ElectroStatic Solutions offers a wide range of services and parts for maintaining and improving your Quad speakers. No matter the age or condition of your Quad speakers we can return the performance to exact factory specifications. Replacement electronics are exact drop-in replacements for original factory boards that meet or exceed Quad specifications. Elements are rebuilt using the exact materials and processes originally employed by Quad.

Customer Satisfaction Guarantee

ElectroStatic Solutions is committed to customer service and your complete satisfaction with the performance of our products. We maintain a large inventory of parts, replacement electronics, elements and upgrades. Orders ship the day of your order. Complete speaker restorations are typically completed in under two weeks. All of our products and services are backed by an unconditional 30-day money back guarantee of satisfaction and a 3-year service warranty.


Given the excellent performance of either Quad in stock form, one might question the need for upgrades. We are skeptical of most upgrades offered for Quad speakers. In most every case the upgrade actually degrades the performance of the speaker. Some well known modifications essentially destroy the speaker in an attempt to improve performance. This type of upgrade approach is generally ill conceived, poorly executed and vastly over priced. There are ways to improve the performance of the Quad without damaging the speaker or breaking the bank!

Contemplating an upgrade should be done carefully. What is the experience level of the person performing the upgrade? What are the merits of the upgrade? Is the upgrade reverseable? Will the upgrade cause permanent damage or change to the speaker? Is the price in line with the claimed improvements?

We believe that any upgrade should be carried out by a technician that has many years experience servicing Quad speakers. The claims of improvement should not be overstated or exaggerated. While some improvement of performance is possible by upgrades, dramatic change is not. Our upgrades produce subtle but discernible improvements and are nothing more than refinements of an already excellent design executed to a high level or performance. Claims of radical improvement should be met with skepticism.

Further, we believe that any upgrade should be fully reversable and cause no permanent damage or change to the speaker. It is our opinion that upgrades that do not meet the above stated criteria should be avoided.

The best sounding Quad will be a Quad that is working to original specification. Many times improvements are heard with modification simply because the speaker is no longer working to specification. Once the speaker is serviced and returned to original performance levels the perceived improvement of the upgrade or modification quickly disappears. Many times the previously perceived improvement actually degrades the speaker.

ESL63 Updates

The ESL63 was changed many times during its 15 year production run. At serial number 11,601 an improved stator structure was implemented. The USA Monitor/Pro version was introduced at serial number 20,000. The Monitor/Pro version is the exact speaker as before with an improved protective screen; more open, more rigid than the previous screen. Improved protection circuitry with the addition of the zener clamp board and a revised input/spark arrestor circuit was added at serial number 29,000.

All Quads, no matter the age or serial number, can be updated to the current Quad performance standard.

Grille Cloth

ESL63 grill cloth

The easiest improvement any owner can make to the ESL63 is to drop the grille cloth to the base of the speaker. This is simple to accomplish by removing the top wooden cap and rolling down the cloth to the base of the speaker. Transparency, resolution and high frequency extension will be greatly enhanced with the grille cloth down.

Some owners, while enjoying the benefits of running the speaker "nude" do not care for the appearance. We have produced a replacement grille cloth made of audio-grade spandex that is more sheer and audio neutral versus the stock grille cloth. This is the best material we have found that sounds as neutral as no grille cloth. The grille cloth is an exact dimensional copy of the original grille cloth and installs in the same fashion.

Protective Screen

ESL63 protective screen

The ESL63 is delivered with a protective safety screen to prevent any shock hazard from the speaker. While the protective screen does assure safest operation of the speaker it does degrade the overall performance. The improved ESL63 Monitor screen (shown on right) is only 64% open area.

For safety reasons we cannot recommend that owners remove the safety screen for enhanced performance. Removal of the screen exposes the user to voltages that are potentially LETHAL.

A better solution is to replace the screen with an improved version having more open area. Our protective screen (shown on left) is a powder coated black steel screen with 80% open area.

Listening tests confirm that the improved screen is virtually identical to listening without the protective screen. The new screen fits the speaker without any modifications or changes and can be replaced with the original Quad supplied screen at any time if desired.


ElectroStatic Solutions produces a range of replacement electronics for Quad loudspeakers. While our primary goal was to produce electronics that meet the same electrical standard as a factory produced board, during development we took the opportunity to improve the circuit layout and overall parts quality. See our electronics section for further discussion on ElectroStatic Solutions produced electronics.

Standard Rebuild

The ESL63 was first introduced to the market in 1981 and some 36,000 units were produced with production ending in 1996. Service life for the ESL63 is typically between 15-20 years. While many units are still in the field providing wonderful performance for their owners, most units are now approaching the end of their service life and require some level of service to maintain proper operation.

ElectroStatic Solutions will rebuild your ESL63 to bring the performance back to ‘as-new’ condition. We replace, rebuild or rework all major components of the speaker and once completed the owner can expect another 15-20 years of service life from their Quad speakers.

A complete rebuild includes:

  • Eight rebuilt electrostatic elements. For further details on our element rebuild process see our elements section.
  • New ElectroStatic Solutions produced EHT high voltage boards. For further details on our EHT boards see our electronics section.
  • Replacement of all internal damping foam. Nearly 15’ of foam is used to damp internal frame resonances and buzzes. Over time this foam degrades and should be replaced.
  • Replacement of protective screen damping tape. Over 30’ of damping tape is used to wrap the protective screen and attach the screen to the speaker frame. Over time the tape adhesive dries out and requires replacement.
  • New dust covers. While generally the dust cover film itself is in good shape, the adhesive used to attach the film to the dust cover frame looses grip. Dust covers will no longer hold their tension causing sagging, buzzing and rattles.
  • Replacement of internal high voltage wire and delay assembly wire as required.
  • Confirm proper operation of delay line assembly, audio transformers, protection circuitry.
  • New audiophile grade 5-way binding posts.
  • New upgraded grille cloth. Available colors are black or brown.
  • Refinishing wood end caps and renewal of plastic base.
  • 72 hour burn-in. Complete electrical testing including frequency response, resonance, and sensitivity to assure operation to original Quad specifications.
  • 3-year service warranty.

Extended Upgrades

In addition to the standard rebuild ElectroStatic Solutions offers the following upgrades:

  • Improved protective screen. Highly recommended for non-Monitor version speakers and a nice upgrade for Monitor version speakers.
  • Updated protection circuitry. Highly recommended for speakers prior to serial number 29,000.
  • Upgraded Input Board with audiophile grade components. Refer to our electronics section for further details.
  • Upgraded R/C Network board. Refer to our electronics section further details.
  • Add spike feet to speaker base

Have a question about upgrading or rebuilding your electrostatic loudspeakers that hasn't been addressed on our website? Please contact us with any questions you may have.