The Class-A Amplifier Site

This page was last updated on 1 May 2004

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The JLH Class-A Amplifier

 

 

Index

 

Last Updated

The JLH Class-A Articles

 

 

The Original Article - Wireless World April 1969

 

184kB

Oscilloscope Traces & Photographs from the 1969 Article

 

538kB

Letter to the editor - Wireless World October 1969

 

39kB

The Postscript - Wireless World December 1970

 

122kB

The Update - Electronics World September 1996

 

142kB

A Little Reminiscing - Electronics World May 2000

 

16kB

Power Supplies for the JLH Class-A

 

 

An updated, regulated power supply for the 1996 version

 

1 May 2004

A Current Boosted LM317/LM337 Regulator

 

14 October 2001

The Capacitance Multiplier

 

17 May 2001

A Simple Voltage Regulator

 

17 May 2001

Additional Information for the JLH Class-A

 

 

JLH Class-A - Single-ended or Push-pull?

 

23kB 

JLH Class-A Update

 

17 August 2003

 

A JLH Class-A for the Quad ESL57

 

4 February 2002

Design Notes

 

27 November 2002

Transistor Substitutes

 

7 November 2001

D C Voltages (for testing / fault-finding)

 

7 May 2001

Earthing

 

7 May 2001

Constructors’ Comments – Sound Quality

 

5 December 2001

Contributed Articles

 

 

A Dutch journey in JLH-land  (By Rudy van Stratum)

 

19 August 2001

 

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HISTORY:   Page created 04/04/2004

04/05/2001 The April 1969 Original page, photographs and oscilloscope traces moved to separate pages

07/05/2001 Simulation Results, Earthing and DC Voltages pages added

10/05/2001 Quiescent Current and DC Offset page added. Link added to Design Notes page

11/05/2001 Comparison of Versions and Transistors moved to separate page. Simulation Results re-titled Simulations

13/05/2001 A Simple Voltage Regulator page added

16/05/2001 Diagram and equation corrected in A Simple Voltage Regulator page

                   Diagrams in Updated Regulated Supply and Design Notes pages redrawn

                   Diagrams corrected in The Capacitance Multiplier page and simple capacitance multiplier circuit added

17/05/2001 Recommended capacitor sizes updated in The Capacitance Multiplier page

                   Minor text changes and second voltage equation added to A Simple Voltage Regulator page

19/05/2001 Comparison of Versions and Transistors page temporarily withdrawn

20/05/2001 Comparison of Versions and Transistors page reissued

22/05/2001 2N3019 added to Transistor Substitutes page

26/05/2001 New link added to JLH Links page

27/05/2001 Para 2 and simulation results for Tr5 added to Comparison of Versions and Transistors page

                   Reference to BD139-16 added to Transistor Substitutes page

05/06/2001 Design Notes page, polarity of C3 in Figure 2 corrected

24/06/2001 Constructors’ Comments – Sound Quality page added

08/07/2001 Constructors’ Comments – Sound Quality page updated

24/07/2001 Constructors’ Comments – Sound Quality page updated

01/08/2001 New link added to JLH Links page

05/08/2001 Design Notes and Constructors’ Comments – Sound Quality pages updated

14/08/2001 JLH new power supply page updated

18/08/2001 Constructors’ Comments – Sound Quality page updated

19/08/2001 Rudy van Stratum’s article added

09/09/2001 Caution regarding high ft output transistors added to Transistor Substitutes page

                   Figures for MJL3281A removed from Comparison of Versions and Transistors page

14/09/2001 Constructors' Comments - Sound Quality page updated

14/10/2001 Current Boosted LM317/337 Regulator page added. JLH Links page amended

04/11/2001 JLH Class-A for the Quad ESL57 page added

07/11/2001 Transistor Substitutes page updated

18/11/2001 JLH Class-A for the Quad ESL57 page updated

19/11/2001 JLH Class-A for the Quad ESL57 page updated

21/11/2001 JLH Class-A for the Quad ESL57 page updated

22/11/2001 JLH Links page updated

05/12/2001 Constructors' Comments - Sound Quality page updated

31/01/2002 Resistor power rating notes added to JLH for ESL57 and Design Notes pages

04/02/2002 Resistor power rating notes on JLH for ESL57 page revised

27/11/2002 JLH Class-A Update page added. Design Notes page amended

                   Links and redundant pages deleted

28/11/2002 JLH Class-A Update page amended

15/03/2003 Addendum added to JLH Class-A Update page

17/08/2003 JLH Update page amended

02/04/2004 A Little Reminiscing and JLH Class-A Single-ended or Push-pull pages added

01/05/2004 Updated Regulated Supply page amended