Sep 7, 2019 at 6:14 PM
Well, they arrived, and I can say it's the best 50 bux I've spent in a long time. It looks as if these were used just long enough for the right channel to go out, then returned, then stored in a hot warehouse.So, just for anyone else wondering: I went back and saw that the worst issue could be a jammed driver, which causes distortion. There were also a few symmetry issues with some cups and yokes. It's quite possible this has any of those issues. Hifiman has been so good about replacements, those factory mistakes must be hiding somewhere.
My open-box m565 arrived a day ago, with a bright new "inspected-approved" sticker sealing the box shut. Unfortunately, the 'inspector' forgot that both cups must function... I might get some via amazon, but no more Monoprice open-box. It's a shame, I wanted some smaller, easily driven planars for on-the-go.
If I can't fix this he4xx, I'll probably buy a new one. It's big and power hungry, but the company knows how to treat customers. That goes further than anything.
The pads are toast, and why I think the cans were stored hot. Almost all of the glue has disintegrated; I first thought the white powder all over them was mold, but it's just the pads shedding. No worries, the rings can be cleaned and re-used. I may even re-glue these pads, they're still pretty un-used. At the moment, my 30mm Chinese hybrid donuts are held on with painter's tape, and they sound great.
So, about the dead driver. After some testing and fiddling, I found that all I had to do was gently tighten this screw until sound returned.
I thought I was going to have to solder, at least! If anybody's fail out of warranty, this is the first thing I'd check. You don't need to pull up the tape to test. Instead, lay the driver face down on a flat surface. With the cable plugged in and music playing, use your finger to gently apply pressure overtop the the wires' entry points. If you hear music, find which wire it is, slowly work the tape up with a tool, then very slowly tighten the screw until you hear music. I backed the screw off until I found the contact point, then tightened only about a 0.5mm turn more. Be sure to firmly press the tape down. These connections look like they could be fragile, and that's why this tape is so strong and firm.
And I am now a planar convert! The sound lives up to it's name: I feel the music is equally coming from a broad plane covering my ears. I completely understand why planar v dynamic is so polarized. I think it really depends on the shape of your ears and what you love about music. If I had one of my collection, this would likely be it, but time will tell. I'm so glad my m565 came half-broken, the he4xx is exactly what I hoped for from a planar.
Thanks everybody here for all your input. It looks like I may splurge on some of the pad suggestions here.