Thank you Paul for having the patience with viewers like me who keep struggling with these concepts, but want to understand eventually.

@Paulmcgowanpsaudio

5 ай бұрын

My pleasure. You're why I am here.

@freekwo7772

5 ай бұрын

This one is so far the best!

Ohms Law. Foundational set of calculations that explain how so many things work. One analogy I use to explain loads and power in a circuit to gearheads (I am one) is power to weight ratio. Same HP engine in car that weights 1k lbs vs 2k lbs. Why is the 1k lb car faster. Same concept of load vs power and like your comment, seeing the light bulb come on is priceless.

Thank you for this. Each time you answer this I understand it better.

I may or may not know a guy who just picked up one of your amps on sale! Crazy good deal! Can’t wait to hear it!

@ryanschipp8513

5 ай бұрын

Which one?

I do appreciate that you answer the same question over and over, and sometimes you have to find the right analogy to click. All of us have different backgrounds, and those who haven't taken years of math and engineering (and even those of us who got lost halfway through Electrical Engineering 201) need the right orientation of the imagination to get it to fit with our experience. With electricity, I like the water analogy: voltage is water pressure, amperage is water volume-per-second, power is "fire hose vs. garden hose vs. kitchen faucet", little sparks are "much pressure little flow". And yes, it falls apart when talking about inductors and capacitors!

@ThinkingBetter

5 ай бұрын

Yeah, when you have worked enough with voltage, current, power and impedance, you get a sense of these like you do with water flow. I've seen many are struggling with power (energy per time) and energy. For an amplifier, what is 100 Watts? Actually, the human body is typically using around 100 Watts or 100 Joules of energy per second. That means your body is using the equivalent power (energy per time) of anything in your home using approx. 1 Amps of current from your US mains socket or approx. 0.6 Amps of current from your EU mains socket such as an amplifier using 100 Watts. A Big Mac contains about 2,250,000 Joules of energy. Thus your Big Mac can keep you going for 22,500 seconds or more than 6 hours. A modern EV might have a battery capacity of 100kWh, which is 100 * 1000 * 3600 = 360,000,000 Joules or the equivalent energy of 160 Big Macs or keeping a human or amplifier playing very loud going for about 1.5 months (do the math).

Blimey, first time in my life that made sense, cheers Paul

Thank you for having the patience of a Saint to go through these beginner electronics concepts! I've known this for decades but it's great for beginners. I think all audio enthusiasts should play with breadboards and components at one point just to get a feel for how the engineering works for audio production.

Nicely done, thanks Paul.

That’s the best explanation I’ve heard for that question 👍🏻🔈

Illuminating. Thanks Paul.

I’ve been struggling to understand this thank you Paul

Good stuff Paul, Cheers.

I got! Thanks Paul 🎉

Brilliant explanation.

love u Paul 💯 nice guys all the time 👍👍 current amp. is the best ans.

Actually, my light bulb went ON! Thank You, Paul!

Power = Voltage * Current. Current = Voltage / Impedance. Thus Power = Voltage * (Voltage / Impedance) = Voltage * Voltage / Impedance. Since a power amplifier actually is a voltage amplifier, the output voltage is a fixed factor against the input voltage. Let's say your output voltage is 10 Volts and the impedance is 8 Ohms, your output power will therefore be Power = 10 * 10 / 8 = 100 / 8 = 12.5 Watts. If you use 4 Ohms, you will get Power = 10 * 10 / 4 = 100 / 4 = 25 Watts. Since you divide by impedance, half the impedance means twice the power. This is true only if the amplifier has low damping factor and can keep the output voltage constant. So what happens to the power if you double the voltage?

Thanks Paul , im sitting in my local coffee house and when you made the fart noise with your mouth i had a couple dozen people whip there heads around and look at me .

Kudos to you Paul for being happy to explain the same thing many times over. Were you a teacher in a previous career? 👍

I have a question. I wired a second set of 6 ohm speakers to the positive and negative terminals of the other pair, then attached the first pair to the amplifier. Is this parallel now? Meaning that it is now 3 ohms as I've read? I have a very cheap amp that I'm using it with but I hear it can get down to 2 ohms per channel (Aiyima A07), I've been running it a lot over the last week and it's still fine. Is this bad for my amp?

Thank you

So are 4 ohm speakers sensitivity ratings typically “boosted” by 3db because the sensitivity test is done at 2.83 volts, which results in 1 watt into 8 ohm load, and 2 watts into a 4 ohm load?

@wally7856

4 ай бұрын

Yes. For a fair comparison they should be tested at 2.0 volts. Although in practice it doesn't really matter because the amplifier you have has a fixed constant voltage output.

