What is a power amplifier?

Paul's series on the basics of audio continues.

[@gerdschneeweis9393]

Paul that is the best explanation for non electricians I ever heard. Thank you 🙏🏻

[@tomday7309]

Thanks for the explanation, Paul. I never thought of what happens in the power amp being a "two stage" action. Your analogy helped as me being an old "clutch popper".

[@jm8080ful]

4:11 when you accidentally stepped on the dog's tail

[@babubabu12345]

Very good Explanation about Power Amplifire by Paul Sir....🙏

[@jacobsgarage1458]

Hi Paul. You definitely missed the opportunity to show us the inside of those monsters 😢 that would have been nice

[@stevenholquin2127]

Now I Was Once Again Dozing Off Listening To My Favorite Audio Guru Paul Talk Softly Like ASMR….and Before I Know It Paul Tossed in This Car Analogy and Audio! “”Think of It As You Have a Big Block Hemi 440 Magnum Dual Quad With a Grabber Hood with The Plumb Crazy Factory Drag Pack With Custom Hooker Headers ❤️ For Extra Torque and a Pistol Grip Shifter With a Non Slip Rear suspension “” Wow 😮 I Woke Up and Thought I Was On The Speed Channel Yet Paul Slipped into This Car Analogy Business and Had a Flash Back…! Does Anyone View Pauls Vignettes Before He Uploads

[@FOH3663]

Nice! The ultra rare Hemi 440! ... ;) Add; Mr. Gasket traction bars Cherry Bomb glass-packs The way we all worship our phones, tablets and computers 𝙩𝙤𝙙𝙖𝙮, ... is the way we centered our lives around cars, stereos, and music collection ... 𝙗𝙖𝙘𝙠 𝙞𝙣 𝙩𝙝𝙚 𝙨𝙚𝙫𝙚𝙣𝙩𝙞𝙚𝙨.

[@stevenholquin2127]

Thanks 🙏 Someone Gets It

[@kobezcarz4558]

Paul is standing there with Ferraris around him like a king! 👑

[@glenncurry3041]

It was interesting to learn that depending on how the output stage/ device went you could hear the driver stage through the speakers. Just no current.

[@birgerolovsson5203]

I have 3 power amplifiers in my stereo. Two 2-channel power amps to my main speakers and a 7-channel power-amp to my center & surround-speakers, all mainly for SACD's 5.1 sound.

[@Bemx2k]

Great set of Speakers

[@user-od9iz9cv1w]

To me a power amp is a power valve. It's job is to accurately produce high power signals that faithfully recreate the source. And it has to be impervious to the reactive push back from the speakers. What differentiates a good amp from an amazing amp is its ability to recreate low level information with phase fidelity. This low level info may only be in microvolts, but this is the stuff that breaths life into music.

[@darrellross8609]

Gjallarhorn mono blocks, here. Best, D.

[@n.m.saseendran7270]

Well explained

[@georgebliss964]

Tube amplifiers use transformers as an equivalent to the second current gain stage in transistor amplifiers.

[@user-od9iz9cv1w]

Actually I'd assert that the power tube is the second stage and the input tube is the gain stage. The transformer is the transmission. Back to his car analogy, the engine cannot start the car from a stop light in high gear. It needs to be stepped down to produce power in first gear. That's the job of the stepdown transformer.

[@glenncurry3041]

Tube amps are two stage with a gain stage followed by a voltage output stage. Tube amps are constant current while solid state are constant voltage. Transformers are for Power transfer.

[@Oystein87]

Easier said: A power-amp is a amplifier without the volume control. So you need something to control the volume between your source and power-amp. Normaly a Pre-amp.

[@banginghats2]

I always thought of an audio current amplifier as a buffer than reduces output impedance and has a lot of current in reserve in the large reservoir capacitors, but doesn't change the voltage.

[@ilianstoimenov6619]

The car analogy is - voltage = horse power and current = torque (kW) 😀

[@PSA78]

Voltage is pressure = torque. Ampere is the volume of the flow = rpm. Total energy accessible or used = Watt. 🙂 Rush hour = Ohm. 🙃

[@Canadian_Eh_I]

So are some amps high watts and low current? Is high current more often better or worse?? Still confused

[@davebutler3905]

According to Fleming's left hand rule, force is proportional to current, not voltage!!! Why are we using power amplifiers that output a voltage proportional to the signal voltage instead of a current proportional to signal voltage?

[@NoEgg4u]

Paul, what about the amplifier's needle?

