as I can be, I think it sounds great. As mentioned above, I was able to get the noise floor down well into my acceptable range. As for power, I seriously doubt I have or will ever be able to pull 400 watts out of any of the boards, especially with any of the DIYSG speakers. So on the Pure 10's, Parts Express RS722 and Clearwave 4TSE speakers, it sounds great. Great lows, punchy mids, crisp highs, all the good words I guess. It just sounds very neutral and "reference" to me, which it should.
Final thoughts: There's alot more I wanted to post, and I've got alot more notes/helpful tips for anyone else thinking about building an amp with Hypex components. If anybody had questions, I'd be happy to answer them the best I could. Anyway, I think that's it. Although it took much longer than I thought it would, it might be one of my favorite DIY projects yet. Hopefully we'll see the 1899 in stock soon, then I can really test the amp

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