Adventures In Audio

Your power amp is average - Here's why

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@ripped2fcuk1:  Have you ever heard or known of the BSS EPC 760/780 series of amplifiers?

Honestly would love to know as i agree with you for the most part.

If not then FYI.. they were designed and built at a huge loss to compliment the Turbosound Flash and Floodlight systems in rhe 90s. To be the best soundijg amplifiers in the world.

Some people say they still are to this day.. myself included. They make mediocre speakers sound fantastic... in juxtaposition to this i have heard B&W 704 speakers running off i think Quad or McIntosh amps and couldnt contain my laughter. Yes the speakers shone through in terms of clarity and tonality but these so called "high ens" amps just couldn't drive them they way my BSS could.

Btw power isnt the problem here, the macintoshs i think are roughly 300w with good current delivery at low impedances. So surely plenty of juice there right?

Whereas i am powering a Monitor Audio BR2 (6ohm nominal) with an amp capable of 1625w sustained (underrated) at sub 2ohm loads.

One thing i, and everyone who has heard it haa commented.on is.that there is NO congestion to the sound at all..and all of the impact, immediacy,.slam, punch, effortlessness... yet also subtlety, softness, silky smooth delivery and space between the musical elements ALL scale as you increase the level (to.seriously high SPLs)

@TheEulerID:  You cannot produce an even slightly meaningful power figure by squaring the peak-to-peak voltage and dividing it by the resistance, even as a peak. There is never, ever, a voltage over the load from a pure sine wave of that sort with respect to the central point of the waveform so it is meaningless in that context.

The only time where it could have a meaning is if the two outputs of an amplifier are operating in what is called "bridge mode", whereby the output of one is a mirror image (180 degrees out of phase) of the other. Then the load will see peaks which are equal to the peak-to-peak voltage, but if that is the case, it's necessary to show both (180 degree out of phase) sine waves, or if you just want absolute values, the difference between the two voltages. In effect, if the two sine waves are " a * sin(ωt)" and "a * sin(ωt+π)" where "a" is the amplitude (half the peak-to-peak voltage), ω is the frequency in radians per second and t is the time in seconds, then the signal across the load will be "a * (sin(ωt) - sin(ωt+π))" which equals "2a * sin(ωt)". So that does yield a sin wave with twice the peak to peak voltage, but only by taking the differential voltage of two power amps 180 degrees out out of phase.

Note that another term for this is "differential mode", and there are amplifiers that do work like that. There are a lot of class "D" amplifiers that do, and they have 4 channels where they can be operated such that there are pairs operating in bridge mode. It's very useful where the DC voltage is low, such as in a car, as the power output can be quadrupled.

However, when sketching out the signal output from the power amplifier, you can't have it both ways. That is draw a simple sine wave and claim that the peak power output is the square of the peak-to-peak voltage divided by the resistance. You either show both sine waves, or the output of the bridged output which will have double the amplitude. The peak output is never, ever, the square of the peak-to-peak voltage (double the amplitude) of a sine wave across the load.

As far as what we hear, it isn't watts, it's sound pressure and that is conventionally measured in dBA, which is a logarithmic scale weighted according to the human ear's responses to different frequencies. Just what that means in terms of amplifier output wattage depends on a large number of other factors, such as the location of the speakers, their efficiencies, the nature of the acoustic environment and so on.

@diegocanale1124:  I have a class D amplifier which never heats so much. I guess it is very efficient.

@TheEmmef:  If you hear "hand picked components" you should shun away. A design should work with tolerances in mind and component specs change over time, loosing the hand picked advantage. And if the design wasn't made for that…

@jaredkilgore7194:  I hope I can live to see the day that the bona fide science evolves appropriately to the subjective nature of the average human experience. This happens to be the case with the evolution of plenty of things in technology and if it wasn't for marketing purposes and a lot of people making a lot of money I'm quite sure that this archaic dogmatic approach to specifications to explain audio equipment and it's predetermined effects, I'm sure this would have already happened. It's funny because the buzz words people look for when they consider something of good quality has no relationship to reality in their subjective terms like distortion for example, mini double blind test have confirmed that people for the most part consider a certain amount and type of distortion to sound better and it would be ridiculous to think that the lower the number the better the quality of an amplifier. Why would so many people prefer valvamps if this were the case?

If there were a collective call from the consumer level maybe this could change things but if you go back in history and look at every technology that has ever existed, what comes to mass market with The idea of what is considered the best is never the best. The best is not as marketable and the best does not generate the highest magnitude of profits. The best technologies have always gone the way of the dodo.

@fernandofonseca3354:  David, you can do better than just silly clickbait...🙄

@AudioMasterclass replies to @fernandofonseca3354: Yes but just because I can doesn’t mean that I should.

