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Educational Series

Electrons - A basic education series from AEI Mazda An excellent introduction from first principles.

Mullard Circuits for Audio Amplifiers Designs from Mullard's Valve application lab.

Some Important British Valves Keith Thrower's selection of landmark developments

Understanding Audio A comprehensive tutorial.

Use of Valves Safety precautions to prevent over-running.

Valve Technology A practical series of artilces published in the Maplin Magazine in 1993

 

Audio Amplifier Designs

A 1 kW Audio Amplifier.

An Economical 3-Valve Audio Amplifier. A basic design with valve alternatives

An EF91 Audio Amplifier.

Audio Amplifier Testing. Sine and squre wave testing using an oscilloscope

Audio Distortion. Types of distortion and causes

 

Brimar 25P1 Amplifier. A 25 Watt design and praise from John Linsley Hood.

Choosing an Output Transformer.Radio Constructor, September, 1951

The Cooper-Smith Bantam 3-4 Watt Amplifier. Radio Constructor, September, 1960

The Cooper-Smith Magnum 20 Watt Amplifier. Radio Constructor, February, 1961

Design for a 50 Watt Amplifier - Main Amplifier. A GEC/M-OV KT88 circuit. Wireless World, April 1957

 

Design for a 50 Watt Amplifier - Pre Amplifier. A GEC/M-OV KT88 circuit. Wireless World, July 1957

Double Triodes and Guitar Amplification. A guide to Types and their suitability.

Double Two Audio Amplifier. A design using the ECC83 and ELL80.

Economical 50 Watt Amplifier. New ratings for KT66. Wireless World, December 1948

Experimental Audio Amplifier. ECC83 and ECC82 as push-pull output valve

 

A Hybrid Audio Amplifier. A 'proper' hybrid with valve output stage

High Quality 10 Watt Ultra-Linear Amplifier. A design for home construction

High Quality Audio Amplification. A chapter from Mullard circuits for audio amplifiers

High Quality Sound Reproducer. Osram 912 amplifer. Wireless World, September 1954

A Low Cost Valve Amplifier. A design from 1969 published in Practical Wireless

 

The 'Microamp'. A two stage SE design

The Mullard 3-3 Audio Amplifier. The original design

The Mullard 5-10 Audio Amplifier. The original design

The Mullard 5-20 Audio Amplifier. The original design

The Mullard ECL86 10 Watt Stereophonic Audio Amplifier. The original design

 

The Mullard ECL86 3 Watt Economical Stereophonic Audio Amplifier. The original design

The Mullard Stereophonic Pre-amplifier. The original design

A New Phase-Splitter. A better long-tail pair

The Neophyte Amplifier. A beginners design with full assembly details

The Osram 912 Amplifier. The circuit and GEC metal-cone loudspeaker

 

The (Osram) Junior Amplifier. A five Watt amplifier to complement the 912

The (Osram) Williamson Amplifier. The original design plus the revised version

A Push-Pull EL91 Audio Amplifier. A suggested circuit by G A French. A working example.

A QQV03-20A or QQV07-50 based Audio Amplifier. Circuit ideas for constructors.

Simple DC Heater Supply for EF86 etc. An ingenious approach to hum reduction.

 

A Small High Quality Amplifier.Using a triode push-pull transformer in a single end design

Small Audio Amplifier. Simple construction with full details

Some Notes on Phase-Splitters. Types of phase-splitters compared

The Stereoplex. A simplex stereo amplifier

A Ten Watt Amplifier With Just Four Valves. A design from 1984 published in Elektor Electronics

 

A Three Valve 9 Watt Amplifier. A suggested design from 1960

Transformerless Output Stages Review article from February 1957

Transformerless Output Stages, More details Review article from March 1958

VA-12: A 20 Watt EL506 amplifier. A design from 1967 from Thorn-AEI Applications Laboratory. See EL506 exhibit.

Valve Technology The final article has five amplifier designs

 

The 'Virtuoso' Design for an 11 Watt Hi-FI amplifier

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Valve Basics

Interpretation of Valve Data

The Meaning of Valve Codes

STC Valve Codes, Mullard Receiving Valve Codes & Mullard Transmitting Valve Codes

Valve Cathodes and The use of Thoria

 

The Valve The elementary principles explained - in 1923.

The Diode The most basic configuration used first as a detector by Fleming .

The Triode A valve with one grid originated by de Forest .

The Bi-grid The first two grid valve.

The Tetrode The original screened grid valve. The SG Valve (explained in 1931.)

 

The Pentode A valve with three grids that overcame tetrode secondary emission. Patented by Mullard/Philips

The Beam Tetrode A different approach to reducing secondary emission and to circumvententing the Mullard patent.

