Yay! Basics! Now I'm a pensioneer I finally have time to spend on the physics/science behind the devices which have brought me so much pleasure when producing sounds I love so much. I'm now on a level of learning to know which properties are important. Basics and their correlation will teach me why they are important. Thank you Amir! More video's from you about basics will be much appreciated.
Thanks Amir for sharing your wisdom. Your brief presentation of electricity came through crystal clear from someone that has a intermediate understanding. Please produce more videos and thank you for making your content so dense without unnecessary tangents probably the hardest part for you/anyone. Praise you Sir
Yeah exactly. ASR product reviews demonstrate the same high value! No audiophile buzzwords or imaginary claims. It's no wonder Amir has achieved great success....and I wish you all the best Sir!
Hi Amir. While serving in the Royal Air force back in the 90s I studied electronics although I was a aircraft fitter, and a hifi buff, it really helped me understand the workings of all things hifi. Thanks for a great RU-vid channel I always look forward to seeing your reviews etc.
Thanks. Originally I was going to do it that way but then decided to cover this topic first. They are inter-related so figuring out the order is tough.
I came about your videos looking for a quantitative 3rd party analysis of speakers, the only ones I've been able to find to do it are you and Erin. Thanks to your videos and the Audio Science Review forum posts I have learned more about sound engineering than I ever would have predicted without going to school for it. I'm fascinated by it all. I would greatly appreciate you continuing your educational content. I never would have imagined that I would fall into this very deep rabbit hole because I just wanted to find a good sound system for my living room.
And I don't mean that reviewers who don't do quantitative analysis don't know what they are talking about, but as a person who just started to get into the hobby, measurements are far more valuable and much easier to use to compare than descriptions of sounds.
Thanks for the comment. For my part, I want to make sure my desire to always explain topics doesn't go beyond what people want to hear! :) So the feedback is great.
I really enjoy seeing other people's way of explaining these concepts! It helps when I'm trying to break down information for people with little to no knowledge on the topic.
Amir, for velocity symbol is lowercase v. The origin of symbol U is the Latin word "urgere" (Alessandro Volta was an Italian physicist), which can be translated into English and means more or less to push or to force. Whole EU use U as a symbol for voltage. There is a couple of other good reasons for that too: 1. to distinguish symbol for voltage from unit Volt (V=2V vs. U=2V) 2. V is symbol for volume
In mechanical engineering, physics, materials science, quantum physics...all use the same symbols and letters. There's only so many to go around. They mean different things in different areas of study.
We are using in Germany and allover Europe the U for voltage which is coming from the latin word "urgere" (translated to English: "to urge") Anyhow we use Volt same as you as SI unit. Just for explanation. 🙂 This makes totally sense since voltage is urging into your device or your body (and can kill it or you when it is too much in combination with a certain amount of current) while current cannot do that without high enough voltage to overcome the resistance of your body first (as long you don't shortcut it - heat will be a problem in this case) since the device is just taking what it requires as long the source can deliver it. One more thing. Even so this video was to basic for me, I think it is extremely well done for people who have no technical background at all and are therefore an easy target for snack oil garbage. As always well done Amir. 👍🏼🙂 Thanks for all the effort you are spending for the music lovers community.
Thx for this; reminds me of my grade 11 physics class in 1968 when I learned how electricity was made and an electric motor worked!! Will keep following for sure! Electricity can go around the world seven times in one second! Thx again.
I think its interesting how the curriculum changes. I doubt they teach it anymore, unless you can wrap a wire around a nail and connect it to a battery,.......................... on a "smart" phone.
Just reverse everything from physics class. Electricity runs backwards for electrical engineers since Ben Franklin developed all the foundational EE equations and didn't have the physics basics and theorized electricity in reverse (it works out either way) and the two disciplines have never united.
Thanks for this, it's important information for audiophiles. The follow-up video could discuss the related topic of impedance. In the days where valve (tube) amplifiers were the only ones available, the output transformer had impedance taps for maximum power transfer to the loudspeaker, usually 4, 8, or 16 Ohms. I wondered whether tube headphone amplifiers would provide taps on the transformer, since headphone impedance varies much more than loudspeakers, usually between 32 and 600 Ohms. A manufacturer has now produced one, but the audio reviewer uses the taps to facilitate tone control adjustment. There is much discussion about which headphone amplifier will drive which headphone. I told them in comments what these numbers mean, but it falls on deaf ears. It would help their audience if they knew what they were talking about.
