Dexdexter
Headphoneus Supremus
- Joined
- Aug 27, 2006
- Posts
- 2,319
- Likes
- 13
Greetings, All!
(I realize that this is a rather LONG post, but if you bear with me, some might find it rewarding!)
I’m relatively new to this fantastic forum. My initial interest had been in run-of-the-mill home audio, and for the past few years I’ve been posting regularly on the Pink Fish Media Forum, HiFi WigWam, Naim Audio Forum, etc. This past Summer, however, I was given my first iPod, so I have broadened my interests to include portable and computer audio. So I first came across Head-Fi in search of a line-out solution to use with my Sonic Impact T-Amp in my desktop environment.
But with the iPod, I’ve also rediscovered the joys of strolling about and listening through headphones. I still had a pair each of Koss Sporta Pros and Sennheiser PX-200s lying about from my NYC days listening to CDs on a Sony D-EJ2000.
Then, last Sunday, disaster struck. I returned home from a family outing only to discover that our 3-month old kitten had savagely chewed-through the cabling on both my portable cans!
The Culprit
(on the right)
Once I managed to compose myself, I was determined not to let this little monster destroy all my mobile HeadFun. As God is my witness, I vowed to re-cable and my ‘phones would sound better than ever before!
I started with the Sporta Pros. Emboldened by reading about the Kramer-Mod here, I began by drilling out the additional holes in the grilles. Then I quarter-modded the foams. Then I fabricated a new cable out of some Cat 6 I had laying around. Even enlisted Mrs. Dexter to fashion the respective channels into nice tight fancy braids! Then I proceeded to fry the tiny connector-PCBs of my Sporta Pros with my rudimentary soldering “skills”. Aaargh! That Darn Cat!
Back to the Shelter, Missy!
So that was my open-can portable option now (literally) gone up in smoke. But I knew that, in order not to entirely botch the PX-200 recabling, I would have to beg the kind assistance of Detlef, my next-door neighbor, an expert solderer who just the previous week helped me to fabricate a mini-to-mini interconnect for my PocketDock.
But he wouldn’t be available until the following weekend. So I set about scouring Head-Fi for a suitable open-phone replacement. Threads involving the Porta Pros grabbed my attention, as did the PX-100. But living in Belgium these days, Koss is considered somewhat exotic here and the prices are rather prohibitive, not to mention confused. For example, the Porta Pros here sell for 60 Euro. And, incredibly enough, the Sporta Pros sell for 80 Euro!
On the other hand, Sennheisers are much more widely available, so a pair of PX-100s for 40 Euro seemed pretty much a no-brainer. Boy, were they! The PX-100s are a real joy to listen to, straight out of the box. Pretty much everything you read about them here is true. Airy and neutral, with scads better bass than my recollection of either the Sporta Pros or the PX-200s, my iPod had come back to life!
Since I still had a few more days waiting for Detlef to come to my rescue, I decided to more thoroughly plan the resurrection of my PX-200s. Unfortunately, my research here on Head-Fi was not encouraging; I failed to find any instances of re-cabling them, let alone modifying them. And my plea for assistance on the DIY forum went essentially unanswered:
http://www6.head-fi.org/forums/showthread.php?t=159854
So the consensus appeared to be that nothing could be done. But I got bold and decided to bite the bullet. With nothing more to lose, I took a tiny flat-head screwdriver and gently began to work and pry the grille, just a little at a time. To my surprise, it ultimately relented enough so that I could get a reasonable finger-hold. Suddenly, it opened-up like an oyster with just a little extra effort!
Upon closer examination, the grille of the PX-200 is simply press-fitted and held into place by four smallish dabs of hot-glue. With the grille off, it was time to examine the driver. Taking care not to disturb the delicate membrane, it too eventually came free with minimal effort. Inspection here revealed that the driver is affixed with but a single dab of hot-glue directly applied to the rear of its magnet and then centrally placed into the frame housing of the PX-200s.
