Quote:
Originally Posted by
Carlsan 
The problem is the headphone high impedance amp. That part, not so much.
That too was addressed in a running manufacturing change.
I used a cheap Chinese camera connection kit knockoff that supposedly allows you override the power limit of the dock connector. I was able to plug my Explorer in, it powered up, and drove my headphones, too. When I unplugged the kit, it broke. So, all I know is that's it possible, which is all I was looking to find out.
As to the OPs question, the Explorer adds a few things over the HRT. Besides the added sampling rate capabilities, the line-out is both analog and digital, it uses the well regarded XMOS chip for asynchronous USB, and has a much better aesthetic design and build quality IMO. The HRT is $100 cheaper and has a lower output impedance. Pick which matters more to you.