[adeadcrab]

Is this the same side you popped away from the grill?

 

[IBJamon]

Is this the same side you popped away from the grill?

After I did that to one side, I made both sides match....

 

[PolloLoco]

I'm only 3 hours into hearing with my Stax srm 300, but so far this Energizer is a big improvement in everything BUT bass. I've packed my Koss E90 away.

As I mentioned the bass is a notch weaker. But the soundstage, layering and clarity are greatly improved. The background and silent passages are dead black. I'm really shocked at the soundstage improvement, without losing detail. I also bought a modified Stax L300 and can honestly say these trade blows. I'm going to keep both as a complement to each other - this combo is likely my end game.

In the 3 hours of listening, I haven't heard a crackle or buzz in my right ear yet. I'll report back if this is true after a week of 2 hour a day listening.

 

[Amish]

I think the E90 is pretty decent actually. It is without a doubt more dynamic than say a Stax tube amp but the Stax is smoother. Both are pretty detailed. (compared to my Stax SRM-T1) I was actually impressed with the E90. Yes I believe any good Stax amp is better but if I were stuck with the E90 I'd be pretty ok with it.

 

[VRacer-111]

I think the E90 is pretty decent actually. It is without a doubt more dynamic than say a Stax tube amp but the Stax is smoother. Both are pretty detailed. (compared to my Stax SRM-T1) I was actually impressed with the E90. Yes I believe any good Stax amp is better but if I were stuck with the E90 I'd be pretty ok with it.

I use my STAX compatible e-stats with the E/90x and it is a very decent driver...not really much difference between it and the STAX solid state ones to me. I do absolutely prefer my full custom Estat rig to either one, but for a generally really good sound that's easily portable, the Koss and STAX solidstate drivers work well and are more similar than different.

 

[PolloLoco]

I use my STAX compatible e-stats with the E/90x and it is a very decent driver...not really much difference between it and the STAX solid state ones to me. I do absolutely prefer my full custom Estat rig to either one, but for a generally really good sound that's easily portable, the Koss and STAX solidstate drivers work well and are more similar than different.

Interesting. Does this mean you have a stax to koss adapter to connect Stax headphones to the e90? I thought a certain resistor in the Energizer was required for stax headphones. I kept the male end of my koss extension cable in case I had a reason to splice together the opposite kind of adapter. To be clear, my friend made a "Koss to Stax" adapter for me - but I haven't seen a reason to make a "Stax to Koss" adapter.

My untrained ears find the Koss esp950 connected to my Stax SRM 300 to be a big improvement in detail, layering and soundstage. The last 6 hours of listening I've had chills run down my spine many times, where I thought the E90 was great, but not amazing. This $320 purchase for a used SRM was hugely more satisfying than a $100 linear power supply to feed the E90.

I have to raise the volume of my Sabaj D5 line out higher for my SRM 300 than on my E90. With both energizers set to 70%, for the E90 my Sabaj D5 volume was at 19 out of 40. For the SRM 300 I go to 25 out of 40 for my usual listening level.

The SRM 300 has a 350v swing, and I perhaps stupidly took a chance on importing a used SRM 323A to play with. If it works (only power on was confirmed) I'll see if its higher voltage swing of 400v makes a difference. It should arrive next week.

After 6 hours, the esp950 coil whine in my right ear returned, BUT its volume was so much lower I nearly missed it. By the time I noticed it, it was gone in under 30 seconds. "Coil whine" may not be accurate, but it's my best way to describe it. I'll report if it gets louder, but I'd be thrilled if that's all I hear from now on. Previously, that noise with the E90 could make me raging mad.

Slightly off topic, previously someone had asked me where I heard that it may not be a good idea to leave the Esp950 charged all the time. I ran into post #27 yesterday looking up info on Koss to Stax combinations:

https://www.head-fi.org/threads/koss-esp950-stax-srm212.771044/page-2

 

[barondla]

Interesting

Interesting. Does this mean you have a stax to koss adapter to connect Stax headphones to the e90? I thought a certain resistor in the Energizer was required for stax headphones. I kept the male end of my koss extension cable in case I had a reason to splice together the opposite kind of adapter. To be clear, my friend made a "Koss to Stax" adapter for me - but I haven't seen a reason to make a "Stax to Koss" adapter.

My untrained ears find the Koss esp950 connected to my Stax SRM 300 to be a big improvement in detail, layering and soundstage. The last 6 hours of listening I've had chills run down my spine many times, where I thought the E90 was great, but not amazing. This $320 purchase for a used SRM was hugely more satisfying than a $100 linear power supply to feed the E90.