@daddymulk:  I collect old Ghetto Blasters, The JVC DC-33L with Turntable has high power output for a Portable System, its 11w RMS X2 but sounds truely awful and not very loud, the original speakers are what lets this system down, 3.2ohm i think, there not even 2 way, the mock tweeter is bass port, speaker cones so stiff they hardly move, it doesn't sound very powerful for the output power but when you connect up some better bookshelf speakers this unit comes alive and sounds wonderful for what it is

@daddymulk:  What about DIN measurement 😊

@rob21:  My amp isn't average. Speak for yourself.

@adissabovic:  Oh, there are different types of power?
I've always thought that power is the product of voltage and amperage.

@arvidlystnur4827:  Let's cut to the point.
I don't care if RMS is an inaccurate way of measuring power. Is not two different amps of the same rms the same power roughly.
It's seems to me your argument is my weight of 183 pounds is wrong because I need to weigh myself by kilos!
Yes I understand that a five hundred watt tube amp can be driven harder than a solid state or even class D, but all three have sufficient headroom to play cleanly at a low volume.
I've got an old knight pa tube amp rated 50 watts.
I guy scoped it and said it's really 60 watts but breaks up at fifty.

@Dj-Jon-E-C:  I not to up on it all but if you got 12v 6amp power supply input and the amplifier claims to be 90% efficient, what would be the true watts unclipped be about, based on a class D tda7498 chip?

@texmuphy68:  Specs should be stated: X Watts with a signal of 1000 Hz at an input of Y Volts output in Z Ohms.

@crossoverchef:  nice

@martineyles:  I thought you had to include the distortion figure to make the Watts RMS figure valid too. Ie. That accepting 10% THD would allow you to measure a higher power level than specifying 0.1% THD. Could you explain that part?

@chuckmaddison2924:  In my opinion, we should not bother. Reason .....My NAD doesn't say, and my Denon does, but it massively exceeds watt goes in.
So why bother.
They are, however, both loud enough to upset my tinnitus and for the wife to say, " Turn that shit off "

@tonyfrench2574:  This nerd just wants to blah

@chinmeysway:  All eye know is that my current speakers eat a lot of volume nob

@jupitermoongauge4055:  I love funny cat videos, thanks for reminding me

@paulburr5072:  Listing to this hurt my head , who cares, does it sound good? that's all that matters

@Gez492:  Is there anything sensible about the often heard comment that Tube watts offer more of that oomph

@AudioMasterclass replies to @Gez492: This is a topic I may address in a future video. Also why British watts are more powerful than American watts. DM


@gavinralph2910:  I've never been too fussed about big numbers on amplifiers, you need low distortion with a flat frequency response for the dB volume you like to listen at.

@RogerMelodicMusic:  Blah Blah Blah Blah🤓

@redleather100:  You really hate hifi don’t you . 😂😂😂 have you been sold something that didn’t meet your expectations 😂😂😂😂😂

@redleather100:  I was well gel of your lounge set up , but it wasn’t your lounge 😂

@nicc5122:  You need to drive your speakers (quoted SPL at "1 watt" [what watt?] ) WITHOUT DISTORTION. The impedence of a speaker changes at different frequences too, not many I suspect listen to music comprised of a 1kHz tone. Did someone say inductance of a crossover? Is the rule of thumb to have an amplifier more powerful than the rated handling of the speakers, and "be careful" not turning it up to 11.

@gunnarkarlsson195:  Music is an uneven load. Loud parts and silent parts. Is it not what is buffered in the capacitors that matters?

@timmy707707:  I am neither an audiophile nor an electrical engineer,. I do know that when I run these two big speakers in my field (15" EV Woofers. JBL 2425 Drivers with Renkus Heinz lenses and some nondescript crossovers) with an old Sansui 661 (15w) or the Marantz 1060 (60w), I get beautiful clean deep tones at volumes that shake the neighbors before I hit the midway point on the volume pots. Still.... I find your talks entertaining and I'm even learning a little bit. Thanks for the insights.

@soundssimple1:  ?? My brain hurts. Been buying hifi gear for 50 years. For me I have always found to buy gear where the amp power matches speaker capability ( using RMS quoted numbers ). Test the gear out in the shop in a room similar to your listening room size. Turn the volume knob up to 9 or 10 o'clock for normal personal listening levels, up to 12 noon to test for when you have just come back from the pub, or into the afternoon regions of 2 or 3 o'clock for party levels. Does this basic approach fill audiophiles with dread ?

@JUST-ENJOY-THE-MUSIC replies to @soundssimple1: No.

@anandarochisha:  Mine sounds really nice and clean and drives my speakers to more than comfy. You are judging to find broad strokes..I suspect nothing is good enough for you and confuse that with being an authority because you have a superiority complex..fused to an insufferable know it all..that 'refers' experts and amateurs alike to the comments section for 're-education'. I will subscribe when you decide not to fail as a human being because this is winning no one over.

