[crazychile]

  Sorry if my original mod description was confusing.  I actually developed my mod so I wouldn't have to dice up the pads.  Rather the mod starts as an insertable ring.  I have taken a picture with half of an insert so you can see the cross-section.  Notice that the foam is pliable but also pretty dense so that there isn't any guessing regarding foam/filling compression.
 

 
As you can see the thick foam ring is inserted under the lip that would be normally used for mounting.  I then glue these two pieces together to ensure a good seal and a flat surface on the rear of the pad.  Then I glue the thinner foam (which is cut in the same shape as the first) to the back and use the adhesive backing to attach the entire pad back to the chassis. 
 
I hope this helps clarify.    
 
Regarding peeling back the adhesive used on the cover-foam... After working with the foam on mine, the tendency for it to tear off in small pieces might make the job very difficult.  The sealing of the ports really did make  big difference though.  I remember there being a port that effected sound on the Stax 007 as well.  Perhaps we have discovered the same principle at play with the Koss?

What I see being used there is essentially weatherstripping. Nothing wrong with this but I'm going to try and cut an appropriately sized ring out of some firm packing foam that retains a consistent shape. Kind of like this stuff:
 
http://www.amazon.com/Cro-nel-CPRs8p6lf600-Protective-Packaging-Perforation/dp/B00HHTEZJE/ref=pd_sim_sbs_328_2?ie=UTF8&dpID=31KAywYlcjL&dpSrc=sims&preST=_AC_UL160_SR160%2C160_&refRID=1EP4NWXCSTF87YYPF7FK
 
...except more dense and about 1/3 inch thick. No adhesive. By making a ring out of this that's about half as wide as the original earpads, I think the insert should be able to stay behind the earpads without any adhesive and have the end effect of making the stock pads seem a little thicker. I'll have to wait until after Christmas to see what shows up as packing material before I try this.
 
Or....
 
I might just order a set of replacement pads from Koss and try hacking those up to use as an insert instead. Props to Koss for making these ridiculously cheap ($5/pr), so this might be a better option.

 

[Gregss]

Hello,
 
Sounds like self stick closed cell insulation foam, 1/2"  or  1/4"  type for putting on windows and such would work well for this mod increasing the depth of the cups. Any problems you can think of?  Size would be right although getting it to bend just right might be hard.  Thinking the 1/4" stuff would be better so if it bunches up some on the curves, it wouldn't get to thick. Any suggestions would be appreciated.
 
A while back in forum, someone complained the rca input jacks on the amp would not let them use better RCA connectors.  Took the back plate off the amp and using a step drill, increased the hole size in the plastic one step only and now have more room for thicker jacks. Still looks great as step drill is self centering and drills cleanly. 
 
Also, after reading about using a more powerful power supply brick to help with better bass modified my power supply by adding two small panasonic capacitors 6" from the end plug that goes into the amplifier - between the supply wires.  Being careful to get polarity right, leads short and everything insulated well with a 1" x 6" piece of heat shrink over the entire mod. 
 

Family	Aluminum - Polymer Capacitors
Series	OS-CON, SEPF

 
Used 27uf  25 volt rated
 
This did seem to tighten up the bass some and as supply seems to normally runs at ~ 1/3d of its rated capacity, doubt it is going to get better than this just by increasing the p/s rating.  Now unit has current storage much closer to the amp, with some of the better caps available. Much less inductance between last capacitance and the amp now.   Anyway, cost almost nothing and is pretty easy, just make sure and get polarity right and insulate well. 
 
Have had headphone now for about two weeks and am quite please with them considering the price. ($600 at Thanksgiving). 
 
Regards,
Greg 

 

[DecentLevi]

@new reformation or anybody, don't you think that peeling back the foam cover of the headphones and taping up the four ports would void the warranty? Or maybe if this is done neatly enough they wouldn't notice, should I have to sent it in for repairs.

 

[Gregss]

Hello,
 
One other point that might be of interest.
 
I really did not like the two separate knobs for the volume control.  After checking how well the two knobs track the volume - seemed pretty well IMHO,  taped the two knobs together on the bottom half so they could not move independently and were at a matching volume.  Then put a small drop of clear silicon glue on the knobs where they almost touch.  Wipe off excess and smooth out with a wet finger.  Looks fine and now both knobs move together. 
 
Silicon glue holds pretty well, but can be removed later if there is a need.  Only takes a bit, don't overdo it. 
 