I have to raise the volume of my Sabaj D5 line out higher for my SRM 300 than on my E90. With both energizers set to 70%, for the E90 my Sabaj D5 volume was at 19 out of 40. For the SRM 300 I go to 25 out of 40 for my usual listening level.

The SRM 300 has a 350v swing, and I perhaps stupidly took a chance on importing a used SRM 323A to play with. If it works (only power on was confirmed) I'll see if its higher voltage swing of 400v makes a difference. It should arrive next week.

After 6 hours, the esp950 coil whine in my right ear returned, BUT its volume was so much lower I nearly missed it. By the time I noticed it, it was gone in under 30 seconds. "Coil whine" may not be accurate, but it's my best way to describe it. I'll report if it gets louder, but I'd be thrilled if that's all I hear from now on. Previously, that noise with the E90 could make me raging mad.

Slightly off topic, previously someone had asked me where I heard that it may not be a good idea to leave the Esp950 charged all the time. I ran into post #27 yesterday looking up info on Koss to Stax combinations:

https://www.head-fi.org/threads/koss-esp950-stax-srm212.771044/page-2

Great thread. Lots of info about Stax amps. Interesting comment about leaving Koss powered up all the time. Would be nice to have more info. Thanks for posting.

 

[VRacer-111]

Interesting. Does this mean you have a stax to koss adapter to connect Stax headphones to the e90? I thought a certain resistor in the Energizer was required for stax headphones. I kept the male end of my koss extension cable in case I had a reason to splice together the opposite kind of adapter. To be clear, my friend made a "Koss to Stax" adapter for me - but I haven't seen a reason to make a "Stax to Koss" adapter.

My untrained ears find the Koss esp950 connected to my Stax SRM 300 to be a big improvement in detail, layering and soundstage. The last 6 hours of listening I've had chills run down my spine many times, where I thought the E90 was great, but not amazing. This $320 purchase for a used SRM was hugely more satisfying than a $100 linear power supply to feed the E90.

I have to raise the volume of my Sabaj D5 line out higher for my SRM 300 than on my E90. With both energizers set to 70%, for the E90 my Sabaj D5 volume was at 19 out of 40. For the SRM 300 I go to 25 out of 40 for my usual listening level.

The SRM 300 has a 350v swing, and I perhaps stupidly took a chance on importing a used SRM 323A to play with. If it works (only power on was confirmed) I'll see if its higher voltage swing of 400v makes a difference. It should arrive next week.

After 6 hours, the esp950 coil whine in my right ear returned, BUT its volume was so much lower I nearly missed it. By the time I noticed it, it was gone in under 30 seconds. "Coil whine" may not be accurate, but it's my best way to describe it. I'll report if it gets louder, but I'd be thrilled if that's all I hear from now on. Previously, that noise with the E90 could make me raging mad.

Slightly off topic, previously someone had asked me where I heard that it may not be a good idea to leave the Esp950 charged all the time. I ran into post #27 yesterday looking up info on Koss to Stax combinations:

https://www.head-fi.org/threads/koss-esp950-stax-srm212.771044/page-2

Have custom STAX adapter cable made by Spritzer that came with the E/90x as it was his personal unit. I do think the STAX SRM-323S I had was better than the E/90(x), but the difference was minor in contrast compared to what the NAD C275BEE stereo amp + Mjolnir SRD-7 transformer brings to them. Actual impactful subbass is something that the SRM-323S and E/90x simply can't do, along will fuller sounding mids.

 

[PolloLoco]

Have custom STAX adapter cable made by Spritzer that came with the E/90x as it was his personal unit. I do think the STAX SRM-323S I had was better than the E/90(x), but the difference was minor in contrast compared to what the NAD C275BEE stereo amp + Mjolnir SRD-7 transformer brings to them. Actual impactful subbass is something that the SRM-323S and E/90x simply can't do, along will fuller sounding mids.

OK - that makes sense. Most of the references to a resistor being needed with most non-stax amps were quoted from Spritzer originally. Perhaps he added one? I recently stumbled on Spritzer's comments when I considered a Kingsound portable energizer.

I got my Stax SRM 323A (400 V swing) in last week, and I switched to it exclusively. In short, compared to my SRM 300 (350 V swing) - it has more bass, but less forward mids. Overall - a little better detail and a more neutral tone. But I'll spend most of this post commenting on the SRM 323A vs the Koss E90.

I pulled the E90 out of it's box this morning, and decided I'd do some back to back listening for comparison. I connected it to it's Wall Wart for power. So I could more easily switch between energizers - I connected the E90 to the single ended headphone out port of my Sabaj D5, and the Stax to the line out. The two energizers stayed powered on for the roughly 4 hour session, and I'd quickly unplug/plug my Koss ESP-950 to either energizer, and switch inputs on the D5 using the remote.

