[Uncle00Jesse]

Exactly how bad is the stock e90 driver unit? I'm wondering if I get these, would that little guy tide me over until I get a better amp..

 

[Hennyo]

It will tide you over, Barely. You'll want a better amp sooner than later, but it will certainly tide you over until you can bring the boom with these things!

 

[jcx]

"better" amp for electrostatics has some different considerations - actually the E90 +/- 600 V supply lets it play louder at bass frequencies  than any of Gilmore's project amps, including the T2 and KGSSHV
 
the "objections" to the e90 can include cheap build with ABS plastic case, cheap volume pot with tiny knob, no "jewelery" connectors
 
possible electrical objections are a general suspicion of switching power supplies in high end audio, Class AB output (instead of Class A), use of op amp gain stage
 
the Gilmore/"Stax Mafia" also has some knock on "capacitor coupling"
 
subtle noise, distortion differences are the most likely actual weaknesses of the e90, along with frustration with the volume pot
 
but the E90 will drive the 950 Louder - in fact putting a Stax jack on it would be a highly amusing start for true blind comparisons

 

[kevin gilmore]

The amp is actually dc coupled output, its ac coupled drive to
a stack of 6 fets in series. Opamp feedback around the whole
mess. There are modifications that would make the thing
much better, but no room inside the box for that kind of
modifications. I still think it sounds better than the hev70 which
is ac coupled output and also opamp feedback.

 

[maverickronin]

Quote:

The amp is actually dc coupled output, its ac coupled drive to
a stack of 6 fets in series. Opamp feedback around the whole
mess. There are modifications that would make the thing
much better, but no room inside the box for that kind of
modifications. I still think it sounds better than the hev70 which
is ac coupled output and also opamp feedback.

What kind of stuff could you do to fix it up if you moved it to a bigger enclosure?

 

[jcx]

 I opened mine up, for an idea of what you'd be working with you could view my pics
 
http://www.head-fi.org/t/262845/the-koss-esp950-thread-esp-owners-please-contribute/285#post_6208556
 
physically you could cut apart  the bottom board to get EMI attenuating spacing between analog input circuitry and the HV sw supply/power entry - just might strain the "no questions asked" warranty policy
 
add filtering to input, outputs of HV supply, add regulated low voltage analog supply to supply the HV sw ps
 
add decent volume pot
 
 
all before considering op amp rolling, increased bias, any circuit/component changes
 

 

[maverickronin]

Quote:

for an idea of what you'd be working with I opened mine up
http://www.head-fi.org/t/262845/the-koss-esp950-thread-esp-owners-please-contribute/285#post_6208556

Thanks.  That looks easier to work on than I expected.

 

[koonhua90]

Would would sound better: Koss ESP 950 with its stock energizer amp or Stax SR 303 with SRM 323A amp?

 

[Hennyo]

Spritzer, I'm surprised you said the E-90 is better than HeV70, interesting.
Perhaps I can connect Ray Kimber with some Orpheus > Stax adapters.

"Would would sound better: Koss ESP 950 with its stock energizer amp or Stax SR 303 with SRM 323A amp?"
 
Definitely, definitely the latter.
 
Edit: Oh sorry, I meant the amp for ESP 950. Not with Sr 303. Personally that's a tough choice. ESP 950 out of a big amp shines. Never heard an Sr 303, but did an Sr 202 and 407. To echo N3rdling, I would say the 202 / 303 are less liked as well.

 

[koonhua90]

Thanks for the reply. Am if Stax on Stax amp sounds better, would the Stax 407/507 be much better than the SR 303?
 
Have anyone compared those to the LCD-3? As good as the LCD-3 is, sometimes I need a more detailed oriented presentation, and I need a headphone that sounds as good, but is way lighter. Sometimes ppl describe that the sound of an electrostatic headphone can sound like it comes out of thin air, and I really want to hear that. 

 

[n3rdling]

The 303/404, Basic, and Pro are some of the less 'liked' Lambdas on HF.  The classics held in higher regard are the Lambda normal bias, Lambda Signature, and Lambda Nova Signature if you don't mind buying used.  

 

[Anaxilus]

Quote:

 
Have anyone compared those to the LCD-3? As good as the LCD-3 is, sometimes I need a more detailed oriented presentation, and I need a headphone that sounds as good, but is way lighter. Sometimes ppl describe that the sound of an electrostatic headphone can sound like it comes out of thin air, and I really want to hear that. 

If you want a detail oriented phone, that's light and has sound appearing out of thin air, the LCD3 and any Audeze is not the way to go.

 

[koonhua90]

Quote:

If you want a detail oriented phone, that's light and has sound appearing out of thin air, the LCD3 and any Audeze is not the way to go.

Yes, well basically I want a different presentation, depending on my mood. The deep punch, focused, smooth grainless sound on the Audez'e can be incredibly satisfying...it would be even greater if some weight can be shed from the headphone.

 

[Anaxilus]

From what you described wanting only electrostats can deliver that IME.  So it sounds like you'd have a nice compliment.

 

[spritzer]

Quote:

Spritzer, I'm surprised you said the E-90 is better than HeV70, interesting.
Perhaps I can connect Ray Kimber with some Orpheus > Stax adapters.
 

 
The HEV70 is the worst of the worst, up there with the first version of the HEV90.  I for one don't think we dismiss the E.90 because of the plastic box and cheap parts.  In fact there are some very nice parts in there and I don't think the volume pot needs to be replaced, certainly better than what's in many other amps.  The simple fact is that the Stax SRM-Xh and its descendants are just far better amps.  Do some small mods to the SRM-Xh and it is a very, very good amp.  
 
I have a lot of Kimber TCSS wire but since I don't know the insulation rating then I'd never use it for high voltage circuits.