On 24/07/2022 11:19, Ian Jackson wrote:
> In message <tbj1nq$gm4k$1@dont-email.me>, Tweed <usenet.tweed@gmail.com>
> writes
>
>
>>
>> It is reputed that no one person knows in fine detail how a modern Intel
>> microprocessor works. However, there’s lots of fields where no one person
>> knows how something works in detail.
>
> I recall having to contact my works parent company about problems I
> having getting one of their products to work. The reply was "The guy who
> designed it is dead, and the guy who might possibly have some idea has
> left town".

I know exactly what you mean!

The pharmaceutical company I worked for had a foamed product which was
made in the USA by one guy. Before he retired, they had him write a
detailed description of the process for his replacement to follow. The
new guy tried several times, but the product did not foam correctly.
They got the old guy back and asked him to make a batch while they
watched. Towards the end of the process (where it kept going wrong for
the new guy), with the old guy peering into the reaction vessel, he
"pressed the button" and it worked perfectly. They asked the old guy how
he knew when to press the button to enable the process to work. His
answer? "It looked right".

There's no substitute for experience!

--

Jeff

On Sun, 24 Jul 2022 09:00:42 -0000 (UTC), Tweed
<usenet.tweed@gmail.com> wrote:

>The problem with getting old is that you know how difficult everything is,
>so it is very hard to get motivated to learn new stuff. Happily the
>youngsters aren’t weighed down with this knowledge and thus take easily to
>new things.

The trouble is that although most modern electronics is very
complicated it's still based on fundamental principles. Much of my own
knowledge of these pronciples was gained by practical experience, but
the knowledge that today's kids will be able to gain by practical
experience will mostly be from things that are already built, so how
will they cope when it becomes necessary to design and build new
things from scratch?

Rod.

Roderick Stewart <rjfs@escapetime.myzen.co.uk> wrote:
> On Sun, 24 Jul 2022 09:00:42 -0000 (UTC), Tweed
> <usenet.tweed@gmail.com> wrote:
>
>> The problem with getting old is that you know how difficult everything is,
>> so it is very hard to get motivated to learn new stuff. Happily the
>> youngsters aren’t weighed down with this knowledge and thus take easily to
>> new things.
>
> The trouble is that although most modern electronics is very
> complicated it's still based on fundamental principles. Much of my own
> knowledge of these pronciples was gained by practical experience, but
> the knowledge that today's kids will be able to gain by practical
> experience will mostly be from things that are already built, so how
> will they cope when it becomes necessary to design and build new
> things from scratch?
>
> Rod.
>

Has the maker movement that involves the Arduino and Raspberry Pi passed
you by?

In article <tbg8l1$3o1ha$1@dont-email.me>, Jeff Layman
<Jeff@invalid.invalid> scribeth thus
>On 22/07/2022 21:33, Ian Jackson wrote:
>> In message <jk00q9FqtroU1@mid.individual.net>, williamwright
>> <wrightsaerials@f2s.com> writes
>>> On 22/07/2022 09:14, Brian Gaff wrote:
>>>> We never knew back then that we were living through an all too short
>golden
>>>> period of TV dx.
>>>
>>> Indeed.
>>>
>> I think that the period from around 1950 to 1980 was a golden age for
>> all sorts of electronic hobbies. Loads of war surplus gear and a vast
>> quantity of components that you could work with. And you could also
>> really understand how things worked. These days, you can't get the bits
>> any more, or it's all done for you (or at least just modules that you
>> can connect together), or you simply can't do it any more.
>
>+1
>
>As a teenager I was often browsing around the electronic surplus shops
>in Tottenham Court Road and Lisle Street in London. I guess other big
>cities had shops of that sort too.
>

Even here in Cambridge we had H. Gee in Mill road who sold no end of
stuff, used to spend most all of my pocket money there in the Sixties!

Few years ago it burnt down, there were thousands of cassette player
belts in there, pitiful to see it all go up and its still in its burnt
state!..

https://goo.gl/maps/NLAN4KHUKqDM3Hz26

--
Tony Sayer

Man is least himself when he talks in his own person.

Give him a keyboard, and he will reveal himself.

