Destat Apparatus - Exploring The Physics Behind It

[allaroundions]

TL;DR Summary

What happens to those ions?

I hope you all have a wonderful day,

Some time ago, I bought a device that is supposed to eliminate static charge on my vinyl records (which aids to the overall sound quality).

I was sitting on the couch and having a deep thought, as me myself have no professional background in physics, I couldn't stand but wonder what happens to those ions after they were generated.

To give more details about the device, it's called "destat" from a japanese audio company (ORB/Sakura/Furutech).

It gives off a high voltage (AC) balanced ion output (balanced meaning equally both positive and negative ions).

Being able to discharge 1000 volts within 10 seconds is quite impressive.

However, I was wondering about the following things:

- What happens when the ions are generated? It has a fan so it's blowing it out in a certain direction. So it's bonding with the ions within the charged object and takes them out. What happens then? Does it disappear or change in (energy) form. Can it go through walls? Does it attach to humans beings as we have quite some water in sodium in our bodies?

- The manufacturer states that the machine shouldn't be on longer than 20 seconds. I wonder why. Are the carbon rods too thin (it looked like around 1 mm to me)? Would the components overheat? Why would they say that?

- And someone made an interesting comment on what would happen if you run a high electric charge through ionized air (something like a Jacobs ladder). Unfortunately, I couldn't find the specific comment so I could share it here. It had something to do with EM waves but I don't recall the specific words he used, don't want to twist his words either. Maybe someone can explain what happens and how the physics works.Thank you all.

Dee

 

[Baluncore]

Welcome to PF.
Vinyl records are good insulators. When they are pulled from a sleeve, they may be charged by friction. When they are played, the surface static is collected by the stylus, to the sound of electrical discharge noise.

If you provide ionised air with + and - ions, the isolated charges on the surface of the vinyl will attract an opposite charge from the air, until it is neutralised.

Ions not used to neutralise the surface, will recombine in the air, or will be attracted to ground or nearby conductive materials.

 

[berkeman]

I used to have a red one of these guns back when I still had an LP player (and yes I had the brush as well)...

https://musichallaudio.com/product/zerostat/

 

[Delta2]

Me on the other hand is wondering why static charge on the vinyl records affect the sound quality during play. As far as I know the audio signal is not stored electromagnetically on vinyl records (like it was in old 80-90s audio and video tapes), so why static charge has anything to do with the audio reproduction from them?

 

[Delta2]

Ah I guess the static e-field affects the head of the player device which head operates electromagneto-mechanically (long word lol). If I am not wrong the head converts the mechanical vibrations from the vinyl surface to an electromagnetic signal.

 

[berkeman]

Ah I guess the static e-field affects the head of the player device which head operates electromagneto-mechanically (long word lol). If I am not wrong the head converts the mechanical vibrations from the vinyl surface to an electromagnetic signal.

That's an interesting question. The static charge in the record grooves could exert small pertubative forces on the needle, but probably more of an issue would be the electrical noise picked up by the piezo (or whatever) element that converts the mechanical movements into the electrical pickup signal. Sounds like a good issue for a Google search...

 

[Baluncore]

The static charge in the record grooves could exert small pertubative forces on the needle, but probably more of an issue would be the electrical noise picked up by the piezo (or whatever) element that converts the mechanical movements into the electrical pickup signal.

The problem is deeper than just EM in the groove.

The stylus is partly housed in and protrudes from the grounded pickup head. Ceramic/piezo pickups are high impedance - big signal voltage, while magnetic pickups are low impedance - small signal voltage, so each will be affected by static discharge differently. If the pickup is well screened, there should not be a problem with the discharge of static surface charge, reaching and affecting the transducer signal.

Perhaps the worst remaining effect of surface charge, is that it attracts dust to the disc surface. That dust comes from the environment, I expect mostly from the skin of the biological residents, but also certain other substances.

The audio track is encoded physically in the floor (mono), or the walls (stereo), of the groove. But contact friction will selectively charge the high ridge that separates the turns of the spiral groove/track. So we should expect dust to initially collect on that ridge. When playing the recording, the stylus will move some fine dust into the groove. Motes may partly fill high frequency holes, which I suspect will generate asymmetry, so even harmonic distortion.

You have skin in the game, and are becoming part of, and altering the recording each time you play it, while it is becoming part of your "ear".

As the stylus encounters dust, it will wear the original recording surface, and break or smear the dust across the critical surface of the recording. You will notice that most new dust will be collected on the stylus. To some extent, grooved recordings are self-cleaning, or should that be self-plowing. The processing of dust by the stylus is a physically noisy process. That noise is added mechanically to the audio track.

Using an ion generator to neutralise the static, reduces the dust, and so reduces wear and high frequency mechanical surface noise.

 

[Delta2]

If the pickup is well screened, there should not be a problem with the discharge of static surface charge, reaching and affecting the transducer signal.

What do you mean by "if the pickup is well screened".

I don't think the accumulation of dust has to do anything with this though I grew up in the 80s we never had a pickup unit or purchased a vinyl record. Audio and video cassettes (VHS, Beta) is the ones I had experience with.

 

[Baluncore]

What do you mean by "if the pickup is well screened".

The "pickup" or "tone arm" holds the transducer cartridge, with the stylus.
See picture here; https://en.wikipedia.org/wiki/Phonograph_record#Vinyl

In a magnetic cartridge, the stylus moved a small magnet. Coils sensed that movement. A mumetal foil, screened the coils from the nearby EM fields caused by static discharges, or EMI.

 

[Tom.G]

British:Screened = American:Shielded
Think window screen, it keeps unwanted things out!

The high impedance ceramic (Crystal) pickups are totally enclosed in a metal case to keep out interference from electrical fields. Output level up to 3 Volts.

The low impedance magnetic pickups are enclosed in a MuMetal shield which has a high magnetic permeability to keep out magnetic fields. Typical output level around 3 - 10 millivolts.

Cheers,
Tom