Hi Paul, with this explanation, can I thus assume that a speaker is a resistor - and 8 ohm would use less current flow because the resistance is less than that of an 4 ohm. Resistance is thus the "blockage created to the water outflow"

So, the amplifier senses the speakers resistance (ohm) and adjusts the current level accordingly? Is this in any way connected to global feedback? Thanks!

@wally7856

4 ай бұрын

No, the amplifier puts out a fixed voltage in relation to the input. It could cares less what ohm load it goes into or even if there is a load at all (solid state amplifier) as long as the current flow doesn't exceed the amplifiers current capacity.

Thank you very much. But why do some amps produce a linear response to changes in the resistance and most don’t?

@philiptong4978

5 ай бұрын

you mean something like 100W at 8Ohm but 180W at 4Ohm? because the device is unable to maintain the same output voltage, e.g. due to non-zero output impedance

@Jeep_on_audio

5 ай бұрын

That's because of the power supply. If you don't have ample supply of power you can't deliver.

@stevengagnon4777

5 ай бұрын

​@@Jeep_on_audiothat's the limiting factor for the amplifier. Many don't have enough reserve in the power supply to provide enough curent to double the maximum output.

The question I have is how does one determine how many amperes(current) an amplifier has, or can produce, and why isn't this information listed in the specs. of most amplifiers?

Good explanation Paul.Hope business is good?

The part the he left out is engineers have discretion in designing for impedance. Some designs hold the output wattage constant at any impedance. Some double it from 8 to 4 ohms. Some pick an arbitrary factor between 8 and 4 ohms. Impedance wave forms in speakers may be interpreted differently. Yamaha says the NS-5000 is a 6 ohm speaker with a nominal wattage of 200 with a maximum wattage of 600. The wave form could be 6 or 4 ohms.

What about tube amps (8 ohm vs 4 ohm)? It seems a Rogue M-180 is the same wattage no matter what tap you choose since Rogue does not even mention it in their specs.

Thx

1) So how does the current or wattage go up just because its "needed"? 2) so at the same volume knob level, which speaker is louder, 4 or 8?

Please correct me if I am mistaken, however given your example... the Loudness we would hear coming out of each speaker (the 8 ohm or the 4 ohm) would be exactly the same. And so despite now playing the music at 4 ohm 200 watts, it is sounding to us exactly the same loudness as the 8 ohm speaker playing with 100 watts. Is this a correct assumption / statement?

@tedhersh9095

5 ай бұрын

No. The loudness of the speaker is a function of the speaker’s sensitivity. Speakers sensitivity is measured as how loud (dB) it is with 1 watt input 1 meter away. It takes double the power to increase the speaker output by 3 dB. If the two speakers we are talking about have the same sensitivity and we play one with 100 watts and the other with 200 watts, the 2nd speaker will be 3 dB louder.

@Jeep_on_audio

5 ай бұрын

Yes. Given the cone surface, weight and suspension stay the same. If you put on a coil with double the windings, you can get more magnetic field out of it and get more push, (more sensitivity) but it doubles the resistance of that coil. What makes it difficult is that the mass of the cone keeps it vibrating which also induces an electric field that interacts with the input. That's why it is impedance (it impedes the input signal) and not just linear resistance. So yes, but it's not that simple in practice. But for understanding you are correct.

@Jeep_on_audio

5 ай бұрын

​@@tedhersh9095 And how do you get a more sensitive speaker? Right. More windings. If you look at the specs of the same drivers that are sold in either 4 or 8 ohm you can see that sensitivity drops on 8 ohm version by 3dB (give or take). 3 deciBell is 10x log 2. Double the power is 0.3Bell or 3 deciBell more.

@johndaddabbo9383

5 ай бұрын

Thank you!

@johndaddabbo9383

5 ай бұрын

​@@Jeep_on_audio Agree, however as an 'all else being equal' Question/Answer my assumption is correct (good). Thanks.

Keep in mind that doesn't mean the 4 ohm speaker is going to play twice as loud. that all depends on the sensitive of the speaker. the most you would get is a 3db increase all being the same.

Is it safe to say you need a high current amplifier to make that work effectively, and is that designation required to be in the specs?

@wally7856

4 ай бұрын

High current amplifier is in the specs but it is hidden under the spec "minimum impedance" each channel can handle. A 2 ohm rated amplifier has twice the current capacity as a 4 ohm rated one.

@valleyguy633

4 ай бұрын

@wally7856 yes, I understand what you're saying. My S 300 more than doubles from 140 @ 8ohms to 300@ 4 ohms, if those numbers are accurate anyway. Thanks for your input.

