[trollchu]

Bit of a scare earlier when the HD250 Linear I's sounded like they had a blown channel after clearing out foam bits and putting the ear pads on. Faint output on one side and crackly. Luckily, after taking them apart and putting them back together, these now work normally. Of course, I tested impedance per side, and also tested output once the driver was removed, where I found that it worked fine while removed. No idea what happened or what may have shifted with the ear pad work or cleaning. Obviously, be careful when cleaning out foam around drivers.

So here's the rest of the details on disassembly, since I was unable to find anything specific in the way of posts, pictures, or videos related to disassembly.

To remove the drivers after removing ear pads (ear pads detailed in my prior post):

1. Optionally pop the driver housing (cup) off of the headband by just pulling straight out with sufficient force. It's simply a plastic ball socket deal. The rest is easier of course when the headband is out of the way.
2. Remove the silver ring by using fingernails to leverage it off. Thumbnail on the housing and index or other nail on the ring is what I found to work best for me. You'll have to unsnap it by working around the perimeter after the first area starts to separate (may pop loose). You or your S.O. may break some nails in the process. Mostly kidding... it wasn't assembled by Hercules and they aren't glued in from factory.
3. Remove the plastic driver holder/surround assy from housing (cup) in similar fashion by using fingernails. Don't worry about the driver, wiring, or any other major parts coming loose - they're all together in the assembly. Maybe you could do this without removing the metal ring first but no idea. There's just a small black plastic doodad at the back end which will be separate and another felt disc once driver assembly separates from the main housing.

Wish I would have taken pictures but was in a frenzy to determine whether this pair was shot. There wasn't any foam behind the drivers on mine to go bad, just the felt type of ring similar to what's on the front side. So I don't see much reason to remove the drivers unless you have a similar problem or have to swap drivers. If you use a can of keyboard duster or similar light air pressure, you should be able to carefully blow out any degraded foam from around the front side without worrying about disassembly. I had quite a bit of degraded foam and didn't notice any remaining in the back after cleaning these earlier without pulling drivers off.

There's also no point in taking the badge off the outside of the housing unless yours are loose. If so, you may want to glue them down while disassembled. They have a couple of metal pins that are bent over on the back side to keep them in place. One of mine was slightly loose so I tried futzing with that thinking there may be a screw or something behind them early on. Nope. Anyway, it won't be loose anymore.

Coincidently, I left disassembly instructions for these in the HD540 thread sometime ago and also left photos. I started it as I did hoping it would catche to Google, but clearly, I failed there. I did note a standardized foam, so the results should be easy to replicate, but sonically, I currently get an extremely similar signature to what Monsterzero described in his former Youtube review out of my own pair. Here's a link for anyone interested:

https://www.head-fi.org/threads/wow-sennheiser-hd-540-reference-are-so-good.670255/post-17120466

 

[ArChaos]

.................................................................
So here's the rest of the details on disassembly, since I was unable to find anything specific in the way of posts, pictures, or videos related to disassembly.
..................................................................

1. First of all, thanks for your great post...
2. Attached here a disassembly scheme of the HD250 with the part names translated in ENGLISH:

 

[trollchu]

1. First of all, thanks for your great post...
2. Attached here a disassembly scheme of the HD250 with the part names translated in ENGLISH:

I remember looking into translating all of that a long time ago and I believe you've shifted some of the translations. Six should be the neodymium magnet, seven, the aluminum voice coil, eight, the silk dome, nine, the polycarbonate membrane, and ten, should be a stabilizer.

 

[QusayM]

By the way, who has listened to the Sony Z1R or to the Sennheiser HD820 and can shed some light on the difference between those and the HD250 either subjectively or objectively?

 

[Monsterzero]

By the way, who has listened to the Sony Z1R or to the Sennheiser HD820 and can shed some light on the difference between those and the HD250 either subjectively or objectively?

I havent heard either but IMO the new ZMF Atrium closed is the logical upgrade. The AC has stronger midbass by a pretty substantial margin and has better and more prominent sub-bass(!!!!) as well. The AC is an absolute bass monster! Much better staging as well.

The main difference between the two besides the price is the AC is a warmer sounding headphone vs. the HD250

 

[QusayM]

I havent heard either but IMO the new ZMF Atrium closed is the logical upgrade. The AC has stronger midbass by a pretty substantial margin and has better and more prominent sub-bass(!!!!) as well. The AC is an absolute bass monster! Much better staging as well.

The main difference between the two besides the price is the AC is a warmer sounding headphone vs. the HD250

The thing is, does having the mid-bass and the sub-bass elevated mean better performance? What about the bass accuracy and the overall resolution? What about the midrange and treble?

 

[Monsterzero]

The thing is, does having the mid-bass and the sub-bass elevated mean better performance? What about the bass accuracy and the overall resolution? What about the midrange and treble?

