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My ESP950 works well, once I figured out the left/right volume knob. It does have a certain intimacy, especially with female vocals. It has a very liquid midrange but the treble can sound grainy and the bass lacks impact. I did try it with a higher-quality amplifier (KGSS) and it gave the sound more weight and less grain, but I still preferred my HD800S (I understand it's not a fair comparison) with most music. Definitely a unique sound and very comfortable, though I wish the earpads were of higher quality.
I am concerned about comments by Thomas Norton on Inner Fidelity (
I have been following this site for a long time and delight in their realistic but un-sarcastic reviews. There will always be design related critiques regarding any device. But Norton’s observations are rather more serious.
He complains about humming and rustling noises, specially on head movement. He suspects that the volume pot may be generating noise when turned. Much more seriously, he reports small electric shocks from the headphone housing!
As others do, Norton reports fantastic sound from these headphones.. But problems of such a basic nature smack of tacky and careless production. I wondered if the reason why the ESP950 is so much cheaper than the Atax is that it is just that much more cheaply made.
I read this review as soon as the Koss came up for the drop. It worried me and I decided to look around a bit more. By then it was gone.
Any similar experiences?
Sujay Rao
I read that review as well when researching the ESP950. The humming noise he experienced was E90 energizer related, which was fixed by Koss. Mine has had no issues whatsoever. I did get an electrical shock on the ear... but that was from me sliding on my seat and building up a charge that then got discharged - I've done the same thing with my TH-X00 PHs before. If anything, the Koss ESP950 feels less cheap than a Stax as far as the plastic goes - the pads and headband do feel cheaper though. Cost wise, you can get the Stax SRS-3100 system for not that much more. If my ESP950 ever has issues I won't hesitate to use the Koss warranty and get them fixed to have them back - absolutely love the detailed yet smooth sound presentation.

Have swapped over to running it on the Stax SRM-323S Driver unit as the adapter cable came in on Thursday. Trying to listen to it for a while on the SRM-323S then swap back to the E90 to get a better idea of any differences. Didn't really notice much of a difference on my system between the two immediately after going from the E90 to the SRM-323S, very slight if any difference I could tell in bass.

I actually bought 2 albums off my bandcamp wish list and a third album within a day of getting the ESP950 headphones... LOL. Recommended album that sounds awesome to listen to on the ESP950 is the Cuphead: Original soundtrack. The track, "Introduction" should give you an idea of what you are in for...
Reassuring. Will try that trackwhen I have the phones. I listen to a lot of classical music. I am told that too sounds awesome on the 950.
Got them in last night and have been listening to them since. Tried on the Vesper pads, but am very dissapointed with how they sound - don't like the change in sound they give, seems like they introduce some reflection/reverb and are slightly harsher. Also seem to introduce a very slight, HD6XX like veil to the sound. Overall think the Vesper pads, even though more comfortable and help bring out more bass, are a detriment to the sound quality to me. More than happy with the stock pads.

As far as how they sound on my system with the stock pads... absolutely fantastic! Incedible detail and intonation changes come across. Slightly bass light for my taste, but the Loki fixed that no problem with 20Hz knob to ~3:00 position. Very nice body to the bass now and feels right playing Haywyre songs, even if not the same bass quantity as my modded TH-X00PH. That's the thing with these, the music feels right and is smoothly presented - like an HD6XX with much more detail and clarity, but less bass output. Waiting on Koss to STAX adapter cable to come in for the used STAX SRM-323S Driver Unit I recently picked up from someone local.

Really loving the ESP950 so far: they are my work setup today with laptop -> Gustard X20U DAC -> Schiit Loki -> E90/ESP950:

What vesper are you talking about, can you take a picture of the earpads? There are many types listed on their site, which did you chose?
All leather, or part leather part suede?

Thanks! :)
They are the leather/Alcantara versions from the Fongaudio website:
So upset I missed this! My Stax amp that I got used cost more than this package! Will this get dropped again?

The Koss drops are some of the best deals on MD ($599 for this, $99 for the KDE250)
Can we have this drop again or how about a stax drop.
Wow this went fast. It must have sold out in 12 hours.
45 is a ridiculously small drop for a deal like this. I got in when it was at 35 sold at about 1 AM, and when I woke up it was sold out completely. Kind of a big impulse purchase, but in the short time I had to research them I found very little bad anyone had to say about them, and a lot of people loving them, so I'm really looking forward to these headphones.
If it makes you feel better, I own a pair of these and they're absolutely amazing. Complaints are around build quality, but given how heavy some of my headphones are, I actually think the plastic-ness of these is what differentiates it.

I'm also a big live music listener, and it absolutely changed everything for me!
What was the final drop price please?
holy fock, thx
These are end game cans, on a budget. I bought mine on an extended black Friday from the Big A last year for $649, paid tax. There is an enthusiast's thread on Head-Fi, you can do better price-wise, if you work hard at it, but usually second hand. For transparent sound, stellar transient response, electrostatics are hard (impossible?) to beat. These are well known for their wonderful midrange, but I'm awed by their high and low end as well. If they have a frequently mentioned shortcoming, it would be lack of booming bass. Hey, we are used to the low end distortion of dynamic speakers. If your playback includes a computer, the best solution isn't EQ, it's a harmonic exciter. Really! Go nuts and swap out for Vesper Audio pads, you'll thank me later. Plus, you don't need a super duper headphone amp to make them sound great. Well, a high current Stax amp someday, maybe. So much for end game on a budget...
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What, specifically, is your harmonic exciter solution? Interested in learning more.
Really, give a try to the product thread in Head-Fi.
Someone, I think a recording engineer, recommended I stop beefing about not having enough bass distortion, recommended a harmonic exciter. Was harder to find than I thought, but I found one that works with Foobar2k...
https://hydrogenaudio/index.php/topic,86083.0.html is the (now defunct) working site for the developer. Settings to use can be found there.
DSP_BassExciter_EN.rar can still be downloaded from
all the other mirrors, etc look like they've expired. Even that one is over 1.5 yrs old.
I used this headphone 8 years ago and it has one of the Best midrange, vocal.
Check the measurements here.
This is an incredible deal!