Drop Koss ESP 95X Electrostatic Headphone System Review 

I bought these Can's after I saw your review with no regrets. Absolutely amazing resolution ! You hear new things in familiar mixes. Female vocals sibilances are very sweet. Male vocal sibilances & midrange are excellent as well. As you'd suggested, I had an ELPAC 9VDC, 4.4A Switching Medical Grade Power Supply and three very large 475uF (physically) KEMET extremely low ESR Capacitors added to the ELPAC's output for an extremely stable 9VDC at the input of the Energizer box. Playing Miles Davis' Tutu brought out the Bass in these Cans when the music required it. Jazz tracks with all the extreme Left/Right instrument placement actually had a very "out there" quality to the sound (i.e they sounded like EARSPEAKERS as advertised). Vocals are center stable. Ordered the Dekoni Earpads from Drop due to arrive in late May. A PS Audio DirectStream DAC Sr. (where I also agree with your findings) feeds my Drop Koss 95X Electrostatic Headphone System.

I love mine. I never hear any creaking or pad noise. I wear glasses and these are the only headphones that cause no discomfort over time. I love the light weight plastic for this reason. I find the pads immensely comfortable. I find them musically wonderful. But more than anything I find the soundstage huge. More than any other phones I own (no reference grade phones tho) I have just discovered the "binaural" conversions and I could not believe how amazing it is. I could seriously watch a surround movie with these. It sounds like my 7.1 speakers right down to the localizations (less the subs, but I hope my future Loki helps that). Thank you to Darin Fong for his conversion software. edited to update: The Schiit Loki is fantastic with these! These can take the full bass boost from the Loki Eq [if you wish] and makes them fantastically full range. Highly recommend this addition. Now I wonder if an iFi regulated 9V power supply will help or be a waste of cash? hmmmm...

Hi. I would just like to report that the piercing sound I heard on these from songs with flutes is now gone. These headphones appear to need quite a significant amount of burn in before they reach their optimal sound. I honestly couldn't be happier with these headphones. They do just about everything right with no significant pitfalls. I finally have a headphone that I can be about 100% satisfied with. Although I would like just a tad more microdetail. However I'd imagine upgrading the amp and getting a better DAC might remedy the problem. They aren't as musical as the akg k812, as detailed as the sennheiser hd 800, or as resolving as the sennheiser he 1. But they hit the sweet spot almost perfectly. For me they are my new reference level headphones.

I highly recommend these as well in my review, if people want to check that out for additional information. I also swapped out my pads for Dekoni fenestrated sheepskin pads (for the 95x specially), in the end, and that helps with the comfort/creakiness a bit. I have a video about the sound changes that result from that pad change as well. Cheers!

Did I spotted the H2go on your desktop 😉 looking forward to the review and added value compared to connecting a DAP

12:50 I told my psychiatrist I had been spongled as a small child

I was considering trying these. Went to the Drop website and the price had gone up by $50. Still a solid buy at $450, but I'd be happy to save the $50. You mention in your review a better power supply makes a noticeable positive difference (a different energizer would likely, too, but that's heftier thing). Was the uprated power supply you used a higher spec wall wart or floor brick, or bigger in-a-box supply? As an aside, but related to this, I have a little Musical Fidelity V90 BHA balanced headphone amp. It was supplied with a tiny wall wart that rattles. This little amp actually sounds quite nice with this, but swapping in a big, nice-quality power supply box from China costing about $60 made a huge difference towards the good. Interestingly, this same supply replacing the wall wart (albeit a better quality one) that came with a Geshelli Labs Archel 2 Pro didn't make any difference (the Geshelli sounded like it's super clean op amp self).

I thought these were high end headphones! Fnarrr Actually, I have one question: Do the Hifiman Sundaras have tons more bass or deep bass, than the Koss ESPs? I own the Hifiman HE400Is, the reason I'm asking (which have tight bass but NOT deep bass by any means, but wonderful rich detail).