@JUST-ENJOY-THE-MUSIC:  Rotel RB 1582MKII is my power amp and I LOVE it! It easily drives my B&W 802D2's and it's damping factor of 800 is also very nice. Cheers.

@scottlowell493:  Many AVR's and budget class D amps really go overboard on faking true output.

@vincentrockel1149:  Average is okay, or at least it's predictable lol.

@tonesbones502:  Another great video.
What the figures actually represent is somewhat irrelevant, people who love hifi equipment have built a general expectation of what the figures should bring and that expectation is generally met. Most enthusiasts can spot a BS wattage figure quoted. Price and presentation are obvious giveaways.

@whatspeedlimits:  Nothing more than a person that heard a little- think they learned a lot. Just because you have an outlet to speak- doesn't mean you should- others may be fooled into thinking you know more than you do. You've even confused yourself. Blowhard.

@DAVID-io9nj:  Gee. isn't it amazing most of us can get wonderful music out of almost anything.

@alnasirvisanji6321:  Personally, and from memory during my decades long romantic affair with Hifi and the countless magazines that I had bought and read.....not to mention as many trips to Hifi dealerships, if at the halfway volume knob setting: my speakers sound too amp has enough Ooomph and whatever square or root of its power, for my ears and is good enough!
My "miserable" 15 Watts of power Quad II valve monoblocks can kick up more dust and put out more sound through my Quad ESL57s than the neighbours can bear! I rest my case!

@gilesdavis6345:  Oh, thanks.😮

@rhodaborrocks1654:  None of this makes much difference if you married a volume control ☹

@mikesaunders4694:  One of my sweetest sounding amps IN NEAR FIELD has a max output of 0.75w through reasonably sensitive Castle monitors (71A diy SET).

@johnanthonycolley3803:  If your amplifiers output is sag'ing

The cause is usually that its Power Supply is failing to deliver the energy that the amps power output stage has demanded.

Few domestic audio amplifiers are designed for continuous rating anywhere near their maximum transient power.

This is possible because we don't need to generate a continuous sine wave at maximum power ..

We are listening to music which ( unless overly processed) likely has an average power of about 30% of the amplifiers transient response power.
( therefore the designer does NOT need to design a Power Supply with the capacity to deliver the amplifier's " Full " rating continuously )

Hence if you attempt to obtain it's transient rating continuously.. it's output falls off ( sags ) 😊

@valentingheorghe1693 replies to @johnanthonycolley3803: Maybe we don't need to generate or listen to a full sinewave signal on our system, but, the fact is, we should be able to do it, if the following situation occurs: we are watching or listening to some musical material on YouTube, near the maximum output of the amplifier, and, suddenly, its predictive listener experience algorithms drop a material about testing an amplifier continuous power output.
You are not close enough to the be able to reduce the volume of your audio system and, suddenly, the test sinewaves, at 40 Hz , 400 Hz, 1 kHz, etc, used in the material start blasting through the system and you don't have a limiter deployed.
Result: bye bye amplifier, bye bye tweeters, bye bye woofers.

Fact: in today's world, the chance of encountering over processed/over compressed audio materials, especially on the streaming platforms, is very high.

Conclusion: don't use any amplifier which is not able to withstand at least 5 minutes of 1 kHz full sinewave at full power output.

@glpilpi6209:  Have you ever serviced any equipment ?. Or are you a clickbait theoriser ?. I'm addressing this question to Audio masterclass man. I have serviced and repaired amps and other audio equipment for 20 year's till I retired from it in the mid 90s .The laws of physics don't change because of prat with a channel on YouTube.

@AudioMasterclass replies to @glpilpi6209: Haha you're funny. If you have something to say then challenge my facts. DM

@labalo5 replies to @glpilpi6209: No DMs let’s see this in public

@carminedesanto6746:  Ok..interesting 🧐
I just run a headphone setup.
2 watts and I’m good .
Bryston BHA-1 ..I’m good 😊

@larryjohnson9019:  Very good attempt to explain a very complex topic that the industry has been wrestling with since the first vacuum tube amplifier. In our opinion you were on a roll until you ventured to the “darkside” by invoking the term “fake watts” to describe a correct and valid measurement derived from a set of proven mathematical equations. Peak power value is not fake, peak-to-peak power value is not fake, and average power value is not fake. Whether or not a given measurement is relevant in a specific context is another thing. One could fairly argue that using rms values to calculate power in an audio system is rather meaningless as well as the rms values used are that of a sine wave–where music signals are anything else but sinusoidal.

Also in an audio system, the job of the power amplifier is not to provide electrical energy “watts” to produce “heat” but to provide electrical energy “watts” to produce kinetic energy transformed by the loudspeakers to produce sound and loudness which is measured in SPL. In fact heat produced in this process is a by-product not welcomed as it means energy is being wasted.

