Ok heres the deal. When i turn of the speakers in both my Luxman l30 and new Marantz pm5004, and when i turn it up real loud (full way) while music is still playing through it i can actually hear the music from inside the amplifier. why is this?
Thanks in advance for your input
Thanks in advance for your input
please explain. p.s im actually studying electromagnetics at uni so do not hold back on the "slang"
If you are studying electromagnetics at uni we should hardly have to explain why current or voltage through a wire can cause it to move and cause sound.
Is it magnetic forces at work when its a transistor itself that is clearly audible and producing the sound ?
What year? Well like others said I would guess its electromagnetic forces interfering with the signal that is being processed. My receiver also does this ( 100$ ).
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Lorentz forces (i.e. normal electric motor action), magnetostriction, piezoelectricity - all methods by which electrical activity can produce sound.
If there is no output load then currents will be low so my guess is piezoelectricity.
If there is no output load then currents will be low so my guess is piezoelectricity.
i hope its not "cheap" ones they are a luxman l30 (around 1970 i think) while the other is a new marantz pm 5004 (bought it in 2012). but i do get what your saying.
Quite interesting. What could be acting as transducer?
The output coil even though almost unloaded? (...except for the...)
The headphone-output voltage-divider?
The FL display picking up power supply 'noise'?
In my car the cabin airflow fan act as a speaker and 'plays' out the ignition-noise of the engine.
The output coil even though almost unloaded? (...except for the...)
The headphone-output voltage-divider?
The FL display picking up power supply 'noise'?
In my car the cabin airflow fan act as a speaker and 'plays' out the ignition-noise of the engine.
Maybe. Its an effect I noted when I first started playing around with amps and semiconductors. A pair of T03 devices can be surprisingly loud.
I once had an amplifier with TO3-transistors, who emitted heights at loud music.
You can very easily locate the place. Take a thin tube (Aquarium tube for example), one end in the ear and whit the other end you can locating the music.
You can very easily locate the place. Take a thin tube (Aquarium tube for example), one end in the ear and whit the other end you can locating the music.
I first noticed it on a high-voltage amp with bipolar transistors in the input stage and PL519 valves in the output stage. The PL519s seemed to produce the sound. I didn't dare to put my ear close to the PL519s, that was a bit too dangerous with 1100 V anode bias voltage.
Yes, I have also noticed it many times, when the speaker is not connected of course, because of masking.
I have heard output transistors/transformers/tubes/power resistor loads "sing".
I have heard output transistors/transformers/tubes/power resistor loads "sing".
I remember those as TV line output valves 😀 You could draw quite an arc from the top cap of those with a (well insulated) screwdriver.
I've never heard of Transistors "singing" due to the piezo effect. I'm not saying that speculation is wrong, I'd have thought it was something a bit bigger than a tiny silicon chip making the noise.
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