In article <tbgmn8$3rhq4$1@dont-email.me>, Brian Gaff
<brian1gaff@gmail.com> scribeth thus
>Gw Smith, Laskys, yes the original, and in other streets Proops of course
>for all their novelties.
> We used to have in Kingston a shop called Southern Surplus, and the floor
>was rotting but it was piled high with gear from the forces, redundant stock
>and returns etc, much fun to be had.
> Brian
>

Up in Lincolnshire Birketts of the street is still there after all those
years!

https://goo.gl/maps/g8Vvdrh8qGdjMuWh8

Is it was it Johns radio in Leeds?, still around?...

--
Tony Sayer

Man is least himself when he talks in his own person.

Give him a keyboard, and he will reveal himself.

On 24/07/2022 21:40, tony sayer wrote:
> In article <tbgmn8$3rhq4$1@dont-email.me>, Brian Gaff
> <brian1gaff@gmail.com> scribeth thus
>> Gw Smith, Laskys, yes the original, and in other streets Proops of course
>> for all their novelties.
>> We used to have in Kingston a shop called Southern Surplus, and the floor
>> was rotting but it was piled high with gear from the forces, redundant stock
>> and returns etc, much fun to be had.
>> Brian
>>
>
>
>
> Up in Lincolnshire Birketts of the street is still there after all those
> years!
>
> https://goo.gl/maps/g8Vvdrh8qGdjMuWh8

That's 3 years old.

John Birkett died three months ago. Anyone know if the shop is still open?

--

Jeff

On Sun, 24 Jul 2022 13:39:24 -0000 (UTC), Tweed
<usenet.tweed@gmail.com> wrote:

>Roderick Stewart <rjfs@escapetime.myzen.co.uk> wrote:
>> On Sun, 24 Jul 2022 09:00:42 -0000 (UTC), Tweed
>> <usenet.tweed@gmail.com> wrote:
>>
>>> The problem with getting old is that you know how difficult everything is,
>>> so it is very hard to get motivated to learn new stuff. Happily the
>>> youngsters aren?t weighed down with this knowledge and thus take easily to
>>> new things.
>>
>> The trouble is that although most modern electronics is very
>> complicated it's still based on fundamental principles. Much of my own
>> knowledge of these pronciples was gained by practical experience, but
>> the knowledge that today's kids will be able to gain by practical
>> experience will mostly be from things that are already built, so how
>> will they cope when it becomes necessary to design and build new
>> things from scratch?
>>
>> Rod.
>>
>
>Has the maker movement that involves the Arduino and Raspberry Pi passed
>you by?

Arduinos and the like are full of ready made electronics. I'm sure
they can teach a lot about digital logic, but possibly not so much
about the behaviour of electrical signals in cables or through the
air. You just plug one ready made circuit module to another using
ready made cables with the plugs already attached, and assume that the
signals will just arrive where they should, unharmed. No need to worry
about impedances or balancing or matching. No need to calculate things
like component values or power dissipations. Just rely on the makers'
specifications and assume everything will work.

Rod.

Roderick Stewart <rjfs@escapetime.myzen.co.uk> wrote:
> On Sun, 24 Jul 2022 13:39:24 -0000 (UTC), Tweed
> <usenet.tweed@gmail.com> wrote:
>
>> Roderick Stewart <rjfs@escapetime.myzen.co.uk> wrote:
>>> On Sun, 24 Jul 2022 09:00:42 -0000 (UTC), Tweed
>>> <usenet.tweed@gmail.com> wrote:
>>>
>>>> The problem with getting old is that you know how difficult everything is,
>>>> so it is very hard to get motivated to learn new stuff. Happily the
>>>> youngsters aren?t weighed down with this knowledge and thus take easily to
>>>> new things.
>>>
>>> The trouble is that although most modern electronics is very
>>> complicated it's still based on fundamental principles. Much of my own
>>> knowledge of these pronciples was gained by practical experience, but
>>> the knowledge that today's kids will be able to gain by practical
>>> experience will mostly be from things that are already built, so how
>>> will they cope when it becomes necessary to design and build new
>>> things from scratch?
>>>
>>> Rod.
>>>
>>
>> Has the maker movement that involves the Arduino and Raspberry Pi passed
>> you by?
>
> Arduinos and the like are full of ready made electronics. I'm sure
> they can teach a lot about digital logic, but possibly not so much
> about the behaviour of electrical signals in cables or through the
> air. You just plug one ready made circuit module to another using
> ready made cables with the plugs already attached, and assume that the
> signals will just arrive where they should, unharmed. No need to worry
> about impedances or balancing or matching. No need to calculate things
> like component values or power dissipations. Just rely on the makers'
> specifications and assume everything will work.
>
> Rod.
>

