The ESP950 is seriously awesome, I'll probably end up picking up a set sometime. Frank, I remember somebody (I think cetoole) opening up the E90 and checking the bias voltage. I think there was some conflicting info that showed a different bias for different E90s. Do you think the squeal might be a result of using the wrong value bias?
I'm the one that bought cetool's pair. I think there is some discussion of the E90 bias value on other forums but I don't remember the conclusions. I think the normal Koss bias is 620V. I seem to remember something about lowering the bias voltage to eliminate the squeal, but I could be wrong. I run mine at standard Stax 580V and I still get an intermittent low level "squeal". Driver replacement cures the problem.
I have a pair of LCD-2 (mk 1) - if I had to choose to keep only one pair, it would be the LCD-2's. But actually owning the LCD-2's AND a pair of electrostatic 'phones is a very nice thing.
If I had to pick a pair of "budget" electrostatic phones I would definitely go with the ESP-950's.
Since I have ESP-950's, Lambda Pro Signatures AND SR-007's - it's is a bit redundant. If I decided to keep two of the three it would be the Lambdas for their "speed" and hyper-detail and the SR-007's for their naturalness and bass. (Some say the Lambda Pro Signatures sound "etched" and while I wouldn't go THAT far, I definitely understand that point of view. If I were in my 20's instead of late 50's and could hear up above 16,000 Hz I might find the "etched" quality of the Lambda Pro Signatures much more apparent.)
But If I had a pair of Lambdas and couldn't afford SR-007's, the ESP-950's make a nice alternative to Lambdas. Or if I had NO electrostats, the ESP-950's make a nice place to start.
Which is all to just put the ESP-950's in perspective.... they are a VERY GOOD headphone and often can be bought for a very reasonable price. In particular they are an excellent way to "get your feet wet" in electrostatics.
I have the LCD-2 Mk1 and ESP-950 as well. I use a Decware mini-torii for the LCD-2 and Woo WEE hanging off the mini-torii speaker taps for the ESP-950. I find I prefer the ESP-950 by a pretty wide margin over the LCD-2 for most of my listening, only preferring the LCD-2 for poorly recorded rock music.
I think these don't get more respect because you can't really talk about them without also talking about their build quality. They feel very cheap and plasticy but that doesn't really bother me as I find them very comfortable and love the sound. Mine have a channel imbalance which I compensate for with the dual volume controls on the mini-torii and I think the left channel is starting to get the squeal people talk about. Even with those issues, they're the first headphones I've owned that have made me feel relatively comfortable with my setup and I'm tempted to buy a second set just to have a backup for the inevitable trips back to Koss, the first of which is clearly coming soon for this pair.
I also found the Koss E90 amp perfectly usable and made even better by using a regulated bench power supply. I'd love to hear them off a really nice dedicated Stax amp.
This thread brings back memories. I bought a pair of these my freshman year in college (1997). I used a sony discman to an Audio Alchemy DDE 1.0 (home made portable battery pack) to the Koss amp. Surprisingly it all fit on the provided Koss travel bag. My pair ran off 6 D cell batteries, and went through them quick! I had the squeal problem, but it was easily solved by a quick tap on the offending earpiece. Also had an issue with "farting" - membrane slapping on deep notes at high volume. Similar to the early Martin Logan CLS panels. All that said, the system rocked. If it hasn't changed since then I am sure there are better systems out there for the money, but back in the day I sure did enjoy them.
So, I'm kind of tempted to purchase this little system. However, it would be my first electrostatic set-up, and I don't want to make any mistakes with it. Would I be able to plug it into my Nuforce and use that as a DAC, or would I need an extra component?
I've been tempted by the ESP/950 before, but had a few concerns.
-Some have complaints about the build quality over time, though I'm not sure if it's more about the headphones or the driver unit. Fortunately, Koss has a lifetime warranty. Unfortunately, that lifetime warranty is only available if you buy brand new from a dealer. (I'm guessing this is why Koss isn't really respected in the audiophile community.)
False - the warranty has absolutely no conditions. You don't need any proof of purchase whatsoever. I am from Canada and purchased my pair used from a fellow Head-Fier from the States. I sent them back with a broken head-band and no cable (I removed the Stax retermination cable before shipping them back). They were sent back to the USA Koss address in a plain used shipping box with nothing more than my name, address and concern. Six weeks later, a brand new pair of ESP 950's complete with Koss cable landed on my Canadian doorstep. They ARE true to their warranty - NO conditions and NO questions asked.
So, I'm kind of tempted to purchase this little system. However, it would be my first electrostatic set-up, and I don't want to make any mistakes with it. Would I be able to plug it into my Nuforce and use that as a DAC, or would I need an extra component?
