I have purchased and am waiting on the Massdrop Grace balanced DAC; the Loxjie balanced tube amp; balanced cables for the HD6xx’s and the HE4xx’s ( Can’t seem to find any balanced cables for the K7xx’s); XLR cables from DAC to Amp. And that’s it. @ $350/shipped for everything.
Does this sound like it might work? The DAC and amp are both 4.5 to 5-star rated on both Drop and Amazon.
I guess I’d ask “Why wouldn’t it work?”
You won’t find balanced cables for the K7XX as the connection at the headphone end is only 3-pin. You’d have to rewire them internally first and swap the socket to something with 4-pins, or hardwire a 4-conductor cable in order to make them balanced.
I ask because I was hoping someone had something similar or at least have the Loxjie and can comment on the quality of sound from it. Pretty sure the Grace DAC will be competent at least.
I have something very similar on my desk at work. SMSL SU-8 into Loxjie P20 powering either HD6XX (balanced) or Beyer Custom Studio (haven’t gotten around to rewiring these to balanced yet).
It sounds fine to me 
There is also a thread on the P20 that has plenty of opinions and useful info here: Loxjie P20 Balanced 6N3 Tube Hybrid Amp for under $100
Wouldn’t the best time to ask that have been before pulling the trigger on it? 
The Grace SDAC Balanced is very competent and enjoyable. I did a proper review of it here.
I did my research before buying either product. I was just wondering if anyone had the same idea ( there is at least one, so I should have read that thread before posting this here). Having two high-rated products doesn’t mean they’ll sound good together, though.
EDIT: Obviously I didn’t do the research here or I’d have seen the posts relevant to my question.
Star ratings on [Mass]Drop and Amazon mean very little to me, given many people who rate and write reviews seldom match the preferences of most people deeply invested in this particular hobby— I’m no gourmand but occasionally write reviews of restaurants. On the off-chance that they do have an interest in “better” audio, that’s no guarantee that they’ll have the same sonic preferences as you either; in my experience, even self-professed neutral-heads, at least those relatively new to the hobby, have divergent beliefs on what constitutes a neutral signature.
Good call on thinking they might not necessarily synergise (I hate this word) well despite both being well-received, high-value performers. I’ve only ever tried the headphones and neither amp nor DAC, but just based on my experience with the K701/HD650 they might benefit from a beefier amplifier (for my tastes K7__ series needs a more relaxed upstream, HD6__ series could use an amp that has good control over the bass).
P.S.
+1, might have been better to ask before placing an order, unless you’re trying to calibrate baselines with other people, in which case not a bad time to ask.
I’ve not heard the grace Balanced Dac but the Loxjie was quite nice, I enjoy my HE 4XX on a hybrid tube presently but I use a Slyvania Tube, so something that’s “leaner” than typical “tube” sound
Still my HD 600 and K702 sound nice on tubes so I don’t see any reason you would have bad synergy. Worse comes to worse just get a JDS Labs ATOM to use with that 3.5mm unbalanced out for the HE 4XX, yea it’s another $100 but you’d literally have all possible basses covered.