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Old 2nd February 2012, 12:28 PM   #1
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Default How the magnetic affect the sound of tube amplifier

Today we receive a lot of thulium magnetic for a researching project (they are super strong magnetic!). The EL-34 PP amp came into my eyes when we were discussing about the project. A strange idea came into my brain suddenly: the magentic can affect the moving path of electron, and the tube is working based on electron emitting and moving, so how will the magnetic affect the tube amplifiers?

I decided to give a try. I have 3 tube amplifiers in the office: a EL34 PP amp, a 12ax7+6N1 tube headphone amp and a 6F3 3W small SE amp. After power on them for a few minutes, I put a magnetic close to the tubes and wave it. There's nothing happen when wave near EL34. But when put the magnetic close to the preamp tube 6N2 of EL34 PP, clear "pop" sound can be heard in the speaker. Then I tried with headphone amp and 6F3, both have clear "pop" sound when wave the magnatic near the preamp tube. But no clear sound can be heard at the power side.

I don't have time to listen how it affect the sound quality. And I don't have golden ears to distinguish the differences. But I think it's a interesting test, gurus with golden ears can try to listen to the sound quality affected by the magnetic, maybe there'll be some amazing result
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Old 2nd February 2012, 12:30 PM   #2
SY is offline SY  United States
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Moving a magnet near the tube will induce a small voltage (Faraday's Law). A static magnet, unless it's ridiculously powerful, will have close to zero effect on the tube's operation.
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Old 2nd February 2012, 12:33 PM   #3
SY is offline SY  United States
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Tubes and magnetic fields

Proof that demagnetizing tubes works
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Old 2nd February 2012, 12:40 PM   #4
M Gregg is offline M Gregg  United Kingdom
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Quote:
Originally Posted by SY View Post
Moving a magnet near the tube will induce a small voltage (Faraday's Law). A static magnet, unless it's ridiculously powerful, will have close to zero effect on the tube's operation.
I can't resist..put a magnet by a CRT and thats it folkes..LOL

Degaussing in progress and no picture...LMAO

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Old 2nd February 2012, 12:46 PM   #5
M Gregg is offline M Gregg  United Kingdom
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While I think about it,

put one by a magic eye tube and thats it as well the electron flow will be stuffed..unless you can demagnetise it.. the display will be distorted..

Its good fun though if you don't mind wrecking an EM80 etc..watch the display twist as the electrons are pulled and pushed about..


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Old 2nd February 2012, 12:52 PM   #6
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Well, if the magnetic can distortion the cateye, it must have some effect on the performance of other tubes. I know the electron beam is enclosed in a small metal enclosure, but there will be effects, more or less. I think some one can find the differences, becuase some declare they can find the difference between 2 power supply cables...
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Old 2nd February 2012, 12:52 PM   #7
godfrey is online now godfrey  South Africa
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What are the grid wires made of? If they're magnetic a strong magnet could move them, possibly causing them to touch the cathode. That would cause an audible "pop".
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Old 2nd February 2012, 12:59 PM   #8
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I believe the audiable pop is not caused by the reason you mentioned. if grid and cathod are short, it won't be slight pop, maybe bomb
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Old 2nd February 2012, 01:03 PM   #9
DF96 is offline DF96  England
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A static magnetic field will bend a beam of electrons - that is how a TV CRT works. It won't make much difference to a triode, because all the electrons end up at the anode eventually.

I can just see the next 'audiofool' trend! Take a 5 dollar magnet, put it in a 2 dollar ceramic case, and charge people 95 dollars for a "static field audio enhancer".
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Old 2nd February 2012, 01:08 PM   #10
M Gregg is offline M Gregg  United Kingdom
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Quote:
Originally Posted by DF96 View Post
A static magnetic field will bend a beam of electrons - that is how a TV CRT works. It won't make much difference to a triode, because all the electrons end up at the anode eventually.

I can just see the next 'audiofool' trend! Take a 5 dollar magnet, put it in a 2 dollar ceramic case, and charge people 95 dollars for a "static field audio enhancer".
Ohhh can I have one..LMAO



Scan coil degauss chassis unit 10$ a pop return every 6 weeks works even better on non ferrous chassis...LOL

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