Electronics for Audiophiles: Voltage and Current

[@mysock351C]

Nice to see a video that breaks down basic concepts that are generally poorly understood aspects of electronics by laypeople.

[@a.h.d.h.2803]

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.

[@nicksundby]

Superb, this is the antidote to hifi bs, more please

[@avro66]

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 KZbin channel I always look forward to seeing your reviews etc.

[@spocktordock449]

Great level of explanation. I now have clarity on several basic principals after years with hi fi stuff.

[@musicm8kr]

Thanks Amir...I'm a civil engineer and kinda remember this stuff, but the refresher is definitely helpful.

[@TheFilletingfish]

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

[@dillonsaudio]

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!

[@kyron42]

I'm glad I'm not the only electrical engineer/Audiophile to hoard power supplies.

[@juanramon9162]

Nice and instructive video, i would love to see more in the future for more advanced topics

[@artetacarlos23]

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.

[@artetacarlos23]

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.

[@AudioScienceReview]

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.

[@circrna]

I like it a lot. We want to understand the basics so that more people appreciate the importance of measurements. Thank you.

[@SithLurker]

Just want to say that I love all your work, but I find this "Electronics for Audiophiles" mini series especially useful. KUTGW!

[@AudioScienceReview]

Great to hear. Thanks.

[@brikaf6001]

Excellent idea, usually one has to pay for this type of instruction, thank you Amir.

[@roberttv7758]

Thank you for this! Short but full of information that easy to understand.

[@richarddortch6122]

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.

[@rickscheck5330]

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!

[@bernardmueller5676]

Great video. I like that you talk about the basics so we can understand more.

[@sirblew]

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.

[@RalfT-DE]

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.

[@mikeeygauthier2959]

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.

[@freeradical431]

I think we built electric motors and electro magnets in about the 6th grade. Washington in the 80s.

[@mikeeygauthier2959]

@@freeradical431 I’m talking about half a century ago! LOL

[@freeradical431]

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.

[@MsSgent]

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.

[@CobraChamp]

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…

[@sbailey101]

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!

[@AudioScienceReview]

You are very kind. thank you very much.

[@Lauren080508]

Great educational video Amir; so kind from you to spread some of your vast knowledge in the field.

[@HandbrakeBiscuit]

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!!!"_*

[@AudioScienceReview]

:)

[@HandbrakeBiscuit]

@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).

[@johnminassian4887]

Amir, this is very helpful; more please and thank you!

[@erics.4113]

Yes 10x to these videos! In-room measurements and using REW would also be an interesting topic.

[@hasanamin1032]

Great idea Amir. Please continue the series and perhaps a video on the knowledge of common electronic components and their testing procedure.

[@AudioScienceReview]

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.

[@frederf69]

I am grateful for your jargon busting videos, thank you.

[@peterwikvist2433]

Thank you, Amir, for educating us. Much needed and appreciated.

[@samuelsalins8309]

Most trusted coverage 👍

[@SLCVideoProductions]

Nicely done Amir! Always good to see these kind of presentations.

[@stewartw99]

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

[@4sale125]

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.

[@PeterComber]

Very valuable info delivered well. Thanks Amir

[@kellmanmartinstainbank4920]

Excellent presentation. Thank you 😊 Would appreciate more.

[@graywyot]

Lots of useful information. Hope you will make more videos like this. Thank you!

[@cityoflights3808]

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.

[@Trump1776]

Love it very informative and easy to understand.

[@johnwright8814]

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.

[@AudioScienceReview]

Thanks. Impedance is definitely to come.

[@Tuco1965]

Excellent informative video. Please share more videos like this. Great to learn more. Thanks!

[@erickxtrem7807]

Great idea Amir. Thanks for sharing your knowledge, not many of the audiophile comunity are also related to electronics.

[@MrColdchillin81]

Best video from you. Informative and useful. Appreciate this very much. Look forward to the full series

[@johndavidson6433]

You did great job explaining this Amir. Know it would great to see you take on inductive reactance, capacitive reactance and resistance and impedance.

