Just like the 901!
Matt, I believe the issue with the BHC is not the power demand of the headphone, but the low impedance leading to sloppy sound. There has been a lot of debate about whether this should be an issue or not (scientifically speaking), but in my experiences it's a poor combination that won't be fixed with higher sensitivity.
Yes, that seems to be the debate. In terms of their impedance response over the frequency range, the planars are all dead flat so no issue with fluctuations in power delivery, but as I understand it (and from what I've heard when listening to the combo), something to do with the Crack's OTL design means that it doesn't have sufficient damping for the planars.
Interestingly, when I run the HE-500s on the Mainline set to high output impedance, they sound identical to the sound on low output impedance, but the Mainline uses output transformers which may interface differently with the drivers compared to the 6080 tube used in the Crack.
OTL amplifiers generally "prefer" high impedance headphones, so they can run out of power with hard to drive low impedance headphones. I've heard a WA2 clip with a HE-500 because of the mismatch.
Well, I hope the new phones are as good or better than the now older HE-400 and HE-500. BUT, I hope they are different.
Different enough so that those of us who own either the 400 or 500 don't feel like we now have an obsolete set of cans. It's great when everyone wins!
Thanks for the update Peter. I think that you mentioned the 560 will have a reworked cable. Does that go for the 400i as well?