Amir, you're a great guy and a huge asset to audio enthusiasts all over - it's important for consumers to know these concepts. Yet you've just ruined the sound of my hi-fi - I swear in the background I can now hear various makers of super expensive hi-fi amps and power supplies screaming *_"Nnnnnnnoooooooo!!!"_*
@Listener - Audio Enthusiast Because a lot of the marketing and sales tactics they use rely on customers being ignorant. Music lovers having a fundamental understanding of basic concepts and how they apply to & the degree to which they affect audio equipment means we can better choose and judge what equipment to buy (or not buy at all, in the case of stupid things like power conditioners and special mains cords and so on).
More countries than Germany use "U" in formulas for voltage, although unit is always "V". "V" for voltage variable is new to me. Example: U = R · I; for 4 Ω and 3 A, potential difference will be U = 4 Ω · 3 A = 12 V → U = 12 V. "v" usually means, while "V" capital letter is the unit, and "U" is the variable. It's like distance, we don't use M for distance, but "d" or any other letter. d = v · t = 3 m/s · 2 s = 6 m → d = 6 m. "m = 6 m" or "M = 6 m" would be weird.
Excellent! This will make a great playlist b your channel What a great idea for a series of videos. You are the perfect person to provide such tutorials, entertaining but factual and science based. Some comments from the most recent power cord review indicated that many “audiophiles” seem to have little to no understanding of basic principles of electricity, including what AC power actually is and how it works., let alone what happens inside the equipment as its regulated and turned into DC. Indeed, they don’t seem to u sweat and how their house wiring works. As you say, one doesn’t need a degree in the topic, just some fundamentals in order to understand what actually matters in audio devices and music reproduction, and what doesn’t.
Thanks for this video. Please do more of these as it helps fill the knowledge gaps for those of us amateurs who learn about electronics through ASR osmosis.
What an excellent presentation! Thank you and isn’t it surprising that manufacturers don’t spend more time bragging about the real electronic strengths of their gear…
Hey Amir, great video, please do more of these electronics primers. Thank you very much for the time and effort you put into your web site and this channel. Surely it is one of the best sources of info that can be found anywhere on this. cheers Stewart
yay for more elementary electronics. in a future video tell us the formula for calculating the distance cables are needed to be off the ground and away from walls for earth-shattering bass, silky smoothy mids, and whipped cream highs. danke.
Good video. Just want to add that in some circles, Voltage is represented by “E” (electromotive force)….as in E=IR. Units are still represented with a “V”, however.
This is good just like all of your other content and all of the others content as long as it is all taken as educational. ;) Educational equals entertainment. For those who seek intelligence
I’ve been an electronics “dork” for over 50 years including ham radio license (age 10) and 2 decades as an electronics technician- component level ( e.g. transistors, caps etc). I’m amazed that I learn something from even your most basic videos like this. I’m so happy to have found your channel. Every other channel was mostly a jumble of audio-phoolery, poetry and subjective junk. PS Audio and Audiphilliac I’m looking at you!
Superb! I learned at least one thing out of every card !!! I believe this kinda of learning/edcuational on basic things is a must now . No stress, but they will be welcomed by all that is for sure ! Again much luv to Amir big boss of the quite revolution of audio LOL 😍
They have certainly fallen out of favor in the last two decades. Still, a number of companies use them for their desktop products. Examples include Schiit Audio, JDS Labs and recently Topping. A number of phono stages come with them.
Thank you Amir for this video!! Yes please keep them coming and thanks for your hard work in managing ASR and fighting for the truth in all things audio. Much appreciated!
Understanding the basics helps the bigger picture. Thanks! I have never been able to hear the differences in certain "accessories" where other people do. Most of the time for me it seems to be a volume variance when it comes to well engineered components. Maybe my ears are actually my friends by saving me from wasting unnecessary money😀. Good components are expensive and well worth!!! but there is possibly a little funny business going on sometimes. Where to start drawing the line?
