Like other Quad mavens, Jacobson didn't set out to become an authority on vintage loudspeakers: He was simply captivated by the first pair of ESLs he heard, and his enthusiasm only grew over the years, bringing him to an even more serious level of involvement. Today, Jacobson's site is a clearinghouse for information on buying, maintaining, repairing, and using Quad's original electrostatic loudspeaker, as well as selecting from among the half-dozen professional and semiprofessional ESL restorers in the English-speaking world.
The subject of all that devotion is a remarkable product, to say the least. The ESL was conceived and designed by Englishman Peter Walker at a time when his firm, the Acoustical Manufacturing Company, had already succeeded with various models of Quad home electronics. (Quad was originally an acronym for Quality Unit Amplifier, Domestic.) But in the mid-1940s, Walker began to work seriously, if intermittently, on creating a practical full-range electrostatic loudspeaker, and in 1955 he unveiled a finished prototype, which wowed listeners at a number of live events.
Regarded from a purely technical point of view, the Quad ESL was extraordinary: a string of notable firsts bundled together in one product. Walker was fortunate to live and work at a time when various plastic films were just coming on the market; with them, he was able to overcome the diaphragm limitations that had hampered earlier attempts by other designers. But Walker was more than just an audio tinkerer who happened to be in the right place at the right time: He was a trained engineer who knew how to roll up his sleeves and hammer away at a problem until it cracked. And the last piece in the ESL puzzle—its unique constant-charge diaphragm system—came about only because Walker knew how to do "the maths," as our English friends would say.
A small pair of fret pullers was the perfect tool for those staples.
Two years after its public debut, "Walker's Wonder" became a commercial reality. For £52, the English audiophile of 1957 could buy a single Quad ESL containing three separate push-pull electrostatic panels. At the core of each panel is a diaphragm of polyester film (12µm thick for the two bass panels, 6µm for the centrally mounted treble panel) coated on both sides with a soluble nylon variant called Calaton and sandwiched between two perforated sheets of PVC, themselves coated with a conductive paint. The latter two elements are the stators, which receive the split-phase music signal from the amplifier by way of an impedance-matching transformer; during use, the stators create a continuously variable electrostatic field that follows the amplified music signal, attracting and repulsing the charged diaphragm.
As conceived, the diaphragm and the front and rear stators in each electrostatic panel are held together with rivets—a quick and easy way of doing things, to minimize construction costs—and that assembly is held firmly in a hardwood frame, covered all around with a polyester film dustcover. (Walker discovered early on that the presence of dust exacerbated the lightning-like condition known as arcing, whereby voltages migrate from one stator to the other, burning the diaphragm and sometimes even the stators themselves in the process.) Although the panels are flat when assembled, they assume a gentle curve when installed in the ESL's open-frame enclosure, which is itself curved from top to bottom. The convex side faces the listener, thus enhancing the line-source tweeter panel's propagation of high frequencies, while bipolar dispersion is inhibited by three layers of wool felt behind the treble panel and a flat lump of jute that's stuck to the inside of the rear grille with a substance that appears to date from the reign of Edward the Confessor: The ESL was designed for use in smallish rooms, and Walker was smart enough to know that most owners would place them closer to rear walls and corners than was ideal.
The sight that greeted my eyes when I pulled the front grill.
Apart from the enclosure and its three electrostatic panels, the ESL contains two other major elements. One is the HT or high-tension unit, which comprises a mains transformer (whose secondary provides more than 600V AC) and a rectifier block, the latter encased in epoxy or wax; the other is an impedance-matching audio transformer, the casework for which also contains an RC crossover network: The Quad ESL is, in fact, a three-way speaker. (Low frequencies are sent to the two bass panels, mids to the whole of the treble panel, and highs to the centermost strip of the latter.)
That's a lot of speaker for £52—and I haven't even mentioned its performance. By an informal count, the Quad ESL appears on more Ten Best lists than any other discontinued product, and I don't think you can name another vintage loudspeaker that's so widely admired, let alone relied on as a reference—let alone competitive with the best of today. The ESL has always been a popular thing: From the time of its introduction until the day in 1982 when Quad quietly pulled the plug, more than 54,000 units were sold. And a lot of them made their way over here.
Quads & caveats
Late last year, I bought a pair of Quad ESLs on eBay. The seller found them at an estate sale in Nashville, and I won the auction with a bid of $660 (uncomfortably close to the retail price of the beast, which contemporary theologians agree would be $665.95), plus shipping and handling. I thought it was a good deal until I saw how much I was being charged just to squeeze two panel speakers and a half-million Styrofoam peanuts into one makeshift cardboard carton: almost $200. If you're buying Quads from someone who doesn't have the original cartons and packing materials, brace yourself.
While I'm on the subject of caveats, here's another: Human nature being what it is, you can probably expect the worst. A few quotes from the eBay description:
"I have powered the speakers up with a Marantz amp, and got sound that was good but not as good as I believe the speakers can be."
"The grills are copper with a few dents and discoloration, but I believe the electrostatic panels have NOT been damaged."
"Not sure of age but I would guess early 60's, that is only a guess!"
So much for Fantasyland. Reality was quite different. The treble panel on one speaker was completely dead (you'll find out why in a moment), and one of the bass panels on the other worked only intermittently. If that's the seller's idea of "good" sound, he must be an audio reviewer. The grilles were an endless maze of dimples and dents, and there was something growing on one of them that looked like the mold on blue cheese. But the seller had the date almost right: My pair turned out to be from 1959, the year Alaska and Hawaii joined the union.
Here's the rear view, with the felt pads still in place.
Still, when I tried them out, those cheesy-looking Quads had some of the selfsame qualities I'd come to expect from my previous ESL experiences. Voices—especially those panned toward the speaker with the working high-frequency panel—sounded uncannily real and there, even more so than with my much-loved Quad ESL-989 speakers. Seriously.
My eBay Quads deserved a new lease on life, but I decided to observe a strict cost limit: $2500 total, including the amount I'd already spent buying the speakers and getting them here. My reasoning: If I can get them to sound as good as the best ESLs I've ever heard for less than $2500—which is to say, just below the price one would pay for a brand-new pair of Merlin VSMs, Spendor SP2/3s, or other very good, very musical speakers—then the trip will have been worth it, and my eBay Quads will clearly be a towering value. Otherwise, as much as I might love them, they'd be little more than an exercise in audio nostalgia.