[SIRKRA]

I've just managed to get my hands

I just got an HD540 ref II (german version) yesterday, and like you I started with the HD520 I 300ohm, and the 540 seems a lot easier to drive, and doesn't need to be turned up as high on the volume. Pleasantly surprised that they have even more attack than the 520's, not to mention more clarity. The earpads are almost paper-thin so I have some velour 'wangs' on order, looking forward to hearing differences or improvements on an already impressive presentation!

The headstrap has no cushioning left in it, which makes it very hot to wear... I dont suppose anybody knows if the strap can be opened to insert new foam or something? I can see stitching on the edges, but I'm not sure if its glued together as well. I'm not confident its strong enough to survive such a procedure if it is glued, as it feels quite fragile

First revision of the 520 is marketed as 600ohm (i don't have one so i don't know if like the 540, but seems like so, there could be 300ohm ones even in first revision, while the second is totally 300, did You measure the resistance? ), both 520 and 540 are at 94 sensitivity.
The strip of the headband is 2 parts plastic, internally, and covered with cloth in a kind of stitched together. opened mine that was in trash for the sake of science.
It is not fixable when opened up, better reconstruct it totally.
Image can be downloaded when clicked on it

 

[Backsplash7]

First revision of the 520 is marketed as 600ohm (i don't have one so i don't know if like the 540, there could be 300ohm ones even in first revision, while the second is 300), both 520 and 540 are at 94 sensitivity.
The strip of the headband is 2 parts plastic, internally, and covered with cloth in a kind of stitched together. opened mine that was in trash for the sake of science.
It is not fixable when opened up, better reconstruct it totally.
Image can be downloaded when clicked on it

Thanks for the image! Thats unfortunate, but at least I know its not safe to attempt it. I'll have to keep my eyes open for some spare parts.
These are the 520's I have, not sure when they were released

 

[SIRKRA]

Thanks for the image! Thats unfortunate, but at least I know its not safe to attempt it. I'll have to keep my eyes open for some spare parts.
These are the 520's I have, not sure when they were released

Never saw that These Had the impedance stamped on, found out in a manual that 520 has neodymium/iron magnet/coil while 540 is neodymium/aluminum, could be that the mass is lighter, resulting easier to drive and a more agile headphone in general acoustic sense.

 

[Starbound]

I've just managed to get my hands

I just got an HD540 ref II (german version) yesterday, and like you I started with the HD520 I 300ohm, and the 540 seems a lot easier to drive, and doesn't need to be turned up as high on the volume. Pleasantly surprised that they have even more attack than the 520's, not to mention more clarity. The earpads are almost paper-thin so I have some velour 'wangs' on order, looking forward to hearing differences or improvements on an already impressive presentation!

The headstrap has no cushioning left in it, which makes it very hot to wear... I dont suppose anybody knows if the strap can be opened to insert new foam or something? I can see stitching on the edges, but I'm not sure if its glued together as well. I'm not confident its strong enough to survive such a procedure if it is glued, as it feels quite fragile

Like @SIRKRA said, and his picture shows, there is a piece of plastic sandwiched inside the outside faux leather shell. I have been wondering also if the headband could be opened carefully (unstitched and then the foam ridges repadded and the plastic band replaced). I think it should be possible to do that, but it would take a lot of time and effort, as you would need to restitch it manually. The headband in my HD540 Ref II is in good condition, but the plastic inside it seems to be cracked. It doesn't affect comfort for me, but it would be nice to be able to repair it. The alternative to that would be for you to build one out of vinyl or leather. I distinctly remember somebody opening the band and replacing the foam in the ridges, but I don't remember if it was in this thread or somewhere else (even a different place in the Internet), so it can be done. I don't think there is any glue involved, just the stitching.

I am doubly surprised by your post. First, I thought all HD520 I were 300 ohm, but the ones that I have don't have the 300 ohm stamp, so now I am guessing it is possible they might be 600 ohm. The misconception comes from the fact that the only HD 520 I manual I found online mentions 300 ohm, though I guess it is possible they switched from 600 ohm to 300 ohm and reflected the change in the manual. The added impedance would account for the extra difficulty driving the headphones, though it is insane if they are actually 600 ohm since I have been driving the HD520 with portable sources (including an MP3 player using an AAA battery as its power) obtaining great, very musical results.

