GarlicBiscuits

Dianne Reeves, Steely Dan, and Robben Ford are wonderful artists worth checking out (HD 800 or not). Slower genres like jazz, vocals, acoustic, ambient/lofi, orchestral, and big band/live performances are such a pleasure with them.

What output on the A70 are you plugging your Zeus Elites into? If it's the unbalanced, there's a chance the A70 wouldn't be optimized with it in mind (as a fully balanced design) and may change the sound. Because it's fully balanced, connecting the Element III to it via RCA (instead of XLR) may further change the sound.

I am only speculating though, so take this with a grain of salt. For all I know, as long as there's no audible distortion, the inputs and outputs may not change anything besides volume.

I found the SRH1540 headband to almost immediately create a hotspot on my head, quicker than other headbands. Those alcantara earpads were really plush and comfy though.

I would take the Sennys for build and comfort any day. They also have a sound that is almost entirely unique to them. The Clear MGs sounded warm and lovely from the one demo I had, but if they're anything like the Radiance that I have also tried, the weight and clamp force end up being a turn-off.

The HD600 line tends to be known for lack of bass presence, particularly with subbass and overall quantity. However, if the old K3 is not a fully balanced DAC/amp design, then the balanced output might be altering the sound in a negative way. I've found that the balanced from my BTR5 starts to distort the bass considerably (especially on my MDR-Z1Rs), whereas the unbalanced (and other amps I have used) are completely fine and distortion-free through their intended outputs.