I have been throughly enjoying the excellent JVC HA S500 and needed to get the wife one (that's what we all use as an excuse right ?) so I ordered the JVC HA S400 (couldn't decided which color, ordered the Red and the Silver)
 
Links to DSnut's thread on the excellent HA S500: http://www.head-fi.org/t/621063/the-new-jvc-ha-s500-40mm-carbon-nanotubes/1080#post_8677801
 
 
Here's the 2 new addition to the HA S500.

 
The Red one caught my eyes, they reminded me of the Audio Technicas.

 
The Silver looks much better in person, the chrome ring lends a classy look to the headphone. (Wife choose the silver)

 
The S500 and the S400 both share the same cable and the headphone connecting bridge are the exact same plastic moldings.
Folded view of the HA S500. (Left) and HA S400 (Right)

 
Beside the larger 40mm drivers the extra cost of the S500 went into the plusher and better quality headband paddings. (To be fair, I can't feel the differences)

 
Outside view of the housings, they are the same size, the S500 has a one piece Gunmetal plated plastic cup (Mine's peeling as you can see here) the S400 has a mirror finish plastic cup surrounded by a painted or chromed ring.

 
Inside view of the housings, the pleather pads are the same, if you click and look at the larger image, it is difficult to tell the larger 40mm drivers from the smaller 30mm drivers.

 
Comparing cup to cup, they appear to have the same diameter.

 
Side by side view of the cups the S500 seems slightly thicker by a few mm.

 
I ended up with the less classy but more hip looking Red S400 (I certainly prefer the looks and finishing of the S400 over the S500) the piano mirror finish may attract finger prints easily but at least they won't peel or flake off like the S500.

 
As I've mentioned over at the S500 thread, I was shocked at how good the S400 sounded out of box, I will usually plug in headphones/iems out of box just to make sure both drivers are sounding and then leave them burning for a week.
Not so for the S400, I was like "Eh?" this sounds like it's been burn before, so I quickly took out the other pair to test and it too sounded the same. Needless to say, I ended up listening to a couple of albums with them.
 
I recall the S500 did not have a very coherent sound out of the box (Bloated bass, recessed mids and undefined highs) and only started to sound decent after about 50 hrs of burning, The S400 out of box sounded like it has 50 hrs of burning done.
 
The bass is there and with a nice deep sub bass extension, certainly not bloated, Mids are nicely balanced and not recessed, the highs are there but could do with a bit more defination. At this point, it wouldn't be fair to compare them to my fully burned in S500 but as it is, they are certainly not that far behind, sound signature between the 2 are indentical.
 
I am wondering how much change burning would have on the S400, if it is as much as the S500 then I think I would really love the S400. As it is currently, I am prefering the finishing and weight of the S400 over the S500, the S400 is so light that you'll soon forget there's a headphone sitting on your head, with the S500, I have to readjust the cups every now and then to ease the pressure of the pads sitting on top of my head.
 
Okay then, I will do an A/B of the S400 and S500 in a weeks time after the S400 have about 150hrs of burn to see which I prefer sonically, stay tuned.
 
Edited - 13 Sep 2012 - Imswjm's impression here:
http://www.head-fi.org/t/626332/the-new-jvc-ha-s400-30mm-carbon-nanotubes/15#post_8697046
 
Edited - 15 Sep 2012 - My A/B comparision between S500 and S400 (with 100hrs+ burn) here:
http://www.head-fi.org/t/626332/the-new-jvc-ha-s400-30mm-carbon-nanotubes/15#post_8700246
 
Edited - 24 Sep 2012 - My comparision between a 200hrs+ burn and Out of Box pairs:
http://www.head-fi.org/t/626332/the-new-jvc-ha-s400-30mm-carbon-nanotubes/45#post_8722512
 
Edited - 26 Sep 2012 - Imswjm's S400 pads recommendations:
http://www.head-fi.org/t/626332/the-new-jvc-ha-s400-30mm-carbon-nanotubes/60#post_8729933
http://www.head-fi.org/t/626332/the-new-jvc-ha-s400-30mm-carbon-nanotubes/60#post_8730217

These look nice. It don't surprise me one bit they sound just like the HA-S500. Might have to check out a pair.

