All depends on how much you want to spend me thinks.
The best I've heard it with was the Luxman P-1u, but at what price...
On the other hand I found the K701 dit pretty well with the LD MKIII as well which is an incredible amp for its price.
About every dedicated headphone amp will outperform your receiver or speaker amps headphone output for sure.
And as the K701 is quite revealing a decent source won't hurt as well.
The best I've heard it with was the Luxman P-1u, but at what price...
On the other hand I found the K701 dit pretty well with the LD MKIII as well which is an incredible amp for its price.
About every dedicated headphone amp will outperform your receiver or speaker amps headphone output for sure.
And as the K701 is quite revealing a decent source won't hurt as well.