The other reason I am surprised is because I didn't realize the HD540 Ref II also had a German manufacturing run. I thought all of them were made in Ireland.

 

[Starbound]

Never saw that These Had the impedance stamped on, found out in a manual that 520 has neodymium/iron magnet/coil while 540 is neodymium/aluminum, could be that the mass is lighter, resulting easier to drive and a more agile headphone in general acoustic sense.

That is true (regarding the driver materials). But also it appears some HD520 (revision 1) headphones must be 600 ohm, as mine don't have the 300 ohm stamp. This is exactly the same thing Sennheiser did with the HD540 I (some of them have a 300 ohm stamp, but I believe it is stamped above the junction point of the headband and the cup, and not below).

 

[Starbound]

Thanks for the image! Thats unfortunate, but at least I know its not safe to attempt it. I'll have to keep my eyes open for some spare parts.
These are the 520's I have, not sure when they were released

Late 80s or early 90s. I think my HD520 version 1 (without the 300 ohm stamp) were probably mid to late 80s. Also, I think the HD520 II came out in 1991 or 1992, so yours are probably around 1989-1991.

Also, as I said earlier, I think it is safe to attempt to fix the headband if you are very careful and patient enough. Personally, I would build a replacement headband out of vinyl or leather, and then I would attempt to fix the original headband so that if the attempt was unsuccessful I wouldn't be left out without a headband. Me, I have a large noggin, so I think I would be fine even without the adjustable portion of the headband.

 

[Backsplash7]

Like @SIRKRA said, and his picture shows, there is a piece of plastic sandwiched inside the outside faux leather shell. I have been wondering also if the headband could be opened carefully (unstitched and then the foam ridges repadded and the plastic band replaced). I think it should be possible to do that, but it would take a lot of time and effort, as you would need to restitch it manually. The headband in my HD540 Ref II is in good condition, but the plastic inside it seems to be cracked. It doesn't affect comfort for me, but it would be nice to be able to repair it. The alternative to that would be for you to build one out of vinyl or leather. I distinctly remember somebody opening the band and replacing the foam in the ridges, but I don't remember if it was in this thread or somewhere else (even a different place in the Internet), so it can be done. I don't think there is any glue involved, just the stitching.

I am doubly surprised by your post. First, I thought all HD520 I were 300 ohm, but the ones that I have don't have the 300 ohm stamp, so now I am guessing it is possible they might be 600 ohm. The misconception comes from the fact that the only HD 520 I manual I found online mentions 300 ohm, though I guess it is possible they switched from 600 ohm to 300 ohm and reflected the change in the manual. The added impedance would account for the extra difficulty driving the headphones, though it is insane if they are actually 600 ohm since I have been driving the HD520 with portable sources (including an MP3 player using an AAA battery as its power) obtaining great, very musical results.

The other reason I am surprised is because I didn't realize the HD540 Ref II also had a German manufacturing run. I thought all of them were made in Ireland.

Here's the germany stamp. Also, I'm not sure how well it will show in the pictures, but these have a small, slightly raised rectangle on the part of the cup behind the plastic headband, as though it was a reserved space to have the resistance printed on it. I dont know if thats common across all ref II's as I'm new to the party.
As for the 520's being 300ohm, they're still harder to drive than the 540's, but as SIRKRA suggested that could be due to differences in coil material. Could be interesting to compare the 300 and 600 versions some day

 

[Backsplash7]

Late 80s or early 90s. I think my HD520 version 1 (without the 300 ohm stamp) were probably mid to late 80s. Also, I think the HD520 II came out in 1991 or 1992, so yours are probably around 1989-1991.

Also, as I said earlier, I think it is safe to attempt to fix the headband if you are very careful and patient enough. Personally, I would build a replacement headband out of vinyl or leather, and then I would attempt to fix the original headband so that if the attempt was unsuccessful I wouldn't be left out without a headband. Me, I have a large noggin, so I think I would be fine even without the adjustable portion of the headband.

