I can't advise you on the mixamp and double amping, because I don't understand any of that, ha! But, in terms of recommendations for you for your current situation you know my opinion (and my good experience with the G6).....send the faulty AE7 back and try the G6 as it fits all your feature / audio quality / & specification needs. As to G6 reliability you'll just have to decide based on what people have said in this thread and any other reviews you can find.
Yes, I use my G6 with Line Out fed to a JDS Labs Atom headphone amp. The 79% windows volume thing is to make sure that it's below the point where it shows some distortion, as found in Amir's review of the G6. If run at 79% windows volume (which equates to -2dBFS) or less then the G6 measures amoungst the very best DACS. I think the only thing to worry about is if 79% windows volume will not be enough volume for your headphone amp & headphones...I think in pretty much all configurations that this will be enough volume. As far as I know I don't think the HD800's are particularly hard to drive, so I think they'll be ok with 79% windows volume on Line Out to a headphone amp. There's not really much point in buying another DAC if you still want the gaming capabilities....plus I suppose there's nothing stopping you from trying the G6 first with any new gear you buy, and if it's not up to snuff then you can buy another DAC at that point.
Just a quick aside for this paragraph...you've got the HD660S and you're using it for music too...well I reckon you should try EQ'ing that one using Oratory1990's EQ curves that are based on the Harman Curve, his curves are great and really do make headphones sound better generally. Here's the link to all his headphones that he's EQ'd (https://www.reddit.com/r/oratory1990/wiki/index/list_of_presets ). He's a professional audio engineer and has an expensive headphone measurement rig which he uses to create the EQ profiles to match the Harman curve.
Hopefully the beta firmware will help.I'll try this beta firmware too and see if it fixes my issue since I couldn't find anything related online unfortunately.
About Oratory1990's EQ you suggest me... I opened up the pdf for my headphones but I don't really know what to do with all that stuff
That sucks doesn't it. What's the Power Cycle issue?
Amir (the owner of this site & the guy that tests all these) said that with his Sennheiser HD650 the headphone listening tests were OK, but you would be operating at or near max volume level. His headphones are 300 ohm (so I assume he was using using High Gain) and 105dB sensitivity, your HD660S is 150 ohm and also 105dB sensitivity, so yours should be a bit easier to drive than his headphones...therefore I think your G6 should provide enough power in High Gain mode, High Gain mode is for 150-300 ohm headphones, so I'd operate it in High Gain mode for your headphones.
(About max output on the G6 though, you wanna be using at a max of 79% Windows Volume to avoid distortion/clipping - Amir noticed that distortion goes away at -2dBFS).
Yeah, that's cool, I know what you mean, I just wanted to point out the 79% thing though so people avoid running it at 100%. The G6 is a massive pain in the ass, it's very finicky/buggy, this is just another one of it's lovable quirks, ha! G6 is ok on my desktop PC though, doesn't really have any other bugs other than the 79% windows volume thing, but when used on my laptop it has a massive number of bugs making it virtually unusable.