Nice effort and cool write up as well! thanks man! i really want to give the jvc line a try more and more after reading impressions like yours..

Thanks for sharing Ghost.  Glad to see they are the same size.  

Love the looks of those silver ones! 

Nice and informative, Ghost. Thanks a lot !
 
Two questions - is the sensitivity of HA-S400 and HA-S500 similar/comparable or it is exactly the same ? The difference in sound should be in the ultimate quantity of the bass available due to difference in driver size - please answer this one after you have at least 50 hours on them.
 
One proposal: since you have 2 pairs of relatively new/unused/not too much burned in of HA-S400 nanotubes, please consider burning in one by whatever method you are using now, the other by the method I will post today here: 
 
http://www.head-fi.org/t/625840/controlled-burn-in-with-predictable-results-for-headphones
 
and report differences you ( and your wife - women are more discernible for sound differences than  men...) should be able to hear between the two in your own words - without me coaching you what to listen for. There is no danger involved if you follow the instructions, only better sound to be gained in the end. If the results of my burn in method should prove to your liking, you can repat the exercise with the one that received more regular burn in, so that you end up with both having the same sound quality. Goes for your "old" HA-S500, too.
 
Should you decide to accept my proposal, please specify the exact type of ear pads you used (please use the same (type) pads on both headphones), as HA-S 500 proved to be quite chameleonesque in SQ with different ear pads - please see HA-S500 thread for details.
 
As always, enjoy your music !

Quote:

dsnuts said:

These look nice. It don't surprise me one bit they sound just like the HA-S500. Might have to check out a pair.

Click to expand...

Yup, what struck me most was how similar they sound.
You should check them out Ds, would really love to hear your take on them.
 
Quote:

angelopsaro said:

Nice effort and cool write up as well! thanks man! i really want to give the jvc line a try more and more after reading impressions like yours..

Click to expand...

Thanks, the scond half of 2012 really belongs to JVC and their carbon nano tube drivers techology, it seems they can't go wrong with their FX40, FXD70, FXD80, HA-S500 and HA-S400.
 
It's never too late to jump on the JVC CNT bandwagon and see what you've been missing.
 
Quote:

dannybai said:

Thanks for sharing Ghost.  Glad to see they are the same size.  

Click to expand...

You're welcome bro, althought I have not brought a caliper to them, the cans appear to be the same size, the S500 are thicker by the step protrusion on the outside.
The S500 also has a more noticable heft to them, evidence only after holding the lighter S400.
 
Quote:

achmedisdead said:

Love the looks of those silver ones! 

Click to expand...

 Yup, me too   ...originally the reds were for the wifey, but after she saw them, I had to settle for the red
Will post some photos of the Silvers later...

Quote:

analogsurviver said:

Nice and informative, Ghost. Thanks a lot !
 
Two questions - is the sensitivity of HA-S400 and HA-S500 similar/comparable or it is exactly the same ? The difference in sound should be in the ultimate quantity of the bass available due to difference in driver size - please answer this one after you have at least 50 hours on them.
 
One proposal: since you have 2 pairs of relatively new/unused/not too much burned in of HA-S400 nanotubes, please consider burning in one by whatever method you are using now, the other by the method I will post today here: 
 
http://www.head-fi.org/t/625840/controlled-burn-in-with-predictable-results-for-headphones
 
and report differences you ( and your wife - women are more discernible for sound differences than  men...) should be able to hear between the two in your own words - without me coaching you what to listen for. There is no danger involved if you follow the instructions, only better sound to be gained in the end. If the results of my burn in method should prove to your liking, you can repat the exercise with the one that received more regular burn in, so that you end up with both having the same sound quality. Goes for your "old" HA-S500, too.
 
Should you decide to accept my proposal, please specify the exact type of ear pads you used (please use the same (type) pads on both headphones), as HA-S 500 proved to be quite chameleonesque in SQ with different ear pads - please see HA-S500 thread for details.
 
As always, enjoy your music !

Click to expand...