Assuming voltage remains constant, does wattage increase as impedence decreases because with less impedence, more current flows more quickly from amp to speaker?

@wally7856

4 ай бұрын

exactly

Could you compare this to water pressure through a hose somehow?

The double with half ohm is logical after I learned it some years ago. But a 100w amp is not always a 100w amp either.. Some messure at only 1kHz on maybe just one channel instead of 20Hz - 20kHz on all channels. That makes higher wattage numbers but the amps behind it is low so it's weak watts. Watts is not just watts. You need both volts and amps to get powerful watts

Would like to know how McIntosh keeps the same wattage in 8-4-2 ohms!🤯… so their amp are weaker?

@danijel-c

5 ай бұрын

Read the documentation.

Just like speaker's impedance that varies thru the Hz frequency supplied by the incoming signal

so in this case the power limit of the amp is determined by the voltage it can produce .

@wally7856

4 ай бұрын

Yes, but there is also a current limit which if exceeded will trigger some sort of protection so that the amp doesn't catch on fire. That's why amps also list minimum impedances it can drive. An amp rated for a 2 ohm load has to output twice the current as one rated for a 4 ohm load (even though both are at the same voltage) so it would have to be designed as such to handle that current.

It may be confusing if we compare to tube amplifier and may be the reason of repeated questions . The main difference with tube amplifier is our care not to loose any watt, which is not the case of solid amplifiers For tube amps for each impedance we dedicate separate output windings of transformers. For them the condition of pemanent output voltage usualy is not true. and max power is (supposed to be) the same and nominal for each spaeker impedance.

💡

The comments are making me crazy. Here it is: Impedance (as the name implies) is opposition to electron flow (current). The lower the impedance, the more current you get, the higher the impedance the less current you get. The wattage is voltage times current. Look up Ohm's law, and drop Z in place of R. The math is the math. For those of you who want the advanced version, look up reactance (X). Enjoy.

Folks might like to look at a picture of an "Ohms Law Wheel" to see all the versions of the calculations.

@carterwilliamhumphrey3373

5 ай бұрын

I might add, drop "Z" in place of "R" in that wheel, and there a twelve formulas telling the same thing.

The only way I can get my head around this is to use an analogy. Is the following a correct way to think about it: An engine of a certain size might be said to produce 100 HP “into” a lawn tractor, but only 50 HP “into” a small car. Same engine, same capacity, but its power delivery can double depending on load.

@Jeep_on_audio

5 ай бұрын

Not a very good analogy. Try a garden hose. Or a canal. Your tap can only supply so much water. The wider your hose is ... Anyway, the amount of water you can spray is not dependent on the size of your hose but on your water supply. Even better: a canal. Water height is in Volts (pressure or potential), width is resistance, current is current and the total amount of water is power.

@edd2771

5 ай бұрын

@@Jeep_on_audio thanks but none of that is helpful. It’s not you, it’s me. My mind doesn’t grasp it.

Another way to look at it is if the amp is powering a one kiloohm load, not much current is going to get through. Say 60 volts X 60 milliamps = 3.6 watts.

Light bulbs going off!

What continues to confuse me is that if Ohms is a measure of impedance, shouldn't something with a higher impedance (8 ohms instead of 4) "impede" the current more, and therefore need more power and not less? I realize that isn't the case, but it seems counter-intuitive to me.

Then why not rate amplifiers according to output voltage?

@V1ralB1ack

5 ай бұрын

because they don't output voltage they output power. Voltage is a measure of force.

@Jorge-Fernandez-Lopez

5 ай бұрын

I guess that's because voltage are gain and music dependent. Most amplifiers are a voltage source, they don't "push" power; speakers "pull" power according to that voltage. Amplifiers just try to output the voltage that they have been told by music and gain. According to that voltage, speaker impedances will pull current that the amplifier will try to give. Power is a calculation, a consequence, nothing that can be push or output. In the same way, a big nuclear power plant won't push or output his power in our little HiFi system.

@TheDanEdwards

5 ай бұрын

​@@V1ralB1ack "Voltage is a measure of force" - Voltage is a potential, not a force.