There's nothing wrong with a large noggin! I wasn't aware that the leather bands had a plastic body inside them, though that makes some sense. I'll have to give the diy route some thought, its probably not too difficult

 

[Starbound]

Here's the germany stamp. Also, I'm not sure how well it will show in the pictures, but these have a small, slightly raised rectangle on the part of the cup behind the plastic headband, as though it was a reserved space to have the resistance printed on it. I dont know if thats common across all ref II's as I'm new to the party.
As for the 520's being 300ohm, they're still harder to drive than the 540's, but as SIRKRA suggested that could be due to differences in coil material. Could be interesting to compare the 300 and 600 versions some day

Thank you for the pictures. Yes, I see the raised rectangle you mentioned, and it looks as if they would have indeed printed 300 ohms if it had that impedance. You are correct, SIRKRA must be right, that is the only logical explanation I can think of. I guess technically speaking, what really determines sensitivity rather than impedance is the dB rating, and I guess that is affected by multiple factors including the coil material and the impedance itself.

As far as the comparison, soon I will be able to compare my HD520 version 1 with an HD520 II (which I am pretty sure is a 300 ohm model). Probably not as interesting as comparing two members of the same generation with different impedances, but still pretty cool.

 

[Starbound]

There's nothing wrong with a large noggin! I wasn't aware that the leather bands had a plastic body inside them, though that makes some sense. I'll have to give the diy route some thought, its probably not too difficult

It depends on how fussy you want to be. Cutting a strip of thin vinyl similar to what the HD520 has should be easy enough. There are also places which will laser cut leather or pleather if you provide them with a template. Some of them can get pretty fancy, but I guess the cost would be unjustifiable probably. Apparently you should never laser cut vinyl (so I just learned), but scissors, a cutter, and some patience should be good enough.

BTW, if I remember correctly you ordered the wang velours. Did you order the velours for some reason? I believe the consensus is that the wang velours are overly bright and the pleathers sound much better, but perhaps you will find that signature will suit you better.

 

[Backsplash7]

It depends on how fussy you want to be. Cutting a strip of thin vinyl similar to what the HD520 has should be easy enough. There are also places which will laser cut leather or pleather if you provide them with a template. Some of them can get pretty fancy, but I guess the cost would be unjustifiable probably. Apparently you should never laser cut vinyl (so I just learned), but scissors, a cutter, and some patience should be good enough.

BTW, if I remember correctly you ordered the wang velours. Did you order the velours for some reason? I believe the consensus is that the wang velours are overly bright and the pleathers sound much better, but perhaps you will find that signature will suit you better.

Ah, I must've forgotten that. I knew that was the guy everyone recommended, and I knew that having the HD560 earpads was supposed to be the secret sauce, so I naturally assumed that sticking to velour was the way to go. Plus these are a little bright with flat original velours at the moment, and I expected having a deeper space would help with that; those pleather wang pads look very shallow. I'll have to report back once I've had a chance to try them.
Will be interested to see how the 520 compare with the 520II though

 

[SIRKRA]

Today i received my 540 reference, didnt' know what version would've came.
It is 300ohm with fabric pads, px1 cable with steel flat plugs, there is just a piece of cloth instead of foams under pads.
I'm eager to compare them with the ref 2.
And btw, it's True that first reference doesn't have the resonator (only gold and ref 2), and has paper (like 430) instead of plastic mesh above the driver.

 

[Backsplash7]

Today i received my 540 reference, didnt' know what version would've came.
It is 300ohm with fabric pads, px1 cable with steel flat plugs, there is just a piece of cloth instead of foams under pads.
I'm eager to compare them with the ref 2.
And btw, it's True that first reference doesn't have the resonator (only gold and ref 2), and has paper (like 430) instead of plastic mesh above the driver.