So, I'm kind of tempted to purchase this little system. However, it would be my first electrostatic set-up, and I don't want to make any mistakes with it. Would I be able to plug it into my Nuforce and use that as a DAC, or would I need an extra component?
No - you would need a Koss to Stax adapter (or Stax cable replacement). They are electrostatic and only work with electrostatic amps. They sound absolutely phenomenal with my Cavalli eXStatA Hybrid amp. I had them also running from my other Stax amps (SRM-1/Mk-2 and the SRM-T1) and they sounded wonderful. Truly an overlooked and exceptional electrostatic headphone!
No - you would need a Koss to Stax adapter (or Stax cable replacement). They are electrostatic and only work with electrostatic amps. They sound absolutely phenomenal with my Cavalli eXStatA Hybrid amp. I had them also running from my other Stax amps (SRM-1/Mk-2 and the SRM-T1) and they sounded wonderful. Truly an overlooked and exceptional electrostatic headphone!
Anaxilus is correct. I'd be buying the whole system, not just the headphones. I don't want to drop the cash for a Stax amp and an adapter if I don't have to.
False - the warranty has absolutely no conditions. You don't need any proof of purchase whatsoever. I am from Canada and purchased my pair used from a fellow Head-Fier from the States. I sent them back with a broken head-band and no cable (I removed the Stax retermination cable before shipping them back). They were sent back to the USA Koss address in a plain used shipping box with nothing more than my name, address and concern. Six weeks later, a brand new pair of ESP 950's complete with Koss cable landed on my Canadian doorstep. They ARE true to their warranty - NO conditions and NO questions asked.
Almost identical to my own experiance. The warranty is phenomenal. I sent mine in without any paperwork except a description of the problem. They not only replaced the drivers, but without being asked, replaced the E90 amplifier merely because the front panel had been slightly damaged. I've had them in twice for driver replacement (once because I blew them up overdriving them with a prototype DIY amp). Absolutely no questions asked, The U.S. Stax disrtibutor could really learn a lesson in customer service from Koss. Best warranty of any audio product I've ever owned.
I do think the ESP950 has been overlooked but it's not been for a lack of exposure and interest from the mafia. I for one am a great fan of the ESP950 but cable, build quality and squeal issues plus the possible demise of Koss all scare people off. The amp is also not the greatest but it has also been misrepresented. It has more voltage swing and lower distortion then most of the "high end" amps out there.
The squeal issue is tied to how Koss setup the dust covers, i.e. they don't really work. To fix this they setup a voltage divider on the bias tap so that it can be lowered if needed. When the amps ship they have an infinite resistor in there (i.e. an open circuit) but Koss can cut the bias down to any voltage they want. The stock amp outputs 600V which is also the B+ of the output stage.
Ohh and the earpads are pleather and a cheap one at that. The bag supplied with the system is made of leather though...
The ESP950 is seriously awesome, I'll probably end up picking up a set sometime. Frank, I remember somebody (I think cetoole) opening up the E90 and checking the bias voltage. I think there was some conflicting info that showed a different bias for different E90s. Do you think the squeal might be a result of using the wrong value bias?
I heard the squealing on 2 different pairs even on my Blue Hawaii. The warranty is excellent, but the costs of mailing them and paying return shipping do add up.
Personally I think they are a good value if you intend to use them with the E90. If you have a more expensive amp you're just better off getting better headphones.
I could never get past their wall of sound effect like a pair of Grados. Even on hard rock and really loud metal I preferred the Stax O2 mk1 to them.
For less than the price of an ESP950 I would get an SR-Lambda and a normal bias transformer box.
I heard the squealing on 2 different pairs even on my Blue Hawaii. The warranty is excellent, but the costs of mailing them and paying return shipping do add up.
Personally I think they are a good value if you intend to use them with the E90. If you have a more expensive amp you're just better off getting better headphones.
I could never get past their wall of sound effect like a pair of Grados. Even on hard rock and really loud metal I preferred the Stax O2 mk1 to them.
For less than the price of an ESP950 I would get an SR-Lambda and a normal bias transformer box.
Cost me a total of $9.50 to ship + $7.50 for return shipping = total $17.00 to get a brand new complete replacement.
Mine are runoff a Cavalli eXStatA Hybrid amplifier - sounds phenomenal!
Never have had a squeal issue.
That's the rig I would love right now, ESP-950s off an eXStatA hybrid. I might need to bite the bullet and do that sometime next year. I just wish I could at least hear the ESP-950s first. I'll have to try to find someone in NY/NJ with them.
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