@wally7856

4 ай бұрын

@@V1ralB1ack They do not output power, they output voltage. An amplifier is a voltage amplifier not a power amplifier. Amps increase the voltage of the input signal and that is all. Amplifiers are exactly the same as the electrical outlet in your house. It provides a constant (120v/240v) source of 60hz electricity. How much power is that outlet producing? None, the power consumed all depends on the load you hook up to it. Put too much load on it and you trip the breaker (current limited voltage source). Your amplifier is the same. It is a current limited (internal protection circuit) voltage source. How much current can go through it before protection kicks in is hidden in the specs under "minimum impedance per channel" spec. @bobc455 Yes, they should be listed by voltage but you know ... marketing and dumb consumers. If you play a 60hz sine wave into your amplifier and your amplifier can reach 120 volts on its output (very high power amplifier) you can use your amplifier as a laboratory grade power source for your electronics. By varying the voltage (volume control) you now have a laboratory grade VARIAC ( variable AC voltage supply). Your amplifier is just a power supply that can alter its voltage and frequency according to the input and volume control. Like all power supplies, it is current limited by design (minimum impedance load).

Explained 50x ? Must be both a bad student and a bad teacher ! :) Seriously, well done Paul ! Power = Voltage / Resistance. If voltage is constant, and resistance is halved, then power is doubled ! Also, power specs of amps can be very misleading... Peak power is useful to an extent. RMS power is also very important. The reality is majority of speakers don't need much AVERAGE (RMS) power to drive it at normal listening volumes. Peak power is of import to drive short bursts.... .

@klaus-udokloppstedt6257

5 ай бұрын

sorry, wrong! Power = Voltage squared / Resistance ( P = U² / R ).

This is why if you have a speaker that is rated 4 ohms…. You really need an amp that has big reserves of power … and… if the spl output is low… really big power is needed…. Dynaudio confidence 5s speakers have a 4 ohm rating so BIG POWER is needed….

What about in a tube amplifier where the output remains the same on a 4 ohm load as an 8 ohm load? Not all amplifiers doubles the power output between 4/8 ohm speaker taps

@V1ralB1ack

5 ай бұрын

tube amplifiers have output transformers. this is good and the ration of output and input resistance is actually better like this and it can really push the bass well

@Jeep_on_audio

5 ай бұрын

No. Paul was speaking about an ideal amplifier. Most amplifiers are not ideal. No amplifier is. Because no amplifier can produce an infinite amount of power. A stable amplifier is an amplifier that can keep a stable potential (V) between a given impedance (or better said; resistance).

@V1ralB1ack

5 ай бұрын

@@Jeep_on_audio that's hypothetical. In reality an amplifier is ideal when it's playing my damn music and from my experience of owning a variety of amps yea tube amplifiers especially a 300b is very very ideal. So yea you're wrong and no one cares about your perfect voltage because we don't live in a perfect world and even if I made you listen to the perfect setup you still may not like it because we have different ears and different preferences

After one half your time of fluff you finally got to the issue. If you went back to tube power amps you'd find 4, 8, and even 16 ohm outputs. And you'd get the same power so long as you used the correct match. That transformer matched the labeled speaker to present the optimum load line to the output tubes. But solid state outputs have voltage limits from the supply with device voltage ratings. And they have output current limits with shut downs based on current ratings. And they can be optimized for a particular load. Included in that rating is heat sinking. It seems that a de facto standard is 4 ohms, partly as cost vs size of capacitors is important to equipment cost. But I've designed amps with 100 milliohms to 3000 ohms load including magnetics. Wats are still watts. And you didn't explain why the current audio industry only rates for the load impedance.

A.k.a. the amp's wattage rating is not a value written in stone. It varies on the speaker load. Voltage is the value written in the wall.

If an amp has 2 40v caps in the supply.and its using the comon 80 percent rule.thats 32 volts + and 32volts - ..thats 50 watts per channel into 8 ohms.and 100 per channel into 4 ohms..

Watts are just a temporary result, Valts are steady

My opinion is to explain voltage..instead .

Ahh!!! I think I got it💡,,, No wait! I'm loosing it. Ohh it's back! 🙂 No I lost it🥴 😬

Wattage? Electric potential is expressed in Volts Electric current is expressed in Ampère Electric power is expressed in Watts Electric resistance is expressed in Ohms. The units are all called after people who had that same lightbulb moment. But trying to explain fundamentals by naming them by their discoverers is very confusing. Giving a good analogy is much more helpful in understanding. Like a canal that transports water. The height of the water is the potential, the current is how fast, resistance is how narrow and the amount of water that flows is the total power. Imagine that and you get it. If you understand something, you can remember it better.

P=(V^2)/R Therefore, as the value of the resistance, R goes down, the value of the power, P goes up.

@TheDanEdwards

5 ай бұрын

"P=(V^2)/R ... P goes up"

NAD makes the best amplifiers in the world and their sales speak for themselves. Their after-sale support is also top-notch.

I really think people are over thinking this. Think of electricity as water. The force of the water is the voltage, the amount is the amps and to get the power you multiply them. Same thing with ohms law just imagine a tunnel the wider and bigger it is the lower the ohms. The smaller and tighter it is the higher the ohms.

