JVC HA-S680 is the next generation of HA-S400 and HA-S500, with the carbon nanotube technology. Just like them, it's not meant to be sold outside of Japan Nevertheless, here we are! They utilize a 40mm driver, but it's not the same driver as in S500 - it is the next generation! Output sound pressure level: 102dB/1mW Playback frequency: 8Hz ~ 26.000Hz Impedance: 32Ω S500 is louder (106dB/1mW) and has 1 Khz less extension at the top. I own S400, so I will be using it for comparison. Sound Quality - upon receiving them, I gave them a short audition. They sounded nothing special, but I had good reasons to believe they would improve: 1) It took me over 200 hours to fully burn-in my S400s, and they didn't sound great until the process was finished. 2) These are Japan-only headphones, and Japanese usually keep the best stuff to themselves 3) SQ was scaling up with better sources - always a good sign. So I started burning them with this noise: https://www.dropbox.com/sh/rnrj5g0mmbldj58/ZhYIByMYOE/White-Pink-Brown%20Noise%20%28For%20burn%20in%29.wav 12 hours in - Small changes here and there 24 hours in - Oh my god, did they burn in already? All the frequencies sound so much better, especially the bass. I compared them to S400, and it became clear that there was still a long way to go - the bass wasn't as tight and vocals weren't as emotional. 48 hours in - Now this a clearly superior headphone to S400. Sound is balanced, similar to S400's sound signature, but the bass hits harder (although just as tight) and the larger pads helped improve soundstage and imaging. Instrument separation is better too. The vocals are very engaging. 72 hours in - No audible differences. This is where I believed that this is a new improved driver, and not just an old repackaged one. The old driver took over 200 hours to burn in, but they perfected the formula and the new one is done in 48! There are a few significant design changes in S680 - 1) Bass ports 2) Larger pads The bass ports are necessary for the harder hitting bass, what surprises me is that the bass is still just as tight as before, despite increase in volume. There is no leakage into the mids either. Comfort - the larger pads increase both soundstage and comfort. For some people, especially women, these may be around-the-ear, for me they are still on-the-ear. However, they are much more comfortable then S400, because they press on the more remote parts of the ear. I've tried the Shure HPAEC840 pads - they are too big, may need to be modified to fit properly. BrainWavz HM5 pads are a perfect fit, but have the same effect as on S400 - soundstage improves, but the bass becomes a little boomy. The HM5 look like they were made for S680, on S400 they looked monstrous. Isolation - the larger pads make it better, but the bass ports make it worse. They are OK to use in an office, but not on a mass transport. Sound leakage is minimal, can be used in a library. Overall, this is a fantastic portable closed phone, my new #1, ahead of HA-S400 and ATH-ES700. They scale well with better equipment, but aren't hard to drive. They also makes a decent desktop speaker - I can put my NFB-11.32 on high gain and volume at 1-2PM - the sound fills the room Price - I have bought it from White Rabbit Express for 96$ including shipping. I've asked one of my Japanese eBay sellers to list it, and he listed all 3 models for 80$ including shipping!!! I guess the pioneers always pay a price... The black one is here: http://www.ebay.com/itm/NEW-Victor-JVC-HA-S680-B-Black-color-Outdoor-type-Headphone-Carbon-Nanotube-F-S-/281216875091 The red one is here: http://www.ebay.com/itm/NEW-Victor-JVC-HA-S680-R-Red-color-Outdoor-type-Headphone-Carbon-Nanotube-F-S-/271332332176 The white one is here: http://www.ebay.com/itm/NEW-Victor-JVC-HA-S680-W-White-color-Outdoor-type-Headphone-Carbon-Nanotube-F-S-/271333864823 I've bought some audiophile items from him