Thanks Analog,
 
On paper, JVC has stated 104dB/1mW for the S400 and 106dB/1mW for the S500, so the S500 should be more sensitive, I can't really tell from my initial impression if that is true as I did not compare directly (A/B) with the S500, however what struck me was how close the 2 headphone's bass sound and I am surprised that the mids could be like that without any burning. Will compare and report back here after the S400 have 50 hrs of burn on them.
 
As for your second question,   ....pardon, what was your second question again ?
 
I have been following your proposal for burning in and wish I could understand half of it.
Sorry I am such a dummy, but I got lost somewhere around the "fish" part, I really need simplified instructions how you did your expedited burning process.
Will keep an eye out on your burn in thread.
 
I know the paddings will change the sound signatures, which is why I intend to stick with the stock JVC padding for audition purposes. 
 
Cheers

Thanks Gosht for the review.  From what seller you bought them? Aoyama or Ikasu?
 
Time to sell a few useless headphones.....
 

I got the red ones as well. I am loving these more and more every day. Everything sounds pretty much perfect on these.
And they make my 'red collection' look even better

Since they look the same size, perhaps you can consider switching the shells! And while you do that, please post pictures of the baffle as well I'm curious if they used different baffles or just added fillers around the smaller S400 drivers.

Quote:

rickdohc said:

Thanks Gosht for the review.  From what seller you bought them? Aoyama or Ikasu?
 
Time to sell a few useless headphones.....
 

Click to expand...

 
Neither !   ...I got mine from Jun Ibaraki san.
 

Quote:

ghostfit said:

Thanks Analog,
 
On paper, JVC has stated 104dB/1mW for the S400 and 106dB/1mW for the S500, so the S500 should be more sensitive, I can't really tell from my initial impression if that is true as I did not compare directly (A/B) with the S500, however what struck me was how close the 2 headphone's bass sound and I am surprised that the mids could be like that without any burning. Will compare and report back here after the S400 have 50 hrs of burn on them.
 
As for your second question,   ....pardon, what was your second question again ?

 
I have been following your proposal for burning in and wish I could understand half of it.
Sorry I am such a dummy, but I got lost somewhere around the "fish" part, I really need simplified instructions how you did your expedited burning process.
Will keep an eye out on your burn in thread.
 
I know the paddings will change the sound signatures, which is why I intend to stick with the stock JVC padding for audition purposes. 
 
Cheers

Click to expand...

Thank you Ghostfit for the answer !
 
Part 2 of burn in cookbook style posted in appropriate thread.
 
"Fish" thing explained : Chinese have a saying that by giving a hungry person a fish is to feed that person for a day; by teaching that person how to catch fish is feeding that person for a lifetime.
 
I could easily start advertising headphone burn in and do it either pro bono or charge for my service = "giving you a fish", or in this case a single pair of properly burnt in phones. I chose to teach you all how you can do it by yourself instead , giving you the possibility to properly burn in all your present and future phones = "feeding you for a lifetime".
 
As always, enjoy your music !

 Funky...

Quote:

analogsurviver said:

Thank you Ghostfit for the answer !
 
Part 2 of burn in cookbook style posted in appropriate thread.
 
"Fish" thing explained : Chinese have a saying that by giving a hungry person a fish is to feed that person for a day; by teaching that person how to catch fish is feeding that person for a lifetime.
 
I could easily start advertising headphone burn in and do it either pro bono or charge for my service = "giving you a fish", or in this case a single pair of properly burnt in phones. I chose to teach you all how you can do it by yourself instead , giving you the possibility to properly burn in all your present and future phones = "feeding you for a lifetime".
 
As always, enjoy your music !

Click to expand...

 
haha I'll try my best to understand and implement it. LoL  Need to use this method to burn my FX40s "to hell" as rickdohc would say.
 
 
 
Quote:

lmswjm said:

 Funky...

Click to expand...

OMG the white ones are so sexy!!! I'll getting them for sure, and thanks ghost for taking the dive into these S400s. I can't imagine how they can be EVEN more light/ comfortable than the feather-light S500s but I'll take your word for it.  Oh I wanna ask you how do the foam? pads on the headband in the S400s compare to the S500s comfort wise? Cuz the pleather ones on the S500s are so soft and nice, so I wouldn't think the foam ones on the S400s would be as good.