But that’s the beauty of things digital. You are worrying about where kids
start. They aren’t going to start by worrying about the things you list,
and probably never have. Those that get their interest piqued might go on
to study engineering. There you will learn about the darker arts. You are
forgetting all the things you never learnt as a hobbyist with war surplus.
Nothing digital, no programming, no coding for FPGAs etc, no digital signal
processing. Electronics has changed over the years.

In article <280qdh1pf6vgvkp826n11s7aondiv9gi8j@4ax.com>, Roderick Stewart
<rjfs@escapetime.myzen.co.uk> wrote:

> Not quite all of it. Somebody must be designing those blob circuits, so
> there's probably about a dozen people in the entire world somewhere who
> still know how stuff actually works. Goodness knows how the next
> generation of youngsters are going to learn it though.

IEEE Spectrum magazine has a "DIY" project in each issue. However it almost
always now involves something like a Raspberry-Pi-alike along with some
soldering and use of a computer controlled 'maker'/ 3D 'printer' to produce
mech parts. So the knowledge base and kit required to get started are tab
above what a teenager looking through boxes of 2nd hand valves might have
had.

e.g. recent issue's example was a Knipkov (spelling?) Disc video camera
where the disc was 'printed' to have square holes!

Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics https://www.st-andrews.ac.uk/~www_pa/Scots_Guide/intro/electron.htm
biog http://jcgl.orpheusweb.co.uk/history/ups_and_downs.html
Audio Misc http://www.audiomisc.co.uk/index.html

On 24/07/2022 11:19, Ian Jackson wrote:
> In message <tbj1nq$gm4k$1@dont-email.me>, Tweed <usenet.tweed@gmail.com>
> writes
>
>
>>
>> It is reputed that no one person knows in fine detail how a modern Intel
>> microprocessor works. However, there’s lots of fields where no one person
>> knows how something works in detail.

How could any one know the fine detail at all levels, and in reality
they no longer need to. Just we we stopped writing commercial programs
in assembler code and now use high level languages for all

>
> I recall having to contact my works parent company about problems I
> having getting one of their products to work. The reply was "The guy who
> designed it is dead, and the guy who might possibly have some idea has
> left town".
>>
>
>>
>

On 24/07/2022 11:19, Ian Jackson wrote:
> In message <tbj1nq$gm4k$1@dont-email.me>, Tweed <usenet.tweed@gmail.com>
> writes
>
>
>>
>> It is reputed that no one person knows in fine detail how a modern Intel
>> microprocessor works. However, there’s lots of fields where no one person
>> knows how something works in detail.
>

They don't need to. Any complex chip is designed using high level logic
description languages so the functionality is fully documented and can
me learnt and understood by new designers.

> I recall having to contact my works parent company about problems I
> having getting one of their products to work. The reply was "The guy who
> designed it is dead, and the guy who might possibly have some idea has
> left town".
>>
>
>>
>

In article <tbj1nq$gm4k$1@dont-email.me>, Tweed
<usenet.tweed@gmail.com>
wrote:
> The problem with getting old is that you know how difficult everything
> is, so it is very hard to get motivated to learn new stuff.

My response hase been different. The more I have discovered, the keener I
have become to find out more. 'New stuff' is interesting - more so when you
can appreciate how impressive the way it was discovered is understood.

> Happily the youngsters aren't weighed down with this knowledge and thus
> take easily to new things.

....alas, that can mean 'learning' what they 'like' in the twitter-sense.
Which can often be nothing like genuine learning about 'stuff' that
requires some study and relates to mere reality. As access to reliable and
useful info has grown, so has a flood of dribble and fasionable 'likes'.

Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics https://www.st-andrews.ac.uk/~www_pa/Scots_Guide/intro/electron.htm
biog http://jcgl.orpheusweb.co.uk/history/ups_and_downs.html
Audio Misc http://www.audiomisc.co.uk/index.html

In article <6GRdf3Li4a3iFwt+@bancom.co.uk>, tony sayer
<tony@bancom.co.uk>
wrote:

> Is it was it Johns radio in Leeds?, still around?...