This is great !!! It helps us understand the concepts of measurements. Would love to see more of this, For example some amps are more 3d than others what measurement / factor determines this. Therefore if this is a key attribute I would like to be able to look at a number of amp metrics to determine which one will give me that
Like it! I like that you start from rock bottom. I would not mind getting a bit more into the details. E.g. show a case where a device does NOT behave like an ideal voltage source, kind of a compare and contrast approach. Also a bit more details about switching power supplies would be nice. I can see that by increasing frequency of the AC you can smooth out the valleys, and omit the capacitor. How far do those go? From 60 Hz to 1 kHz, 40 kHz, 1 MHz? Or is a time delay done on overlapping 60 Hz waves? Could yield similar results, but may also cause interference peaks. Any relationship to Nyquist limit? That sort of thing. I have no clue about electronics, just a biologist. I do know the 4-diode Graetz circuit, but that's about it. You threw in primary and secondary windings in your transformer explanation. That may need a bit of explanation for some folks (no problem for me). I know it is so hard to explain things in your area of professional/research expertise to a GE audience. It is much harder than talking shop to colleagues, everybody rolling jargon. So thanks for doing this.
I agree with several comments about how it is quite reckless to claim that current is not dangerous. This is so very easily misunderstood, as is "voltage is not dangerous". I would add to the dangers of current vs. voltage discussion a couple of things: 1. DC and AC have different effects on the body. For AC the frequency is also important. 2. In electric cars, the electronics might operate at 400V or even 800V and the battery is capable of providing a huge amount of power (current for that voltage), so I would be very careful about talking "car batteries" and what they are capable of these days. :) Thanks for the otherwise nice educational video and all the other invaluable work on debunking audio myth!
A video devoted to the topic of voltage "sag" would be particularly useful. While it is a real phenomenon in specific scenarios, it is also used by some audiophiles to rationalize the purchase of amplifiers with current capability very greatly in excess of what is needed for the speakers or the headphones. When this is called into question, people who are convinced that more amplifier power invariably improves sound quality will often start talking about dynamic peaks and about the crest factor, etc. These also are perfectly real considerations, but the fact that they are real considerations does not mean that greater current capability for an amplifier will invariably improve sound quality. With respect to the concept of current limiting, Ohm's Law assures us that current is fully determined by load voltage and load impedance. This implies that if current is lower than the value that, according to some reason, it should be, this will occur if and only if the voltage across the load is lower than the value that, according to some related reason, it should be. A good and well-known example is what happens with batteries when they go bad. The intrinsic voltage of the battery often does not decrease by much when the battery ages or runs down. Rather, what happens is that the internal impedance of the battery, in series with load connected across the battery terminals, increases. When this occurs, the load's share of the voltage decreases because its share of the series resistance decreases. Additionally current will decrease due to the overall increase in the series impedance, however the current through the load will always be related to the voltage across the load in the manner required by Ohm's Law. Which is to say, load current will not decrease independently of a corresponding decrease in the load voltage. This is absolutely, universally true. Thus, in the case of an amplifier that responds to overload by reducing current and power, this is necessarily accompanied by a reduction in voltage, and as such, the question that begs for an answer is why this circumstance would be deemed to be expressly about the amplifier's ability to deliver current, as opposed to its ability to deliver voltage. If an amplifier does behave this way, the reason it does is probably that it is designed to behave this way. That is, there is circuitry that responds to high output current or to excessive heat buildup by reducing the voltage gain, thereby lowering the output voltage and, accordingly, the load current. If there is no circuity of this particular sort, what happens in this case, if output current is high and/or there is an excessive buildup of heat? If the amplifier goes into voltage clipping, this will lower the mean output voltage over time, which will lower the output current. Another possibility is that the amplifier does not tolerate heat as well as it should and begins to overheat with no voltage clipping. If the amplifier does not have the means to protect itself either by reducing the voltage gain or by shutting down, it would potentially sustain damage. Another possibility, though, that is sometimes brought up, is shrinkage of the DC voltage rails (+/-) provided by the power supply. (No Seinfeld jokes please.) If this actually happens, it would lower the threshold for voltage clipping, thereby having the aforementioned regulating effect. And this could possibly be done by design, as a self-protection mechanism, although