I really like your button up where did you get it?

Can you attach another headphone amp with pre outs into the koss energizer and turn up the volume on the koss while using the other headamp as volume control? Hope that makes sense

yea... those circuit boards are old-school alright... nobody solders capacitors and resistors and other parts through a board anymore in that fashion.

You definitely don’t want carbon dust near a electrostatic driver.

These are horrible to my ears. Sorry Drop I love you.

The ESP 950 debuted around 1990 and sold for about $2000 US currency at the time.

I bought a pair about a month ago, and I found that they were incredibly resolving right from the start, especially compared to my previous main pair of headphones, the original LCD-2 from Audez'e. There was something missing in the lower end, but I bought the Vesper Hybrid pads, and they really helped to increase the bass presence, though at the cost of some treble sparkle, but they kept the incredible details and soundstage precision they had with the stock pads (I can pinpoint exactly where the sound comes from). I highly recommend these. I also got a linear power supply yesterday, and it is true that it helps bring a bit of treble sparkle back, as well as some bass slam, but the difference is slight. I will keep using the linear power supply, but the cost was really high for the change, so do it only if you can get one relatively cheap. The final change I recommend: increase the clamping force by bending the headband slightly. They are very loose out of the box, and increasing the clamping force helps create a better seal for bass. So, should you get them... Well, they ruined my other headphones for me, so yes. Once you go 'stats, you don't go back.

I own an original set of ESP-950 phones. They are about 9 or 10 years old. I also have a collection of other headphones from Audeze, Sennheiser and about half a dozen other quality phones. My Amps are from Woo Audio (wa22), Decware (Taboo 3) Schiit (Mjolnir 2) Mcintosh (MHA150). I enjoy all this equipment, each having its own virtues. But, The Koss ESP950 phones are the ONLY phones I was ever able to genuinely hear a significant difference between interconnect cables. I won't go into this cable vs that cable stuff here, but I will say that the difference is most significant with woodwind instruments, acoustic guitars and instruments that have a rich harmonic content contributing to their individual timbres . And I don't know if the Massdrop phones include this, But the original Koss ESP-950 includes a LIFETIME no questions asked repair or replacement policy. Very handy when after about 5 years the drivers can start to sound a bit scratchy. I think this is because of some reduction in dielectric strength allowing a few sparks to jump around as the years pass. Just my 2 cents.

Thanks for the instructive video, great! - What further improves the sound is replacing the supplied standard power supply with a higher quality one, for example an "ifi ipower Ultra-speed low-noise power supply". It leads to an overall quieter, yet very present acoustic stage, the money invested is really worth it!

Really nice review! I bought the set from Massdrop for 400$, and I was actually surprised to hear you mention several things that I've written for my own Massdrop review of them (specifically how well they do psychedelic and fast music, how well they play at low volumes, stuff like that that I haven't heard mentioned by most others). The volume thing is really nice, as I'm young and certainly appreciate my hearing, so avoiding hearing damage is high priority. I'm actually into a lot of electronic music and expected to find them lacking given most of the comments on Massdrop, but I actually really like them, even for stuff like synthwave.granted, a good amount of the electronica I enjoy asides from that is more ambient in nature, which I guess isn't what most people were basing their recommendations on.

The pads are actually 'new' with the Drop cans. The original Koss pads were 'vinyl' and very thin ... and pretty crappy. I had a Koss set and upgraded to the 'Vesper' pads. I don't know how much of a difference there is between the Drop pads and the Vespers, but the Vespers added lots on the comfort end as well as some on the low end. They also EQ well (for non-bassheads at least) and are a great value at $400 for sure. I sometimes regret selling them ...

Looking good! Appreciate the review!

