One Thing Audio
Quad
Reviews, ESL 57, A return to Form
A return to form
Do you lust after Quad's ESL 57 electrostatics but worry about the lack of servicing? Jon Marks seeks restorative help from Classique Sounds and One Thing.
The three short legs fitted by Quad to the ESL 57 do a fair job but the loudspeakers sound a lot happier when they're higher off the floor on solid stands.
Ah, serial numbers 12599 and 12273, you have indeed seen better days. The miserly sum of £1OO made you both mine, but I have to say you possess all the sparkle, life and speed of a wet blanket. Connected to my favourite CD player, turntable and amplification, you had me wondering at the fuss surrounding ESL 57s.
If this rings bells with you, you've obviously been through the same anti-climax of purchasing a pair of Quad's vintage super-'speakers in less than mint condition. As Haden Boardman comments in Vintage Virtues this month, even when they're only pale schadows of their former selves, ESL 57s can still sound better than a lot of other loudspeakers. The problem is, with Quad no longer servicing these electrostatics, where can you have a poorly pair spruced up?
We decided to get a test set of ESL 57's fully refurbished by Classique Sounds / One Thing Audio. 12599 and 12273 were duly handed over for diagnosis. As the list of woes said, the 'speakers were "working but sounding tired". This was a bit of an understatement as there seemed to be precious little treble above 4kHz or 5kHz, all the crispness and pizzazz of a month-old lettuce and bass that was murky and indistinct.
On the bench some typical ailments showed up. The blocks which supply the panels with their Extra-High Tension voltages (6kV for the bass and 1.5kV for the treble) were down on one 'speaker and up on the other. This meant new blocks with modern rectifiers (£100 per pair).
A new patient prepares to undergo examination.
None of the panels were torn or burned, but the bass stators were well past their prime. Their three separate sections are connected by conductive bridges which often go open-circuit. While the loss of a section won't stop a panel functioning, it means it will take longer to charge and will produce muddier bass. The cure is to clean away the detritus and replace the bridges.Rebuilding and soak-testing bass and treble panels costs £130 each for the former and £150 each for the latter, although not all of them invariably require treatment - nine times out of 10, it's the tweeters that have given up the ghost.
HAPPY TO BE CLAMPED
One sure-fire way of sending '57s to their graves is by over-driving them. Later samples were protected by factory-fitted 'clamp' boards, which prevent input voltages exceeding the 33volts which Quad quote as a maximum. Our examples lacked clamp boards but had escaped damage.Seeing as they were going to be used on the end of a pair of Musical Fidelity X-A200 monoblocs (over 300 watts into 8ohms), ours were duly fitted with CLP1 clamps (£45 per pair).
Classique Sounds offer rebuilt EHT blocks as well as brand new replacements.
If you're going to be driving your '57s with a large solid-state amp, clamp boards are a wise precaution.
Soak testing of rebuilt panels is carried out on the test jig pictured above.WIRED FOR ACTION
Once the major surgery on the moving parts was complete, the wiring loom came in for some attention. Most of the old wire was removed and fresh EHT cable soldered in place. The final stage of servicing involved fitting new 'speaker sockets and testing the input transformers along with their associated crossover resistors and caps. After a thorough valet (£20 per ESL, including relaquering the feet and the side strips, touching up the grille and frame), the Quads were ready for a last listening session before they returned to World Towers.
ELECTRO-ECSTATIC?
After the disappointment of their initial sound, I was hoping for something more promising this time, especially considering our ESL 57s had been given the full treatment, bringing their total cost including purchase up to around £1000.
Having hooked up the Quads to the X-A200s, a battery-powered DPA 50s pre and a Trio L-07D turntable, I gingerly fired them up and allowed them an hour to settle down. The first LP under the DNM Lexe/SME V was Joan Armatrading's Back To The Night.
Some panels, like the bass one to the right, have had a very hard life. On the left is
a rebuilt treble panel.FILM STARS
What emerged from those featherweight diaphragms was superbly crisp and clean across the whole of the frequency range. Cymbals had a speed, clarity and freedom from distortion which only the rarest of esoteric dome tweeters can get close to. Vocals were also untainted by the normal cone and box colorations, the result a natural transparency which really opened up recordings.
Swapping to a modified Pioneer DV-505 DVD player and Talvin Singh's Anokha compilation of Dance music, I homed in on the bass. Positional foibles aside (hunting out the right spot in a room for '57s can be a very time-consuming business), the bottom-end was taut and very nimble. The long-lived myth of the Quads being bassless was also banished, this album's heavier tracks benefitting from a satisfying (if not furniture re-arranging) extension.
As Haden notes in Vintage Virtues, it's the low-frequency 'sludge' which most box loudspeakers pump out that plays a large role in lending their presentation extra weight. Even compared to relatively inexpensive panels like the Magneplanar SMGas (which aren't electrostatics and have higher diaphragm masses) most boxes sound slow, blurred and boomy.
Tori Amos' Boys For Pete with its spiky harpsichord and vocals (which are more shrieked than sung) failed to provoke any nasties in the Quads. In fact, whatever was played through them had a dynamic freedom which made even the sprightly SMGas sound dull and sluggish.
Checking the three bass stator section to ensure continuity across them.
A rejuvenated '57, unclothed to show the central treble and two bass
panels. The input transformer is sitting on the bench.BUY, BUY BABY?
If you're thinking of buying a pair of '57s and having them overhauled, it would probably be more sensible to opt for a cheap, tired set and have the necessary work done (usually just EHT units and treble panels rather than spending £400 on a good but not perfect pair.
Considering our totally revamped ESL 57s cost around £1000, the results more than justify their price tag. Contemporary electrostatics aren't particularly cheap but Classique Sounds' servicing restores the Quads to a position where they can hold their head high in some exalted (for which read expensive) company.
This article first appeared in HiFi World April 1999.