it would be a decidedly inferior technique in comparison with reducing the voltage gain. The scenario that is interesting (because it is something that lots of people think happens), is that in connection with the depletion of charge in the filtering capacitors in the power supply, shrinkage of the voltage rails will occur naturally. (No Seinfeld jokes please.) To be honest I'm not certain whether this will or won't happen, but what I recall from a long time ago when I actually studied this stuff a teeny bit, is that what will happen when the capacitors don't have the capacitance they should have in order to deal with the load impedance and the output current, the ripple factor will increase. To my recollection, this is what is supposed to happen when the filter capacitors aren't up to the task. Yet people often talk about voltage sag on the DC rails when the filter capacitors aren't up to the task, with no mention of any increase in the ripple factor. I am disinclined to think that this is the correct way of understanding what happens in the scenario where the filter capacitors are not up the task. I've also read where people claim that you need to have expensive power cords in order that the filter capacitors will be able to do what they are supposed to, when the filter capacitors aren't able to do what they are supposed to do, again with no mention of increase in the ripple fact. This, to my way of thinking, is completely off the rails. This strikes me as something that could be answered fairly easily with help of an oscilloscope (once upon a time I owned one and I have no memory of what happened to it). Use the scope to display the rail voltage, and use a high-current variable resistor of some sort, in parallel with the speaker or headphones (or just the variable resistor without the real stuff), and watch what happens to the rail voltage when the load impedance is gradually lowered. Does the DC rail voltage gradually shrink, or does ripple appear? It would be interesting to do this with both a moderate quality amplifier and an expensive amplifier with the claim of high current capability, to determine whether what happens to the rail voltage is fundamentally different for different amplifiers, or whether the difference is merely a difference in the threshold (for load impedance) where the ripple exceeds some tolerance level. (Assuming that the amplifiers don't shut down or enter a protection mode before the ripple factor noticeably increases.) Personally I think this would be enlightening and I am hoping that Amir will be stimulated by what I have written, to do this or something similar. What exactly happens at the voltage rails when an amplifier is pushed to the limit or when the music presents the amplifier with a signal that has a high crest factor? Does the DC voltage actually shrink?
Thanks Samir for the clear disclosure of the fundamental concepts. As a follow-up related to what Tom was describing, it would be useful to correlate the concept of GAIN to the U and I source, and how all these interwork with the load impedance Z. Thank you again Samir.
Would love a video that covers the nitty gritty details about output/input impedance matching (e.g. source to preamp to power amp). Particularly the scenarios that can lead to problems when pairing devices. A deeper dive into input sensitivity would also be helpful. Thank you for making these videos, and especially for the existence of ASR! It has been an incredibly helpful resource for better understanding the actual science that makes for great audio.
Impedance matching has been on my todo list. Had forgotten about it though so thanks for the reminder. :) And thanks for the kind words. Much apprecited.
We have been Gain matching in car audio for years. Class D stable to 1 or .5 ohms for years, clipping indicators for the last 5 years and for some reason the hifi realm hasnt or doesnt but thinks it should cost 100 times more.
Very good video. At some point it may be useful to explain amplifier output impedance and damping. Some people like to use amplifiers with a higher output impedance which means they like their bass less damped.
Good stuff! ⚡ I would like to add that current and voltage are load dependent. You have 1000 watts per channel, but it can't go anywhere without the required load to demand that power! Lot's of people just don't understand, they have all this supposed power but it won't go anywhere unless they have a load great enough. Current drives voltage thorough resistance; But nothing moves without a load. Cheers 🍻
@@FOH3663: Voltage won't go anywhere without a load, it's just present and that's it. Voltage also will not go anywhere without enough current to drive it. The simple act of trying to measure voltage can bring it down to zero if there is not enough current to support it. Since all conductors have resistance, voltage cannot move through the resistance if there isn't enough current to sustain the voltage. So the way I try to explain this to people is simply "Current drives voltage thru resistance". Make sense?
@@Finite-Tuning Is this an endless loop, chicken before the egg argument of causality? As I said, they're inextricably linked... Their product is key ...
Great channel. Have you thought about measuring phono cartridges as not one else seems to do it since the demise of Stereo Review. I have a number of Shure test LPs I would be glad to donate to the cause. Phono preamps would be good to measure as well to see how well they follow the RIAA curve. I grow tired of the AAA crowd that thinks that only Analog can be great.
