Cathode ray tubes use an external magnet to deflect the electron beam, right?

I have some very strong, rare-earth (neodymium) magnets, and wondered if I could affect the performance of ordinary amplifier tubes. I used my tube-type hi-fi as a "test bed."

I moved the magnet around the glass envelopes. I could not discern any audible change. However, most tube internals are effectively surrounded by the plate, so I suppose that the electrons are unaffected by the magnet?

Surely an eye tube might show some effect? I'll try that the next time I have a radio with an eye tube on the bench.

What am I trying to accomplish, and for what purpose?
I don't rightly know.

Here is a cheap source for rare-earth magnets, with various shapes, sizes, etc. http://www.allelectronics.com/make-a-store/category/370/Magnets/1.html

They are handy to have around - believe me, if you use them as refrigerator magnets, they won't fall off!

They have one that is spherical, about the size of a marble. I'm wondering what use that might have?

At one time, I toyed with the idea of using a permanent magnet to magnetize the core of a speaker field coil that was open. I gave up the idea, but I forget exactly why.
Doug

WARNING: these rare-earth magnets can be very strong. If you get two of them close, whatever is between them can be badly pinched.

Also: a heart pacemaker's programming can be changed if exposed to a strong magnetic field. So, if you have a pacemaker, don't even think about playing around with strong magnets. More info here: http://www.enginova.com/should_wearers_of_heart_pacemake.htm

ALSO.... keep them away from children!!! There have been MULTIPLE cases where kids have SWALLOWED these magnets. They get into the guts and adhere to one another causing blockage or perforation of the bowels which can lead to DEATH. Consider yourself warned.....

yeah... I imagine.. magnetically dead kids are a a real pain to try to get up off a metal floor.

Ha!

Regarding magnets and tubes, a magnet will affect an eye tube. A magnet will also bend the electrons inside of an ordinary amplifying tube, but won't affect the audio much (just as a weak cathode with a hot spot doesn't usually affect the audio too much). A magnet will also play havoc with a vacuum fluorescent display (modern cousin to the eye tube).

To see a magenet affect a radio tube, get one that glows blue inside. Watch the blue glow when you hold the magnet near.

T.

a friend of mine had a kid that stuck a metal marble or something in their nose. trying to get it out made it go in further. a rare earth magnet is what they used to get it out.

moral of the story dont stick marbles in your nose

:Ha!
:
:Regarding magnets and tubes, a magnet will affect an eye tube. A magnet will also bend the electrons inside of an ordinary amplifying tube, but won't affect the audio much (just as a weak cathode with a hot spot doesn't usually affect the audio too much). A magnet will also play havoc with a vacuum fluorescent display (modern cousin to the eye tube).
:
:To see a magenet affect a radio tube, get one that glows blue inside. Watch the blue glow when you hold the magnet near.
:
:T.

Magnets, from hard drives, are so strong they will stick to the side of glass tubes. Magnets are attracted to metal elements inside the tube.

Watch out for fingers. I use these magnets to hold a calendar to the side of a metal cabinet. Hard to change pages without pinching a finger.

Norm

:a friend of mine had a kid that stuck a metal marble or something in their nose. trying to get it out made it go in further. a rare earth magnet is what they used to get it out.
:
:moral of the story dont stick marbles in your nose
:
::Ha!
::
::Regarding magnets and tubes, a magnet will affect an eye tube. A magnet will also bend the electrons inside of an ordinary amplifying tube, but won't affect the audio much (just as a weak cathode with a hot spot doesn't usually affect the audio too much). A magnet will also play havoc with a vacuum fluorescent display (modern cousin to the eye tube).
::
::To see a magenet affect a radio tube, get one that glows blue inside. Watch the blue glow when you hold the magnet near.
::
::T.

:Magnets, from hard drives, are so strong they will stick to the side of glass tubes. Magnets are attracted to metal elements inside the tube.
:
:Watch out for fingers. I use these magnets to hold a calendar to the side of a metal cabinet. Hard to change pages without pinching a finger.
:
:Norm
:
::a friend of mine had a kid that stuck a metal marble or something in their nose. trying to get it out made it go in further. a rare earth magnet is what they used to get it out.
::
::moral of the story dont stick marbles in your nose
::
:::Ha!
:::
:::Regarding magnets and tubes, a magnet will affect an eye tube. A magnet will also bend the electrons inside of an ordinary amplifying tube, but won't affect the audio much (just as a weak cathode with a hot spot doesn't usually affect the audio too much). A magnet will also play havoc with a vacuum fluorescent display (modern cousin to the eye tube).
:::
:::To see a magenet affect a radio tube, get one that glows blue inside. Watch the blue glow when you hold the magnet near.
:::
:::T.

All:
We used magnetron tubes in the weather radars of our airplanes. They put out a pulse of about 60 to 75 kW, and had a range of several hundred miles, if you had a big storm. The magnet that caused the electrons to spin were *very* powerful. I have one, it can probably lift 10 to 15 pounds. As said above, watch fingers when they are between magnet and metal.
Lewis