Koss ESP/950 electrostat thread

[spritzer]

Yes. 

[Oak Forest Audio Dood]

Welp I guess I need to finally get around to trying the Vesper pads as I'm pretty happy with these Stock! So the Angled Vesper Pads which ones exactly are you guys using? I got a response back with a lot of options, are we going with the all Velour or?

But alas I'm here trying to figure out what amp to get for my little 95X... the Octave II @spritzer seems nice. Tho I'm hearing these open up with even more juice sadly $1500 is about my cap for this venture...

Any one else have any thoughts? 

 

[grawk]

I was pretty happy with stock pads, and a blue Hawaii with my esp950s

[ilikebananafudge]

I have flat (15mm thick all the way around), all-leather Vesper pads with fast-fill foam that I'm really enjoying. I find them much more comfortable than the stock pads and I think they emphasize the bass a bit. As for the amp, I have a re-capped SRM-1 Mk2 that I like, especially when fed with the pre-amp output of my Gilmore Lite Mk2. I also like the ESPs a lot better since I removed the foam on the baffle under the earpads. I think it makes them sound less muffled and more alive, especially in the treble.

[Mach3]

On 7/4/2020 at 12:57 AM, ilikebananafudge said:

I have flat (15mm thick all the way around), all-leather Vesper pads with fast-fill foam that I'm really enjoying. I find them much more comfortable than the stock pads and I think they emphasize the bass a bit. As for the amp, I have a re-capped SRM-1 Mk2 that I like, especially when fed with the pre-amp output of my Gilmore Lite Mk2. I also like the ESPs a lot better since I removed the foam on the baffle under the earpads. I think it makes them sound less muffled and more alive, especially in the treble.

I custom my Vesper a while ago, angled 20mm to 15mm all lambskin as it super soft with memory foam, super comfy.

[Oak Forest Audio Dood]

So yea Angle'd Vesper Pads and the removal of that nasty foam make a difference! 

@spritzer , I thank ya for your recommendation and guidance, it makes quite the improvement

[PolloLoco]

I apologize beforehand if I should have started a new thread, but I figured folks with a Koss ESP950 or Koss ESP95X like me might be curious about the earlier Koss models.  If you try this, besides the risk of electrocution, Spritzer has stated before that these weren't designed for pro bias - so I may be slowly killing these Koss ESP6.

When I first bought my Koss ESP95X, my desk and work area were better set up for closed headphones, though I loved the clarity and speed of stats.  So I became curious if not obsessed with the earlier closed Koss stats.  I bid on, but ultimately decided not to buy several versions of the ESP9.  During the lockdown I decided I needed a new and more ambitious nerd project.  So I bought a Koss ESP6 and decided to wire them to the male end of my Koss ESP extension cable.  I ripped out most of the internals first, but left them closed with minimal damping.  Sadly, being closed, they lost most of the stat character.  Like they sounded originally through the standard headphone jack out of my amp - they still sounded congested and echoey.

I had read on another forum about someone that wired their Koss ESP9 for the Koss E90 amp, but they left the PCB.  I decided to go one step further, and leave the drivers nearly completely exposed.  The first attempt at making  them open was disappointing.  The two layers of felt over the drivers, and the plastic grills on the pad side were the culprit - when I removed them I was shocked at how good they sounded.

Now that I know they sound good I'm going to make or buy a better cable as opposed to my jerry-rigged mess, and create a nice grill.  Overall the mids and treble sound clearer than my Koss ESP95X though the sound stage is more intimate.  I have not tried them directly back to back, but I will eventually.  I suspect a lot of people may be put off by the agressive treble.  Sadly, they're still bass light even with my Stax SRM717  but I've been listening to them with a 3 decibel boost under 100Hz, and they sound fantastic to me.

I believe the Koss ESP6 were originally wired single ended.  The black and yellow cables are connected to each stator.  But is it possible I've inadvertently connected one side to ground and am damaging my amp?  I'd appreciate any feedback on that.

 

 

[spritzer]

The ESP6,7 and 9 were all single ended so the amp won't like that at all if you've somehow connected the back stators together.  You can isolate them though as I did back in the day on my esp6's. 

[PolloLoco]

Thank you sir!  As usual you're a scholar and a gentleman.  I figured that by removing the PCB I divorced the two stators.  I just verified it with my voltmeter, they're not connected.

 

Is it possible that one of the stators is grounded, and that that might damage my amp?  If so, can I just test by touching each stator with my voltmeter, and checking continuity with the cable?

 

Edit:  I just answered my own question.  I remembered I had an extra driver, from the first broken pair of Koss ESP6 I had played with.  So I busted out my voltmeter to verify that the top and bottom bolts are connected to different stators.  The stators are not connected to each other once the PCB is gone.  So my amp should be safe.  The headphones might eventually die due to the high bias, but thats a risk I'm comfortable with.

[PolloLoco]

Here's a picture of my finished project.  It's been super rewarding.  I love the way they look.  I had convinced myself that the ESP 6 conversion sounded better than my Koss ESP95X, but after a head to head review - that's definitely not true.  Whether closed or open, or with the many different pads I've tried - I've been unable to get meaningful bass out of these.

 

On a different note - I have the nagging feeling that when I went from my jury rigged cables to the removable Kaldas cables, I may have reversed positive and negative wires to each earcup.  If so - if the positive wire is going to the back stator and the negative is going to the front stator - would I be able to hear a significant difference?

 

 

Edited October 9, 2020 by PolloLoco
clarification