Thanks. Yes, I have thought about measuring cartridges and get frequent requests to do so. The challenge is how. What turntable to use and how to demonstrate correctness of measurements. On Phono stages, I have measured good number of them. You can see the list of them in this latest review: www.audiosciencereview.com/forum/index.php?threads/ifi-zen-phono-review-phono-stage.35240/
Re the U vs V "confusion“ inGER. In EN the term "Voltage“ and esp. it’s abbreviation “V” is used synonymously with the Unit! “Volts” also abbreviated with a “V”. In GER the unit “V” is of course also used in keeping with international convention. BUT! instead of “Voltage” we use “Tension” (Of course in its GER form=“Spannung”) to indicate the physical entity. For us it actually AVOIDS confusion using “U” as you pointed out. Love your videos 1000👍! You integrate expertise and data with levelheaded sense while appreciating the personal/subjective elements. KUDOS 🖖
Furthermore: The symbol for voltage is U. The origin of this symbol is the Latin word „urgere“, which can be translated into English and means more or less to push or to force.
@@StefanHoops Spain, France, Switzerland also use U for the symbol or variable, and V for the unit. Otherwise, it will be a little odd, like using "m" (meters) for the symbol.
I've already stated this but I don't see the comment. It is not crucial to provide the exact voltage or current to many , many different devices. It is common practice in residential and commercial installs to use 1 universal power product with a budget that is greater than the devices may need. We use P.O.E. injectors for the wireless access points, I.P. cameras and keypads we install. The P.O.E. injector is 48v. The access points require the 48v but the cams and the keypads do not ,yet they all work. this is because they simply draw the power they need to work. Under power any of these devices and they won't work properly or at all, but generally products will pull the power they need.
Also, measure the voltage of your adaptors before plugging them in. The one time I didn't I cooked an ESR meter (12volts) with a "12 volt" adaptor outputting 24 volts. I can't even repair it because the main chip and 2 voltage regulators got smoked, which I am unable to find replacements.
This a an awesome idea to get your knowledge out to non electrical engineers. Thank you so much!! One question. You mentioned that a shock could occur in a device that is not plugged into the mains. How does this happen? Is it because the capacitors hold a charge? If so what is the safe way to get inside a piece of audio equipment and avoid electrical shock? Thanks.
Exactly right. Without understanding electronics fully, there is no guaranteed safe way to know that there is no danger. If you can identify the internal power supply and keep your hands away from it, that helps. Be sure to have socks and shoes on and don't tough anything else metal. Also, pull out the power cord while the unit is on. That will usually drain them. But again, there is no guaranteed foolproof way. This is why some of us who have worked with electronics for years, have stories to tell of being shocked!
I would like more info on matching impedance: output impedance in dacs and input impedance on amps, how it affects the signal. Is it similar to headamp output impedance and headphone impedance that you mention? Also the concept of load impedance.
Definitely a topic to cover in my todo list. In general, you never, ever want to match impedances in audio! Doing so causes power loss and no benefit. You want the source to have the lowest impedance and target, highest although a 10:1 ratio is good enough.
You forgot to mention that on DC adapter type supplies, such as those used for guitar pedals, the plug polarity is important too. Guitar pedals need center negative on the plug, although some generic adapters have multiple tips, and some can even switch polarity, so they can be used with different polarities and tip sizes. Also, tube amps step up the 120V AC (and rectify it) to a higher DC voltage for the plates of the tubes, in order for them to operate properly.
"Current alone is not dangerous" the same way you can say "Voltage alone is not dangerous" without voltage there is no current. (generally) You can be on view KV potential on the whole body without noticing if there is no current flowing But but even a view mA trough he body give you a shock
Most people are safe from electrocution because they have a high impedance to ground. Fic that and those KV sources will send you to heaven before you can say a prayer!
@@AudioScienceReview Because they have high impedance the current is low. only if the KV source is a "high" current source. Static electricity for example can be may kV but is save
U isn't voltage, it's tension. Tension, by definition, is potential difference and difference in German is Unterschied. Hence the U. Shold have used the S for Spannung if you ask me. Similarly, I isn't amperage but *Intensité de courant* or just current. We only express it in amperes. R isn't ohmage, it's resistance. P isn't wattage, it's power, f isn't hertzage it's frequency... :)