I got myself reacustomed to the E90 by listening to FLAC files for an hour, and was thinking to myself - wow, the E90 sounds better than I remembered. I started to think that this test wouldn't go the way I expected it to.

So after the first hour, I decided I would listen to a song I liked or disliked the complexity of - and then I would switch. The first big difference came with Imagine Dragons, "Bleeding Out". The bass track was messy and confused in the background on the E90. I switched to the Stax, and I could better make out the instruments in the background - it wasn't the poorly mastered mess I initially thought. Paying attention to the bass, it was definitely stronger on the Stax, though not by a huge margin. I don't think a basshead would be satisfied, but it more regularly hit the level of bass I could feel instead of just hear.

Then I listened to Ingrid Michaelson's "Everybody" and was floored by the differences between the two energizers. I listened to the song 3 times with each energizer, not only to confirm - but revel in the differences. The big difference is detail and layering. On the E90 - her voice sounds slightly thin. On the Stax, her voice was full, warm - and I picked up so much more detail. For example, she played with vibration and slightly raspy notes several times - and I couldn't catch that with the E90 at all - even if I raised the volume higher. The instrument placement was sharper, I felt a 3D soundstage - if not a large one. To me - these changes weren't subtle AT ALL.

Guster's "Summertime" was similar in that I felt all the instruments around the lead singer were sharper and more well placed. The soundstage was just better defined. Then Guster's "Rocketship" was also eye opening. On the E90 - the lead singer's voice just sounds like an echo. That's the impression I've always had. It's hard to explain, but listening with the Stax - his voice sounds "haunted", exhausted, lingering. I was getting details that helped capture an emotion the song was trying to convey.

Anyway - I'll listen again tomorrow morning, switching the inputs to each energizer see if that affects anything. If I don't reply - it's because there was no difference.

Overall - I'd rate my original Koss ESP950 experience as a 7/10. With a linear power supply or battery - 7.5/10. With the Stax SRM - a 9/10.

I suspect the added current that Stax amps supply - allow the Koss to be faster, picking up that much more detail. One other thing to note - over the last 2+ weeks listening to the ESP950 with stax amps, I picked up the coil whine in my right ear 4 times. Each time I had to strain to identify it - I was actively looking for it. It was about half the volume of the E90. Also - each time it went away within 30 seconds. This was over a listening period of roughly 40 hours. I'm not sure if it's the lower bias voltage, but whatever causes this whine/hiss/crackle - it seems to be less excited by the Stax amps.

I'm selling my Stax amp on EBAY, not because I regret the purchase - but because I now have upgrade fever. I will eventually end up with a balanced stax amp, like the 353X, and the SRM 300 should tide me over.

 

[barondla]

Nice unit comparisons. Your descriptions give me a good idea what to expect when upgrading. Thanks for doing these tests and reporting the results.

 

[PolloLoco]

Nice unit comparisons. Your descriptions give me a good idea what to expect when upgrading. Thanks for doing these tests and reporting the results.

No problem, I hope it was useful. I'm a nerd and an engineer so I love these experiments my wife finds mind numbing. I was actually so excited this morning to find concrete differences in my listening experience.

 

[darinf]

FYI, it's been a while, but we finally have more Vesper Pads in stock. They're trickling in. Only 4 pairs of Alcantara for now. I have a bunch on order.

 

[theangelboy]

So I received my ESP/95X today and just unpacked it. I've been listening for about 15 minutes. Really interesting headphones. First impressions are really good. They are so flipping transparent!

Anyway, my question for all of you electrostatic headphone veterans. How do you store them? With all of my dynamic and planar 'phones I hang them on modified bamboo banana stands. However, those drivers are much more resilient to dust than electrostatics (at least as I understand it). I know Stax sells a plastic bag that goes over a headphone stand but that's not particularly attractive. I would love to hear (or see) how some of you store them.

P. S. Apologies if this question has already been asked on this thread but I read through about ~150 pages did some searches and couldn't find anything relevant.

 

[adeadcrab]

I'm using a shower cap to put the headphones in for long-term storage (when I'm using the Elex instead!).

 

[Amish]

Anyway, my question for all of you electrostatic headphone veterans. How do you store them? I would love to hear (or see) how some of you store them.

I bought two of those STAX covers. One for my Koss and one for my Stax headphones.

https://www.headamp.com/order/stax-...ImwZ5G65zLdEwsIrrJv7V8G-76w0uJ9oaAnsQEALw_wcB