Firsts in High Fidelity
Subtitle: The Products and History of H.J.LEAK & Co. Ltd.
Publisher: Audio Amateur Inc.      www.audioxpress.com
Published: January 2000
Language: eng
Format: Paperback
Number of pages: 280
ISBN-13: 9781882580316
Subjects: Science/Mathematics
Description: History of this impressive British audio company and their unique and innovative designs are chronicled with great attention to detail. Includes over 300 illustrations and presents 30 circuit diagrams from the company's product range.


TABLE OF CONTENTS:

Introduction	11

Acknowledgements	12

Foreword	14

1. Personalities	16

Harold Leak	16

Frank Hawkins	20

Ted Ashley	21

Phil Biggs, Fred Blackman and John Leak	23


2. Inception	24

The Beginnings 1924-34	24

1934 to 1945	25

Standard 13 Watt Chassis	29

Standard Telephones and Cables	30

GEC and the Type 15 Point One	31

Negative Feedback and Stability	35



3. Operations	38

Company Structure and Staff	38

Staff Recruitment	39

Staff Numbers	40

Sporting Clubs	41

The Annual Henley Weekend	44

Company Premises	45

Uxbridge Road	46

Out Workers	47

Brunel Road	50

Downham Market	52

Factory Output	53

Quality Control	53

Company Publications	57



4. The TL/12	61

The Birth of Hi-Fi	61

The Move Away from Sub-Contracting	62

Industry Personalities    	64

The TL/12	67

Production Variations	73

RC/PA	76

5. The Leak Idiom	78

Construction Practice	78

Transformers	80

Laboratory Facilities	82

Industrial Design	83

Export Markets	86

American Distribution	87

Australian Distribution	90

Simon Gray Pty Ltd	90

H. J. Leak (Aust) Pty Ltd	92

Other Countries	95

6. More Products	96

Mark 1 Moving Coil Pickup	96

Mark 2 Moving Coil Pickup	98

Stereo Pickup	102

Truspeed Turntable	104

VS-Tuner	107

FM Tuners	109

Trough-Line FM Tuner	110

Trough-Line II	113

Trough-Line 3 and Trough-Line Stereo	115

Equipment Cabinets	119

Portable TL/12 System	121

7. Pre-Amplifiers	123

Evolution and Design	123

RC/PA/U	126

Vari-Slope	126

Steep Cutting Filter	129

Varislope II	130

Point One	131

Varislope III	134

Point One Plus	136

Point One Stereo	137

Varislope Stereo	138

Stereo Adaptor	139

Varislope 2 Stereo and Varislope Mono	140

8. Power Amplifiers	143

Evolution and Design	143

First Stage	143

Second Stage	144

Output Stage	145

Development	146

TL/25 and TL/25A	148

TL/10	150

TL/12 Plus	152

TL/25 Plus	155

TL/50 Plus	158

Stereo 20	160

Stereo 50	162

Stereo 60	164

9. Germanium and Silicon	166

Stereo 30	166

Stereo 70 and Stereo 30 Plus	173

Stereofetic FM Tuner	176

10. Loudspeakers	180

The 550 Loudspeaker	180

The Ionophone, Plessey and the “Duad”	181

Ribbon Speakers	182

Electrostatic Speakers 	184

Leak Sandwich	187

11. Rank-Leak	198

The Selling of Leak to Rank	198

The Rank-Leak Era	199

Leak Delta Series	200

Leak 2000 Series	203

Leak 3000 Series	205

The Finale	208

12. Reference Data	210

Circuit Diagrams	210

RC/PA Pre-Amp	211

RC/PA/U Pre-Amp	212

Vari-Slope Pre-Amp	213

Point One Pre-Amp	214

Varislope II  Pre-Amp	215

Varislope III Pre-Amp	216

Varislope III (Series N) Pre-Amp	217

Point One Plus Pre-Amp	218

Varislope Mono Pre-Amp	219

Point One Stereo Pre-Amp	220

Varislope Stereo Pre-Amp	221

Varislope 2 Stereo Pre-Amp	222

“Point One” Type 15  Power Amplifier	223

“Point One” 30 Watt Power Amplifier	224

TL/12 Power Amplifier	225

TL/10 Power Amplifier	226

TL/25A Power Amplifier	227

TL/12 Plus	228

TL/25 Plus	229

TL/50 Plus	230

Stereo 20	231

Stereo 50	232

Stereo 60	233

Stereo 30	234

Stereo 30 Plus	235

Stereo 70 Amplifier	236

T.R.F. Tuner	237

VS-Tuner	238

Trough-Line FM Tuner	239

Trough-Line II FM Tuner	240

Trough-Line Stereo FM Tuner	241

Stereofetic Tuner	242

Leak Product Listing	245

De-Emphasis Circuits for the Trough-Line Stereo	248

Amplifier Restoration	249

Resistors	250

Capacitors	250

Power Transformers and Chokes	252

Output Transformers	253

Connectors	254

A Modified Sandwich Mark II Loudspeaker	255

Harmonic Distortion	257

Suppliers	258

Leak Internet Resources	258

Leak References	259

Advertisements	261

General Audio Bibliography	262

Index	265