QUAD ESL 63 Service Manual

1AudioLabsThe Quad ESL RefurbishingPicture BookSheldon D. Stokes [email protected]://www.quadesl.comNovember 3, 2000

10CHAPTER 3. MAJOR PARTS & DISASSEMBLYchapter. The input transformer and crossover is located in the metal box bolted tothe frame base on the left

100CHAPTER 9. IMPROVEMENTS & ADD-ONSR4.000R1.00018.00011.2503.00011.2500.7500.7508.000Quad ESL StandsBy Sheldon D. StokesFeb 6, 1996http://www.qua

10118.50017.50012.2°5.000Speaker Bottom5.0003.000Quad ESL StandsBy Sheldon D. StokesFeb 6, 1996http://www.quadesl.comFigure 9.8: Quad ESL Stand Design

102CHAPTER 9. IMPROVEMENTS & ADD-ONSno impact on the ESL circuit performance. When the voltage across the tube isexceeded, 1500 volts in this case

10379QUAD Parts:Diodes:Zener Diodes:GP02-30BZT03C220Part Specs:Diodes:Zener Diodes:3 KV ???220 Volts 5 WattsSDS Labs Suggested Replacement:CP Clare CG

104CHAPTER 9. IMPROVEMENTS & ADD-ONS

Chapter 10System & Room ConsiderationsThe Quad ESL is an amazingly transparent and detailed speaker. It will easilyshow deficiencies in source comp

106CHAPTER 10. SYSTEM & ROOM CONSIDERATIONSby the pressure field generated by a close proximity to a wall or other large object.If room considerati

Chapter 11Shipping & StorageThe Quad ESL’s are large speakers, there’s no doubt about it. As such, shippingcan be a problem. The speakers aren’t a

108CHAPTER 11. SHIPPING & STORAGE

Chapter 12Needed Supplies & ToolsThere really aren’t any exotic tools needed to repair a set of ESl’s. Patience andcare are the keys to success. A

11Figure 3.1: Removal of Wooden Trim StripsAfter the input transformer screws have been removed. the transformer boxcan be tipped on it’s side and the

110CHAPTER 12. NEEDED SUPPLIES & TOOLSTools:Item Brand UseStretching Jig See Figure 4.10 Diaphragm attachmentRazor Blades SIngle Edge Removing dia

111of the speaker, so the thicker mylar does not impact the speaker performance in anegative way.The ESL Information eXchange provides the expensive a

112CHAPTER 12. NEEDED SUPPLIES & TOOLS

Appendix AQuad ESL Service ManualThe notes in this section are for the guidance of the engineer who has some expe-rience of carrying out repairs to th

114APPENDIX A. QUAD ESL SERVICE MANUALFigure A.1: Quad ESL Components

115No output at allSuspect EHT unit or audio transformer unit after checking more obvious thingslike external connections, not forgetting the leads un

116APPENDIX A. QUAD ESL SERVICE MANUALThe component loudspeaker units of the QUAD electrostatic loudspeaker mustbe handled with the utmost care partly

117Figure A.2: Rectifier Block Types and Connectionsviewed from the rear). This is held in position solely by four screws whoseheads are accessible bel

118APPENDIX A. QUAD ESL SERVICE MANUALTo replace the rectifier block of the EHT unit, undo the two 4BA nuts secur-ing it to the framework of the EHT un

119their positions, and remove the board. Clean all loose dust cover material fromthe wooden frames since any pieces left to flap will buzz.Spread enou

12CHAPTER 3. MAJOR PARTS & DISASSEMBLYFigure 3.2: Cut Grille Grounding WiresFigure 3.3: ESL With Back Grille Removed

120APPENDIX A. QUAD ESL SERVICE MANUALFigure A.3: Input Transformer ModificationFigure A.4: New Style Input Transformer

121Undo the screws all around the periphery of the rear grille and remove thegrille.Tilt the loudspeaker to permit access to the underside of the base

