My Sennheiser HD 555 Mods - More of the "Silk Purse Project"
Jul 10, 2009 at 7:42 AM Thread Starter Post #1 of 20

Zaubertuba

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This is the first stage of my little experiment in trying to "make a silk purse out of a sow's ear," as it were. These are the mods I've made to my Sennheiser HD 555's thus far. I've included a brief summary of what effect each mod had (at least to my ears). If you want more detail (or are just plain bored), check out my "Whole Hog Blog."

These mods have been done before by different folks, but I haven't seen the effects of all these various mods compiled in a systematic manner. I thought it might be interesting for folks to see what my results were with each mod., and maybe compare their own impressions--be they similar or different.

For more background on the project, check out the project blog at the link in my sig.

You can see a gallery of pictures of the mods here.

So, without further ado, here's the mods:



555->595 Mod. - Simply removing the little foam "surround sound" insert from the inside of the headphone does a lot of the work, to my ears, attributed to the Soundstage Mod.

Improvements: Greater transparency. Brought the whole soundstage forward--and broadened it, somewhat. Gained some lovely little details. Stop here if you want to resell your 555's later--most of the rest of these mods are not reversable.



Soundstage Mod. - Whereby you cut the interior plastic grille from the headphone frame.

Improvements - Tightened bass (I really didn't expect this). Greater accuracy & separation within the soundstage--both in width and depth. Note with respect to width, I didn't notice a "widening" of the soundstage as with the foam removal mod.; the placement of instruments just seemed much more deliberate within the space that was already there.



HCW "Foam" Mod. - A foam baffle for the interior of the headphone capsule. I later "beefed up" this already fairly heavy-handed mod with a lining of polarfleece--still leaving the back of the driver itself open:

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Improvements - Yet more improvement to separation. Slightly more bass response. Overall tonality is flatter (mids not so pronounced).

Caveats - The most significant changes to tonality were with this mod. I really had to spend some time trying different configurations/materials to get the voicing right.



Recable - Recabled (double-entry) with Mogami 3106.
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Improvements - More bass extension and impact. Greater dynamic sensitivity and impact across the board. Clarity across the frequency spectrum.

Caveats - The Mogami 3106 is rather stiff. It looked rather cumbersome for a single-sided entry, but seems to balance nicely for a double-sided entry. I don't notice it (physically) when I'm listening--it just sounds great!



"Removing the Veil" - Well, at least that protective nylon screen on the inside of the phones.
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Improvements - Opened up the highs. I know, it's just a nylon screen, but I really can hear a difference!

Caveats - I'm going to need to build a special headphone stand to protect my drivers when the 'phones aren't on my head.
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The results so far are are a wonderfully detailed and listenable headphone. I may play around a bit more with the voicing yet, especially if the tonality changes with further burn-in, but it seems awfully nice as it is right at the moment.

I daresay my foray into modification idiocy has actually paid off quite well...and to think that I haven't even gotten to the diy balanced headphone amp part--yet.
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<Disclaimer> Remember, YMMV. I assume no responsibility for the resellability or listenability of your headphones. Be *really* careful taking the screws out when you open these up. I always held the phones so the drivers were *above* the screw I was working on, then carefully dropped the screw into my open palm below the drivers. Place the screws someplace safe and secure so they don't suddenly decide to get friendly with the magnets and perforate your drivers--one person (not I) already had this happen to them. I also don't assume responsibility for any lost sleep due to enjoyment of your "rediscovered" HD 555's.
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<Disclaimer off>
 
Jul 10, 2009 at 4:42 PM Post #3 of 20
Quote:

Originally Posted by OutdoorXplorer /img/forum/go_quote.gif
Some picture will be good..


LOL--I haven't had time to see if I can link to the pics directly from my facebook gallery. In the meantime, there's a link at the top of my post to the gallery. I made it bold so it's easier to pick out.
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Sep 6, 2009 at 4:02 PM Post #5 of 20
I only did this mod up to opening and cutting the grill. Sound much more airy and smooth. I also like the deeper bass. Would you say they are better than your hd595
 
Oct 8, 2009 at 11:39 PM Post #6 of 20
Quote:

I only did this mod up to opening and cutting the grill. Sound much more airy and smooth. I also like the deeper bass. Would you say they are better than your hd595


Yes! I just did the mod, too... but to make it complete, remove the screens. It makes the soundstage huge, transients clear and undistorted, and instruments even more airer and 3D. It will seem like speakers are in front of you! Image specificity will be dead accurate, and attacks with treble will not sound flat (not more treble, but MUCH more airer!). I can hear so much detail!