[@zizendorf]

Legitimate question: Why don't I need/have a power amp - never have? Should I? I've been totally content with my 100 watts/ch hybrid integrated.

[@hoobsgroove]

one thing is why is hi-fi power amplifiers only running on 2 to 3 PPV where professional power amplifiers can go up to 12 volts input that is better way.

[@schemkesa]

It's easy, it has to make the signal strong enough to drive the speakers without ANY coloration, distortion whatsoever. Nothing more, nothing less.

[@nickthequick]

I always watch these videos and I learn a lot - but I still don't understand electricity no matter how many times I try

[@masterazlan6999]

Im usin an iem but still usin monoblock...Peace!

[@TheDanEdwards]

Paul... has done better. And yes, surely some will comment that it is the _current_ , not voltage, which is making those transducers move, and while that is certainly true we should remember that Paul is by practice an electrical engineer, and they are taught to design circuits with the potential (voltage) drop (across whatever they put in their circuit) in mind. It is afterall the _Electro-motive Force_ which makes the current flow.

[@savvassidiropoulos5952]

actually, the transducers move with the voltage. They just need much current to sound loud.

[@ThinkingBetter]

Neither voltage alone or current alone does any work. It's an entirely wrong way to look at it. Moving air with a speaker cone is essentially work that takes energy. This is equally true for dynamic speakers, electrostatic speakers or whatever speakers. Energy per time is what power is about. One Watt is defined as 1 Joule of work per second. One Big Mac contains 2.25 Million Joules as a reference. Thus if you could run a speaker with an average power of 1 Watt with no losses on the energy from a Big Mac, it could play for 2.25 million seconds. That's about 26 days of continuous music. A human body might burn some 100 Watts on average, giving you around 6 hours of energy on eating one of those Big Macs. Yes, power is voltage times current, but it still boils down to power doing the work and theoretically, someone could create a speaker that ran on water pressure through a hose instead of electricity through a speaker cable, and it would still be power and energy transfer driving it.

[@PSA78]

​@@ThinkingBetterYuup, correct, and if people understood a little bit more about energy we wouldn't have as many fad diets or car reviewers raving on about torque. 😄

[@ThinkingBetter]

@@PSA78 Yes, you are very spot on. You can find lots of car related videos here in KZbin trying in the most ignorant ways to explain and compare torque (twisting force) and horsepower (unit of power equal to 746 Watts). And modern fast food is a disaster in unhealthy energy. A Bic Mac contains some 54 chemicals and while it can keep you going for some hours, eventually it will kill you.

[@PSA78]

@@ThinkingBetter Yes it's an old misconception that torque matters for acceleration or pulling heavy loads, if time is involved then it's energy released which is hp, but it seems hard for them to either understand or get away from the old. "Hp sells cars, torque wins races" is one of many bad/faulty quotes that's used. 😄 Actually even fruit like an apple contain ~40 chemicals naturally, everything around us is a chemical, and at the end of the day it's always the dose that makes the poison. 💊 We should to focus on lean protein and fibers, some essential fatty acids, minimise the amount of saturated and trans fat. But once you break it down to the correct levels of each individual macro and micro nutrients as well as calorie balance for weight, then it's not going to make or break anything by enjoying Some soulfood. 😋 They even did one extreme study with basically a candy diet, as they lost weight all health markers improved, naturally it's not going to be healthy longterm, but it certainly gives a perspective. 😄

[@ThinkingBetter]

A power amplifier is technically speaking a voltage amplifier (output voltage = input voltage x gain factor) with ability to drive high currents in a low impedance (typically 2-8 Ohms) speaker load. Power is voltage times current. If the input impedance of a power amp is 100K Ohms and the input signal is 0.5V, the input "burns" 0.5Vx0.5V/100K Ohms = 2.5 micro Watts from your source output e.g. pre-amp via RCA signal. Yes, power is also burned on an RCA cable, even it's a tiny amount. If your speaker output is 20V, meaning 20Vx20V/8 Ohms = 50 Watts in 8 Ohms, you amplified the voltage with 20V/0.5V = 40 times and the power with 50 Watts / 2.5 micro Watts = 20 million times. Thus calling it a power amplifier does make some sense 🙂But still, the reason the 40 times voltage amplification is more of a true gain factor is that the 20 million power amplification factor, in this example, entirely depends on the speaker impedance, which varies greatly by frequency.

[@robertdecrock4038]

Lol 🤗😎

[@onnonugteren2935]

No to simple, didn't learn a thing. 🙂