JVC HA-RX900 modifications, a picture tutorial. (56k, forget about it...) - Page 13

I've had my JVC HA-RX900s for over a year and I'm guessing that has been enough time for the break in.

The only mod I've done so far is to remove one layer of felt.

So I'm ready to recable, were is a recomended place to mail order the cables from?

Never mind this post, it's the wrong cable.
 

Quote:

Originally Posted by Tacoboy 

I've had my JVC HA-RX900s for over a year and I'm guessing that has been enough time for the break in.

The only mod I've done so far is to remove one layer of felt.

So I'm ready to recable, were is a recomended place to mail order the cables fro.

Ready to place order for recabling RX900s, currently the Mogami 2534.

I will order 30 feet ($36), 15 feet for the RX900 and the other 15 feet for recabling my ATH-AD700 in the future)

Or is there better cable to get?

I would pay a few dollars more for a better cable

I'm going to be recabling my RX900,

Where the wires are soldered to the magnet, it does not have markings for telling which is positive and which is ground.

I can say that the bare wire on one looks gold colored and the other copper.

Maybe i can use the DMM?

Yeah, use a DVM set for low ohms. I think these are 64ohms so set range for <200 ohms.

One probe on the plug and one on the driver. Tip is left +, middle ring is right+ and bottom (closest to plug body) is ground.

With probe touching positive on plug test both terminals on driver. Terminal with least resistance is positive, mark with a sharpie.

You could also use your meter on continuity check and not have to read Ohms. But I've gotten false readings on drivers before (continuity thru driver). Although it should work.

Hi everyone.

I have the little brother RX-700 and now I would like to wash the band that covers the head, but I don't know how to remove it. Is it possible?

I can see that there are two screws on both sides, but I can't get to them since there's the plastic bar in front and so there's no way I can use a screwdriver.

Am I missing something?

Thank you.

Can you comment on how your recable went and any changes it made to the 'phones?

Thanks.

Quote:

Originally Posted by Tacoboy 

I'm going to be recabling my RX900,

Where the wires are soldered to the magnet, it does not have markings for telling which is positive and which is ground.

I can say that the bare wire on one looks gold colored and the other copper.

Maybe i can use the DMM?

Quote:

Originally Posted by TopPop 

Quick update: these phones are way too heavy to be worn for an extended period of time, so I opened them back up, and removed all of the extra pieces of Dynamat, except for those in the inner ring (closest to the driver) in Step 6.

The phones are much lighter now, and I can't tell any difference in the sound. I would now recommend only putting Dynamat on the magnet, inside cup surface (Step 3), and inner ring of Step 6 (could still be optional, though, I'd imagine).

Thank you so much for your extremely interesting 3d !

Actually I bought one month ago the JVC and just now I read your excellent description.

I have already peeled the felt.

If I understand well the problem is the vibration of the frame on which the driver is mounted.

Like in a speker with a too thin/weak baffle maybe ?

What amazes me is that even from a cheap driver as that one mounted in the JVC a very strong performance can be obtained

I will try with some small lead like these one

http://www.google.it/search?hl=it&rlz=1T4ACAW_itIT427IT427&q=lead%20adhesive&um=1&ie=UTF-8&tbm=isch&source=og&sa=N&tab=wi&biw=1345&bih=492

Thank you very much again.

Regards,

ginetto

P.S. regarding the felt, I have the feeling that no felt is the better solution in the end

I am afraid to destroy everything so I just peeled a layer off.  Look at the Grado, just a very open screen between the diaphragm and the ear. And good transparency as a result

Like in speakers as well.

Quote:

Originally Posted by Clincher09 

So how does this mod sound compared to the AT M50s? I've been looking at the AT's but if this mod sounds better I think I'll give it a try instead. 

I have the same exact question!

Quote:

Originally Posted by j2kei 

it is possible to reverse the dynamat? the thing is like tar to me, extremely hard to work with. especially when you work it in, the sticky substance kinda oozes out.

If your Dynamat is gooey I would NOT use that on the inside of a headphone.

You get one or 2 extremely hot days and you have a soupy mess inside those cans.

I do car audio for a living and have had to deal with cheap deadener liquefying.

Are you sure it's authentic Dynamat and not roofing mat?

Quote:

Originally Posted by Rex81 



Perhaps we can agree that the best solution is to buy both and see for oneself!

AMEN to that! Exactly what I've done.

Listening to some Patricia Barber right now on my HARX700's and checking tracking info on my HARX900's due to arrive in a few hours.

Yes I'm late to the party.

I've put about 140 to 150 hours on my HARX900 and performed all the mods

Instead of Dynamat I used a blue colored non hardening clay......I started by covering the entire outer cup with about 1/8" of clay.

I covered most of the little pockets on the back of the baffle and placed a thin whispy amount of polyfill in the cup. It was so thin I had a difficult time finding it on my white table.....it was so thin I almost breathed it in.

No bass......the headphones had no life at all.

So I decided to take out all the pieces on the back of the baffle and reduced the amount of clay on the outer cup down to a circle the size of a quarter.

Still.....no bass

Then ...down to a circle the size of a dime. This improved things a bit as it brought some of the low end back.

As I played some music with all the clay removed I realized that the cups need to have some vibration to them....not good in a H--Fi sub enclosure but this is a different cup of tea.

These things just need to vibrate.

I needed to find a medium between killing all the cup vibration and possibly cleaning up some of the mids because of the tremendous amount of vibrations.

I settled on three small dots 1/4" in diameter placed in a triangle pattern at the outer edges of the cups....nothing else except for the thinnest whispiest amount of polyfill.....acftually 1/2 of my first attempt.

Now the headphones are a different animal compared to at the 80 hour burn-in mark pre  mods.

I removed all the felt including cleaning up all the holes.

With no felt some of the upper mids/lower treble can be quite peaky.

Playing any song on Tool's Lateralus reveals an almost unbearable guitar tone that is no where near what comes out of either my Sennheiser HD205, AT AD700, AT A700, HARX700 or even my Sony MDR-V900HD.

Replace the felt and things get a bit less peaky.

So I do suggest to anyone doing these mods..... Do not throw out the felt ring.

When I removed mine it stayed intact just basically sliced in half.

Remove all the felt and adhesive from the holes and you now have a modular system where you could use:

1) no felt or lens........2) just acoustic lens, or 3) acoustic lens plus felt.

You could also experiment with different types of felts and fabrics to find something that works better.

These cans are no longer bass heavy but have an ample amount of bass and still have a very revealing amount of low level detail.

The upper mids and lower treble can be a bit brash so the felt is a nice option with some recordings.

I have pics if anyone is still interested in the materials I used in my mods.

It's still a work in progress but these cans are still intriguing and I always find myself going for the HARX900 first when listening to new music or CD's I dig out of my collection.

More to come........

As a follow up I hooked up a high quality DAC to my headphone setup and much of the problems I was experiencing vanished.

I should have figured this was the case since much of the problems are not present when playing FLAC files through my computer setup.

It's now like HEAVEN listening to these headphones and I really want a dedicated DAC and headphone amp since I'm using an Adcom preamp for my amp.

I know that a top notch DAC can un veil the sound but I figured the DAC's in my CD player were of higher quality considering it was actually made 3 years after my digital preamp.

So, in the end, do you suggest me to do the felt mod as indicated in the first post, without removing it all, or should I leave the headphones as default? I've suggested this to a friend of mine, he's not an audiophile. Ofc he won't wanna do all the mods, and he seeks deep bass, so I don't think the stuffing will be good for his tastes. But will the felt mod make these headphones too harsh?