Happy listening

@MC-jv6fs:  Your channel is very fine. Its a prove for taste , profession and knowledge. - One question i do have : you used some harp- music in one of your videos. Where can i get this and can i get mor of it ? This music was so beautiful that my mind instantly stood still an was banned. Like in Einaudis´s music. This is no compliment. Its my feeling .

@AudioMasterclass replies to @MC-jv6fs:

@leqin:  Can I just point out that Audiophil works at Cheshire Audio in Crewe, and he doesn't sport anything like as much hair as the imposter in your video's :.)

Oh and the last thing I would call myself is an audiophile and my power amp says Naim on the front, and it is far from average - it shows me all the cock-ups made in recording studio's all over the world every single day.

Love the channel - I learn something from every video. Thanks.

@craigellsworth3952:  Is it any coincidence that audio Phil looks like a typical salesman at a high end audio shop between '75 and '85?

@Rob-Wijnschenk:  By the way, there is also the problem of phase shift between voltage and current when the resistance drops (or elevates). This is also of great influence in the delivery of power!

@jayedgar2373:  I have glossed over the replies to MC's vid, and I apologize if any comments were related to my post. First off, what kind of amps are we talking about? SS, hybrid or valve (tube). There topology is different when driving speakers (and what kind of speaker your driving). Speaker efficiency is paramount in tandem with the amplifier. Amplifier loading varies greatly. SS (solid state) amps (class A, AB and D) load voltage differently due to there topology. Tubes are stage gains in amplification (continuous power) through there rated transformers. Watts are only a combination of values (volts*amps* to 1J (W) over distance, ect.). Voltages (and current) are really the key factor when driving speakers. The input signal is DC current (0.4v to 3.0v max). The amplifier takes that signal voltage and "amplifies" that signal (0.4v = low gain to 3.0v = max gain or RMS). The truth about watts when it relates to current supplied to the speaker (volts/amps) is the speaker itself. @ 1 watt, the efficiency of the speaker will determine how that watt is driven. Low efficiency speakers will not produce much work (load) through the speaker. Where as high efficiency speakers will produce a more audible load. Less watts are needed to achieve higher gain (volume) loads on high efficiency speakers. @ 20watts, a 96db speaker will produce a high range of sound (decibels) than low efficiency speakers which require more current load (watts) to produce the same loudness gain. Even low efficiency speakers will use around 40 to 60 watts per channel to achieve high gains (loudness) with a good, stable power (driven) source. The basis for MC's video shows the actual (driven) loads required when using speakers as a load reference. If you have a good pair of speakers (depending on the efficiency) you would be hard pressed (and possibly go deaf) when driving your speakers @ 100w per channel continuous loads (even under extreme low end bass frequencies). Most speakers load at around 30 watts per channel comfortably and the gain is actually quite high. Low efficiency speakers do well at around 50 watts per channel. So, what do you even need a 1000 watt BS amp for? Even if that amp could produce 1000 watts, you will only be using a fraction of that power to drive your speakers comfortably.

@Rob-Wijnschenk:  It is even more complicated because the load of an amp normally not a resistor. A loudspeaker is a complex (reactive) load, the resistance of an '8 ohm' speaker can drop at some frequencies to 1 ohm!! Most amps can not deliver the current (and the 'rms' power) that is required at 1 ohm. It is better to have a modest power amp that is capable to deliver enough current! Keep going with your channel, you ar a very nice story teller (even for my age :)
Rob (from Holland)

@andrewbrazier9664:  I've seen a new budget pair of 8ohm bookshelf speakers from a manufacturer that also makes high end speakers with a claimed low impedance value of 6.4 ohms.!
A few positive reviews Inc 1 on U tube about how musical they are for the price (£349 🇬🇧 pair)
I assume these could be driven well by even the most "average" amplifier

@paullongtailpair3812:  Dear David. I have viewed this video a few times ( because I'm dutch and it take me a bit more effort to follow English, totally my fault ) and I looked at the info in the link. I believe it isn't that complicated. Let's use your example of 1 V rms over a 1 Ohm resistive load. Starting with 2.828 V p-p, divide it by 2 = 1.414 V p(peak). The current is 1.414 V p / 1 Ohm = 1.414A p(peak). Power is the multiplication of Voltage and Current. 1.414 V p * 1.414 A p = 2 W p(peak). Now we can say: to convert the peak voltage to rms divide the peak value by SQR2 ( 1.414 / SQR2=1 ) the same apply for current. This means that the conversion from Power-peak to rms is the following: P p / (SQR2 * SQR2 ) --> Power-peak / 2=power rms.

@AudioMasterclass replies to @paullongtailpair3812: I'm finding it difficult to fault your logic. Perhaps other mathematical brains can join in this thread. DM

@iqnill:  Why don't audiofools just get a pair of studio monitors?

@Stuartrusty:  Interesting you should come across power output for cyclists. On a good day I can average 180 watts and peak 550-600 watts. Is it RMS though? 🤷‍♂️ No, in cycling terms it is usually measured on watts per kilo. For a 77kg chap like me that's around 2.34 watts per kilo. TDF riders are usually 3 times this.