122APPENDIX A. QUAD ESL SERVICE MANUALFigure A.5: Quad ESL schematic

Appendix BESL 63 InformationServing the newer Quad electrostatic speaker, the Quad ESL63, is really beyondthe scope of this book, however rebuilding t

124APPENDIX B. ESL 63 INFORMATIONFigure B.1: Quad ESL63 schematic

Bibliography[1] Sanders, Roger The Sanders Electrostatic Loudspeaker, The Audio Ama-teur, April 1975, pp 18-28[2] Sanders, Roger The Sanders Electrost

13Figure 3.4: ESL Power Supply AssemblyFigure 3.5: ESL Input Transformer Assembly

14CHAPTER 3. MAJOR PARTS & DISASSEMBLYFigure 3.6: Broken Input Banana ConnectorFigure 3.7: Removal of Front Grille Staples

15Figure 3.8: Removal of Front Grille Retaining ScrewsFigure 3.9: ESL With Front Grille Removed

16CHAPTER 3. MAJOR PARTS & DISASSEMBLYFigure 3.10: Removal of Front Grille Foam PaddingFigure 3.11: Removal of Panel Retaining Brackets

17Figure 3.12: Removal of Input Transformer Retaining Screws

18CHAPTER 3. MAJOR PARTS & DISASSEMBLYFigure 3.13: Removal of Power Supply Retaining ScrewsFigure 3.14: Unsolder Power Supply Connections

19Figure 3.15: Unsolder Input Transformer ConnectionsFigure 3.16: Input Transformer Assembly Removed

2Dedicated to my loving and tolerant wife. And my parents who instilled asense of wonder and a confidence to try things that seemed difficult or impossi

20CHAPTER 3. MAJOR PARTS & DISASSEMBLYFigure 3.17: Cut Bias Wiring Insulation

21Figure 3.18: Unsolder Bass Panel ConnectionsFigure 3.19: Removal of Bass Panel

22CHAPTER 3. MAJOR PARTS & DISASSEMBLY

Chapter 4Bass Panels4.1 DisassemblyBoth the bass and treble panels are rebuilt in essentially the same way. The elec-trical connections differ between

24CHAPTER 4. BASS PANELSbias supply wire must be removed, it is attached to a wiring harness and boltedthrough two rivets on the panel. A small screwd

4.2. STATOR INSPECTION AND REPAIR25Figure 4.1: Quad ESL Bass Panelsdifferent stators to be interchanged.4.2 Stator Inspection and RepairBass panel sta

26CHAPTER 4. BASS PANELSFigure 4.2: Removing The Dust CoversFigure 4.3: Un-soldering Rear Bass Stator Wire

4.2. STATOR INSPECTION AND REPAIR27Figure 4.4: Un-soldering Front Bass Stator WireFigure 4.5: Removing The Bass Bias Wiring Harness

28CHAPTER 4. BASS PANELSFigure 4.6: Removing The Bass Stator Insulating TapeFigure 4.7: Drilling A Bass Panel Rivet

4.2. STATOR INSPECTION AND REPAIR29Figure 4.8: Bass Panel DiaphragmFigure 4.9: Removing The Bass Panel Diaphragm

Chapter 1IntroductionThe Quad ESL1, introduced in 1957, has become a true icon in the realm ofhigh performance audio. It was revolutionary when it was

30CHAPTER 4. BASS PANELS4.3 Diaphragm ReplacementAfter the stators have been cleaned and inspected, the next step is to install areplacement diaphragm

4.3. DIAPHRAGM REPLACEMENT31takes a lot of pressure and is real drudgery. The coated area of the diaphragm willturn a darker color and won’t easily wi

32CHAPTER 4. BASS PANELS42.5"18.0"33.5"17.5"8.5"6.0"1/4 x 6" Carrage boltWasher, and Wingnut2" flat corner bra

