How high do you need to get if your 6L6 is broken?

[Tim Wescott]

So, if the 6L6's in my guitar amp get broken, how high above the earth's
surface do I need to get before they'll work? How high before they'll
really work right?

International space station? Synchronous orbit? Asteroid belt?
Interstellar space?

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

I'm looking for work -- see my website!

[Alie...@gmail.com]

On Friday, September 16, 2016 at 3:20:00 PM UTC-7, Tim Wescott wrote:
> So, if the 6L6's in my guitar amp get broken, how high above the earth's
> surface do I need to get before they'll work? How high before they'll
> really work right?
>
> International space station? Synchronous orbit? Asteroid belt?
> Interstellar space?

Been reading Golden Age SF again? The "open-air electron gun" trick was used in George O. Smith's _Venus Equilateral_.

This guy claims to have gotten a 12AV7-equivalent to run at 133 Pascal, equivalent to ~85,000 feet altitude (16 miles) but he had to crank up the voltages:

http://www.sparkbangbuzz.com/els/vt-vac-el.htm

To get commercial-grade vacuum you need to get into Low Earth Orbit.


Mark L. Fergerson

[matt]

On 09/16/2016 06:19 PM, Tim Wescott wrote:
> So, if the 6L6's in my guitar amp get broken, how high above the earth's
> surface do I need to get before they'll work? How high before they'll
> really work right?
>
> International space station? Synchronous orbit? Asteroid belt?
> Interstellar space?
>

If there's a hole in the envelope, won't the electrons fall out?

[upsid...@downunder.com]

You also need to think at power dissipation issues, since there s no
convection cooling,

Of course running the anode red hot especially on the night side of
the orbit, facing the cool sky will help lot in terms of radiative
cooling.

[jurb...@gmail.com]

The Digikey website for a high voltage depletion mode FET ?

[Robert Baer]

Tim Wescott wrote:
> So, if the 6L6's in my guitar amp get broken, how high above the earth's
> surface do I need to get before they'll work? How high before they'll
> really work right?
>
> International space station? Synchronous orbit? Asteroid belt?
> Interstellar space?
>

I think that if you modify a (hand) bicycle pump properly, you can
get a useful vacuum for that purpose.
Or maybe use one of those aquarium aerator pumps; the kind that uses
a rotating cam to displace the tube that goes thru it.

[Robert Baer]

That is what the grid leak detector is for; put the pan underneath.

[Phil Allison]

upsid...@downunder.com wrote:

>
>
>
> You also need to think at power dissipation issues, since there s no
> convection cooling,
>
> Of course running the anode red hot especially on the night side of
> the orbit, facing the cool sky will help lot in terms of radiative
> cooling.
>

** The only way the plate of a power tube loses heat energy is by radiation. However, most of it is in the far infrared and so gets absorbed by the soda glass envelope. Once its temp rises, the envelope radiates back and helps keep the plate hot. The glass is cooled by convection and some radiation too - at max rated power dissipation, the surface temp settles to about 200 C.

In the vacuum environment of space,ignoring the possible effect of direct sun light, the envelope can also only radiate heat but like the plate has a rest temp of zero absolute, instead of room temp of 295K.

The true situation at thermal equilibrium is non obvious.


... Phil

[tabb...@gmail.com]

You won't need an envelope


NT

[Phil Hobbs]

You'd have to reactivate the cathode when you got up there.

Cheers

Phil Hobbs

[Phil Allison]

tabb...@gmail.com wrote:

>
>
> You won't need an envelope
>
>

** Try sticking your hand on the exposed plate - fool.

Plus, the whole plate structure is at risk of collapse with no envelope to support and protect it.



.... Phil

[krw]

Without gravity, the drip pan won't work.

[Joerg]

On 2016-09-16 15:19, Tim Wescott wrote:
> So, if the 6L6's in my guitar amp get broken, how high above the earth's
> surface do I need to get before they'll work? How high before they'll
> really work right?
>
> International space station? Synchronous orbit? Asteroid belt?
> Interstellar space?
>

Only about three feet, the height of the drawer where your credit card
is 8-)

http://www.thetubestore.com/Tubes/6L6-5881-Tube-Types

Or course, the real hardcore selfmade-man would never do this and
instead fix the tube or build a new one from bare metal and glass:

https://www.youtube.com/watch?v=EzyXMEpq4qw

--
Regards, Joerg

http://www.analogconsultants.com/

[Jeff Liebermann]

On Fri, 16 Sep 2016 17:19:52 -0500, Tim Wescott
<seemyw...@myfooter.really> wrote:

>So, if the 6L6's in my guitar amp get broken, how high above the earth's
>surface do I need to get before they'll work? How high before they'll
>really work right?
>
>International space station? Synchronous orbit? Asteroid belt?
>Interstellar space?