[@deejay6083]

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

[@RalfT-DE]

Funny, it seems that both of us explained the U at the same time. 😉

[@DescartesRenegade]

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.

[@SlickBlackCadillac]

Thanks Amir. Audiophiles are to EE what guitarists are to music theory. We need all the help we can get.

[@GarrettWilliams-RoadHustler]

Loved it. There is so much I wish I knew more about. Thank you for spending your time helping me.

[@jeankazamer9166]

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 😍

[@robertyoung1777]

This was great; brought back memories of high school physics class. Please do more about electricity and electrical components.

[@kyron42]

Passion for Sound told me power cables make a difference to the sound but then he's not an electrical engineer.

[@gitech7450]

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

[@philipppaulk]

Proud to use U for calculating with voltages every day.

[@johngutmanis3580]

I love learning about electronics! Please more information like this!

[@Thoughtflux]

A great video! Please do keep them coming.

[@DruNicholsMD]

I'm starting to dable with creating my own circuits and this was very helpful! Thanks!

[@jonekoo]

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!

[@thomasashley369]

Thanks Amir, educational and insightful.

[@prapor16601]

Thanks for making this things a bit clearer

[@zachansen8293]

cranking out the videos! Love it. I'd never heard of a wall wart that outputs AC - that's fairly uncommon, right?

[@AudioScienceReview]

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.

[@Jorge-Fernandez-Lopez]

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.

[@yonas04]

And you americans dont usw A for current either

[@fwabble]

0.03s into the video - 'liked'

[@tombarber8013]

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?

[@DushkoKantardjiev]

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.

[@AudioScienceReview]

Sure, I plan to cover impedance, gain, etc. in future videos.

[@DalKangh]

Thanks Amir. More like this please.

[@saxon4065]

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?

[@nathandaniels4823]

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.

[@AudioScienceReview]

Yes, I have seen that notation as well. It is mostly used in electrical circuits as opposed to electronic.

[@mixxeerr]

Yes please keep doing these videos... super informative.

[@syf13]

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.

[@AudioScienceReview]

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.

[@freeradical431]

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.

[@ahmonge]

Great job, Amirm. Congratulations!

[@adriangoris2116]

Thank you for this lecture. I look forward to the next one.

[@chefsteve8381]

You should bring out a book ...sure to be a best seller..

[@AudioScienceReview]

Thanks. Books are so hard for me to write. I wrote one once. I took me many months.

[@plasticpippo201]

loved this video Amir! already looking forward to more of these

[@dihydrotestosterone]

Even as basic concepts I need to stop and think about what you just said..... you are way smarter than me.... 😅🤣😂

[@nikosidis]

Thank you Amir. I like your educational videos.

[@vkvedam]

Superb Amir, keep them coming and it's 'Fundamentals' 🙂

[@markwilson0077]

Thank you! Yes do more videos like this please!

[@joentell]

Thank you professor. I appreciate these.

[@HelmutRockstroh]

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 🖖

[@StefanHoops]

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.

[@Jorge-Fernandez-Lopez]

@@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.

[@ericstefko4852]

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

[@EvilNui]

I would appreciate some understanding of electricity. My working theory is mystical gremlins, so I am all for this series! Thanks :)

[@danielgeiger7739]

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.

[@AudioScienceReview]

All good suggestions. Let me finish a first pass of all the basic components and then we can build on them to cover th concepts you mention.

[@komhst]

Nice educational video!

[@CodyMarion01]

Please do more. This is very useful.

[@34332]

Very useful information Amir. I would certainly be interested in follow-up series 👌

[@jtavegia5845]

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.

[@AudioScienceReview]

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/

[@carlosarques]

Very good job!!!

[@MALAKASAM]

Looking forward to these videos.

[@Finite-Tuning]

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]

Current is load dependent, but voltage isn't necessarily. Also, "Current drives voltage thru resistance" Care to elaborate on that, or cite example?

[@Finite-Tuning]

@@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?

[@FOH3663]

@@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 ...

[@Finite-Tuning]

@@FOH3663 : Clearly you're just looking for an argument. Good luck with that!

[@FOH3663]

@@Finite-Tuning Hardly I'm saying stop, this is an endless loop. I do appreciate your presentation. fwiw.

