Valve Workshop Weekend - Book Here

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The National Museum of Computing

The museum at Bletchley Park is holding a special Valve Weekend on Saturday October 14 and Sunday October 15. Numbers are strictly limited.

TNMoC Valve Workshop - Day 1


Registration and Coffee


Welcome, Timetable, Location of Facilities, Fire Precautions etc.


Valve History


Basic Valve theory, types of valves


Valve coding systems


Health and Safety Radioactive valves, poisonous materials, high voltages


Simple multimeter valve tests


Introduction to valve testing and matching


Other technologies contemporary with valves: relays, CRTs, Dekatrons etc.




Valve circuits in Audio (Charles Coultas)


Power Supplies


Audio amplifiers


Valve circuits in Radio (John Pether)




Visits to EDSAC, WITCH and HEC-1 valve computers


Visit to Tunny and Colossus


Valve circuits in Colossus (Phil Hayes)




Valve circuits in EDSAC (Nigel Bennee)


Wind up and Questions




TNMoC Valve Workshop - Day 2 - Fully Booked


Reminder on Health and Safety with additional information on soldering irons etc.


Description of project kits and decision on which project will be done by each participant:


'Valvesound' guitar pedal


Astable Multivibrator


Ring Modulator ('Dalek' voice changer)


Stereo headphone amplifier


Handing out of kits








Testing, debugging, demonstrating


Wind up, questions




About the Presenters

Steve Kay BA, PGDCCI, MIEEE: worked for OSRAM making electric lamps in the 1970s, but then moved into Computing, specializing in Data Communications and eventually Network Security products as a Principal Test Engineer with HP. My early interest in valves mainly stems from playing bass guitar in pop groups in the 1960s and Country and Western groups in the 1970s. I have a 50W valve amplifier at home which I dust off from time to time. I am currently the Vice-Chairman of the Volunteer Supporters' Association at TNMoC.

Charles Coultas: Played in a school band (lead guitar), Cliff and the Shadows were our inspiration. Used valve amps - EL34 GZ34 ECC83. Learned all about valves at college, there wasn't really anything else in those days. Rediscovered valves when I met Tony Sale at Colossus rebuild. A member of the Heath Robinson rebuild team.

John Pether: joined the then GPO in 1969 as an apprentice. Served 36 years before taking early retirement. During that time I was on internal construction - installing telephone exchange and repeater equipment. Circuit provision which involved providing trunks and junctions between exchanges and the provision of private data circuits. Main interests are: Amateur radio - licensed since 1969 - and model engineering - built and run a 5 inch gauge livesteam locomotive. Member of theColossus rebuild team right from the start and currently working on Heath Robinson.

Phil Hayes: Studied electronics at Brighton in the early 70s, then worked at several large companies and organisations until I moved into data communications in the early 90s. I finished my working career as a Network Security Architect for one of the major clearing banks in the city. My interest in thermionic valves came about when I was involved on the construction of a 1 Megawatt Medium Wave transmitter for the Foreign and Commonwealth Office in the mid 80s. As a volunteer I joined the Colossus Rebuild Project in 2000, and then in 2011, I was approached by the National Museum of Computing, to take on the full time role of Chief Colossus Engineer.

Nigel Bennée: PhD FBCS MInstP Teenage years spent playing with valves. After gaining a PhD in Nuclear Physics had a brief spell working for Ferranti at Bracknell then 11 years for SHAPE Technical Centre in The Hague. On return to England together with his wife ran Lucidata Data Communications Consultancy until a few years ago when retirement and the lure of the EDSAC Replica project has kept him busy exercising old and almost forgotten skills.