Audio Gear 101: Transformers Explained
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- Опубліковано 31 тра 2024
- Ever wondered what he role of a transformer is in analogue audio gear? Learn from EveAnna Manley of Manley Labs in this clip.
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This video is completely inaccurate, Transformers are an alien race from the planet cybertron. They have the unique ability to transform into vehicles, and sometimes even animals.
More than meets the eye!
Lol
Thats not right transformers are clinics were parents take their kids to be mutilated.
Primary winding induces voltage into the secondary winding.
😂😂😂😂 if I didn't know what you are talking about I would have believed you
The core is also laminated to reduce eddy currents.
A robot that turns into a car duuuuuhhh 😂
It is a resonant coupling. Impedance matching device. An electrical equvalent to a mechanical transmission. A proper load mechanism. It is not passive. It has many characteristics.
That explanation was probably quite confusing for someone who doesn't know already how a transformer works.
Simply put, the transformer in this case converts a high voltage AC, into a lower voltage AC.
As the power output from an amplifier is (simplified) it's output voltage times it's output current, the high output voltage means the amplifier will not be able to supply much output current.
So, if it's connected straight to a standard 4-8 ohm speaker, the output will be very weak, as it get limited by available current, rather than available power (the distortion may also increase to much more than wanted levels and the amplifier circuit could overheat - because it's being overloaded).
The transformers job is to lower the voltage and increase the output current - so that the output doesn't get overloaded and all (or at least the majority of) the available power from the amplifier, can be used to drive the speaker.
EDIT: I forgot to mension - running DC thru a transformer isn't a great idea either. It does block DC in the way that no DC is transferred thru it to the speaker - but the primary winding may act almost like a short to DC (current get limited by only the resistance of the winding and not by inductance, as it does for AC), causing it to overheat. It will most likely also saturate the core - causing very high distortion levels on the AC signal as well (far more than what's wanted). To block for example a DC component of the signal, a capacitor is much better to use.
Okay an Introduction Thank Tou transformers are simple until rhe get complex but you get a thumbs up
For staying true to rhe mission!!
All information can help grow the industry
I must have a transformer from that very room in my Manley Core.
Yoou could have gotten someone who does not confuse the hell out of this subject.Something basic like:Transformers are used to change AC voltage levels, such transformers being termed step-up or step-down type to increase or decrease voltage level, respectively.
Don’t they have somewhat different applications when using them for audio vs power? I would think impedance and decoupling would be more important to the context of an output transformer to drive speakers, for example.
@@almightytreegod The only difference audio, compared to power, is in the transformer it self - it needs to handle a very large frequency range compared to power transformers (most power systems is built to run on just one frequency or within a narrow frequency range - compared to audio, where one transformer may handle everything from 20 Hz to 20 kHz or sometimes even better). But it works the same way.
If the voltage is stepped down, the available output current steps up - and the opposite. The thing is that the output from a tube amplifier is high voltage, but can't supply very much current (way too low output current to drive a standard 4-8 ohm speaker).
So the transformer steps down the voltage and that way increases the output current, so the amplifier output doesn't get overloaded and it's available power can be used to actually drive the speaker.
@@Speeder84XL good to know, thanks… now that you mention it, what would determine a transformer’s frequency range?
@@almightytreegod For power transformers, it's mostly the properties of the material used for the core. Any transformer can be configured to work at pretty much any frequency (it's all about having the right amount of turns on the primary for the applied voltage, lowest working frequency, minimum cross section area of the magnetic path and max allowable magnetic flux density
- the amount needed on the secondary to get the wanted step up/step down ratio is then calculated from that)
- but the core material will have a strong impact on efficiency and how much power that can be transferred for a given size of the transformer.
Materials meant for high frequencies (for example transformers in switch mode power supplies), such as ferrite cores, can handle the rapid changes in magnetic flux density at high frequencies well - but can't handle a very high magnetic flux density before they saturate (saturation really something to avoid, as it will cause the input inductance to plummet with huge reactive current in the primary and massive power loss as a result - and also distorted waveform at the output).
But, at high frequencies, not much input inductance on the primary winding is needed either, to limit the magnetization current so the magnetic flux density doesn't get too high.
Iron cores on the other hand, can handle much larger magnetic flux density before saturation, but rapid changes in flux density will cause a lot of power loss in the core it self (due to eddy currents and magnetic hysteresis). So, those are the best to use for low frequencies (where it will allow for more magnetic flux density to build up in each half cycle - but the changes in magnetic flux density will happen at a slow rate).
Now for audio transformers, they are probably a lot larger than mains ones (and defenitely huge compared to the high frequency ones in switch mode power supplies). As most tube amplifiers don't seem to have a very high power output, this might be acceptable.
But, the transformer have to be configured to have enough input inductance to handle the lowest frequencies, without saturation
- for audio, this probably means 20 Hz or even lower. Now another problem will appear - leak inductance.
Not all of the magnetic field from the primary winding is "absorbed" by the core, but a little bit of it leaks out. This inductance will act like if an inductor is put in series with the primary winding. The more turns on the primary winding, the higher this stray inductance become.
It is still not enough to be an issue at low frequencies
- but the audio transformer also needs to handle high frequencies well (up to at least 20 kHz). Now that inductance become significant.
A normal iron core transformer for mains power (50 or 60 Hz) will saturate at 20 Hz (unless it's input voltage is lowered far below it's normal working voltage), but still transfer almost nothing at 20 kHz (the leak inductance will limit the input current so much that not much makes it to the secondary and the voltage will be pulled to almost zero by even small loads).
Now, think about one that is able to handle 20 Hz without saturation at it's normal working voltage and still be able to transfer 20 kHz.
This is indeed the hardest part - according to what I have read, they use special winding techniques and stuff to mitigate the problem with leak inductance. The core also looked like an ordinary iron core - but as she said, they have experimented with different alloys, so it's probably not just the typical found in ordinary mains transformers either.
Awesome info. Thanks. 😊
I could listen to her explain things all day long.
I really like her Manley videos.
Tons of knowledge.
Hmm... I thought of transformers as them transforming voltage or current. Never thought of them transforming impedance.
This was the most confusing description I've ever heard. Maybe do it again when she's fully awake.
I've said in at least a dozen live streams "when you run music through a mile of copper wire wrapped around and iron core it just sounds better"...
Excuse me! A mile?!
I am sorry to say but being an electronics engineering graduate, the explanation for DC not passing through is very poor even for the common public and this can mislead them away from a proper analogy for the true logic.
she doesn't seem to know what she's talking about
Cheers.
They are robotic entities capable of turning themselves into vehicles. But they also may be equipped for battle as a means of self and territory defense
Anyone else think she sounds like the principal from lab rats