@Mikexception

5 ай бұрын

Under thinking is also not good idea. Force of water is not usefull in hydraulic. rather in disasters. You mean preassure? Amount and preassure are at it's peak in oceans But it is unknown by multiplying get any power

At the risk of being pedantic, is the light bulb going off or coming on? I guess there's some modern terminology happening here, but still...

I would have done it on a whiteboard😂❤

Instead of changing the speaker from 8 to 4 ohms, simply add an identical 8 ohm speaker in parallel. Now what happens? The voltage remains the same, the current doubles, the power doubles, and the SPL goes up by 3 dB. Of course there are fairly few amplifiers that succeed in doing this trick.

@RectifiedMetals

5 ай бұрын

Why don’t you just add a 8 ohm resistor? Get the same impedance.

@Mikexception

5 ай бұрын

​@@RectifiedMetals.With second speaker we double power of music - why not?

Ohms law.

One problem with tech people trying to explain things like this is how they joggle with terms and names. When building the model at first he speaks about amps (in this case referring to Ampere in plural and not amplifiers...) then in the end he switches to the term "current" witch ruins the whole thought model for most of us. I'm still struggling to get a deep understanding of electricity, only having a superficial knowledge on how it works. Maybe one day...

It is simple and a little complicated. The simple part is defined by Ohm's Law (V=IR) and Watts Law (P=IV). Then in general, understand that voltage sets the volume. You don't need to remember the formula, just know that this is the what you need to Google when you want to know anything to do with power in a circuit. The complicated part is that every speaker has a level of efficiency at turning power into sound and that is determined by their efficiency. At a given voltage how much sound pressure? That's the published efficiency ie 90dB at 1W at 1meter.

We learn through repetition. Young minds need things repeated on average 5 times, many times more as we get older, so audiophiles need things repeated a lot.

Apparently... a coat hanger sounds ''just as good'' as an exotic, super expensive, snake oil speaker cable.

@InsideOfMyOwnMind

5 ай бұрын

Context to the subject at hand is a good thing. Please share ..if you dare.

@brucermarino

5 ай бұрын

It depends on the cost hanger. Thanks!

I=U/R

Filiement just burnt out.

A lightbulb has just gone off in my head. It’s drawing 100w. A lightbulb simultaneously went off in my girlfriend’s head. It’s drawing 50w. Does that mean she has a higher impedance to your explanation?

@a.dejager7062

5 ай бұрын

Yes, if both bulbs run on the same voltage.

I hate to say it .... but that wasn't very well explained at all .... You simply have a 100 watt amp ok 👍... it's putting out 10 volts and this drives an 8 ohm speaker .... now I = V / R from ohms law ... which equates to 1.25 amps where V = 10 and R =8... now POWER is derived from the current squared X R ! This equates to 12.5 Watts ... now if R was halved to 4 ohms then the power would be exactly twice this ... the amplifier ( if it has a good power supply and rugged output stages ) will keep giving a constant 10 volts ... or more .... right up to it's maximum voltage swing ... in which case this simple formula still applies ... ok 👍

Just tell the truth. Power is the most bullshit way to rate an amplifier. A traditional speaker never stays the same impedance during playback. The amplifier has to deal with this forever fast change, and the majority of them fail to provide the specified power the entire time.

@razzman2987

5 ай бұрын

A class A amp will provide it continue.

@Paulmcgowanpsaudio

5 ай бұрын

Gee, what do you really think? Of course a loudspeaker's impedance dips and rises during playback and it is the ability of the power amp to handle those dips and bumps without changing amplitude. To do that (especially the dips) requires power (current). Which is why we like to see power amps who can double their wattage spec into half the impedance. That allows you to maintain a constant voltage in the face of impedance dips. I think you can safely say this woitout resorting to antagonizing statements like "tell the truth". Keep it civil, please.

@carterwilliamhumphrey3373

5 ай бұрын

I don't it seemed to work well for Bell Labs for over a century and counting. But please enlighten us about a better way to do this.

Early compositions ..some interesting melodies and beat patterns (almost lost entirely, MP3 remains, might find the CD versions yet ..post-war). UNRELEASED Compositions: MP3 Backup DJ 13 - Originals Jan 2007 kzread.info/dash/bejne/mKGV0dyvgcfaoKQ.htmlsi=6EeK3kbycIy8h-c0 UNRELEASED Compositions: MP3 Backup DJ 13 - Originals Spring 2006 (Early Compositions) kzread.info/dash/bejne/oqCJq9tuiMe9dLw.htmlsi=x2syE2ZgPtSjEiQW