The Hexode A valve with four grids

The Heptode The Pentagrid Converter with five grids

The Octode The valve with six grids

 

The Nonode The valve with seven grids

The Magic Eye The valve tuning indicator

The Cathode-Ray Tube The heart of display systems

The Heil Tube Microwave energy generator

The Magnetron A diode in a magnetic field

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General Articles

100 Metres and Below The evolution of the ultra short wave

1934 - Frequency Changing From the Mullard 1934-35 Valve catalogue

1934 - Mullard 2 Volt Battery Valves From the Mullard 1934-35 Valve catalogue

1934 - Mullard AC Mains Valves From the Mullard 1934-35 Valve catalogue

1934 - Mullard Universal Valves (AC/DC) From the Mullard 1934-35 Valve catalogue

 

A Dynamic Mutual Conductance (gm) Analyser The Radio Constructor, June, 1956

A General Purpose EF50 Circuit B9G The Radio Constructor, October, 1954

A Magnetic Digital Storage System Electronic Engineering, July, 1949

A Practical CV172 Noise Generator The Radio Constructor, August, 1956

Amplifying Crystal The Transistor: New from Bell Labs. Wireless World, October 1948

 

Aspects of Design Application notes from Mazda. AEI 1960

Automatic Receiver Production Details of the ECME system

        Automatic Circuit Production Proposed improved system from 1956

Automatic Volume Control. Basics and the Wunderlich valve

Basic Introduction to the Valve From a beginners series in 1966

Basic Technical Aspects of Valves How a valve works

 

BBC Television A history of the first public service. Published in 1948.

The Cathode-Ray Microscope A 1939 article detailing the principles of operation.

Choke or Capacitor Input? Significance of the two systems in power supplies.

The Dawn of Broadcasting in the UK The earliest history of Radio Broadcasting

Eckersley's Baby Brookman's Park BBC Transmitter in 1929

 

Electron Multipliers An avalanche of electrons

The Evolution of Our Photographs See how digital photography compares to film

The First Airborne Radar. From a roomfull to a doorknob

The First All Valve Computer. The Colossus rebuild at Bletchley Park

The First Kurhaus Radio-Concerts. Part of the history of Dutch broadcasting

 

Professor Sir John Ambrose Fleming

Pioneer. A short biography of Sir John Ambrose Fleming.

The Origin of the Valve. A few words from the inventor.

How I Invented the Thermionic Diode. Details from the inventor.

 

Focusing Cathode Rays. An explanation of electron optics from 1954

Forward Projection in the Home. Converting a rear-projection TV Chassis

The Four-Electrode Valve. A one valve radio with a space-charge (bi-grid) grid valve

The History of the UK Valve, 1904-1925 An excellent book - a `must have'

The History of the UK Valve, 1926-1946 An excellent book

 

How Little Distortion can we Hear A mathematical analysis from 1957

How To Build a Two Valve Set A practical project from cigarette cards in 1929

How To Make a Valve Amplifier A practical project from cigarette cards in 1924

How To Make Your Own Wireless A practical project from cigarette cards in 1924

Klystrons and Microwave Triodes A PDF file of a 1946 book

 

Locked Oscillator Discriminator The EH90 TV FM sound demodulator

Magnetophon Recorders Processes involved in manufacturing the tape

The Manufacture of Ebonite Materials and processes for making high-grade ebonite

Marconi the Pioneer Brief account of the early spark gap experiments

Metal Coated Valves Taken from Popular Wireless November 14, 1931.

 

Metals used in Valve Manufacture Taken from Vacuum Tubes by K Spangenberg (1948) 1001 .

The Miller Timebase Circuit Used with a transitron circuit to form a quality timebase

Obtaining High HT Voltages with Standard Transformers. Useful for triode PAs.

The Optics of Projection Television. Early 1950's Mullard system.

Osram Valves.The Osram Miniature Valve Story. An extract from an Osram data book.

 

Osram Valves. The Early Days

Pin Connection aid from Mullard. A slide rule marketing aid and a way to identify unknown valves.

The PL36 in Pictures. We dissect a television line output valve

Reliable Valves and the User. An essay on reliability, by E G Rowe of Brimar Valves.

Sealing of Glass to Other Materials. Taken from Vacuum Tubes by K Spangenberg (1948) 1001 .

 

Sinclair Launches Mini TV The 1983 small flat screen television

The Skin Effect A non mathematical explanation

Stabilisation and Smoothing with Thermionic Valves A better power supply for audio pre-amp or input stages

Stabilised Power Supplies: , Part Two , Part Three & Appendix Designs by M G Scroggie, Wireless World, 1948

The Story of the Valve This makes a perfect introduction to the valve and its history

 

Tetrodes with Screen Feedback Further light on the Ultra-Linear circuit

The Transitron Circuit Used with a Miller integrator to form a timebase or oscillator

Travelling Wave Tube Amplifiers Theory and practice of these high gain microwave amplifiers

Television Reception on Band V An early look at receiving UHF signals on a domestic receiver

Ultra Linear Operation Reduced harmonic distortion in audio amplifiers

 

Wireless Telephony. Marconiphone equipment from 1920's cigarette cards.