[@HobbyTalk]

Loved this, thanks!

[@FOH3663]

This'll likely go down as a most commented on video... Voltage and Current are inextricably linked, and the interplay between them can be expressed so so many ways. There will be a lot of "yes, but what about ..." Myself, I'm compelled to take exception to and address several comments already. That said, fully grasping Voltage and Current, and the manner in which they are interdependent is vital in the physics of all elements of audio.

[@petersierpinski848]

This was a great video and I'd like to see more. Reading through ASR I've begun to pick up a little understanding, but these videos will help a lot. A quick question. I have an old Quad 303 power amplifier (1967 build) for which the listed input voltage is 0.5v. My setup is a Topping e30 to a Quad 33 pre-amp, to the Quad 303 power amp. The Topping outputs 2v and I use inline attenuators (10db) between the DAC and preamp - because otherwise the volume is crazy at 2. If I were to get an Aiyima T9 - or other tube buffer amp with DAC - would I still need to use the attenuators between the buffer and power amps? I would to begin with but if one day I was feeling experimental, would I damage the power amp as the video says to use the voltage something needs and no more. Thanks.

[@AudioScienceReview]

It is a complicated thing to answer but I think you already know the issue. It all depends on the sensitivity of the amplifier and the type of volume control it has.

[@kinasc1575]

Many thanks for this Amir.👍

[@JC-eh5be]

Thanks Amir for this video. I cames across a website the other day in which it was mentioned how important is to "correctly plug" audio devices to the socket. "Shouldn't be an issue in the US/UK as in those countries there's only one way to do It but in many others, neutral and phase pins from the plug can fit 2 ways to the socket". The benefits (they say) are two: better protection for the equipment and audio improvement (better sound scene, more"open"....blah,blah,blah...). Don't think so but is there any logic behind this? Thanks!

[@AudioScienceReview]

I have seen those reports as well. There can be situations where you could get hum in one polarity vs the other (I have measured the difference at times). But that is the extent of the audibility. If you are not hearing such noise, then I would not mess with the polarity. On safety, such devices better be double insulated. Otherwise, they are dangerous either way.

[@b00m3rh4nd_sol]

thank you great video

[@teashea1]

A good video ---- good presentation style also

[@webmarketing40]

Hi Amir! Thanks again for your job. I have a power supply issue with my small headphone dac/amp powered by pc usb (power + data). When I connect/disconnect it to the pc usb or when sometimes I launch an app, I listen an uncomfortable bang noise. i saw in AliExpress a small board that announces correct this issue, but because I´m a nerd in this issue, I´m not sure if it will help me. (USB Power Filter Noise Eliminator USB anti-interference filter board for Amplifier PC computer Power purification) Thanks.

[@AudioScienceReview]

Hi there. Thanks for kind words. I have tested a number of such noise eliminators and none do anything useful. If you are going to try one, get it from some place with easy return.

[@donalddluckerii3147]

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.

[@AudioScienceReview]

Good point.

[@outboardfun3353]

I would like you to review the puritan audio psm156 . I'm thinking of buy one and it is getting great reviews

[@gordthor5351]

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.

[@adrianmorrish8494]

Thanks Omar/anyone else kind enough to reply, very helpful and an area I am still fuzzy on not being an electrical or electronic engineer or even a dangerous amateur. I have the most issues with low impedence planars for headphones, so a lot of the ifi Zen level equipment seems to have issues with low impedence devices, I have heard this described as current starved. What is the design principle that causes this I.e. they can often drive high I pedence headphones but connect an 8ohm or lower headphone and ey struggle unlike my other amps.

[@AudioScienceReview]

The fact that the impedance is "low" (generally anything less than 50 ohm) means that the amount of current limits power, not voltage. A good headphone amp has both current and voltage so you can drive a huge variety of headphones and not worry. On the other hand, some headphone amps like tubes can only deliver voltage and do poorly with low impedance headphones. I will do another video on this topic in the future.

[@DougMen1]

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.

[@jeffreythurston1822]

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.

[@AudioScienceReview]

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!