@AudioMasterclass replies to @Stuartrusty: I would guess that the aim would be to measure the equivalent heating power, same as in audio. Whether cycling power meters actually do this I shall leave for more dedicated cyclists than I to worry about. DM

@analoghardwaretops3976:  Every Electrical & Electronics Engineer knows that
(1V × 1A) AC = 1W , which means it's the Rms value (& not something " derived from P-P) that is
the electrical equivalent of thermal power / heat produced in a "purely" resistive load of 1 Ohm. , that produces THE SAME power consumption / heat generation when passing 1A of DC current from a 1V DC source through the same resistor. so the method of explaining by juggling P-P ac
to show such end results is
IMHO flawed.
Hence "RMS watts" or
" continuous rated power" is more correct in specifications , even if not technically accurate ...
Yet the question of how much is wasted as heat & how much is converted to music is a different matter altogether.

@frankgeeraerts6243:  Nice AI !

@nottodaypal2143:  so my amp is average? just like your videos😁

@AudioMasterclass replies to @nottodaypal2143: Hmm, I've looked at my YouTube statistics and, by inference, your amp is actually doing pretty well. DM

@nottodaypal2143 replies to @nottodaypal2143: ⁠​⁠@@AudioMasterclasspretty well,average… Potato, potahto😂. keep up the good work😊👍🏻

@user-le8ho1ml5b:  My humble view is PA specifications should contain peak output power per channel (all available channels driven) with some predefined low level of distortion (let's say, THD below 0.1%) for unlimited time period. The average loudness will depend on input signal statistics - dynamic range, for example.

@peanutbutterjellyjam2179:  Is it April 1st already?😉

@edmatzenik9858:  One small mistake, and it is small but in hi-fi and pedantry that's where the fun is: what you're trying to say is not "your power amp is average." you're trying to say "your amp power is an average."

@hugobloemers4425 replies to @edmatzenik9858: Yeh, but that is not click bait (for audiophiles)

@cubemerula5264:  Debbie is both irritating and misogynistic. You could consider abandoning that lousy idea.

As far as the content is concerned, a useful question would be is there a solid correlation between RMS and real world power? If yes, then the spec used is arbitrary and just numbers. If my amp is rated 110w into 8 RMS and can drive my speakers to the SPL I want with no clipping, but you tell me it's not really 110 it's actually 55w although this doesn't change its performance, I don't really care. My only question is whether every 110w into 8 is in fact a real world power of 55w? This would mean that when buying an amp, if I come across one spec'd with real world watts of 55, I'd know it's good enough for me and it would come to 110w RMS.

I, in fact, never cared that much about the number of watts. I looked for sufficient power + some headroom. And this is an easy task for me since I don't listen to loud music. I see amp only as serving the speakers I want to listen to. Amp in itself is not that important. If it can amplify, it's good.

At my listening position, the loudness measured (A-weighted, average dB, long listening session - more than half an hour) is 76dB. Peak is 86 at least (for music, sometimes more). Amp shouldn't overheat or clip at 96 (accounting for the headroom). Going by, also vague, relation between watts and SPL + the drop due to distance + reinforcement of the room and the fact there's two speakers in stereo, and you get 90W/ch into 8ohm for a rather low efficient speaker of 84dB.

This 90W I stated is the RMS. My only question is would every 90W RMS rated amplifier give me the results I'm looking for?

@Douglas_Blake_579 replies to @cubemerula5264: There is a reason every yardstick is the same length...

IF they are tested against the same standard... the answer is Yes.

@nsfeliz7825:  so many strong opinions from people whove never built a single electric circuit in thier lives😂

@epi2045:  Have a Mark Levinson dual mono amp 100wpc 8 ohms, rated down to 2 ohms - 400wpc. It’s 104lbs. However my 6wpc custom tube amp is my preferred amp.

@nikolaki:  A few years ago I starting gigging and needed a bass combo that I could drag around the London Underground.
I chose a Hartke Kickback 12. Is it light and loud. Perfect.

On the front, it stated it was a 500W amp. I was so embarrassed by this assertion that I immediately took a piece of gaffa tape and covered that bit of the faceplate.

@Mikey__R replies to @nikolaki: Bass amps went class D a few years ago. I'm pretty certain digital watts have much less umph than analogue class AB watts.

I think they were taking the power amp modules from car stereos and using them directly in bass amps, complete with the fictitious peak power claims.

@janinapalmer8368:  The true power of an amp is the equivalent of the DC power it could deliver

@sandongabundunga9052:  Hello, are you there? I'm Watt. Yes, who are you? What's _What's your name name? Watt's my name. Yes, what's _\es, _\es, what's your name name? My name is John Watt. John what? Yes. Are you Jones? No. I'm Knott, Will you tell me your name then? Will Knott, Why not? My name is Knott, Not what? Not Watt, Knott.