4.3. DIAPHRAGM REPLACEMENT33Figure 4.11: Diaphragm Stretching JigFigure 4.12: Bass Epoxy Application

34CHAPTER 4. BASS PANELSFigure 4.13: Bass Panel Diaphragm CuringFigure 4.14: Bass Diaphragm Heat Shrinking

4.3. DIAPHRAGM REPLACEMENT35Figure 4.15: Bass Diaphragm Rivet Hole MeltingFigure 4.16: Bass Panel Bolt Tightening

36CHAPTER 4. BASS PANELSFigure 4.17: Bass Panel Insulating Tape ApplicationFigure 4.18: Bass Panel Insulating Tape

4.4. DUST COVER REPLACEMENT374.4 Dust Cover ReplacementThis section is useful as a final step when completely rebuilding panels or if thebass panel is

38CHAPTER 4. BASS PANELSFigure 4.19: Bass Panel Dust Cover Removal4.25. The front stator wire is carefully fed through the hole in the stators andquic

4.4. DUST COVER REPLACEMENT39Figure 4.20: Bass Panel Dust Cover SuppliesFigure 4.21: Bass Panel Dust Cover Supplies

4CHAPTER 1. INTRODUCTIONis unrivaled, even by modern speakers that have the benefit of forty plus years oftechnology advancement and larger final costs.

40CHAPTER 4. BASS PANELSFigure 4.22: Bass Panel Dust RemovalFigure 4.23: Bass Dust Cover Taping

4.4. DUST COVER REPLACEMENT41Figure 4.24: Bass Dust Cover Heat ShrinkingFigure 4.25: Completed Bass Panel Terminal Strip

42CHAPTER 4. BASS PANELS

Chapter 5Treble Panels5.1 IntroductionThe Quad ESL treble panels do not suffer from the degradation over time thataffects the bass panel diaphragms an

44CHAPTER 5. TREBLE PANELSFigure 5.1: An Obvious Treble Panel BurnThe felt pad is stapled to the rear of the treble unit through the wooden strips.The

5.2. DISASSEMBLY45corner rivets, that the stators are not cracked by exerting too much force whendrilling out the rivets.At this point, the two stator

46CHAPTER 5. TREBLE PANELSFigure 5.2: Removing The Rear Felt PadWhen learning the rebuilding technique, it’s not uncommon to have to rebuilda panel se

5.2. DISASSEMBLY47Figure 5.3: Removing The Dust Cover Retaining Screw AssembliesFigure 5.4: Removing The Dust Cover

48CHAPTER 5. TREBLE PANELSFigure 5.5: Removing The Insulating TapeFigure 5.6: Removing The Bias Wire Retaining Screws

5.2. DISASSEMBLY49Figure 5.7: Drilling Treble Panel RivetsFigure 5.8: Treble Panel Burn

Chapter 2General ESL OperationElectrostatic Speakers are conceptually very simple devices, an electrical diagramis shown in figure 2.1. The heart if th

50CHAPTER 5. TREBLE PANELSFigure 5.9: Removing The Old Treble Panel DiaphragmFigure 5.10: Conductive Paint Repair

5.3. DIAPHRAGM REPLACEMENT51Figure 5.11: Grinding Epoxy On Previously Rebuilt Panel5.3 Diaphragm ReplacementThe diaphragm can now be replaced, this is

52CHAPTER 5. TREBLE PANELSFigure 5.12: Treble Panel With Previous Epoxy Ground Offlock lubricant, to a cotton ball and firmly rub the graphite into the

5.3. DIAPHRAGM REPLACEMENT53of the film so that it is lined up on the stator like it was when it was masked off.Then lower the jig so the film touches t

54CHAPTER 5. TREBLE PANELSFigure 5.13: Panel Repaired And Ready To Rebuildcovers, this is shown in figure 5.22. Great care should be taken when testing

5.4. DUST COVER REPLACEMENT55Figure 5.14: Mylar Diaphragm Taped To Stretching JigFigure 5.15: Vacuuming Panels And Mylar Diaphragm