The interface between the grille and the driver, while snug, is not tight. So I was able to lay the driver facedown into the grille in order to await solder-surgery from Detlef. In the meantime, I took the opportunity to more closely examine my PX-100s. Aside from the expected open vs. closed back difference, the main physical distinction between the two is found in their respective grilles. They are essentially identical, employing the same 12 spirally arranged sound apertures with the exception being that the PX-100 has an additional circular hole dead-center, while the PX-200 remains closed-off at the center of the grille. So this got me thinking, but more on that in a moment…
Yesterday, I gathered my PX-200 bits and the cable that I had originally intended for my Sporta Pros and headed next-door to Detlef’s. He was able to expertly solder the cable into place as well as a new right-angle mini plug in well under 20 minutes.
(A note of CAUTION here: When attempting to re-cable either a PX-100 or PX-200, be mindful of the fact that the PCB containing both the signal and ground terminals resides in very close proximity to the highly magnetic rear of the driver. Therefore, the entire driver assembly must be physically held down while soldering, or it can potentially leap upward and onto the soldering iron, putting both the PCB and the driver membrane at severe risk of extinction!)
When I returned home, I finished my new cable by heating the shrink-fit in all the appropriate places. Finally, I was ready for a listen. What I heard was certainly pleasing, but hardly earth-shattering. Ease of drive had improved somewhat, probably down the fact that I was now employing double the amount of signal wire in the new cable, offering less resistance. But switching over to my PX-100s revealed the much-discussed disparity between the two models; the PX-200s simply sounded muddy and veiled by comparison, with the PX-100s revealing superior detail, treble clarity, and tighter bass response. It seemed silly to me that with these two cans being so similar and all, that the more expensive option was so far off the pace of the cheaper one. I was left wondering, was there some way to close the rather infuriating performance gap between the two?
I headed straight for the electric drill and before I could talk my self out of it, I knocked 8mm holes straight through the center of my grilles.
(Another note of CAUTION: Drilling through plastic is never a picnic. You must use a moderate drill-speed. Too slow and you risk the bit slipping or cracking something; too fast and you generate excess heat which can melt and distort the plastic.)
I used a file to remove excess plastic burrs and clean up the holes. And although I suspected that my work was not yet complete, I couldn’t resist popping the grilles back on and listening to the results.
Quite a difference here! Bass leapt to the fore in similar fashion to the PX-100s. Clarity increased markedly, as did the soundstage. But the treble was simply overwhelming quite near the point of shrill. In fact, it was all a bit too much! So onward to Phase Two.
As I had been thinking about the differences between the PX-100s and the PX-200s, I had at first neglected to consider the respective pads employed by the two. At first glance, the PX-200 uses thicker cupped pleather pads better suited for attempting some kind of seal, while the PX-100 utilizes foam pads that stretch uniformly across the surface of the grille. However, the effective driver surface of the PX-200 is actually barely covered at all, save for the thinnest of cloths overlaying the inner diameter of the pleather cups. Certainly, the thicker foam must play a significant role in the sonic signature of the PX-100.
Therefore, I determined that a layer of foam added to the center of the modified grille would likely be necessary to mitigate the slightly overpowering aspects of the initial modification and hopefully restore some kind of proper balance to the sound. Fortunately, I had saved the foam pads from my late, lamented Sporta Pros. I cut out a pair of circular pieces approximately 14mm in diameter so that they could rest within the natural recess surrounding the newly-bored center hole, but still without obstructing any of the original apertures in the grille.
I then placed 4 tiny dabs of glue and spread them evenly around the perimeter (being extremely careful not to allow any excess that could potentially spill into the driver) and put the foam into place. Since the center of the cup does not make contact with the ear due to the surrounding pleather padding, there is no need for concern that the foam will be pressed into contact with the membrane of the driver.
Result? Following extensive A/B comparison between the newly-modded PX-200s and my new PX-100s, to my ears, the performance gap between the two has now closed dramatically. For me, the addition of the foam in Phase Two of this mod has successfully tamed the over-bright tendencies that initially accompanied the hole-drilling of Phase One, redressing the overall tonal balance without sacrificing the substantial gains achieved in bass response.
