Originally Posted by Schopenhauer
Also, if possible, a brief bit about how it pairs with the HE-500 would be most welcome!
I don't use the JDS Labs C5 much, as most of my listening is in The Lab with the Stack o' Schiit. That said, I did try the C5 with the HE-500s and HE-560s. I was pleasantly surprised with the HE-500s. I'd tried a previous pair, but didn't think much of them. They went belly up, got a replacement, measure the impedance at around 33-34 ohms, then gave them a try. Got more than enough volume without distortion, on both low and high gain, IIRC. Now, I didn't do tons of testing, probably didn't listen to really quiet stuff, but what I heard made me think I could use the C5 in a pinch.
Not so much with the HE-560s. They are less efficient, power hungry beasts. Not at HE-6 levels, from what I've read, but they do seem to enjoy a fair amount of current.
Not sure I'll get around to listening to the K712s again. They're boxed up, I'm hoping to sell, and I'll be pretty busy the next few weeks. If it helps, the C5 drives the Q701s just fine.
I normally run my C5 hooked up to the line out of a Rockbox'd iPod Classic.