That name rings a bell. IIRC we(1) bought a 100GHz IEP(?) frequency counter
from them second-hand.

(1) = my old research group. mumble decades ago.

Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics https://www.st-andrews.ac.uk/~www_pa/Scots_Guide/intro/electron.htm
biog http://jcgl.orpheusweb.co.uk/history/ups_and_downs.html
Audio Misc http://www.audiomisc.co.uk/index.html

On 24/07/2022 09:24, Roderick Stewart wrote:
> On Sat, 23 Jul 2022 12:51:51 -0000 (UTC), Tweed
> <usenet.tweed@gmail.com> wrote:
>
>>> But even that doesn't have the circuit diagram.). I also tried to get an
>>> old Cossor 3339 oscilloscope working, but could not get it to scan.
>>> Today, you'd get a module, often with unmarked or anonymised ICs, or
>>> buried under a blob of epoxy resin. What fun is there buying from eBay,
>>> other than you not knowing exactly what you might be getting from a
>>> Chinglish description?
>>>
>>> In the Electronics Surplus shops you could look at and pick up all sorts
>>> of equipment that you had no idea of what it was or what it did, and
>>> often the shop owner didn't either. It was a journey of discovery, and
>>> /you/ did the thinking, not someone else doing it for you with a
>>> ready-made kit.
>>>
>>
>> There a lot of room for thinking, there’s endless small developer kits with
>> microcontrollers and even FPGAs if you really want to exercise the brain
>> cells. The world has moved on.
>
> Not quite all of it. Somebody must be designing those blob circuits,
> so there's probably about a dozen people in the entire world somewhere
> who still know how stuff actually works. Goodness knows how the next
> generation of youngsters are going to learn it though.

It's a matter of degree. Enthusiasts never had to make their own valves
or transistors.

--
Max Demian

On Monday, 25 July 2022 at 13:36:17 UTC+1, Max Demian wrote:
> On 24/07/2022 09:24, Roderick Stewart wrote:
> > On Sat, 23 Jul 2022 12:51:51 -0000 (UTC), Tweed
> > <usenet...@gmail.com> wrote:
> >
> >>> But even that doesn't have the circuit diagram.). I also tried to get an
> >>> old Cossor 3339 oscilloscope working, but could not get it to scan.
> >>> Today, you'd get a module, often with unmarked or anonymised ICs, or
> >>> buried under a blob of epoxy resin. What fun is there buying from eBay,
> >>> other than you not knowing exactly what you might be getting from a
> >>> Chinglish description?
> >>>
> >>> In the Electronics Surplus shops you could look at and pick up all sorts
> >>> of equipment that you had no idea of what it was or what it did, and
> >>> often the shop owner didn't either. It was a journey of discovery, and
> >>> /you/ did the thinking, not someone else doing it for you with a
> >>> ready-made kit.
> >>>
> >>
> >> There a lot of room for thinking, there’s endless small developer kits with
> >> microcontrollers and even FPGAs if you really want to exercise the brain
> >> cells. The world has moved on.
> >
> > Not quite all of it. Somebody must be designing those blob circuits,
> > so there's probably about a dozen people in the entire world somewhere
> > who still know how stuff actually works. Goodness knows how the next
> > generation of youngsters are going to learn it though.
> It's a matter of degree. Enthusiasts never had to make their own valves
> or transistors.
>
> --
> Max Demian

I made my own diode, from a small lump of galena I found in the Ochils and literally created my own crystal set. Wound the coil too, but the capacitor was bought. It worked, but OTOH a factory made diode was a lot better.

On 28/07/2022 20:23, R. Mark Clayton wrote:
> I made my own diode, from a small lump of galena I found in the Ochils and literally created my own crystal set. Wound the coil too, but the capacitor was bought. It worked, but OTOH a factory made diode was a lot better.

When my dad was in the RAMC and was in Italy in the war home-made
crystal sets were common. They used blue razor blades as detectors.

Bill

"williamwright" <wrightsaerials@f2s.com> wrote in message
news:jkguf6Fig7pU1@mid.individual.net...
> When my dad was in the RAMC and was in Italy in the war home-made crystal
> sets were common. They used blue razor blades as detectors.