56CHAPTER 5. TREBLE PANELSFigure 5.16: Application of Treble Panel EpoxyFigure 5.17: Smoothing Treble Panel Epoxy

5.4. DUST COVER REPLACEMENT57Figure 5.18: Weighting Panel While Epoxy CuresFigure 5.19: Heat Shrinking Treble Panel

58CHAPTER 5. TREBLE PANELSFigure 5.20: Applying ITO Coating To Treble PanelFigure 5.21: Bolting Treble Panel Together with Bolt Assemblies

5.4. DUST COVER REPLACEMENT59Figure 5.22: Testing Treble Panelplies needed are shown in figure 5.23. These include enough mylar film to coverthe two dus

6CHAPTER 2. GENERAL ESL OPERATIONAudio Signal inPower SupplyStatorDiaphragmInput TransformerFigure 2.1: Basic Electrostatic Loudspeaker Componentsand

60CHAPTER 5. TREBLE PANELSFigure 5.23: Treble Panel Dust Cover Ready To Be Rebuilthave two layers of tape; one from each adjacent side.After all four

5.4. DUST COVER REPLACEMENT61Figure 5.24: Treble Panel Dust Covers Glued To FramesFigure 5.25: Finished Treble Panels

62CHAPTER 5. TREBLE PANELS

Chapter 6Power Supply6.1 IntroductionThe Quad ESL power supply is typically problem when a Quad ESL that has neverbeen abused looses efficiency. This i

64CHAPTER 6. POWER SUPPLYavailable from digikey. The two 750megohm resistors are placed in series makingone 1500 megohm resistor, and this resistor is

6.3. LAMP REBUILD65back into the boxes and the potting wax poured back into the boxes. After theboxes have cooled, they can be reinstalled in the powe

66CHAPTER 6. POWER SUPPLYQuad ESL EHT BlockGndTrebleBassTransSDS LabsPower TransformerTreble Panel (1500v) Bass Panels (6000v)330 kΩ2.2 mΩAll Diodes:

6.4. BULGIN REPLACE67Figure 6.2: Quad ESL Power SupplyFigure 6.3: Unsolder EHT Block

68CHAPTER 6. POWER SUPPLYFigure 6.4: Unscrew EHT BlockFigure 6.5: Replace EHT Screws

6.4. BULGIN REPLACE69Figure 6.6: Wax Ready To Be MeltedFigure 6.7: EHT Boards Removed From Melted Wax

7240v220v120v110vMains In330 kΩ2.2 mΩ1500 PIV0.01 µFRectifier BlockEHT UnitInputLoadingChokeAudio Transformer180 kΩ180 kΩ180 kΩ180 kΩ180 kΩ 180 kΩ150

70CHAPTER 6. POWER SUPPLYFigure 6.8: Cooled Boards Ready To RebuildFigure 6.9: EHT Boards With New Diodes

6.4. BULGIN REPLACE71Figure 6.10: Unsolder Neon Bulb LeadsFigure 6.11: Carefully Removing Neon Bulb Cover Retaining Rivets

72CHAPTER 6. POWER SUPPLYFigure 6.12: Neon Lamp Partsare often sold without the plugs. The need to replace the connectors stems morefrom the inability

6.4. BULGIN REPLACE73Figure 6.13: Unscrew Broken Bulgin ConnectorFigure 6.14: Bulgin and IEC Connectors

74CHAPTER 6. POWER SUPPLYFigure 6.15: Grinding Round Hole For A Square PlugFigure 6.16: Installed IEC connector

Chapter 7Input TransformerThe Quad input transformer is an essentially trouble free portion of the speakers.The audio input jacks are a weak point in

76CHAPTER 7. INPUT TRANSFORMERFigure 7.1: Unsolder Audio Input Jacksufacturing tolerances. So a discharge tube that arcs at a low voltage will protect

