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Tubes In Oil

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I have one of those Heathkit Cantennas. The guy just gave it to me. He was afraid of the PCB's in the oil

I bought mine at the Miami Heathkit store around 1970. They come with no oil and you fill it yourself with whatever you want. He may have got his used, and there was a PCB oil panic in the 80's.

There was a transformer manufacturer in Hollywood Florida that simply closed up shop and vanished when the PCB panic started. I got some rather nice large green high voltage transformers out of their dumpster.

I had a Cantenna but I managed to blow it up.

Let's just say that I won a bet back in the mid 70's as to who could build the most powerful RF amplifier that could be driven from a 5 watt radio. I was reading somewhere north of 1200 watts and still tweaking when the Cantenna went open and the fire gods danced all over the tune and load caps, at which point the breaker in the panel popped.

The amplifier survived with nothing more than some burnt spots on the variable caps. It used a 6146 to drive a 4PR400 (a pulse rated 4-400) on 3500 volts. The tube, socket, and silicon rectifiers were scavenged from a discarded CO2 laser.

It was the only thing that I ever build that truly scared the )*&#(@ out of me. The blue fire would erupt on those variable caps under normal operation if someone tried to squeeze it for max power and yelled loudly at the radio. Poor shielding caused desk lamps to glow when turned off, and TV reception was wiped out for blocks around. I wound up giving it away after winning my bet.
 
That electronic computer for the color press was sure something. Plenty of other good stuff in that issue. Mercury delay lines, mixing consoles, FM relay stations (thru some stations that still exist), coax TV networks and thanks to an advert, I now know who made the metal case for my old Halicrafters SW radio.

"Mumble Tubs" if in Univac. (showing age.. yeah, the Space Age!)
 

PRR

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> "Mumble Tubs" ....

Ha! I know what a "tub file" is; knew a guy hired to carry the tubs around. But "mumble"??

The *only* "Mumble Tubs" reference I find on Google is an Italian book, which is clearly on-topic, but I don't see an explanation.
 

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PRR

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Heater-less thermionic vacuum tubes. You run them in a 350-600C oven, they get low emission but sufficient for many operational functions.

Part of a general trend to pre-made "micro-modules", from 1952's CordWood through RCA's transistor m-modules of 1959 and Kilby's integrated electronics. RCA modules were $39, TI's Kilby-chips started at $450, didn't come down until mid-1960s.

McCullough sticking with tubes for now.
 

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PRR

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Liquid Cooled Microphone

Not really "tubes", but a precursor.

The basic radio transmitter is a high frequency alternator or tuned spark-gap. For code you add a key. Some hacker put a variable-resistance microphone in place of the key, and listeners heard voice!

In this scheme the microphone has to handle more power than the antenna absorbs. As transmitters grew, the mikes had to be beefed-up. Fat carbon chambers and large cooling plates.

The next step was to dump the carbon and use circulated liquid as the variable resistance.
 

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Pencil Tube Phono in Oil

Hello all,


two years ago I build a MM phono preamp using 6021 tubes. It was my contribution to a challenge using a pickle jar for audio projects. Since each of the tubes is radiating more than 2 VA and there is no heat convection inside the closed glass, I filled it with silicone oil. Works like a charm :D


Best regards, Daniel
 

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Mumble tubs -the mumbling is also mentioned here:
The Electronic Mind - How it Remembers, August 1956 Popular Electronics - RF Cafe

Didn't see any other references except recent mentions in a couple other places. Well lets not let the term die, as no one remembers this fine thing any more.

The delay line gear made some slight audible noises although the assemblies used ultrasonic frequencies, and RF for timing synchronization. I was told by an old employee that the engineers developing it coined the term as slang because the UNIVAC would 'mumble to itself' in those cylindrical 'tubs' of mercury lines. Repeating the same string of data over and over, until it was needed. I have never seen one in operation but think the fans in those huge computers must have drowned out anything not listened to with a stethoscope.
electronic-magnetic-memory-core-popular-electronics-august-1956-5.jpg

Not sure one would want to put one's ear to the end of that as they were heated to a uniform temperature to regulate propagation speed. I'd love to have one to play with though. The patents give a ton of info on how exactly they were operated. Each strip of electronics is a memory line electronics. Number of bits that will fit in the line is related to propagation time of the pulsations through the mercury column under the strip.

Maybe the closest thing to the experience attainable today would be an old mechanical disk drive (think full height 5.25" 5 megabyte drives in personal computers, and also the big stuff) -each drive makes its own low frequency sounds not exactly related to how fast the heads move from one spot to the next. You don't hear them so much but on a real old PC with a hard drive like that you can feel the case vibrate with the head seeks and if you put your ear to one you will hear a lot of interesting fun sounds when the disk is being worked.

back to the oil. Mercury.. impractical but what an abstract cooling medium it would be for low frequency work.
Now made curious, checked a few substances for thermal conductivity to keep those tubes cool.

These are all from the www various engineering sites like engineeringtoolbox.com
thermal conductivity in W/m K:
Silver 407
Cobalt 386
Copper 385
Gold 315
Lithium 301
Beryllium 218
Aluminum 205
Bronze 110
Phosphor bronze 110
Brass 109
Lead 34.7
Aluminum Oxide 30
Mercury 8.3
Alcohol, methyl 0.204
Ice 1.6-2
Water 0.6
Ethelyne glycol 0.25
Oil, Castor 0.148
Alcohol, ethyl 0.171
Oil, machine SAE50 0.17
Alcohol, propyl 0.161
Oil, olive 0.15
Polypropelyne Glycol 0.147
Oil, transformer 0.136
Carbon Tetrachloride 0.104
Air 0.024
R-12 (gas/liquid) 0.007 / 0.09
 
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the closest thing to the experience attainable today would be an old mechanical disk drive

We had a room full of Data General and DEC mini computers on a sub floor in the 80's to run all the Automated Test Equipment and laser trim stations in a microelectronics manufacturing facility. I was a Mr. Fixit for that place. You didn't hear much when the room was full of people but there were all sorts of sounds coming from the disk packs and tape drives that became quite audible after all the people left at 1 AM.

Modern (OK, newer) version.....wire a bunch of floppy disk drives, a few hard drives, and a couple of scanners together with some Arduinos and software and you have the Floppotron.....a musical instrument....sort of.

YouTube

YouTube
 

PRR

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Mumble tubs....
Mercury.. impractical but what an abstract cooling medium it would be for low frequency work.
Now made curious, checked a few substances for thermal conductivity to keep those tubes cool......

Thanks for the tub info.

The difference Mercury or say Silver is that Mercury is liquid at convenient temperatures. So thermal conductivity is almost moot. You want some decent Specific Heat, and then physically move the merc to some place else where heat may be dumped.
Liquid metal cooled reactor - Wikipedia

Note that conductive metals can be pumped without rotors (seals).

Even crazier folks can boil Mercury. (It's not that hot, 357C.)
Mercury vapour turbine - Wikipedia
Mercury as a Working Fluid. Avoid Workplace Accidents Involving Mercury.
 
two years ago I build a MM phono preamp using 6021 tubes. It was my contribution to a challenge using a pickle jar for audio projects. Since each of the tubes is radiating more than 2 VA and there is no heat convection inside the closed glass, I filled it with silicone oil. Works like a charm :D
That's cool, man!
I'd bet cheap salad oil from rapeseed or sunflowers would do exactly the same job ;).
Best regards!
 
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