From days gone by
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24-07-2016, 08:40 AM
RE: From days gone by
The US space programs use transistors- ASICs. The black boxes are designed to conduct heat to the base plate, where heat pipes radiate the heat into the best cold sink you can find- space. The outside face of a radiator is designed with emissivity and reflectivity such that it works even when facing the sun (though not as well). No air in space for cooling. In ancient rocketry days, tubes were wrapped with copper wire, which attached to a heat sink. The only tubes you will find in current US space programs are the Traveling Wave Tube Amplifiers (TWTAs) that are used to amplify the downlink (space to ground) signal.
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24-07-2016, 09:51 AM
RE: From days gone by
[Image: oldcomputer1_zpsymlkidmf.jpg]

[Image: dobie.png]Science is the process we've designed to be responsible for generating our best guess as to what the fuck is going on. Girly Man
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24-07-2016, 10:04 AM
RE: From days gone by
(22-07-2016 09:03 PM)Bucky Ball Wrote:  "land lines"
TV antennas
We're having an antenna installed because we can't get the local digital channels (5.3, etc) on satellite.

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24-07-2016, 10:05 AM (This post was last modified: 24-07-2016 10:26 AM by yakherder.)
RE: From days gone by
(24-07-2016 09:51 AM)Dom Wrote:  [Image: oldcomputer1_zpsymlkidmf.jpg]

My grandmother still uses an old dos machine that mostly runs programs from dual 5 1/4 floppy drives, though it has a 40 megabyte hard drive upgrade. She is a casual writer, but got used to using an 80s version of Leading Edge Word Processor and refuses to learn a new system.

She does have a newer computer as well, which we got her in a fruitless attempt to get her to switch. But she only uses it to check Hotmail, which we have to re-teach her how to use every time they change the layout of the homepage and put the login link in a different location or something. Remarkably, after 35 years of use, the old upgraded to an 80286 system in the early 80s is still running fine.

'Murican Canadian
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24-07-2016, 11:13 AM
RE: From days gone by
(24-07-2016 07:26 AM)onlinebiker Wrote:  
(24-07-2016 12:48 AM)Thumpalumpacus Wrote:  [Image: sn-vacuum.jpg?itok=WGuUDKwj]

Mostly used in electric guitar amplifiers any more ... Dad ain't sending you to the five-and-dime with a pocketfull of 'em to learn which one shit the busket in the TV.

But good lord, don't they make glorious noise?
There's some stuff that tubes still do better than transistors....

Enough so - that the Russians still use them in their space program.

In space - heat doesn't "rise" as there is no "up".. Transistors have to be air cooled - and if a simple fan goes out - they usually don't last long under heavy load. Tubes? They'll take serious heat without degrading. Another plus - they handle radiation bombardment better than a transistor. They're "bulletproof"..

Big Grin

Yeah, it's my understanding that they're EMP-resistant, so militaries use them.

Russian tubes are highly thought-of amongst us guitarists, Chinese less so though they've definitely improved their reliability.

Last year, I passed up buying an old Baldwin organ at a thrift shop for about $100 -- I've got a bum hip and couldn't line up the friends to help me move this thing. I didn't want it to play (I play a little keyboard, but not that well). I wanted it because it had nine 12AX7s and eleven 6BQ5s ... all Raytheon-built. Thing was worth $500 just for the tubes in it.
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24-07-2016, 11:43 AM
RE: From days gone by
(24-07-2016 10:05 AM)yakherder Wrote:  My grandmother still uses an old dos machine that mostly runs programs from dual 5 1/4 floppy drives, though it has a 40 megabyte hard drive upgrade. [...]

I still use the DOS command if I wanna drill down into files.

—My first "computer" that I purchased 32 years ago. Yikes Shocking

[Image: spectrum.png]

The Spectrum featured Zilog's Z80A 8-bit processor running at 3.5MHz, 16Kb of ROM hosting BASIC, with 16Kb of DRAM, 256x192 pixel display, 8 colors, monotone sound through a tiny inbuilt speaker, a rubberised keyboard, and audio tape connectors. Each key had three functions, and there was no text editor.

And of course there was no HDD; we had to use one of these babies, which ran at the speed of a supercharged snail...

[Image: business_00006_panasonic_rq_tape.jpg]

Those were the days..... sadly long gone..... Sad

I'm a creationist... I believe that man created God.
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24-07-2016, 12:13 PM
RE: From days gone by
Jesus... I had that exact Panasonic cassette recorder....

.......................................

The difference between prayer and masturbation - is when a guy is through masturbating - he has something to show for his efforts.
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24-07-2016, 12:52 PM
RE: From days gone by
(24-07-2016 07:26 AM)onlinebiker Wrote:  
(24-07-2016 12:48 AM)Thumpalumpacus Wrote:  [Image: sn-vacuum.jpg?itok=WGuUDKwj]

Mostly used in electric guitar amplifiers any more ... Dad ain't sending you to the five-and-dime with a pocketfull of 'em to learn which one shit the busket in the TV.

But good lord, don't they make glorious noise?
There's some stuff that tubes still do better than transistors....

Actually, objectively they dont. Tube amps sound better than semiconductor amps because of a feature that makes then technically inferior.
They sound better particularly in "overdrive". Overdrive means the guitar player is adding distortion intentionally, someting you would never do if you wanted to correctly transmit information.
Tube amps tend to add distortion way before max power output and slowly increase in doing so. For some (evolutionary?) reason this sounds "good" to human ears.
Semiconductor amps work without any distortion up to max power where they suddenly "add" all distorion at one. So a guitar player wouldnt be able to smoothly control "overdrive".

(24-07-2016 07:26 AM)onlinebiker Wrote:  Another plus - they handle radiation bombardment better than a transistor. They're "bulletproof"..
Big Grin
I dont know if this applies in geneal, but early in my career i applied for a job in a company designing electronics for ESAs Rosetta mission.
They didnt have tubes, only "normal" circuit boards. I asked them about robustness against cosmic rays and they told me that they use very common semiconductors, but special "radiation hardened" versions. The difference in cost was jaw dropping. 10€ vs 10.000€ each piece literally!

Ceterum censeo, religionem delendam esse
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24-07-2016, 01:44 PM
RE: From days gone by
(24-07-2016 12:13 PM)onlinebiker Wrote:  Jesus... I had that exact Panasonic cassette recorder....

Me too. They were popular.

[Image: dobie.png]Science is the process we've designed to be responsible for generating our best guess as to what the fuck is going on. Girly Man
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24-07-2016, 01:53 PM
RE: From days gone by
(22-07-2016 08:37 PM)Full Circle Wrote:  [Image: The-grim-70s-and-Meat-Loaf-combo.jpg]

I remember having to slide a matchbook under the tape when it started getting wonky...

...and having to listen to the whole thing to get back to the one hit that was usually on the tape. Fast Forward was just too much to ask. Undecided

See here they are the bruises some were self-inflicted and some showed up along the way. - JF

We're all mad here. The Cheshire Cat
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