I have them with the vesper all leather pads. I had to switch the pads with the stock because they were uncomfortable and gave me anxiety because of the pad texture. The all leather pads increase the tightness of the bass and improves the overall definition of the sound. I do somewhat regret buying these headphones, mostly because of the build, and the fact that upgrading to a new amp will cost quite a bit later down the road. So I agree with everything you said in the video. If possible, I would like to see if you can order the conversion cable from Darin Fong and pair these with a better amp, to see if it's worth upgrading. One problem that I have with the sound is that these become piercing when songs with flutes are played, the flutes become piercing and unnatural sounding. I am thinking about just using an eq to tame that frequency though. One last thing about these headphones, they seem to need quite a bit of burn in before they sound anywhere near good, as on first listen they sounded veiled and closed in, but after using them for a while now the sound has opened up quite a bit. I like these as much if not more than the HE1 that I tried at NY soho. One thing that I didn't like about the HE1 was the warm sound. I'm just not a fan of tube sound to be perfectly honest. These definitely are not as detailed as the HE1, but the way the sound presents itself, the "stat" like airiness and lightness, is pretty much the same. Although the HE1 is much punicher then these. I would compare the bass of the HE1 to more like a planar in how much punch it has. The HE1 have more definition and the sound is much fuller. I just wish massdrop could have had koss upgrade the build on these. I don't really feel all that proud owning a pair of headphones that sound expensive, but look like a children's toy. Koss is a joke in that regard. They're in a really good position right now as I'm sure many people would like to get their hands on a nicely priced electrostat. They need to give these things a makeover and tune the sound a bit. After which I'm sure these would sell like hotcakes. So many headphone companies are competing to design new planar magnetic headphones, but why aren't any companies competing to make better, more cost effective electrostats?

5:30 The through-hole resistors standing is to save space, the little fiber glass sheaths are most likely to prevent arcing to the collector of the transistor (which would be an instant-death seentence). I find the metal shielding in the lower compartment interesting. IMO there should be a plastic or laquer coating on it to prevent sparks from jumping to it (or maybe the air gap is sufficent?).

I'm curious how well the Koss take bass boost via EQ (I'm currently using a Mini Loki). I had a pair of Stax SR 7 that was a bit bright with rolled off bass and certainly no punch, but that large diaphragm soaked up bass EQ like a dry spongle:), and turned what I experienced as an unpleasant fatiguing sound into a quite enjoyable one. I wonder how the Koss handles bass EQ?

I thought it was 'Stators'?

I have the 95X and I totally agree with teh sound. They have a reserved neutral tuning that I think is a bit relaxed in the highs aswell as the lows. I dont Eq many cans but I tyhink they really are helped by a bit of high and low. The wispy sound eminating from teh driver is what I think people call the etherial quality of electrostats and its a cool sound. They do have amazing detail in my opinion for a 500 usd can. They are indeed very light on the head. I will look for a linear

I have a pair of original Koss [Closed Back] ESP-9 headphones. I believe I purchased them in the 1980's.

I blew up the plastic Exciter box (one too many mods, I guess). I got a STAX SRM-007tA Headphone Amp $500 on eBay to drive the ESP/95X's. What a HUGE difference ! Plays much louder and way smoother. My ears aren't pained on certain freq.'s on specific musical passages. Toss the plastic Exciter box if you can !

The Oratory 1990 pEQ settings are near vital for these headphones.....with the pEQ I rate them 8.5/10, without pEQ 6/10 and not worth the price.

It's not softening of either end of the spectrum but this gives a FLAT response on nearly the entire range. People mistake this for being a weak headphone but are listening to a truly FLAT and smooth response unlike those other phones that have manufactured "bump" in them for you "bumpkins". The RAT found they have the FLATTEST response of any phone.

Thank you for the detailed review. I bought the Sundara & the 95-X ESP for the difference in their voicing. I agree with with all of your comments here regarding this HP. I have recommended the Koss to friends that are interested in casual serious listening as entry product because of the neutral sound signature and the low barrier to entry they provide since there is no need to buy a headphone amplifier. Can someone here recommend the better of the two replacement pads available…. Vesper vs Dekoni?

