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An interesting variation.

Postby Steve Anderson » Thu Jun 14, 2007 9:05 pm

Have a look at this site, it's geared towards audio, but still uses tubes at a (comparativley) low voltage using batteries...

http://members.aol.com/sbench/6088pre1.html

No, I am not Steve Bench...

There was also a range of tubes/valves that were designed to work with an anode voltage of 12.6V, using space-charge techniques they were intended for car radios. The 12CX6 being an example of a sharp-cutoff pentode used in RF and IF stages of car radios.

Steve A.
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Postby AncientBrit » Thu Jun 14, 2007 10:42 pm

Steve,

Nice CRT.

Uses PDA I presume?


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Postby AncientBrit » Thu Jun 14, 2007 10:44 pm

Steve,

Nice CRT.

Uses PDA I presume?


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Postby Steve Anderson » Thu Jun 14, 2007 10:54 pm

AncientBrit wrote:Steve,

Nice CRT. Uses PDA I presume?

Graham


Yes,it does, but only to a moderate amount.

Compare the following picture to a bunch of MOSFETs, which do think is more interesting? Not just you Graham, but all. This is just a collection of EL84s, (6BQ5) used in almost all radios through the 50s and 60s along with its cousin the EL90 (6AQ5) as the audio output stage.

Am I hitting home here?

Steve A.
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Postby DrZarkov » Thu Jun 14, 2007 11:47 pm

Of course they are beautyful, and I like the sound of a valve-radio. In our living-room there is apart from the Technics-amplifier and tuner an old "Mende" radio which is used very often. Even on shortwave it gives better results than my Degen 1102 "world-receiver". (But no SSB...)

If I start to make a replica of a Baird Televisor or a TeKaDe Telehor I would make it with valves, of course. No problem with the voltage, only in my current project it would have made much difficulties to built-in another transformator for the 80 V for the LED array.
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Postby Viewmaster » Fri Jun 15, 2007 2:32 am

DrZarkov wrote:If I start to make a replica of a Baird Televisor or a TeKaDe Telehor I would make it with valves, of course. No problem with the voltage, only in my current project it would have made much difficulties to built-in another transformator for the 80 V for the LED array.


LED? That would be a dirty word for an all valved NBTV. Neon would be the new in word, don't you think?

I'd really like to see an NBTV using AC/DC valves, such as CL33 o/p bottle and CY31 as the HT rectifier. EF37s as the audio amps.

How about someone designing the motor control PLL using valves? :shock:

Albert.
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Postby Steve Anderson » Fri Jun 15, 2007 12:16 pm

Viewmaster wrote:How about someone designing the motor control PLL using valves? :shock:

Albert.


Well, it could be done. If you wanted a vacuum-state version of the part of the 4046 so commonly used it would require about six 5965 or ECC88 valves, both of which are listed as for use in computers! The part of the 4046 used here is just four flip-flops and some output drivers.

This then feeds something like a EL34 or EL37 as the output device. One of the hardest things might be getting DC motors that run on a few hundred Volts!

I agree, LEDs would be a no-no. A large bulbous Neon please! Attached pic is about the best I can find at the moment.

Steve A.

When it comes to tube computing the two most famous are the 'Colossus' at Bletchly Park, and the Eniac in the US.

Colossus was the size of a living room and weighed about one tonne. Its 2,400 valves replicated the pattern of an encrypted Lorenz message as electrical signals. This breakthrough in computing remained a secret for many years, to the extent that two Americans took the credit for inventing the computer in 1945.

By today's standards for electronic computers the ENIAC was a grotesque monster. Its thirty separate units, plus power supply and forced-air cooling, weighed over thirty tons. Its 19,000 vacuum tubes, 1,500 relays, and hundreds of thousands of resistors, capacitors, and inductors consumed almost 200 kilowatts of electrical power.

Now run that lot off your laptop battery!

...just as a bit of trivia, I did some number-crunching and the battery in my laptop would power Eniac for 250 micro-seconds!!!!
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Postby Steve Anderson » Fri Jun 15, 2007 2:49 pm

Viewmaster wrote:I'd really like to see an NBTV using AC/DC valves, such as CL33 o/p bottle and CY31 as the HT rectifier. EF37s as the audio amps.

Albert.


Well, here they are in all their resplendant glory...

Steve A.
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cy31_resize.jpg
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EL37a.jpg
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Postby AncientBrit » Fri Jun 15, 2007 5:31 pm

I agree, I like "bottles" (valves) and CRTs.

But with the move to digital TV / radio all the heritage TVs and radios will no longer be able to receive signals off-air.

I suppose you'll have to use RF modulators to get them to work.



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625-Alive.

Postby Steve Anderson » Fri Jun 15, 2007 5:45 pm

AncientBrit wrote:All the heritage TVs and radios will no longer be able to receive signals off-air.

I suppose you'll have to use RF modulators to get them to work.

Graham


I think I've posted this link before, it's only really applicable to the UK and one or two outposts of the Empire (Hong Kong and New Zealand for example). They have been applying to get a licence to transmit 405 line TV at infrequent times in the UK at low powers, I don't know if they have been successful.

http://www.bvws.org.uk/405alive/

What I like is their opening gambit..."Welcome to 405 ALIVE, the website with absolutely nothing new on it!"

I imagine that in time there'll be a 625-alive society. And with a nod to our friends across the pond, a 525-alive society.

Steve A.

What doesn't seemed to have emerged is the 819-alive society, the old and unique French TV system. Monochrome of course!
Last edited by Steve Anderson on Fri Jun 15, 2007 6:15 pm, edited 4 times in total.
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Postby AncientBrit » Fri Jun 15, 2007 5:48 pm

Thanks for the link Steve,

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