CAVEAT: Please note that my PX-100s are still quite new and hardly run-in. Nonetheless, the overall difference between my modified PX-200s and the stock originals is not subtle! They are now far easier to listen to for extended lengths of time. In fact, two days into this project and I’m having a difficult time finding significant sonic distinctions between the 100s and the 200s. Of course, achieving a proper seal with the modified PX-200s remains exactly the same as it was before, yet I somehow suspect that it has become far less of an issue.
So what can we call this two-phase procedure? I’m christening it The AchroMod ™ (deriving from the term “achromatic”, meaning “absence of color”) since it effectively lifts the sonic veil long-plaguing the stock PX-200s and places it into the more neutral realms occupied by the PX-100s. (And, of course, it’s not actually trademarked, that’s just for fun!)
And who can benefit from The AchroMod ™? Well, certainly any DIY-adventurous folks who are less than thrilled by the performance of their PX-200s. If enough people attempt it and report success, I can well imagine that the AchroModded PX-200 might finally be viewed as a viable closed-can alternative to the PX-100, just as Sennheiser originally envisioned, but ultimately failed to execute. And if some folks from Sennheiser are lurking about, perhaps this could eventually inspire beneficial changes to the production version of the PX-200.
But all of this means nothing unless others here are willing and able to give it a try. I look forward to reading your thoughts and experiences and I will be more than happy to answer any questions that I can!
Cheers, Dex
(DISCLAIMER: The AchroMod ™ as detailed here was performed on a pair of Sennheiser PX-200s produced sometime in 2003. As such, I cannot begin to speculate whether or not Sennheiser have altered their assembly methods on subsequent production runs of this model that may impede or otherwise render impossible the relatively painless removal of the grille and driver for modification as outlined above. Consequently, I can make no definitive representations whatsoever or bear any responsibility for unfortunate results. In other words: PROCEED AT YOUR OWN RISK)
(I realize that this is a rather LONG post, but if you bear with me, some might find it rewarding!)
I’m relatively new to this fantastic forum. My initial interest had been in run-of-the-mill home audio, and for the past few years I’ve been posting regularly on the Pink Fish Media Forum, HiFi WigWam, Naim Audio Forum, etc. This past Summer, however, I was given my first iPod, so I have broadened my interests to include portable and computer audio. So I first came across Head-Fi in search of a line-out solution to use with my Sonic Impact T-Amp in my desktop environment.
But with the iPod, I’ve also rediscovered the joys of strolling about and listening through headphones. I still had a pair each of Koss Sporta Pros and Sennheiser PX-200s lying about from my NYC days listening to CDs on a Sony D-EJ2000.
Then, last Sunday, disaster struck. I returned home from a family outing only to discover that our 3-month old kitten had savagely chewed-through the cabling on both my portable cans!
The Culprit
Once I managed to compose myself, I was determined not to let this little monster destroy all my mobile HeadFun. As God is my witness, I vowed to re-cable and my ‘phones would sound better than ever before!
I started with the Sporta Pros. Emboldened by reading about the Kramer-Mod here, I began by drilling out the additional holes in the grilles. Then I quarter-modded the foams. Then I fabricated a new cable out of some Cat 6 I had laying around. Even enlisted Mrs. Dexter to fashion the respective channels into nice tight fancy braids! Then I proceeded to fry the tiny connector-PCBs of my Sporta Pros with my rudimentary soldering “skills”. Aaargh! That Darn Cat!
Back to the Shelter, Missy!
So that was my open-can portable option now (literally) gone up in smoke. But I knew that, in order not to entirely botch the PX-200 recabling, I would have to beg the kind assistance of Detlef, my next-door neighbor, an expert solderer who just the previous week helped me to fabricate a mini-to-mini interconnect for my PocketDock.