@thelawman4684:  Isn't average power what hifi mags used to refer to as "continuous power"? From what I remember, power amps can push out a lot more watts for very short bursts (dynamic power), but cannot maintain that power long term. The other important issue is with, say, 100 watts into 8 ohms, what is the power into 4 ohms? Ideally, it should be 200 watts, etc, but with lesser amps the power does not double as the resistance is halved.

@RichSDet:  To me , a full bandwith (5-50k) is a better indicator of what’s at hand.

@Hi-EndAudioGuy replies to @RichSDet: Why would you care about bandwidth beyond just over 20kHz as humans? You're not going to hear it and in fact some of that ultrasonic stuff can distort into the audible range.

@G8YTZ:  Quoting Watts RMS at a particular frequency is really a comparison (Who sits in front of the speakers, listening to a sinewave?) like the procedure for measuring the fuel consumption of a car or the range of an electric car it’s just a comparison and not necessarily representative of the real world.

I guess another approach would be to have a standard musical track lasting say, five minutes that incorporates various types of uncompressed music. The total average power is measured, and then divided by the time to come out with a power number. Clipping would not be allowed.

To get a more accurate number, you would have to include transient power and slew rate etcetera.

But the true way of measuring power handling capability, it’s probably with a 2 tone and a 3 tone test and then to measure the intermodulation distortion. This is what we do with radio-frequency amplifiers to measure linearity for a given power level.

@ONEHENDRIX:  Thats a hell of an audio room.

@Douglas_Blake_579 replies to @ONEHENDRIX: Green screen

@QuinnKallisti:  Thanks this is a good start to that Amplifier power video I asked about : P Legend !

@6doublefive3two1:  What's a Watt?

@Douglas_Blake_579 replies to @6doublefive3two1: one Joule per second.
Also 1 amp on 1 volt for one second.

@crazyprayingmantis5596:  Put whatever numbers and letters you like on it, i couldn't care less, all that matters is if it sounds good in your room

@user-sr9ht4qg8m:  So i need to connect my amp to my bicycle and see how fast/far it goes to know the true wattage 😮 got it😊

@davidatrakchi2707:  The value of RMS is derived from squaring the values of the sine wave, (the negative side climbers up), finding the area of the new wave form and divide it by the length (an integral) In such case sine waves will show a ratio of 0.707 of the amplitude.

The average value of the sine wave without squaring the values is 0.623

I hope I remember the average ratio correctly, been ages since I learned this and no one uses the avarage ratio, only RMS is used for obvious reasons

@amazoidal:  I have a Parasound 2350 with 600 x 2. I don't worry about enough power.

@przemyslawpraski8985:  'The first watt is what counts' Nelson Pass 😂

@AudioMasterclass replies to @przemyslawpraski8985: Comment readers may like to investigate further DM

@analoghardwaretops3976:  RMS or AVG. it does not matter to the ears...thats only for mathematical definition and clarity...
As long as the loudspeaker system can handle the power outputted to it by the amp. , without annoying audible distortion to the listener and without it getting damaged or detoirating it's performance, it should not matter how much power is lost in heat or how much power is converted to sound energy , as long as the
owner/listener is convinced that he/she is happy with it.

@JDavidG.700:  Sounds good to Me!

@user-bu4wg1ok5n:  I can't recall what the Federal Trade Commission (FTC) specified when it cracked down on audio amplifier power claims back in the late '70s. But I always took it to mean watts calculated from the continuous RMS voltage of a sine wave, all channels driven, at the specified distortion, measured for all frequencies claimed in the frequency response, within one decibel. The output load was also specified. That was the performance I would shoot for when designing a power amplifier for a given "RMS power".

Now, RMS voltage depends on the waveform being analyzed. For a sine wave, it's root 2 over 2 times the peak voltage, or approximately 0.707. For a square wave, it's 1 times the peak voltage. For real music, it's... who knows? How loud are you playing it? How efficient are your speakers? How was it compressed, peak limited and clipped? Even the musical style, the amount of dynamic range contained in the original performance, and subsequently, how it was mixed and processed makes a big difference in the amount of actual power needed to reproduce it accurately and at a realistic volume. Of course, a lot of the fidelity may have been lost before it ever even hit the vinyl or CD.

@cubemerula5264 replies to @user-bu4wg1ok5n: Great answer.