At least 0.001 torr at an altitude of 59 miles or higher:
<http://tubecrafter.com/tubecrafter_012.htm>
<http://www.calctool.org/CALC/phys/default/pres_at_alt>

One problem might be that if you're flying at 59 miles altitude,
there's not enough air to conduct sound, so nobody will hear your
guitar playing.

Incidentally, vacuum tubes in otter space are making a comeback:
<http://www.theregister.co.uk/2012/05/24/nan_vacuum_tubes/>
--
Jeff Liebermann je...@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

[jurb...@gmail.com]

>"One problem might be that if you're flying at 59 miles altitude,
>there's not enough air to conduct sound, so nobody will hear your
>guitar playing.

Not much convection or conduction cooling either.

[tabb...@gmail.com]

On Saturday, 17 September 2016 14:54:33 UTC+1, Phil Allison wrote:

> tabbypurr wrote:
>
> > You won't need an envelope
>
> ** Try sticking your hand on the exposed plate - fool.

after you

> Plus, the whole plate structure is at risk of collapse with no envelope to support and protect it.

NT

[Lasse Langwadt Christensen]

Den lørdag den 17. september 2016 kl. 00.20.00 UTC+2 skrev Tim Wescott:
> So, if the 6L6's in my guitar amp get broken, how high above the earth's
> surface do I need to get before they'll work? How high before they'll
> really work right?
>
> International space station? Synchronous orbit? Asteroid belt?
> Interstellar space?
>

I guess you'd have to be pretty high to start wondering how high
you need to be ;)


-Lasse

[Phil Hobbs]

On 09/16/2016 08:50 PM, nu...@bid.nes wrote:
> On Friday, September 16, 2016 at 3:20:00 PM UTC-7, Tim Wescott
> wrote:
>> So, if the 6L6's in my guitar amp get broken, how high above the
>> earth's surface do I need to get before they'll work? How high
>> before they'll really work right?
>>
>> International space station? Synchronous orbit? Asteroid belt?
>> Interstellar space?
>
> Been reading Golden Age SF again? The "open-air electron gun" trick
> was used in George O. Smith's _Venus Equilateral_.

VE was great fun, if you could ignore the extreme cheesiness of the
romantic subplots.

And of course charging up Murdoch's pirate ship with an electron gun
wouldn't have affected anything inside, because the skin is a big
Faraday cage.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510

hobbs at electrooptical dot net
http://electrooptical.net

[M Philbrook]

In article <WoednTBN_cuV7UHK...@giganews.com>,
seemyw...@myfooter.really says...

>
> So, if the 6L6's in my guitar amp get broken, how high above the earth's
> surface do I need to get before they'll work? How high before they'll
> really work right?
>
> International space station? Synchronous orbit? Asteroid belt?
> Interstellar space?

if you can sit on the edge of a black hole without getting suced in
yourself, you maybe able to generate enough vacuum void to allow it to
conduct properly.. But then again, the hole will also be sucking up
other gases while it passes by..

So in short, you may get the performance of a gassy tube!

Get your space gear on!

Jamie

[Alie...@gmail.com]

I thought about going there...

As it happens, I was high when I wrote my reply, and am right now. I use pot* to supplement the naproxen I take for my osteoarthritis because what the docs want to do to me is more invasive (like steroid injections into my joints) and has side effects I prefer not to experience (from skin irritation to death!).

I hope that doesn't get me kicked out of The Deplorables...

* One reason I moved to WA State- it's legal here


Mark L. Fergerson

[Robert Roland]

On Sat, 17 Sep 2016 09:04:52 -0700, Jeff Liebermann <je...@cruzio.com>
wrote:

>At least 0.001 torr at an altitude of 59 miles

It is not only about pressure. In a tube, the getter is used to remove
the last few gas molecules. At altitude, although the pressure is OK,
there will be a continous supply of gas molecules, causing rapid
cathode detoriation.
--
RoRo

[Robert Baer]

Use zen...BE the drip.......

[jurb...@gmail.com]

On Saturday, September 17, 2016 at 4:58:21 PM UTC-5, Robert Roland wrote:
> On Sat, 17 Sep 2016 09:04:52 -0700, Jeff Liebermann

> wrote:
>
> >At least 0.001 torr at an altitude of 59 miles
>
> It is not only about pressure. In a tube, the getter is used to remove
> the last few gas molecules. At altitude, although the pressure is OK,
> there will be a continous supply of gas molecules, causing rapid
> cathode detoriation.
> --
> RoRo

Ever hear of a ceramic cathode ? A local CRT rebuilder around here used replacvment guns with ceramic cathodes. The picture was a little different because it did affect the gain of the tube somehow, but it looked better than it did before, and they lasted forever.