Working well for me.
 
Happy Holidays,
Greg 

 

[new reformation]

  @new reformation or anybody, don't you think that peeling back the foam cover of the headphones and taping up the four ports would void the warranty? Or maybe if this is done neatly enough they wouldn't notice, should I have to sent it in for repairs.

I have designed my mod to not impact the Koss warranty (though, if some stories are to be believed, there is little that can...). 
 
Putting tape on these headphones voids a warranty about as much as putting a sticker on a macbook IMHO.  If you are really worried, just peel the tape off before you send it in for service.   Koss sends cover-foam whenever you by pads to replace what the headphones came with.  If they give you cover-foam to install, they can hardly be mad at you for removing the old stuff.
 
Now, modding the headband could be considered more serious, but that's why I bought an extra headband directly from Koss.  

 

[new reformation]

 
So you are using a source to the preamp then to the E90, like with speakers. ?  Interesting. Why not. So you are turning the E90 to max and then using a preamp. You could do the same with a dap, using it as a source and its amp section as the preamp. So I did that right now. 

I know you posted a while back, but I wanted to clarify.  
 
Because I think the weakest link in the chain is the amping section of the E/90, I have actually been leaving the volume pot pretty low.  I use the VERY good amp capabilities of the Valhalla 2 to do the "heavy lifting".    My theory as to why this sounds best is that when an amp is taken to its limits it shows its weakness in a much more obvious way.  If I can keep the E/90 doing very light work, it should be much better sounding than if it is literally working as hard as it can.  This should also maximize the influence that the tube preamp has upon the overall sound.

 

[DecentLevi]

My ESP 950's are SO LOOSE that it feels like they could fall off even when I'm not moving - then with a mild movement they always shift. Really uncomfortable / annoying. I have a narrow shaped head which may have something to do with it. Would anyone recommend I bend the heck out of the headband to try to increase the clamping force? Or is it made out of an easily breakable material? Thanks

 

[DecentLevi]

@new reformation I finally got around to trying your mod of closing the "4 ports" on each sides of these 950's. However after lifting up one of the corners, I was not able to find ANY ports! I examined all 4 corners very carefully, including feeling for holes, with a bright flashlight, and looking very carefully under the one I pulled up, and I still can't find any ports. Am I looking in the wrong place, or is your headphone different than mine? Thanks in advance...
 

 

[crazychile]

Here's a $5 option to sticking weatherstripping on the back of your pads...

1. Buy a pair of ESP-950 replacement pads from Koss. ($5)
2. Cut away the inside ring of the earpad, at the midway point of the cushion, between the inner and outer edge.
3. Pull the foam from the cut outer ring, throw away the inner trimming and all the pleather.
4. Take the outer foam ring and shove it under your existing installed earpad.

Its easier if you start at the bottom of the earpad and push the foam around each side before finishing at the top. Since the foam is the same outer diameter as the earpads, you'll have a little extra bunched up at the top, Thats not really an issue, just push the foam as far to the outside as you can, and there shouldnt be much left over. The nice thing about this is that theres no adhesive, and you dont have to disassemble anything to install or remove.

 

[obobskivich]

I know you posted a while back, but I wanted to clarify.  

Because I think the weakest link in the chain is the amping section of the E/90, I have actually been leaving the volume pot pretty low.  I use the VERY good amp capabilities of the Valhalla 2 to do the "heavy lifting".    My theory as to why this sounds best is that when an amp is taken to its limits it shows its weakness in a much more obvious way.  If I can keep the E/90 doing very light work, it should be much better sounding than if it is literally working as hard as it can.  This should also maximize the influence that the tube preamp has upon the overall sound.

The Valhalla 2 isn't doing any "lifting" for the ESP/950 - the E/90 is doing 100% of the amplification, as the Valhalla is incapable of providing an appropriate output for any electrostatic headphone. As far as "working as hard as it can" - the E/90 can go to absolutely insane listening levels before you get into clipping (Koss' specification puts it somewhere near 140 dB SPL), so I don't think there's any fear of it being "overworked" for these headphones (remember, it is DESIGNED for these headphones) - no idea for other cans. As far as it being "such a weak link" - someone a few years ago said that if Koss encased the thing in aluminum, threw fancier silk-screening on it, and removed the TRS and battery features, and tripled the price, people would largely stop feeling the E/90 to be a problem component and hail it as a marvel of fidelity and quality. I'm not sure specifically how true that is, but I do certainly think it takes a bum rap because it looks humble and provides basic (in/out) functionality.