@paulstubbs7678:  Two big problems, First, whilst my main current main amp is rated at 40W RMS per channel, it will probably never produce that, that is unless I listen to lots of organ music, and then ride the volume control to maximise the output without hitting the clipping point, quite hard and kind of pointless. 95% of my music will never produce more than a handful of watts from that amp, assuming I keep it below clipping (Except my AC/DC tracks, where clipping is usually not noticeable, sometimes beneficial, excellent tweeter destructor)
The other problem is 99% of speakers have a very dynamic impedance curve, and an amplifier has to be able to keep its set output signal voltage level even if the speaker's impedance drops from, say 8 ohms to 2 ohms. (which actually means the amp has to put out bursts of way more power, do the math but with 2 instead of 8 ohms) If it cannot hold the voltage level then one hears a pile of distortion as it's output crashes.
This is the problem with a lot of those mini high power amps you find using Google, once you get past that bull quoted ratings, using something like PMPO rather than RMS, (and they add the two channels together for 2X, something real HiFi does not) you also have to then derate them an awful lot to allow for normal speaker impedance dynamics. they have NO margin for a load that drops it's impedance below the rates 4 or 8 ohms they quoted, so best of luck getting a good 10W out of that 600W mini beast you just ordered.

@christopherward5065:  Is power about in this case about work done? The amplifier could be rated on a steady-state sine-wave but that's not what is actuallu amplified in real-world use. The work done will vary with the frequency of the signal. The work done in terms of energy transferred per second at 1V amplitude at 100Hz vs 10,000Hz would be higher at the higher frequency. More energy is transferred per second at the higher frequency. More work would need to be done to move the mass of a speaker cone and the air that's loading it per second if it maintains the 1V amplitude but has to move backwards and forwards 100 times more per second. The area under the voltage vs time graph would be greater at the higher frequency. 100 times more Joules per second needed. The intensity of the two frequencies would be very different. An amplifier with a music signal only produces brief moments of a range of given frequencies at a time and the intensity and frequencies are for small fractions of each second. The amplifier will mostly be doing very little work at any given frequency during a music signal. Music is made of continually varying collections of frequencies for very short periods of time and each of those frequencies also continually varies in amplitude. The amplifier just needs to be capable of transferring the required amounts of Joules per second as collections of undistorted waves that can do work driving the cone masses of the loudspeaker.

@joeythedime1838:  So if my T+A PA3100HV integrated has a manufacture's rating of: RMS output per channel into 8 Ohms: 300 watts
RMS output per channel into 4 Ohms: 500 watts
Peak output into 8 Ohms: 380 watts
Peak output into 4 Ohms: 700 watts
Power bandwidth: 1Hz - 150kHz
Frequency response + 0 / – 3 dB: 0.5Hz - 180kHz
Slew guess: 60V/µs
Damping factor: > 65
Signal/noise ratio: > 115dB
Total harmonic distortion: <0.03%
Reservoir capacity: 120000µF Then what is the "real or average" power rating?

@crazyprayingmantis5596 replies to @joeythedime1838: Who cares, all that matters is that it sounds good
Put whatever numbers and letters you like on it, I couldn't care less

@joeythedime1838 replies to @joeythedime1838: @@crazyprayingmantis5596 I am just wonder what the math works out to be.

@spacemissing:  Even if "Watts RMS" is wrong, at least it is a standard that can be easily applied to
any number of amplifiers tested by the same method and then used to compare them.
In other words, let's Keep doing it wrong so we don't have to Test Everything All Over Again to a Correct standard.

@stevemawer848 replies to @spacemissing: Agreed, it's like the published figures for fuel (or electrons) consumed by a car - meaningless in itself for the real world but useful to compare against others.

@Justwantahover:  Nominal.

@99Duds:  Love these comments.
On a side note, I thought was just here to compare notes.
Think I learned something today.

@rabit818:  Now that I am an aging hipster, the volume control is normally set at 9 o’clock. If I can hear all the soft and loud musical bits, I am pleased. So my aging 37 wpc amp is a great companion.

@stevemawer848 replies to @rabit818: The volume control is really just an indication of the strength of the input signal rather than a measure of how loud things sound.

@36karpatoruski:  This guy could be Paul McCartney’s twin, just needs a bit more hair.

@carlsitler9071:  Why doesn't my Marantz surround receiver sound as good (two channel) as my BasX even though it cost over three times as much?

@crazyprayingmantis5596 replies to @carlsitler9071: Because Marantz is overpriced Denon

@obscurazone replies to @carlsitler9071: What do you mean when you say "doesnt sound as good"? Vague terms are endemic in hifi land.

@hugobloemers4425 replies to @carlsitler9071: Because it is surround, how many amplifiers on the tits of one puny power supply?

@stevemawer848 replies to @carlsitler9071: @@obscurazone Vague terms may be endemic but they have to be since the outcomes are always subjective and we all have different ears (it'd be embarrassing to have to share just one!) and sound processing capabilities.

@carlsitler9071 replies to @carlsitler9071: @@obscurazone To me, it sounds warmer and less dynamic whereas my BasX sounds more neutral with crisper highs and upper mids.

@darryldouglas6004:  I think whatever way you measure the watts the most important thing is to have an amp matched to the speakers maybe with a slight cushion. 500 watt amp driving 500 watt speakers. NEVER crank the amp all the way it can spike over peak and damage speakers. Lastly if it sounds good it is good…. To you. 😃

@cubemerula5264 replies to @darryldouglas6004: What is a 500 watt speaker?

