Is there a good book for learning about valves/tubes?

What I can't stand is the quality of the music my (now departed) daughter plays through it. I always loathed the tinny "transistor radio" sound when growing up; this is worse.

Curiously I might find it relaxing to hear one type of "music": the sounds of a waterfall or a cloudburst in the Amazon rain forest.

The latter is famously synthesised by the percussionist Nana Vasconcelos. He gets the audience to clap randomly, slowly at first, then faster, then more slowly.

I once watched a professional percussionist, Dame Evelyn Glennie, see that. Her jaw /literally/ dropped and flapped around.

When I had such intercontinental events discussing 60GHz systems, everything seemed to go smoothly. Didn't bother with video, but did share X-desktops.

I don't know how modern multiparty Zoom parties work.

"My" first machine was a Telefunken TR4, the first commercial micro-programmed machine ever. It was withdrawn from military service and donated to the univ. AEG-Telefunken always was somewhat distinctive, Teak wood panels everywhere and they paid their engineers above average, sort of an aristocratic company. When Daimler-Mercedes bought them, that was quickly rectified & they were soon a me-too company.

The TR4 had 48 bit registers with a neon lamp for each bit. Mostly OC604 / AC122 / 151 / AC157.

< >

Disk drives were Boroughs(?) with > 1m diameter, a 3phase motor and a leather belt between the platters and the motor. And each track had a head of it's own.

But it was able to compile Spice 2G4.

In a certain sense this was my first PC. Operators worked it from 9 to 5 and some of us EE students were allowed to run it for the rest of the time. Sometimes I missed the last train to my home town an hour past midnight. :-)

Cheers, Gerhard

Wiki says the EDSAC 2 (fully operational in 1958) was microprogrammed.

I had a car when I went to university (if you call it that--it was a Fiat 128 with an 1100 cc engine) so I didn't miss any trains, but I did spend some nights in the terminal room hunched over a green glowing 3270 trying to get this Danish observatory's radiative transfer code running.

Good times--teaching myself Fortran while debugging somebody else's code that simulated physics I didn't yet understand. ;)

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs 
Principal Consultant 
ElectroOptical Innovations LLC / Hobbs ElectroOptics 
Optics, Electro-optics, Photonics, Analog Electronics 
Briarcliff Manor NY 10510 

http://electrooptical.net 
http://hobbs-eo.com

OK maybe this helps. I would like to learn enough so I can look at a schematic of basic valve circuits and be able to work out what it is and what it does.

Also very important: You didn't like the road runner joke?

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** So you are never going to answer the question.

..... Phil

All valves require heater power to conduct. All only conduct once the heater is hot. diode: lower i, much higher Vf than silicon. Current limiting under overload triode: same as a fet, but high Va usually required pentode: as triode but the screen grid requires a fair bit of +ve V at lowish i. Pentodes have less Cag & more gain. Hexode, pentagrid etc: bit more complex.

NT

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** Shame about cold cathode tubes then ... ** By pure coincidence, I was looking at max plate I in relation to 6L6GC a nd 6550 types this morning.

The figures are not published in the max listings but some info can be glea ned from sets of graphs. Max available plate current is a function mostly o f screen volts, plus any inherent limits on cathode emission - which varies with tube condition and brand.

For Russian made examples in good condition I found max plate I to be 400 a nd 750 mA respectively, long as the screen supply was 450V or more.

However, a used US made Sylvania 6L6GC was able to pass 550 mA under the sa me ( 50Hz pulse) test conditions.

See link for details of my test set up:

..... Phil

The OP asked for an introduction , obviously there is far more to the subje ct.

and 6550 types this morning.

eaned from sets of graphs. Max available plate current is a function mostly of screen volts, plus any inherent limits on cathode emission - which vari es with tube condition and brand.

and 750 mA respectively, long as the screen supply was 450V or more.

same ( 50Hz pulse) test conditions.

I_max degrades over the valve's lifetime, and the harder you push it the le ss well it lasts. Hence in some apps the valves last & last, and in some ha rder pushed designs they don't. Valves effectively have guidelines.

NT