I like the Stax because of how open it is. I am in a position where I need to hear things around me right now and Stax has been invaluable for it. I imagine the Koss is similar. For analytical listening it would be awesome in a sound isolated room because outside sounds will mess with you.

Considering the proprietary technology in this they are actually pretty cheap.

Do not shit on the build of the energizer unit. That is choice and easy to fix.

Very nice review, balanced and informative! I wasn't really thinking of Koss but after hearing your take on these estats I see the place for them!

Hey 👋! Nice review. Would this be an absolute upgrade over the HD600? Any other recommendation you could give up to about $700??

Great review. Could someone please tell me how clear these sound compared to a Sennheiser HD800

Hello, Currawong. Which linear power supply would you recommend for these headphones? If possible could you post a link to a purchase page for one. Thanks!

This was a fantastic review and informative history. It's strange that there are channels who regularly review headphones run by man children who constantly swear and basically tell you nothing about how the unit works. Your channel is a breath of fresh air. Thank you.

any way to make power bank work with those? The whole system look bulky, but they are actually very lightweight.

I had a set of Koss ESP-9 back around 1980. Had to drive them with your power amp and I think the step-up transformer would saturate. I'm sure I wouldn't have bought them unless they were dirt cheap. Somebody must have been unloading a boat load of them. Heavy uncomfortable junk.

Old Apple shirt, nice! :)

Absolutely love my ESP-95X headphones. Only qualm is with the seal below the ear, which is sub-optimal (I press on the back of the headphone for a bit more clamping force and the bass is far better).

I like to listen to music while lay down, so it is important info that the sound changes when something is near your ears. I’m still probably going to get them! My last open backs where Hd598 and id fall asleep and roll around with them.

Do you experience a 'rattling' sound whenever they try to reproduce particularly emphasised bass? I've heard three pairs now that all had the same issue, but I'm quite surprised that I haven't been able to find anyone else talking about it. Great review though - spot on with all your comments!

I wonder how it will sound with the Sbooster BOTW P&P ECO MKII 9V-10V.

You got on on Shpongle

I’d say that review is pretty spot on. I’ve had these for a few weeks now, and am generally pleased with them as I listen to lots of acoustic folk music. I did find some classical tracks particularly moving on these headphones. I think I’d like to try a linear power supply with them. Would you mind linking to something reasonably priced that you think would work well?

Wearing them backwards

So when is the Topping D90 review coming? And how does it stack up to the Yggy?

I seriously considered getting these out of curiosity when they were at $400 recently (they are at $450 ATM). However, the number of people on Drop's forum having quality problems with these--notably an intermittent or worse hum or buzzing in one channel--is ridiculously high. Koss does cover these with a lifetime warranty, but I don't want to spend a lifetime shipping them to Koss for repair.

magnets in dinamic and planar magnetics headphones are not gud for my brain. Does electrostatic headphones made and magnetic field similar to other tecnologies when functioning?

I love these, but only with the Schiit Loki in the chain. Otherwise, just too thin sounding for me.

BTW, how do you like the topping d90, you said you've got that right? I'm looking at it, as potential desktop upgrade Dac. It's got the akm4499 chip, correct? Interested in this, being it has most of what I'm looking for in a Dac.. Just wondering your more basic opinion of it, regarding, if you think it's a quality product, truly worthy of the price, for an all around usage type; for again, a more versatile use..?

Do you use an lps with your 789? The house i live in has old crappy wiring

Have you had any problems with noise with your unit? I've on my third unit from faint hissing/squealing. Any tips on how to avoid that. I've kept mine clear of any humidity or moisture or dust and have babied them.

Nice shirt!

It’s essential to know how they compare to the Koss ESP 950, by the absence, can we assume you didn’t do such a comparison? Or if you did, then what were the differences?

5:17 Have these people never heard of surface mount? No wonder energizers are so expensive...

It's sound bad at high volume or it's juste more suitable for quiet music genre?

Hello, can you recommend me somes dac/amp for hifiman sundara besides ifi zen dac (200-300)?