Stax SR-007 Omega II electrostatic headphones Michael Fremer, May 2007
I know this isn't strictly analog, but have mercy! I've wanted to hear Stax's Earspeakers for decades, and when the opportunity presented itself, I couldn't say no. The SRM-007tII is a three-input, tube-powered energizer/amplifier capable of powering two sets of Stax electrostatic headphones. It includes a volume control, which means you can base a headphone audio system on it. You can also use it as a swell late-night accessory by driving it from your preamp's Tape Out, though at $3900 for the amplifier plus headphones, it's a pricey accessory.
I spent a few months of very-late-night listening with the extraordinary Staxes, which had all the pluses and minuses of electrostatic loudspeakers. They were superbly open, transparent, extended, "fast," and subjectively linear. On the other hand, even as earpieces firing into tiny canals, their dynamics were somewhat limited compared to the best moving-coil headphones, such as AKG 701s, and while the SR-007II's bass response was very good—especially as Stax has increased the size of the diaphragm—it, too, lacked the punch and impact of a good dynamic driver. So even in headphones, the well-known tradeoffs of electrostatic drive-units persist.
That said, the combination of tube warmth and electrostatic transparency, plus superb build quality and a very comfortable fit, added up to a Class A listening experience. I was sorry to have to return them. If you've got plenty of money and a music-loving kid in college, you could give him or her a heck of a dorm-room hi-fi.—Michael Fremer