What is special about the razor blades being blue? Were there different
types, colour-coded, with the blue ones found to be best as detectors
(diodes)? A quick google doesn't bring up any references to the phrase,
other that showing photos of razors with blue handles and references to
Gillette's "Silver Blue" blades which seem to be a brand name.

On Fri, 29 Jul 2022 03:20:20 +0100, williamwright
<wrightsaerials@f2s.com> wrote:

>On 28/07/2022 20:23, R. Mark Clayton wrote:
>> I made my own diode, from a small lump of galena I found in the Ochils and literally created my own crystal set. Wound the coil too, but the capacitor was bought. It worked, but OTOH a factory made diode was a lot better.
>
>When my dad was in the RAMC and was in Italy in the war home-made
>crystal sets were common. They used blue razor blades as detectors.
>
>Bill

My first home made radio used a ready made diode, but I still remember
the thrill of realising I'd put such a thing together and it actually
worked, and not only that but I'd made it having seen the design and
description in a book and understood *how* it worked.

I could see from the schematic in the book that apart from an
earphone, the working of which I already knew, the radio proper
consisted of only three components - a coil, a capacitor and a diode -
and the rest was just wire. Seing how simple it was, I thought "Even I
could understand that", which is what inspired me to read the
explanation more carefully and have a go at building one.

Subsequently I messed about with lots of radio circuits, often winding
my own coils with whatever I had, and realised that at a pinch I could
have made my own tuning capacitors too, out of baking foil and paper
perhaps, and possibly a diode from a lump of coal or a couple of rusty
nails, so I could have made the whole thing from very basic components
and understood what every one of them did.

The first integrated circuits I used contained circuitry for things I
had already had experience of building using discrete components, so
there was no mystery about them; they just saved a bit of work. I had
even made logic circuits out of relays, where you could actually see
what they were doing, so no mystery about those either. I consider
myself lucky to have lived through the particular years of electronic
development that I did, because if I were a youngster today I'm not
sure if any of today's ready made mystery boxes that you just plug in
and expect to work would have inspired me in the same way.

Rod.

On 29/07/2022 09:17, NY wrote:
> "williamwright" <wrightsaerials@f2s.com> wrote in message
> news:jkguf6Fig7pU1@mid.individual.net...
>> When my dad was in the RAMC and was in Italy in the war home-made
>> crystal sets were common. They used blue razor blades as detectors.
>
> What is special about the razor blades being blue? Were there different
> types, colour-coded, with the blue ones found to be best as detectors
> (diodes)? A quick google doesn't bring up any references to the phrase,
> other that showing photos of razors with blue handles and references to
> Gillette's "Silver Blue" blades which seem to be a brand name.

Google "World War II" + "crystal sets"

Bill

"williamwright" <wrightsaerials@f2s.com> wrote in message
news:jki3inFo2lfU7@mid.individual.net...
> On 29/07/2022 09:17, NY wrote:
>> "williamwright" <wrightsaerials@f2s.com> wrote in message
>> news:jkguf6Fig7pU1@mid.individual.net...
>>> When my dad was in the RAMC and was in Italy in the war home-made
>>> crystal sets were common. They used blue razor blades as detectors.
>>
>> What is special about the razor blades being blue? Were there different
>> types, colour-coded, with the blue ones found to be best as detectors
>> (diodes)? A quick google doesn't bring up any references to the phrase,
>> other that showing photos of razors with blue handles and references to
>> Gillette's "Silver Blue" blades which seem to be a brand name.
>
> Google "World War II" + "crystal sets"

I've found various references to "blue razor blades" but none that explain
the significance of the colour blue. Were razor blades colour-coded in the
past, in a way that used to signify something - like modern green-top
plastic milk bottles are semi-skimmed and blue ones are full-fat (or is it
totally skimmed?). Or green hoses are unleaded petrol and black ones are
diesel? Were there other colours of razor blade at the time which didn't
work as well as detectors?

On 29/07/2022 16:17, NY wrote:
> I've found various references to "blue razor blades" but none that
> explain the significance of the colour blue. Were razor blades
> colour-coded in the past, in a way that used to signify something - like
> modern green-top plastic milk bottles are semi-skimmed and blue ones are
> full-fat (or is it totally skimmed?). Or green hoses are unleaded petrol
> and black ones are diesel? Were there other colours of razor blade at
> the time which didn't work as well as detectors?