Ultra Linear Output Transformers Stability of ultra linear push-pull output stages at high frequencies

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Valve Specific Articles

The 20 kW Tube The external anode from 1922

American Loctal Valves Characteristics and dimensions - June 1939

Amplification by Secondary Emission The Mullard EE50

Acorn Antiques High Frequency Valves Ready for War

The Arcotron A cold cathode power switch

 

An Acorn Valve Datasheet From a valve packed in 1936

An Introduction to Valve Construction From Maplin Magazine, January, 1994.

The Beam Tetrode. Re-published from The BVWS Buletin Vol 33 No. 2.

The Bi-grid Valve. A needless invention?

Choosing a Valve Thoughts of Brian Dance in 1960

 

Choosing a Videcon A summary of various tubes based on the vidicon.

The Class B Audio Amplifier New battery output stage

A Classic Unmasked The inside of an EL37 output pentode

Class B Amplification Choosing the right components for the driver stage

Cold Cathode Trigger Tubes What they are and how to use them

 

Corona Voltage Stabilisers What they are and how to use them

The Double-Diode Triode A new type of multi-valve - in 1933

The Early Cossor 'Tin Hat' Valves Cossor's 1922-1925 ranges

EE50 Operation A secondary emission pentode explained.

The EF80, Making thereof. Mullard produced a boxed set of components and a film

 

The EF91. not the valve that won the war

The EM34 in Pictures A range of implementations for this tuning indicator

EM87 - A new voltage-level indicator for tape recorders. From Mullard Outlook September 1961.

The Famous EF50 Valve of WW2. How Television helped the seeing eye of RADAR

Footless Valves. New Tungsram range from 1939

 

Frame Grid Valves. Brian Dance explains

Frame Grid Valves. Direct replacements or not?

The French 'R' Valve. The origins of the famous R Type

Gas Filled Counting Tubes. The Dekatrons

The Gated-Beam Valve. Quite special

 

German Valves from WWI. An article by Andy Cowley

Grid Current and Grid Blocking. An explanation by Brian Dance

HF Pentodes. An explanation of multi-grid HF valves from 1933

Image Orthicon Camera Tubes. Principles of operation

The Latest Octodes. The EK3 from 1939.

 

Locked-seam Cathodes A new technique for Mullard TV Valves

Mazda Output Triode PP3521 A new audio output valve for DC mains sets

Metal Striptease! We undress an American 6J5

The Metal Valve A contemporary account of the Catkin valve.

Mullard PL500 Line Output Valve Introducing the Cavitrap anode.

 

The Mullard Twin-Panel Picture Tube Bonded face-plate construction.

The New EL34 Audio Pentode. The original press release details

New Mullard Television Valves. From Mullard Outlook in 1962

New Tubes for Old. CRT re-gunning in 1958

New Valves for Stereo Output. The ELL80 and 6DY7

 

Nuvistor Valves. Innovation at the end of the valve era

PC88 - UHF Tuner Valve. Mullard introductory description.

A PC97 Tutorial. An extract from an In Your Workshop feature.

The Pentode. A 1933 article by Stanley Mullard.

PFL200 from Mullard. A double pentode on a B10B base.

 

Planar Electrode Valves for VHF. A 1952 article from Wireless World.

The Round Valves. A brief history of Captain Round's valves.

The R4, R4A, R4B and R4C. A specialist WWI valve series for heterodyne receivers.

Small Power Valves. Designs for specific applications - 1955.

Special Quality Valves. 1955 Progress report by Brimar engineering division.

 

Storage Cathode-Ray Tube. An article from 1953 on CRTs as computer memory.

The Tunograph. The first 'Magic Eye' tuning indicator?.

Valve Cathode Life. An article from 1951 about cathode resistance.

Valves and Their Habits. An article from 1965 on valve operating behaviour.

Valves for Band III, IV & V. An article from 1954 on UHF valve design.

 

Valves for Microwaves. An article from 1953 on how microwave valves work.

Valves for Single Sideband Reducing ageing in balanced modulators

Valves in PA Equipment. An article from 1937.

Which Valve Shall I Buy? A guide from March 1924.

Wooden Crates for Large Valves. Examples.

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Subject Themes

The Cathode-Ray Tube Articles on CRTs.

Stereo? Articles on Stereophony.

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Enabling Technology Articles

The Sprengel Vacuum Pump From Chemistry World February 2008

The Gaede Diffusion Vacuum Pump From Chemistry World May 2009

Last updated April, 10, 2017.
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