But he wouldn’t be available until the following weekend. So I set about scouring Head-Fi for a suitable open-phone replacement. Threads involving the Porta Pros grabbed my attention, as did the PX-100. But living in Belgium these days, Koss is considered somewhat exotic here and the prices are rather prohibitive, not to mention confused. For example, the Porta Pros here sell for 60 Euro. And, incredibly enough, the Sporta Pros sell for 80 Euro!
On the other hand, Sennheisers are much more widely available, so a pair of PX-100s for 40 Euro seemed pretty much a no-brainer. Boy, were they! The PX-100s are a real joy to listen to, straight out of the box. Pretty much everything you read about them here is true. Airy and neutral, with scads better bass than my recollection of either the Sporta Pros or the PX-200s, my iPod had come back to life!
Since I still had a few more days waiting for Detlef to come to my rescue, I decided to more thoroughly plan the resurrection of my PX-200s. Unfortunately, my research here on Head-Fi was not encouraging; I failed to find any instances of re-cabling them, let alone modifying them. And my plea for assistance on the DIY forum went essentially unanswered:
http://www6.head-fi.org/forums/showthread.php?t=159854
So the consensus appeared to be that nothing could be done. But I got bold and decided to bite the bullet. With nothing more to lose, I took a tiny flat-head screwdriver and gently began to work and pry the grille, just a little at a time. To my surprise, it ultimately relented enough so that I could get a reasonable finger-hold. Suddenly, it opened-up like an oyster with just a little extra effort!
Upon closer examination, the grille of the PX-200 is simply press-fitted and held into place by four smallish dabs of hot-glue. With the grille off, it was time to examine the driver. Taking care not to disturb the delicate membrane, it too eventually came free with minimal effort. Inspection here revealed that the driver is affixed with but a single dab of hot-glue directly applied to the rear of its magnet and then centrally placed into the frame housing of the PX-200s.
The interface between the grille and the driver, while snug, is not tight. So I was able to lay the driver facedown into the grille in order to await solder-surgery from Detlef. In the meantime, I took the opportunity to more closely examine my PX-100s. Aside from the expected open vs. closed back difference, the main physical distinction between the two is found in their respective grilles. They are essentially identical, employing the same 12 spirally arranged sound apertures with the exception being that the PX-100 has an additional circular hole dead-center, while the PX-200 remains closed-off at the center of the grille. So this got me thinking, but more on that in a moment…
Yesterday, I gathered my PX-200 bits and the cable that I had originally intended for my Sporta Pros and headed next-door to Detlef’s. He was able to expertly solder the cable into place as well as a new right-angle mini plug in well under 20 minutes.
(A note of CAUTION here: When attempting to re-cable either a PX-100 or PX-200, be mindful of the fact that the PCB containing both the signal and ground terminals resides in very close proximity to the highly magnetic rear of the driver. Therefore, the entire driver assembly must be physically held down while soldering, or it can potentially leap upward and onto the soldering iron, putting both the PCB and the driver membrane at severe risk of extinction!)
When I returned home, I finished my new cable by heating the shrink-fit in all the appropriate places. Finally, I was ready for a listen. What I heard was certainly pleasing, but hardly earth-shattering. Ease of drive had improved somewhat, probably down the fact that I was now employing double the amount of signal wire in the new cable, offering less resistance. But switching over to my PX-100s revealed the much-discussed disparity between the two models; the PX-200s simply sounded muddy and veiled by comparison, with the PX-100s revealing superior detail, treble clarity, and tighter bass response. It seemed silly to me that with these two cans being so similar and all, that the more expensive option was so far off the pace of the cheaper one. I was left wondering, was there some way to close the rather infuriating performance gap between the two?
I headed straight for the electric drill and before I could talk my self out of it, I knocked 8mm holes straight through the center of my grilles.
(Another note of CAUTION: Drilling through plastic is never a picnic. You must use a moderate drill-speed. Too slow and you risk the bit slipping or cracking something; too fast and you generate excess heat which can melt and distort the plastic.)
