james444 said:

   
Don't know about the others, but I removed my filters altogether and replaced them with a small amount of cotton swab. Then I used small pieces of dried alcohol swab to protect the nozzle before I put the tips back on.
 
The result is a RE600 with considerably better treble presence than stock, but still sounding very smooth and devoid of high frequency peaks.
 

Click to expand...

 
When you say cotton swab, you mean small round cotton balls? And how much did you put in?

redrich2000 said:

  When you say cotton swab, you mean small round cotton balls? And how much did you put in?

Click to expand...

 
Cutting the top off a Q-tip will give you about the right amount to start with. Fine tuning is subject to experiment. Less cotton = brighter (but potentially spikier).
 

james444 said:

   
Cutting the top off a Q-tip will give you about the right amount to start with. Fine tuning is subject to experiment. Less cotton = brighter (but potentially spikier).
 

Click to expand...

 
Thanks, I think I'll use cotton balls but now I have a sense of how much.
 
Now, could you explain a bit more about how you did the dried out alcohol swab?

redrich2000 said:

  Thanks, I think I'll use cotton balls but now I have a sense of how much.
 
Now, could you explain a bit more about how you did the dried out alcohol swab?

Click to expand...

 
Just get one of those from your doctor or pharmacy, wait for the alcohol to evaporate and cut two pieces out of it (about 8-10mm).
 
Place it over the nozzle and put the tip back on. That's it.
 

james444 said:

   
Just get one of those from your doctor or pharmacy, wait for the alcohol to evaporate and cut two pieces out of it (about 8-10mm).
 
Place it over the nozzle and put the tip back on. That's it.
 

Click to expand...

 
This is probably obvious but you mean two circles to cover the nozzles?
And is that just to keep the cotton in? Or is it needed to stop other gunk going down?

redrich2000 said:

  This is probably obvious but you mean two circles to cover the nozzles?
And is that just to keep the cotton in? Or is it needed to stop other gunk going down?

Click to expand...

 
Yes, squares or circles.
 
An additional alcohol swab layer isn't needed, but it will ensure that the cotton doesn't come out and it's more resistant against gunk than the cotton itself.

james444 said:

   
Yes, squares or circles.
 
An additional alcohol swab layer isn't needed, but it will ensure that the cotton doesn't come out and it's more resistant against gunk than the cotton itself.

Click to expand...

 
Thanks for the info. I'll have a play once I get them and see how I go.

Owners of the newer RE-400 batches, can you comment on the build quality improvements? Specifically the strain reliefs near the earpieces? I remember those looking rather precarious, when I inspected a friend's pair about a year ago. How would you rate the overall build quality of the present version?
 
Also, if anyone can compare the build quality to the VSonic VSD3S, that'd be great. Specifically the cables and connection points/joints.

Going by pictures of the re400b the construction around the earpiece looks similar, the plug is L-shaped rather than 45 dgs. I wonder if it is better than the re400 in build and SQ (especially in balanced mode).

I personally prefer the RE-400 to the RE-600 sonically.
The RE-400 has a lighter, more airy sound with well extended but smooth treble. The RE-600 has a heavier, more weighty sound with a bias towards bass-lower midrange. The overall midrange can sound harsh and peaky at times and the treble is too smooth for my taste...
To me, the 400 sounds more like a traditional HiFiMAN house sound headphone while the 600 just sounds... different. 
Different strokes for different folks I suppose.

I agree with you RE400 is better than RE600,

I have been listening to the RE400 since Saturday and I love it. The clarity is impressive, especially vocal music is simply beautiful. The bass works for me, it's there when you need it and not overpowering in any way. It's definitely not a bass monster which is a good thing. It sounds great straight from my Samsung Note 3, but can still improve with an amp, I would say it's a great middle ground - sounds great from a smartphone and even better with an amp. Even my humble Fiio E5 improves the sound, with a better amp the results are great. I won't go into too much detail, there are plenty of reviews of the RE400. At $79 it's a very impressive value.

In terms of construction, I can't judge after only a couple of days, but visually it seems very well constructed. I'm not sure how many iterations were there, but this is what it looks like currently:



The most important thing in an IEM for me is comfort and the RE400 is easily the most comfortable IEM I've ever had. I always struggled with IEMs - after around an hour my ears always started hurting and I had to take them out. Not with the RE400, they are simply perfect as far as fit. Their small size certainly helps. Here's a comparison with an old MEElectronics M9 that I had laying around:



They are obviously in different price categories so I won't comment on SQ differences but in terms of fit it's like the differences between stuffing pliers in your ears versus small comfy pillows.

I'm very happy with the RE400 and it will now be my first choice for on the go listening.

Just got my RE-600. I asked for the non-balanced S version but I think I've got the regular version. There's a straight plug with three black rings and the converter cable. But they seem to work with the straight plug in a non-balanced source?
 
Edit: the balanced cable works out of my headstage arrow but not straight from iphone or ipod.

First impressions. Packaging = massive overkill. Sound = much less dark than I was expecting, very spacious. 

Totally agree that the packaging is massive overkill, could have saved it from the price. Soundwise it is very very good.