Koss ESP950

Discussion in 'Headphones' started by OJneg, Sep 30, 2015.

  1. JimL

    JimL Tongues KG's hairy starfish for fun

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    The SRX Plus is based on an old Stax schematic that they published for DIY use in the 1970s. It is not a Kevin Gilmore design, although Kevin was kind enough to design circuit boards for it. I modified/updated it by substituting constant current loads for the plate resistors, constant current sources in place of the diff amp tail resistors, plus a regulated power supply.

    I plan to bring it to the Albuquerque meet if I can sort out some noise problems it has had recently. Will also be bringing a modified SRM-T1, SR007 Mk II with port mod and SR009.
     
  2. cskippy

    cskippy Creamy warmpoo

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    Updated links on page 5 with Vesper pad measurements.
     
  3. shipsupt

    shipsupt Admin

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    Thanks for taking and posting the measurements.

    I have installed my new pads and I'm enjoying the comfort.
     
  4. Timb5881

    Timb5881 New

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    The 950 headphones are a steal when you can get them under $700. I have had mine for over 20 years, and they still sound great.
     
  5. Mach3

    Mach3 New

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    Got mine last year for $500. I don't think anything new or used can match it in terms of price performance at any level as a kit.
    Such a totally underrated and forgotten relic, especially when you consider it more than 20 years since with was release.
     
  6. Divad al-Rahsir

    Divad al-Rahsir Facebook Friend

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    That depends. I also got mine cheap and I spent a lot of hours comparing it to the HD600, trying to figure out which one was better. For me, it was the Senn. To be clear, I would be happy with either of them, but my preference was the HD. I've read that better amping can improve the Koss's performance, but then you're looking at an amp that costs more the the headphones, requires some cable surgery, and - and this is the kicker - still might not sound better than the HD600 to me. I'm not willing to take the gamble.

    One thing that I have to give to the Koss is the comfort level. They don't clamp hard, the band sits right where it's supposed to on my head, the pads breathe enough to keep my ears from sweating in hot weather, and they're extremely light. Just very, very nice to wear.

    And there's that. These things must have been insane when they were first introduced.
     
  7. Mach3

    Mach3 New

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    I should have mention I did purchase thicker pad for them. Due to the reason you raised with the clamping force.
    Don't get me wrong I love my HD600 but I don't think it has anywhere near the speed or sound stage as the 950.
     
    Last edited: Aug 13, 2017
  8. AllanMarcus

    AllanMarcus Friend

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    I love the HD600. I put it on and all my zits get popped at once! :)
     
  9. Mach3

    Mach3 New

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    Just an update to my renew found love of the ESP-950 and how awesome they are after completing this project.
    It's been a while since I wanted to do a mod so I can have a transportable high end rig.
    I've finally found some time to finish the mod. Pro-Bias cable for the ESP-950 (Plug purchased from Moon-Audio)
    Mod the power section of my Stax SRM-252S and add an ODAC to the unit.

    After hearing the ESP-950 on the SRM-252S I feel like getting a hammer and smashing the crap out of the E90 amp. Simply for denying me the ESP-950 true potential.

    Oh man what a massive difference. Everything is so much better. Clarity is phenomenal, bass is clearer with more meat, vocals are so natural. Earpads are from Vesper Audio angled full sheep skin leather.

    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]
     
  10. redrich2000

    redrich2000 Facebook Friend

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    Does anyone have photos of what mods they did to these? I've got a old set of A250s, the dynamic little sister of the the ESP-950. They sound beautifully open, airy and spacious. I used to love them as is but am finding myself more and more treble-sensitive as I get older and these now need the treble toned down and the bass improved.
     
  11. Divad al-Rahsir

    Divad al-Rahsir Facebook Friend

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    1.5 year update:

    Some weeks back, I was considering selling the 950's, as I hadn't listened to them in a year or so. I resolved to really put some hours on them before doing that, while also possibly making a few tweaks as necessary. During this time, I continued to use my speakers and the HD600's, in roughly that order. (I did some other silly things as well. Playing Fallout 76 with the audio coming through a cranked Crack to headphones? Fatiguing, but surprisingly entertaining.)

    Short version: I've changed my mind on these.

    Long version, freeform and disorganized: I've always thought that the whole "transducer break-in" thing was a bullshit way of explaining brain burn-in, even if it kinda-sorta makes some sort of logical sense. These really did start to change a bit after a number of hours though. As an experiment with far too many variables to be valid, I went ahead and did something that may have been foolish - as I was already breaking in a Yggdrasil by running music 24/7, I went ahead and ran the 950's as well. I let them go for the better part of a week with breaks, as I normally use speakers when I'm home.