before, he's really good. Also, you can buy them directly from Kakaku for 65$-75$ depending on color and your location: http://www.head-fi.org/t/690493/the-jvc-ha-s680-s400s-and-s500s-big-brother-is-here/75#post_10051650 Other users' impressions: Painful Chafe: http://www.head-fi.org/t/690493/the-jvc-ha-s680-s400s-and-s500s-big-brother-is-here/75#post_10054263 http://www.head-fi.org/t/690493/the-jvc-ha-s680-s400s-and-s500s-big-brother-is-here/75#post_10054585 http://www.head-fi.org/t/690493/the-jvc-ha-s680-s400s-and-s500s-big-brother-is-here/210#post_10125322 MichaelGordon: http://www.head-fi.org/t/690493/the-jvc-ha-s680-s400s-and-s500s-big-brother-is-here/195#post_10122273 http://www.head-fi.org/t/690493/the-jvc-ha-s680-s400s-and-s500s-big-brother-is-here/225#post_10126378 http://www.head-fi.org/t/690493/the-jvc-ha-s680-s400s-and-s500s-big-brother-is-here/285#post_10171649 yay101: http://www.head-fi.org/t/690493/the-jvc-ha-s680-s400s-and-s500s-big-brother-is-here/270#post_10170918 http://www.head-fi.org/t/690493/the-jvc-ha-s680-s400s-and-s500s-big-brother-is-here/285#post_10171599 http://www.head-fi.org/t/690493/the-jvc-ha-s680-s400s-and-s500s-big-brother-is-here/300#post_10173065 GeneralPsycho: http://www.head-fi.org/t/690493/the-jvc-ha-s680-s400s-and-s500s-big-brother-is-here/330#post_10185348 Lifted Andreas: http://www.head-fi.org/t/690493/the-jvc-ha-s680-s400s-and-s500s-big-brother-is-here/270#post_10167502 http://www.head-fi.org/t/690493/the-jvc-ha-s680-s400s-and-s500s-big-brother-is-here/270#post_10171131 Aillas: http://www.head-fi.org/t/690493/the-jvc-ha-s680-s400s-and-s500s-big-brother-is-here/390#post_10200915 Ji-L87: http://www.head-fi.org/t/690493/the-jvc-ha-s680-s400s-and-s500s-big-brother-is-here/450#post_10235981 Jdg711: http://www.head-fi.org/t/690493/the-jvc-ha-s680-s400s-and-s500s-big-brother-is-here/480#post_10279173 Ebrian: http://www.head-fi.org/t/690493/the-jvc-ha-s680-s400s-and-s500s-big-brother-is-here/555#post_10378905 http://www.head-fi.org/t/690493/the-jvc-ha-s680-s400s-and-s500s-big-brother-is-here/570#post_10386751 http://www.head-fi.org/t/690493/the-jvc-ha-s680-s400s-and-s500s-big-brother-is-here/600#post_10393919 K.T.: http://www.head-fi.org/t/690493/the-jvc-ha-s680-s400s-and-s500s-big-brother-is-here/630#post_10412522 http://www.head-fi.org/t/690493/the-jvc-ha-s680-s400s-and-s500s-big-brother-is-here/630#post_10412626 http://www.head-fi.org/t/690493/the-jvc-ha-s680-s400s-and-s500s-big-brother-is-here/645#post_10416493 Nzhao20: http://www.head-fi.org/t/690493/the-jvc-ha-s680-s400s-and-s500s-big-brother-is-here/660#post_10420014 http://www.head-fi.org/t/690493/the-jvc-ha-s680-s400s-and-s500s-big-brother-is-here/660#post_10420308 Misubi1000: http://www.head-fi.org/t/690493/the-jvc-ha-s680-s400s-and-s500s-big-brother-is-here/555#post_10381373 http://www.head-fi.org/t/690493/the-jvc-ha-s680-s400s-and-s500s-big-brother-is-here/570#post_10387157 http://www.head-fi.org/t/690493/the-jvc-ha-s680-s400s-and-s500s-big-brother-is-here/630#post_10412710 http://www.head-fi.org/t/690493/the-jvc-ha-s680-s400s-and-s500s-big-brother-is-here/675#post_10424944 http://www.head-fi.org/t/690493/the-jvc-ha-s680-s400s-and-s500s-big-brother-is-here/675#post_10431184 Marcswede: http://www.head-fi.org/t/690493/the-jvc-ha-s680-s400s-and-s500s-big-brother-is-here/750#post_10514928 The burn-in procedure: 1) Use https://www.dropbox.com/sh/rnrj5g0mmbldj58/ZhYIByMYOE/White-Pink-Brown%20Noise%20%28For%20burn%20in%29.wav 2) Adjust the volume so that the middle noise is too loud for comfort 3) Take the headphones off, and add another 20-30% volume 4) Keep burning 24/7 5) Give it at least 48 hours 6) Once burn-in of the driver is done, please let your brain burn-in as well - it will take a few days for the brain to adjust to the sound. At first, the brain will refuse to process the soundstage and clarity that HA-S680 can produce, but it will give in eventually.