Have fun testing those! I always wondered if those original fabric earpads are as bad as people seem to think, they certainly look comfortable at least. I'm not a fan of the thin cloth instead of proper filter foam, I find it hurts my ears quite quickly, and even a 1hour or shorter listening session with just cloth I end up with tinnitus for a couple of weeks.
By the way, by 'resonator' are you talking about the white paper disks that sit between the driver cover and the filter foam? Because my ref II didn't come with them. I thought it was just the golds and 560 that came with those. The seller had included some home made rings made out of some sort of felt material, which greatly increased and muddied the bass, and likewise reduced the detail and clarity, and I much prefer them without those in there. Do the official ones behave similarly, or am I missing out on something good?

 

[SIRKRA]

Have fun testing those! I always wondered if those original fabric earpads are as bad as people seem to think, they certainly look comfortable at least. I'm not a fan of the thin cloth instead of proper filter foam, I find it hurts my ears quite quickly, and even a 1hour or shorter listening session with just cloth I end up with tinnitus for a couple of weeks.
By the way, by 'resonator' are you talking about the white paper disks that sit between the driver cover and the filter foam? Because my ref II didn't come with them. I thought it was just the golds and 560 that came with those. The seller had included some home made rings made out of some sort of felt material, which greatly increased and muddied the bass, and likewise reduced the detail and clarity, and I much prefer them without those in there. Do the official ones behave similarly, or am I missing out on something good?

Thank You! At the moment i'm quick listening ( can't really already compare with the ref 2 because of the different pads, foams, cables ), this has incredibly matched driver, both measure the same ( while my ref 2 that has 2 different drivers because one was serviced differ by 9ohms ) and the only "problem" is that has a bit of foam worn out from the back of the drivers ( the one in the middle, that controls mid tones ).
Only the gold has a white felt filter, i've even seen one with double felts in photos, so it's a mistery even for those.
Other 540's were never intended to use with felts.
The resonator is the added plastic circle above the middle of the driver, where high notes propagate, it helps to mitigate and control better that spectrum ( circled in the photo ).
This pads are actually really comfortable, very open/transparent ( if you point a light from the inner you can see the orangy foam within ), less hot ( than the hd 430 one that i've in the ref 2 ) and more thick.
I'm with you about the cloths, to my ears they are bright with cloths, for sure brilliant and energetic but it's ok only for a short listening.
I'm going to put the 430 foams even in this one.
With this setup, cloths and this open pads the sound is too much on the bright side, there are all the characteristics i find on the ref 2 but brighter ( too much for my taste ).
I found out that this cans are extremely sensitive regarding pads: i tried the 430 one original ( with the pleather new ) and the 430 one with the pleather peeled off by the time ( revealing the inner fabric ), and the sound was so lifeless, bass almost gone, mids so thin.

Did your ref 2 come with cloths or foams?

 

[SIRKRA]

Ok, instead of editing the other post, i'm adding a write up, i've listened and tried various setups ending with the same setup as per ref's 2.
Cloths and fabric pads for me are a no no, i'm a lot sensitive to highs.
With foams on, much better, less offensive, added warmth.
Fabric pads are not so bad but i don't like them, they add a bit of space in the soundstage and detail but much bottom is lost and they add a "ZING" ( kind of metallic edgy sound ).
Hd 430 pads much better, they add warmth, a good bottom added, you loose a bit of soundstage
Cables are a bit different too, ref 2 cable is more warm than the PX1 one.
For my ears the best setup for ref 1 is: HD430 pads and foams, px1 cable, for ref 2: HD430 pads and foams, ref2 cable.
Overall they're not so different but i think i can hear the resonator working in ref 2 compared to the 1 ( it is like the highs of the 1 could hit you directly while the resonator in the 2 diffuse them before hitting you ), as 1 is more bright even with the same setup.
The 1 leaks more sound. ( dunno why as they've the same damping )
After listening, I can say that if one has the ref 2, is not missing anything that the 1 could have, as i'm sensitive to highs i'm much with the ref 2 more mature/linear sound, i would call the ref 1 more "edgy" or "sparkly", is not offensive but is more tiring, i could never listed the 1 for long as the 2 that i could listen forever.