I think people are somewhat off-base talking about the reason that some of us feel that the 007 (esp. mk I) really come alive with an amp capable of higher voltage swings - and it is NOT just volume.
The SLEW RATE is important. Most electrostatic amps just can't swing ENOUGH voltage FAST ENOUGH (with low distortion) into the reactive load of an electrostatic driver.
If everything else was equal - slew rate, distortion, etc - then higher voltage swing would only mean a louder output. But when it comes to electrostatic amplifiers, things are NOT equal, and so the QUALITY of sound that a given electrostatic earphone is capable of has limits imposed on it by the amplifier's capabilities. An amplifier that is capable of delivering the best in terms of high slew rates and low distortion is also capable of greater-than-average voltage swings.
Listen to an 007 on a DIY T2 then listen to it on an SRM-T1 - or even the SRM-727 etc- you'll hear the difference. And that difference is NOT just "moar volume."
Unlike in conventional headphones where the cable does not measurably affect the output of the headphones, in electrostatic headphones it actually can definitely play a major role. It depends entirely on the amplifier whether or not it will matter. Electrostatic drivers are capacitors, and the cables are capacitors. As it turns out, the cable is quite a fraction of the total capacity of the headphones. Increasing this capacitance may or may not change the sound quality. Electrostatic drivers run at such high voltages, that slewing the voltage in these capacitors actually takes milliamps or even tens of milliamps of current (might not sound like much, but we're at hundreds of volts!). If the amplifier has sufficient drive power and is well designed, it really shouldn't change anything. If it's a lower power amp or lower design quality, it might be at least measurable.
In terms of conventional headphones, imagine a case with a 300 ohm driver, where the cable is 100 ohms. Changing this cable to 300 ohms by extending it would change the impedance of the system and would change how it is loading the amplifier. Fortunately for conventional dynamic drivers, cables are <<1 ohm.
Given the bias currents and topology of the Blue Hawaii, it is my opinion that there might be a very slight measurable difference using a 15 foot cable, but I would be shocked if the difference could be perceived by any human (of course assuming you're unaware of the difference in cable length). On the other hand, if one were using a Stax transformer box, I would be quite surprised if the average listener couldn't tell a difference.
These quotes deserve to be united since they are both related. I have found both beautifully explained. Thank you.