As far as how you've stacked two amplifiers and two gain sections, what you're likely doing *is* maximizing the preamp's "overall influence on the sound" in the form of introducing more noise/distortion thru running a very hot signal into the E/90 and then knocking that signal down with the E/90's preamp. The E/90 itself isn't horribly sensitive so it will put up with this to an extent, but eventually you will get into input clipping (*not* a "deficiency" on the E/90's amp stage - you're just running the input too hot) and that will sound awful all around. You may want to consider a tube buffer or tubed ES amplifier if you want tubes plugged into everything, vs stacked gain sections and multiple pot-based volume controls in-line.

DecentLevi: I think the headband is spring steel on the inside, similar to Audio-Technica headphones. I forget what the headband costs by itself, but it shouldn't be horribly expensive - I'd try buying a replacement and bending that one to fit, so if you do break it you've got the original (or just know that you can get a separate replacement and if you break the original you're waiting for a new one in the mail, or whatever). The 950s are relatively loose fitting, but they shouldn't be flying off your 'noggin during normal listening, so I think a bit of bending may be needed (I don't know that I'd start with "bend the heck" though).

 

[WilCox]

As far as it being "such a weak link" - someone a few years ago said that if Koss encased the thing in aluminum, threw fancier silk-screening on it, and removed the TRS and battery features, and tripled the price, people would largely stop feeling the E/90 to be a problem component and hail it as a marvel of fidelity and quality. I'm not sure specifically how true that is, but I do certainly think it takes a bum rap because it looks humble and provides basic (in/out) functionality.
 

 
+1
 
I've compared the E/90 to my Stax SRM-717 and SRM-tA (both now long gone) and found that the E/90 gives up little to the STAX amps.  I agree that the physical appearance of the E/90 often causes it to be dismissed without giving it a fair shake.

 

[obobskivich]

+1

I've compared the E/90 to my Stax SRM-717 and SRM-tA (both now long gone) and found that the E/90 gives up little to the STAX amps.  I agree that the physical appearance of the E/90 often causes it to be dismissed without giving it a fair shake.

IIRC in one of the more techy STAX threads (why "IIRC"? because this may have occurred somewhere else, on someone's blog, on some other site, etc but my recollection is that it was on head-fi), an E/90 donated its life to science and was ripped apart (iirc parts of it are glued (like the front panel) and it cannot be fully disassembled without damage), and it was found to have fairly decent, if unexceptional, parts and output specifications comparable to the less esoteric STAX and third-party amps (it has pretty massive max voltage output, but if I recall right it has somewhat less current output capacity than the larger STAX amps; I don't recall what effect, exactly, this has on electrostatic headphones (which are largely capacitive and often described as running on a "currentless charge")). *shrug* It works and its simple, and it does it without being huge or getting hot, so I can't complain.

 

[ambchang]

The amps do make quite a bit of difference. I have tried the e/90, the srm-001 mkII and 007tii with the 950 and there is without a doubt differences between the three. To me, the srm-001 mkII was by far the best, the 007tii has nice extension on either side but the balance sounds very odd, the e90 sounds nice but it does lack a bit in resolution and extension.

The e90 does its job very well and to have that as part of a package for $600 is just a phenomenal deal. I didn't let my Koss go until I got the Sr-007 with the KGSS, it's really that good.

 

[doctorjazz]

I was using a Stax amp (323b, I believe), adaptor cable, and I felt it was better sounding than the e/90 as well...the combo was close to my ZOTL/Hifiman 560 combo, better inn some ways though overall I preferred the 560 .

 

[DecentLevi]

So I tested the aforementioned mod covering the vents on each headphone for increased punchyness. Unfortunately after finishing one side and carefully comparing it's sound to the un-modded side, (multiple times, using mono source and switching it around), I was able to decifer 0 improvement, so I just left the one side modded and cut my losses. The loss being that the side I had modded required over an hour of super-tedious craving back the rubbery covering on all four corners microbe by microbe with an x-acto knife to reveal the port, which really mucked up the corners with scratching, bunched covering, etc. Luckily though the sound is exactly as it was before 

 and the pads cover the blemishes.
 
But here's something positive: I found an ultra easy way to increase the seal of the ESP 950's! Just simply bend the metal part of the headband which goes between the 'phones and the headband, and within a few seconds - PRESTO! These headphones stay on much more snug!