Was originally going to post the deets in ‘Systems & Synergies’ thread but feel it belongs here more:
This is the Koss ESP/95X electrostatic headphone system, featuring the Soekris 1421 DAC pumping signal into a Gustard P26 Preamp (with the Burson Classic opamps).
Underneath the Koss energiser is a 9V / 2.5a Linear Power Supply.
Earpads are from Dekoni, nice thick leather (unlike some flimsy Focal earpads I’ve purchased from there). Be sure to give these earpads some conditioner to soften them up.
In terms of changes of sound:
-
The earpads. Lately giving the Koss headphones a second lease on life, I thought they were hazy in the midrange, boring, with a weird bass hump but also lack of sub-bass.
The earpads make the low end much more linear and clean, cutting the bass hump while also increasing the sub-bass. They cut that hazy area in the 1-2Khz range, and as a result highlight the low treble region much more and overall increase the tonal balance of the 95X. -
The source: a good source shows what electrostats can do. I had been feeding signal from my OTL amp, the 95X was still agile and speedy in transients, but also a little hazy and grainy. Feeding them signal from this beefy class A preamp shows off their lightning fast transients while making the sound as transparent as these headphones are capable of. The Classic opamps from Burson add a touch of tube warmth, I prefer angling these headphones to the warm side of neutral as that’s what they do best.
I had experimented with the stock 95X earpads and a tube preamp, the Dekoni pads and solid state preamp combination is the more transparent and resolving overall, though. -
The Linear Power Supply: supplies immediate power to the energiser, fleshing out the low end and midrange, maybe adding some sparkle to the top end also.
The headphone stand from Grump Goose serves no purpose other than to hold the headphones for me on those inconvenient occasions when I’m not listening to music! 
In honesty, my LCD-X has a more honest tonal balance, the snare drum sound just right for example. But the 95X is probably the king of warm, relaxing sound for me. The tonal balance is maybe 85% of something more reference like the LCD-X, whereas in stock form it would be 50%.
Next on the list of mods? A new amp for sure! Would have to be the Stax SRM-400S, and the Microzotl Z10E. Also Vesper pads, they would have to be perforated leather like Dekoni for the tonal balance that the Dekoni achieves.