I used a file to remove excess plastic burrs and clean up the holes. And although I suspected that my work was not yet complete, I couldn’t resist popping the grilles back on and listening to the results.
Quite a difference here! Bass leapt to the fore in similar fashion to the PX-100s. Clarity increased markedly, as did the soundstage. But the treble was simply overwhelming quite near the point of shrill. In fact, it was all a bit too much! So onward to Phase Two.
As I had been thinking about the differences between the PX-100s and the PX-200s, I had at first neglected to consider the respective pads employed by the two. At first glance, the PX-200 uses thicker cupped pleather pads better suited for attempting some kind of seal, while the PX-100 utilizes foam pads that stretch uniformly across the surface of the grille. However, the effective driver surface of the PX-200 is actually barely covered at all, save for the thinnest of cloths overlaying the inner diameter of the pleather cups. Certainly, the thicker foam must play a significant role in the sonic signature of the PX-100.
Therefore, I determined that a layer of foam added to the center of the modified grille would likely be necessary to mitigate the slightly overpowering aspects of the initial modification and hopefully restore some kind of proper balance to the sound. Fortunately, I had saved the foam pads from my late, lamented Sporta Pros. I cut out a pair of circular pieces approximately 14mm in diameter so that they could rest within the natural recess surrounding the newly-bored center hole, but still without obstructing any of the original apertures in the grille.
I then placed 4 tiny dabs of glue and spread them evenly around the perimeter (being extremely careful not to allow any excess that could potentially spill into the driver) and put the foam into place. Since the center of the cup does not make contact with the ear due to the surrounding pleather padding, there is no need for concern that the foam will be pressed into contact with the membrane of the driver.
Result? Following extensive A/B comparison between the newly-modded PX-200s and my new PX-100s, to my ears, the performance gap between the two has now closed dramatically. For me, the addition of the foam in Phase Two of this mod has successfully tamed the over-bright tendencies that initially accompanied the hole-drilling of Phase One, redressing the overall tonal balance without sacrificing the substantial gains achieved in bass response.
CAVEAT: Please note that my PX-100s are still quite new and hardly run-in. Nonetheless, the overall difference between my modified PX-200s and the stock originals is not subtle! They are now far easier to listen to for extended lengths of time. In fact, two days into this project and I’m having a difficult time finding significant sonic distinctions between the 100s and the 200s. Of course, achieving a proper seal with the modified PX-200s remains exactly the same as it was before, yet I somehow suspect that it has become far less of an issue.
So what can we call this two-phase procedure? I’m christening it The AchroMod ™ (deriving from the term “achromatic”, meaning “absence of color”) since it effectively lifts the sonic veil long-plaguing the stock PX-200s and places it into the more neutral realms occupied by the PX-100s. (And, of course, it’s not actually trademarked, that’s just for fun!)
And who can benefit from The AchroMod ™? Well, certainly any DIY-adventurous folks who are less than thrilled by the performance of their PX-200s. If enough people attempt it and report success, I can well imagine that the AchroModded PX-200 might finally be viewed as a viable closed-can alternative to the PX-100, just as Sennheiser originally envisioned, but ultimately failed to execute. And if some folks from Sennheiser are lurking about, perhaps this could eventually inspire beneficial changes to the production version of the PX-200.
But all of this means nothing unless others here are willing and able to give it a try. I look forward to reading your thoughts and experiences and I will be more than happy to answer any questions that I can!
Cheers, Dex
(DISCLAIMER: The AchroMod ™ as detailed here was performed on a pair of Sennheiser PX-200s produced sometime in 2003. As such, I cannot begin to speculate whether or not Sennheiser have altered their assembly methods on subsequent production runs of this model that may impede or otherwise render impossible the relatively painless removal of the grille and driver for modification as outlined above. Consequently, I can make no definitive representations whatsoever or bear any responsibility for unfortunate results. In other words: PROCEED AT YOUR OWN RISK)