I do not know.

Bill

On 29/07/2022 16:17, NY wrote:
> I've found various references to "blue razor blades" but none that
> explain the significance of the colour blue.

I wondered, when I saw this, if they are talking about an interference
blue colour, due to a very thin oxide layer on the steel, rather than an
actual blue paint.

On Friday, 29 July 2022 at 16:18:29 UTC+1, NY wrote:
> "williamwright" <wrights...@f2s.com> wrote in message
> news:jki3in...@mid.individual.net...
> > On 29/07/2022 09:17, NY wrote:
> >> "williamwright" <wrights...@f2s.com> wrote in message
> >> news:jkguf6...@mid.individual.net...
> >>> When my dad was in the RAMC and was in Italy in the war home-made
> >>> crystal sets were common. They used blue razor blades as detectors.
> >>
> >> What is special about the razor blades being blue? Were there different
> >> types, colour-coded, with the blue ones found to be best as detectors
> >> (diodes)? A quick google doesn't bring up any references to the phrase,
> >> other that showing photos of razors with blue handles and references to
> >> Gillette's "Silver Blue" blades which seem to be a brand name.
> >
> > Google "World War II" + "crystal sets"
> I've found various references to "blue razor blades" but none that explain
> the significance of the colour blue. Were razor blades colour-coded in the
> past, in a way that used to signify something - like modern green-top
> plastic milk bottles are semi-skimmed and blue ones are full-fat (or is it
> totally skimmed?). Or green hoses are unleaded petrol and black ones are
> diesel? Were there other colours of razor blade at the time which didn't
> work as well as detectors?

The blades would probably be steel, and blue is the colour steel goes when partly tempered. I doubt that this was significant other than these were what were available.

IIRC I used regular wire, but given the low band gap in lead sulphide as a semiconductor maybe it was something else.

On 29/07/2022 19:42, R. Mark Clayton wrote:
> The blades would probably be steel, and blue is the colour steel goes when partly tempered. I doubt that this was significant other than these were what were available.

As suggested in my response, I think this is actually the result of an
oxide layer of the order of the wavelength of light.

>
> IIRC I used regular wire, but given the low band gap in lead sulphide as a semiconductor maybe it was something else.

As I suspected, the razor replaces the crystal, not the contact, see
<https://www.etsy.com/uk/listing/707690484/cornell-ww-ii-foxhole-razor-blade>.
I suspect this is a rather controlled instance of the rusty bolt
effect, as mentioned in the caravan aerial thread.

In article <6P-dnStVPqKmE0P_nZ2dnUU7-fWdnZ2d@brightview.co.uk>, Max
Demian <max_demian@bigfoot.com> scribeth thus
>On 24/07/2022 09:24, Roderick Stewart wrote:
>> On Sat, 23 Jul 2022 12:51:51 -0000 (UTC), Tweed
>> <usenet.tweed@gmail.com> wrote:
>>
>>>> But even that doesn't have the circuit diagram.). I also tried to get an
>>>> old Cossor 3339 oscilloscope working, but could not get it to scan.
>>>> Today, you'd get a module, often with unmarked or anonymised ICs, or
>>>> buried under a blob of epoxy resin. What fun is there buying from eBay,
>>>> other than you not knowing exactly what you might be getting from a
>>>> Chinglish description?
>>>>
>>>> In the Electronics Surplus shops you could look at and pick up all sorts
>>>> of equipment that you had no idea of what it was or what it did, and
>>>> often the shop owner didn't either. It was a journey of discovery, and
>>>> /you/ did the thinking, not someone else doing it for you with a
>>>> ready-made kit.
>>>>
>>>
>>> There a lot of room for thinking, there’s endless small developer kits with
>>> microcontrollers and even FPGAs if you really want to exercise the brain
>>> cells. The world has moved on.
>>
>> Not quite all of it. Somebody must be designing those blob circuits,
>> so there's probably about a dozen people in the entire world somewhere
>> who still know how stuff actually works. Goodness knows how the next
>> generation of youngsters are going to learn it though.
>
>It's a matter of degree. Enthusiasts never had to make their own valves
>or transistors.
>

Made a valve once, many years ago and it worked albeit a simple
triode!...
--
Tony Sayer

Man is least himself when he talks in his own person.

Give him a keyboard, and he will reveal himself.