77Figure 7.2: Unbolt Audio Input JacksFigure 7.3: Grind Input Jack Holes For A 5-Way Binding Post

78CHAPTER 7. INPUT TRANSFORMERFigure 7.4: Finished Input Transformer (With Gas Discharge Tube)

Chapter 8Wiring & ReassemblyReassembly of the Quad ESL requires reversing the steps taken to disassemblethe speaker. However, extreme care should

8CHAPTER 2. GENERAL ESL OPERATIONDiaphragmStatorsDust Cover FramesQuad ESL Panel (Exploded View)Figure 2.4: Quad ESL Panel block diagram

80CHAPTER 8. WIRING & REASSEMBLYFigure 8.1: Treble Panel Installed In Frameouter lip a bit of a struggle. Care must be taken not to puncture the d

81Figure 8.2: First Bass Panel Installed In FrameFigure 8.3: Second Bass Panel Installed In Frame

82CHAPTER 8. WIRING & REASSEMBLYFigure 8.4: Bass Panels Pushed Into PositionFigure 8.5: Installing the Top Retaining Bracket

83Figure 8.6: Installing the Bottom Retaining BracketFigure 8.7: Panels Installed and Ready To Wire

84CHAPTER 8. WIRING & REASSEMBLYWiringBoth bass panels in the Quad ESL are wired in parallel. This step is performedfirst when reassembling a speak

85for the treble and bass panels. The newer input transformer style is shown at thebottom of figure 8.11. The required connections for the bass and tre

86CHAPTER 8. WIRING & REASSEMBLYFigure 8.8: Soldering Bass Panel WiresFigure 8.9: Insulating Bass Wiring With Heat Shrink Tubing

87Figure 8.10: Soldering Input Transformer ConnectionsFinal Mechanical AssemblyThe front and back grilles can now be reinstalled. First the foam pads

88CHAPTER 8. WIRING & REASSEMBLYBackFrontbassbrownbluegndbassbrownbluegndbassfrontbassbackbluefrontbluebackbrownbackbrownfrontOld StyleNew Style15

89Figure 8.12: Soldering Bias Resistors In PlaceFigure 8.13: Soldering Power Supply Connections

Chapter 3Major Parts & DisassemblyThe Quad ESL is relatively easy to disassemble, but care should be taken not todamage the thin front grille and

90CHAPTER 8. WIRING & REASSEMBLYFigure 8.14: Wiring Neatly Dressed and Ready For Final AssemblyFigure 8.15: Input Transformer Finished and Bolted

91Figure 8.16: Power Supply Finished and Bolted In Placepanel can be easily seen. A simple solution if you have found damage to the basspanels before

92CHAPTER 8. WIRING & REASSEMBLYFigure 8.17: Applying Glue For Front Grille PadsFigure 8.18: Attaching Front Grille Pads

93Figure 8.19: Stapling Rear Felt To Treble PanelFigure 8.20: Screwing The Rear Grille In Place

94CHAPTER 8. WIRING & REASSEMBLYFigure 8.21: Problems Caused By too Long Side Panel ScrewsFigure 8.22: Shortening The Side Trim Strip Screws

Chapter 9Improvements & Add-OnsProbably the biggest two improvements to the Quad ESL’s are elevating them us-ing stands and replacing the fairly o

96CHAPTER 9. IMPROVEMENTS & ADD-ONSFigure 9.1: Cutting Wire Mesh To Size For Replacement Front GrillesFigure 9.2: Bending Wire Mesh To Shape

97Figure 9.3: Attaching The Grille Cloth To The MeshFigure 9.4: Stapling The Grille To the ESL Frame

98CHAPTER 9. IMPROVEMENTS & ADD-ONSFigure 9.5: Suggested Hardware For Stand Mountingfor mounting stands.Figure 9.5 shows one type of possible hard

99Figure 9.6: Drilling Holes For Stand HardwareFigure 9.7: Installed Stand Hardware