I wonder if scope tubes use them because it has been a long tie since I've seen one with a weak CRT. I got a Tek 561A that'll burn your eyeballs out if you turn it too high. That was built before I was was born.

Anyway, how high do you have to get ? High enough to get online and get a pair of (I think) 6550s for like $75 if you're lucky and put in your credit card number. Or high enough just to listen to mono, which takes an extra joint.

[Tim Wescott]

First you take your glove off and expose your hand to the vacuum, and
then - oh wait, we can stop there, your hand has just been freeze-dried.

--
Tim Wescott
Control systems, embedded software and circuit design
I'm looking for work! See my website if you're interested
http://www.wescottdesign.com

[Michael A. Terrell]

Tim Wescott wrote:
> So, if the 6L6's in my guitar amp get broken, how high above the earth's
> surface do I need to get before they'll work? How high before they'll
> really work right?
>
> International space station? Synchronous orbit? Asteroid belt?
> Interstellar space?

The 6L6 is a steel cased tube. How would you break it?

--
Never piss off an Engineer!

They don't get mad.

They don't get even.

They go for over unity! ;-)

[Dennis]

On 09/23/2016 01:06 AM, Michael A. Terrell wrote:
> Tim Wescott wrote:
>> So, if the 6L6's in my guitar amp get broken, how high above the earth's
>> surface do I need to get before they'll work? How high before they'll
>> really work right?
>>
>> International space station? Synchronous orbit? Asteroid belt?
>> Interstellar space?
>
>
> The 6L6 is a steel cased tube. How would you break it?
>

He probably means the 6L6GB - a later (cheaper?) variant with a glass
envelope.

[Tim Wescott]

The 6L6-G looks best.

[Phil Allison]

Dennis wrote:

>
> Michael A. Terrell wrote:
> >
> >
> > The 6L6 is a steel cased tube. How would you break it?
> >
> He probably means the 6L6GB - a later (cheaper?) variant with a glass
> envelope.
>

** Of course he did, metal 6L6 tubes are not used in guitar amps.

The type recently passed the 70 year milestone of continuous production with no end in sight.



.... Phil

[Phil Allison]

Phil Allison wrote:
>
>
> The type recently passed the 70 year milestone of continuous production
>

** Of course that should be 80 year milestone.

The Wiki needs updating.



.... Phil

[Bill Beaty]

On Friday, September 16, 2016 at 3:20:00 PM UTC-7, Tim Wescott wrote:
> So, if the 6L6's in my guitar amp get broken, how high above the earth's
> surface do I need to get before they'll work? How high before they'll
> really work right?

Don't your's flash purple if you whack the strings hard enough? No need for CRT-type vacuum. Might only be 1e-3 Torr.

[Bill Beaty]

On Saturday, September 17, 2016 at 11:18:15 AM UTC-7, Phil Hobbs wrote:
> VE was great fun, if you could ignore the extreme cheesiness of the
> romantic subplots.

And wasn't there a '50s James Blish short story with vacuum-based animals on a large asteroid, with "smell imaging?" The mean free path was tens of meters, and they'd evolved the ability to see via molecular beams from heated ground (or from hot prey animals.) The bad guys' outgassing warm space suits were attracting the vacuum-based predators to attack.

[Tim Williams]

"Bill Beaty" <bi...@eskimo.com> wrote in message
news:b50f4161-b7f0-4844...@googlegroups.com...

Common misconception -- that's electrons escaping through holes in the
plate, bombarding the glass, which fluoresces from high UV / soft x-rays /
electrons.

I've also seen blue glow from innocent little tubes like 12AU7s and 6SN7s,
but only at higher voltages. It's a combination of excess energy (enough to
escape the plate and still excite the glass) and intensity (enough to be
visible).

I've also seen a few types of plate material, where the fluorescence is
visible on the inside coating of the plate. But definitely not a volumetric
(ionized gas) thing!

Gassy tubes have a distinctive volumetric glow, in the electron beam area.
You can also recognize atomic lines of popular gasses (most often Ar and
N2), if you have a keen eye (and a diffraction grating!). The others are
more diffuse: wide fluorescence peaks, or continuum radiation.

Tim

--
Seven Transistor Labs, LLC
Electrical Engineering Consultation and Contract Design
Website: http://seventransistorlabs.com

[John Fields]

---
Nice.

John Fields.

[John S]

On 9/16/2016 5:19 PM, Tim Wescott wrote:
> So, if the 6L6's in my guitar amp get broken, how high above the earth's
> surface do I need to get before they'll work? How high before they'll
> really work right?
>

> International space station? Synchronous orbit? Asteroid belt?
> Interstellar space?
>

A few tokes should do it.