    When I finally put them on, they sounded...I'm not sure how to explain it, but the bass and the slam were noticeable - not huge, but noticeable, but that was a significant change. I cranked them up a bit (not particularly loud, as I tend to listen on the quiet side of things) and they started popping like crazy. I played around with them a bit, turned them off and on again, and figured that they'd have to go back to Koss. I set them aside until I had time to do this.

    Fast forward a few days and I decided to take another listen, if for no other reason so that I could explain to CS what the problem was. The pops were gone and they sounded great. I did some switching between the 950's and the Senns in a decidedly unscientific manner and I have to say, I'm pleased with the 950's now. The Sennheisers still have better bass and slam (with a different amp, and on balanced outs - like I said, decidedly unscientific) but the 950's were almost good enough in that department, and just sounded remarkably clear in comparison. The soundstage sucks, but I'm surprised by how much I'm willing to sacrifice for that clarity.

    I went ahead and replaced the pads with those fancy leather ones to see if that improved the sound at all. I'm not sure that it did, but it didn't hurt anything and they're more comfortable, so no harm no foul.

    I'm not getting rid of the 600's. They remain my reference. However, I'm hanging on to the 950's for the time being. I'll play with the EQ a bit and consider a new amp if the right one crosses my path. I like these. They're not perfect, but what is?
     
  12. drgumbybrain

    drgumbybrain Science Nut

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    059ACD70-3125-4D01-BAE9-FCEDB46FB625.jpeg Sorry to open this thread from the dead.
    Last week I bought new fond audio pads and a stax 323x to use with koss 950.
    And the upgrade was very impressive. It’s very very different from the standard koss.
    Almost todl set for 900 euros.
    Do you guys think that a better stax amp in the future worth it?
     
    Last edited: Jul 30, 2019
  13. M3NTAL

    M3NTAL Friend

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    I think the pad change is a bigger upgrade than an amplifier in the ESP950's case. Unless you think the 950 will tide you over for the rest of time, I wouldn't mess about with chasing amplifiers. I have an exstata that was purposely built for the 950 and it is not getting much use. It is better than the stock E90, but honestly probably wasn't worth the headache (financial and other stuff that was personal/specific with my build)
     
  14. adeadcrab

    adeadcrab Acquaintance

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    I had read these anecdotes over the web that a stax amp makes the 950 better. I didn't want to fork out the cash for one, so I settled for a linear power supply to the 950 energizer, and found similar results. Drums sounded more real, everything was vivid.

    How close this is to an upgraded amp, I don't know, but the difference is such that I am happy with the setup as it is (95X here).
     
  15. WhiteNoise

    WhiteNoise Facebook Friend

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    I ordered those vesper angled pads today. I was informed it would take up to 20 days before they ship. /sigh. My biggest complaint with my 95/X would be the poor sealing of the stock pads. I find the stock pads comfortable enough but man do they seal for crap. Just using my fingers to tighten up the seal provides an immediate improvement to SQ. So I do have high hopes for those pads.

    I have the Stax SRM-T1 arriving this Friday. I'm quite happy with the stock energizer but want to test a Stax amp with the 95/X.

    I also want the new STAX SR-L700MK2 but looking to sell some gear to fund it. If I just buy it my wife might leave me! Kidding but she does not understand my passion for music and gear.
     
  16. purr1n

    purr1n Desire for betterer is endless.

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    Definitely, even up to the T2DIY. When I owned T2DIY, I thought the Koss (with the crappy stock pads) was marvelous.

    Another thing worth trying might be to seal the space where the pad meets in the housing with electrical tape.
     
  17. WhiteNoise

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    Do you mean like a layer or two just placed on the housing before placing the new pads on? I haven't taken mine off yet. Is there a slight gap there?
     
  18. Mach3

    Mach3 New

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    The 950 scales really well with better amp. Currently running them off a Stax SRM-600 Limited
     
  19. WhiteNoise

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    (To my ears anyway) I personally don't think a Stax amp makes a big difference. The E90 works very well with the ESP95. I expected a big improvement after reading what others claimed but IMO it is not a big enough improvement to justify the cost. I have three electrostatic amps and I just don't hear that big difference. The better upgrade is to just buy Stax headphones.
     
    Last edited: Aug 25, 2019

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