Last year ZMF came up with a patented damping system (ADS) that has been in the Atrium open, Auteur classic, Caldera and now the Atrium closed. The ADS gives each of these headphones an amazing sense of a 3D soundstage, allowing the mids, highs and bass extra room to breathe. So, while the HD250 is a brighter headphone with more treble energy, I do not feel that the resolution is better on the HD250.
The mids are relaxed on the AC vs HD250, which has more upper mid energy, but again the ADS give the mids on the AC extra room in the stage so they can be focused on better by the listened if needed.
All of that being said, like the HD250, the bass of the AC is the star of the show. When I'm using the HD250 I rarely listen to midrange focused music genres. I have the K240 sextetts for mids as well as other ZMF headphones that are more mid-centric. Similarly I don't use the sextetts for bass intensive music either.

In my headphone collection I have go to headphones for specific genres:

K240 sextetts, Atrium open, Auteur for rock, metal, blues, americana
Verite open,Verite closed, K701 for extra staging
Caldera for transparency, speed and accuracy
HD250, Atrium closed for bass centric music like EDM, trance, reggae
I feel that except for the K701 and K240 sextetts, all of my other headphones do a pretty good job of being all-arounders, including the HD250 and the AC.


Don't get me wrong, the HD250 remains one of my favorite headphones ever, but its role in my collection as the Top Dog for bass, it has been replaced by the Atrium closed.

If you're inclined, I discuss the HD250 in my review of the Atrium closed.

 

[fredrikie]

I have a nice condition hd250 linear 1 300ohm. Curious how different this is from the 600ohm model. The pads my pair are still solid. Is it worth swapping to different pads? I measured the frequency response of my pair and they are wild lol

 

[NickT23]

I have a nice condition hd250 linear 1 300ohm. Curious how different this is from the 600ohm model. The pads my pair are still solid. Is it worth swapping to different pads? I measured the frequency response of my pair and they are wild lol

I have 600 ohms and I doubt it will sound any different. Hd250 is bright and has slight recessed treble. On a solid state, quite anlytical and forward. The answer is no, stick with stock pads. Just my own opinion.

 

[QusayM]

I have 600 ohms and I doubt it will sound any different. Hd250 is bright and has slight recessed treble. On a solid state, quite anlytical and forward. The answer is no, stick with stock pads. Just my own opinion.

In my experience, the HD250 is both bright and warm although it is actually quite neutral if you look at its frequency response. The thing is, the HD250 scales incredibly well and sounds different from amplifier to amplifier. The major "problem" with it is the recessed midrange. By the way. I have found and purchased the HD230 on eBay. In my humble opinion, they are much better when it comes to the midrange while they perverse the characteristics of the HD250 at both ends. I assume that they achieve that thanks to the dual drivers they have (a woofer and a tweeter).

 

[NickT23]

In my experience, the HD250 is both bright and warm although it is actually quite neutral if you look at its frequency response. The thing is, the HD250 scales incredibly well and sounds different from amplifier to amplifier. The major "problem" with it is the recessed midrange. By the way. I have found and purchased the HD230 on eBay. In my humble opinion, they are much better when it comes to the midrange while they perverse the characteristics of the HD250 at both ends. I assume that they achieve that thanks to the dual drivers they have (a woofer and a tweeter).

No, it does not sounds warm at all maybe unless using a warm amplifier. Why pad roll by the way ? What is the issue with stock pads ?
As for 'recessed mid range', think that mostly part of the sound signature.

 

[QusayM]

No, it does not sounds warm at all maybe unless using a warm amplifier. Why pad roll by the way ? What is the issue with stock pads ?
As for 'recessed mid range', think that mostly part of the sound signature.

Well, I tried it on three different amplifiers and I could notice the extension in the low frequencies region. Then those amplifiers must be "warm" although I am not sure that is the accurate definition of this term.

I am not the guy who asked about pad rolling but actually I thought about trying to do so just to experience the difference.

Maybe you are right about the sound signature. In any case, I would definitely choose the HD230 over the HD250.

 

[NickT23]

Well, I tried it on three different amplifiers and I could notice the extension in the low frequencies region. Then those amplifiers must be "warm" although I am not sure that is the accurate definition of this term.

I am not the guy who asked about pad rolling but actually I thought about trying to do so just to experience the difference.

Maybe you are right about the sound signature. In any case, I would definitely choose the HD230 over the HD250.

Like I said, could be the sound signature of the amplifiers and they are not transparent. Have you tried with tubes ?
But why HD230 over HD250 ? Just curious.

 

[QusayM]

Like I said, could be the sound signature of the amplifiers and they are not transparent. Have you tried with tubes ?
But why HD230 over HD250 ? Just curious.

The HD230 has a more expressive and more pleasant midrange. In addition, their treble is more tolerable for me. I am super sensitive to treble as my ears are relatively smaller than average.

 

[NickT23]

The HD230 has a more expressive and more pleasant midrange. In addition, their treble is more tolerable for me. I am super sensitive to treble as my ears are relatively smaller than average.

Have you tried HD250 with tubes ? Well, even HD250 can sometimes be overly bright with some music.