Promise: If you take the screens off, your grilling cut mod will truly be complete! It really makes for a holographic, accurate sound!
 
Oct 30, 2009 at 8:48 AM Post #7 of 20
Can you give some details into how you recabled with both sides? Maybe pics too if it's not too late?
 
Oct 30, 2009 at 8:57 AM Post #8 of 20
Quote:

Originally Posted by fenixdown110 /img/forum/go_quote.gif
Can you give some details into how you recabled with both sides? Maybe pics too if it's not too late?


if i don't remember wrongly, someone posted this before.

http://www.sennheiser.com/sennheiser/icm_eng.nsf/resources/HD%205x5%20Kabelmontage_eng.pdf/$File/HD%205x5%20Kabelmontage_eng.pdf
 
Oct 30, 2009 at 11:01 AM Post #9 of 20
Perfect! Thank you, sir.
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Sep 8, 2010 at 2:59 PM Post #11 of 20
Quote:
can someone give me that link for dual entry.  it asks for a username/password all i want is the pdf thanks!


It's actually just a PDF showing how to take off the earpads and replace the (single-sided) cable.For dual entry, you'd need to drill a hole on the other earcup for the cable to go in through, and you need to desolder the old cable and put on the new one. Probably more work than it's wholly worth for these cans, unless of course you have a Godly source and amp.
 
Sep 14, 2010 at 11:24 AM Post #12 of 20


Quote:
Can you give some details into how you recabled with both sides? Maybe pics too if it's not too late?





Quote:
It's actually just a PDF showing how to take off the earpads and replace the (single-sided) cable.For dual entry, you'd need to drill a hole on the other earcup for the cable to go in through, and you need to desolder the old cable and put on the new one. Probably more work than it's wholly worth for these cans, unless of course you have a Godly source and amp.

 
 
Sorry I've been out for awhile, guys!  I honestly can't vouch for the value of dual-entry or no (too many variables changed when I recabled to be sure), but it's not tough.  I just carefully drilled a hole in the right headphone shell, using the left headphone shell as a template.  I can't remember but I'm pretty sure I drilled a small pilot hole first.  Start your drill bit at a 90-degree angle to the plastic and then angle it gradually down to drill straight "up" into the shell as the bit gains purchase.  Just take it slow, don't spin the bit too fast, and you'll be fine.
 
Come to think of it, a Dremil tool might be a bit safer and cleaner.  
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I think someone actually figured out a way to bypass the circuit boards but that seemed a really scary proposition to me when I tried to do it.  I just unsoldered the stock cable from the circuit board for each driver and re-soldered the new cable on the pads.  If you look above you can see I used some cable ties as an interior strain relief to keep cord pressure from pulling against the solder joints.
 
Been awhile since I've had these apart. Maybe I'll try and open them up again and take some more pics.  
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Sep 14, 2010 at 11:28 AM Post #13 of 20


Quote:
Quote:

I only did this mod up to opening and cutting the grill. Sound much more airy and smooth. I also like the deeper bass. Would you say they are better than your hd595


Yes! I just did the mod, too... but to make it complete, remove the screens. It makes the soundstage huge, transients clear and undistorted, and instruments even more airer and 3D. It will seem like speakers are in front of you! Image specificity will be dead accurate, and attacks with treble will not sound flat (not more treble, but MUCH more airer!). I can hear so much detail!

Promise: If you take the screens off, your grilling cut mod will truly be complete! It really makes for a holographic, accurate sound!


I forgot to mention--when I was using my NAD preamp, which had a very "warm" sound signature, this mod was great.  When I later went to my balanced a47 amp, removing these screens ended up sounding a little too bright (it was the same for my HD580's), so YMMV.  Fortunately this particular mod is easy and reversable.  Maybe I'll pull them again after I do my JISBOS amp.  
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Sep 14, 2010 at 12:37 PM Post #14 of 20
Based on the dual entry mod, I myself bypassed the circuit board and the little jumper pins.  All I did was took a small flat-head screwdriver and pried everything out.  Then I just cabled both drivers and met them in the middle of the line.  It works great.  Much easier than remember where those little jumpers go and what goes what on that little board.  I am going to post a how to on the whole thing shortly so stay tuned.
 
Sep 14, 2010 at 1:09 PM Post #15 of 20


Quote:
Based on the dual entry mod, I myself bypassed the circuit board and the little jumper pins.  All I did was took a small flat-head screwdriver and pried everything out.  Then I just cabled both drivers and met them in the middle of the line.  It works great.  Much easier than remember where those little jumpers go and what goes what on that little board.  I am going to post a how to on the whole thing shortly so stay tuned.


I'm impressed!  Very interested to see how you did it!  
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