Happy to report that Sennheisers HME26 600ohms work well with Nova using Audio Hi cables (Left tip Right ring). The rest goes to the sleeve. Same for the mic cable, using Audio Hi for tip. Gain for slate mic needs to be all the way up in the Nova but level is just fine. I compared side by side HME26 600ohm vs HD26 100 ohms and I think there's something around 3-5db level difference between them but the Nova's HP out can handle it perfectly well. I feel HME26s are a tini bit less brighter than HD26, like high freqs aren't as crisp as the 26s, I guess it could be due to the Ohms difference. Also for the record "cable 7" of the optional cables for the Sennheiser HMEs/HDs is made of steel which makes it more resistant but also more stiff and worst of all much prone to get cable noise thru movement and wiggle, the transmission thru the cable to the ear cup is quite noticeable so I would not reccomend it for bag work. Leaving here this for the record