Image interference in TV sound to amplifier

Hello, when you say modify the frequency, does it saturate?

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No, the sound of the interference becomes lower or higher depending on the surface of the "inlays."
JP

Question 1: When you say in 3 houses in 3 different cities, was it always at your home or at someone else's too?

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Good evening, interesting problem, there should be a way to measure the frequency of the sounds produced by the subtitles, using a frequency meter and then see what this frequency corresponds to and how it can manifest via the subtitles.

Or could it be a frequency incompatibility between certain devices???

I am just suggesting.

Best regards, STARGATE43.

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Hello,
your problem is common with the audio circuits of cathode ray televisions, and it tends to worsen with age.
It is due to the fact that all circuits, image and sound, operate on the same transformer: when the image is very bright or has very bright areas, the cathode ray tube "pulls" from this supply and the filtering of the power supply fails. The interference you hear are mainly harmonics of the scanning frequency: 100Hz, 150Hz, 200Hz, etc... in varying proportions depending on the image.
The phenomenon should indeed worsen if you increase the brightness setting.
The filtering capacitors tend to lose their performance as they age (like batteries), so this phenomenon intensifies with age.
Solution: take the audio signal upstream of the television.
For example, use, if necessary, the audio outputs from sources (VCR, DVD, DVB-T adapter, "box" etc...) or derive the sound from these same sources (there are SCART cables that allow this, for example).

Linux Mageia 1 Firefox ESR 10

Thank you all!
In parallel, I reached out to a friend who knows quite a lot.
I'm throwing everything here in a jumble:

I've read this too.
I've always had this problem ever since I connected an amplifier to my setup, so for over 25 years.
The additional notion you bring is that of: "luminance circuit" which I haven't seen anything about to this day.
To note: the symptoms were the same
- on 5 different TVs including yours that you gave me, a Sanyo and a Sony Trinitron, so maybe a weak power supply???
- on coax antenna amplified or not and on SFR internet decoder (the TV is not directly connected to the box, there's a decoder in between),
- on the TV tuner or any VCR or 2 different DVD recorders,
- with 3 or 4 different amplifiers tried,
- with several audio cables either homemade or commercial.
- with connection to the audio terminals of the SCART, on the audio cinch output when it exists and even on the headphone jack thus at different voltage levels and impedances), or on the audio output of a VCR,
Some say they solve the problem by replacing the SCART with HDMI => is the SCART a crappy system?
(Anyway, no HDMI on the TV).
Others by placing the box upright rather than lying down (so here, no decoder, it's the box that is directly connected to the TV, so it's probably interference between the 2 power supplies).
So:
Put a grounded metal plate between the TV and the decoder or the amplifier??? (after you test the quality of my ground).
If the radiation comes from the TV or its power supply...
What do you think?
JP

By the way, I also posted on the "commentcamarche" forum, I just received this reply:
Hello,

your problem is common in the audio circuits of cathode-ray tube televisions, and it tends to worsen with age.

It is due to the fact that all circuits, image and sound, operate on the same transformer: when the image is very bright or has very bright areas, the cathode-ray tube "draws" on this power supply and its filtering is compromised. The noise you hear is mainly harmonics of the sweep frequency: 100Hz, 150Hz, 200Hz, etc... in varying proportions.

The chemical filtering capacitors tend to lose their performance as they age (like batteries), so this phenomenon worsens with age.

Solution: take the audio signal upstream of the television.

For example, use, if necessary, the audio outputs of the sources (VCR, DVD, TNT adapter, "box," etc.) or derive the sound from those same sources (there are SCART cables that allow this, for example).

RESPONSE:
your method is wrong
this TV was connected to my home theater amp and it worked very well.
you need to do this.
box gain: 95%
TV gain, as low as possible
amp gain as low as possible

reminder; the RCA output is standardized to 0.5v or 500mv at 0db
the ear has a selectivity of 3db.
-3db on an RCA output is in log 0.50... so 250mv
never a power supply will be weak enough to create noise of 250mv.
the ripple (voltage variation) of a power supply is generally < 10^% on a tired power supply.. i.e. about 0.9 db roughly (it is hardly heard unless there are harmonic issues)

except... except if the volume of the output is very low.. there the signal will be drowned in the noise of the power supply.
so: all RCA signals as strong as possible and all amp gains towards the speakers as low as possible is the simplest and most effective solution.
try

MY RESPONSE:
Deriving the sound upstream, I've already done it without much success in the past, I'll have to try again to see with my current setup...
On the other hand, it's annoying because if I take the sound directly from the decoder, the sound from the DVD player and the media box with hard drive won't be amplified anymore... What a hassle! But still worth trying...
JP

Haven't attempted so far due to lack of time...
JP

Good evening JeanPierre, I think I have already suggested something that goes in the direction of the question I am about to ask you:

Is there, in all the installation configurations, a single common element (device) that is present in all these installations? You say that you have experienced this phenomenon with many devices of different brands and models, ok, in 3 different houses, ok, in 3 different cities, ok, was there a common device every time the phenomenon occurred? Or was it each time a completely different installation from A to Z?

Otherwise, there is still one common point in all of this, which is the electricity itself, you will tell me, in 3 different cities, but in these 3 different cities, the electricity supplier is the same.

I can only see that element left.

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Hello, STARGATE43,
There have been 5 different TVs, 3 or 4 amplifiers (not home theater) including Dual, Realistic, and NAD, and the sources: several VCRs, 2 DVD recorders, a rooftop antenna either direct or amplified... The 3 cities are indeed close to each other, Lille, Hellemmes, and Tourcoing. What are you thinking?
Best regards.
JP

In the sources, I forgot: currently SFR decoder connected to ADSL modem...
JP

Hello Jean-Pierre, what am I thinking? I was foolishly thinking about the electric current itself, but at that moment, it wouldn't just be you who would be a victim of this phenomenon. I'm digging a bit into everything and anything; this way, we can eliminate certain things and narrow down the search so that in the end we arrive at THE cause.

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To find out if this comes from the power sector, redo the connection I indicated and install ferrites on the power cables.
Otherwise, place them on the SCART connector.

PS: we do not connect an installation without grounding; if there isn't one, install one.

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