@stevemawer848 replies to @darryldouglas6004: @@cubemerula5264 It's a colloquial way of saying a speaker capable of handling a 500 watt input without being destroyed.

@carlsitler9071:  Does my 160 wpc $80 Aiyima a07 give me deep, effortless, natural bass, rich mids and sparkling highs and do it loudly? No. Does my 150 wpc Emotiva? Yes. Are they both great for their price? Yes. In my limited experience, my receivers didn't sound as good as my amps. Maybe it was the low price I paid. To get the same sound quality, I would guess an integrated amp would cost 25% to 50% more than a similarly powerful amplifier.

@Douglas_Blake_579 replies to @carlsitler9071: That's probably because the Aiyima is only 50 watts per channel.

Do a search for the "tpa3255 spec sheet" you'll see...

@Hi-EndAudioGuy replies to @carlsitler9071: Never look at the advertised watt rating for inexpensive class D because those are rated at 10% THD. Check out the real testing results like this:

@snakeoilaudio:  I think that the Number that manufacturers print on their boxes and in their brochures is pretty much pointless and only gives you an indication of how it is build. And with how it is build I don't mean good or bad but about their circuit philosophy. I categorize amps in 3 categories, 1 below 20w, 20-100w, above 100w. The point is, when listening music at home you will use something between 1-5 watts with over 90% of the speakers available, there are only very few speakers available that need more power like magnetostatic speakers or these kinds of things, but over 90% range between 85-90db efficiency therefore more than 5w starts to be pointless.

The more interesting question is about the damping of the amp (damping means how much control your amp has over your speakers). It is a little counter-intuitive, but more damping does not equal better. There are speakers where more damping equals better and there are speaker where more equals worse. A B&W 801 with it's fairly heavy 12-inch woofer needs some control so an amp with high damping is very good but one of these vintage Tannoys with a very light 12-inch paper cone woofer does not want high damping so you could drive it with a tube amp (these amps have basically zero damping).

In general you want an amp with as little amplification as possible but if you build a 10w amp then unfortunately it will not have any damping so even though more amplification equals worse sound quality in order to control your speaker a 100w amp might work better even if you are only using 5w

@stevemawer848 replies to @snakeoilaudio: I did read one review of a speaker (can't remember which, some bookshelf job, I think) that "soaks up watts like an acoustic sponge". That description has stuck with me for decades! 🙂

@snakeoilaudio replies to @snakeoilaudio: @@stevemawer848 yes these kinds of speakers do exist, like a BBC 3/5 this legendary nearfield studio monitor. But it is an exception and not the average.

@stevemawer848 replies to @snakeoilaudio: @@snakeoilaudio That rings a bell! Made by Rogers, if memory serves.

@snakeoilaudio replies to @snakeoilaudio: @@stevemawer848 yes, the design was licensed to 7 different manufacturers, Rodgers, Spendor, Harbeth etc

@kevinmccahill7522:  I think you should give audio Phil a break. He spent more money on his stereo than I spent on my education, and it shows.

@markcolegrove:  How you arrive at a particular value is interesting in itself but is not too useful unless all the amp manufacturers are using that same method.

@Douglas_Blake_579 replies to @markcolegrove: For the most part ... they are.

@analoghardwaretops3976 replies to @markcolegrove: ​​​@@Douglas_Blake_579( ...all amp manuf ... & others) , ..all have been educated in similar ways and its only those who are able to think ..( & more so )
DO OUTSIDE THE BOX may present or produce something extraordinary /revolutionary that becomes a successful alternative.

@Douglas_Blake_579 replies to @markcolegrove: @@analoghardwaretops3976
Hey ... aren't you the guy who invented the 16 inch yardstick?

@analoghardwaretops3976 replies to @markcolegrove: @@Douglas_Blake_579 YEAH YEAH YEAH...for that 16 " yardstick ..each inch was
B.S. 2.25" long..

@hellomeatrobots:  My brain hurts.

@AudioMasterclass replies to @hellomeatrobots: Not as much as mine making this vid. DM

@mellotronin54:  I know my power amp is average. And I do not care. I cannot afford audiophile quality and to be honest I do not need it , I know some do . I am a musician and our instruments cost enough without the top dollar for a listening experience. We make sounds with the best we can afford.

@analoghardwaretops3976 replies to @mellotronin54: .. Listening to musician playing their instruments....that's the most natural & original the human ears..😊😂❤..THANKS A TRILLION...

@sonycarp8271:  Sorry missed out the 2, 🤔

@sonycarp8271:  I'm going revisit this vid, 🎹

@SubTroppo:  In audio specification a Watt seems to be that piece of string that my physics teacher was talking about when he posed the question "How long is a piece of string?". ps I'm thinking of ditching the electric fire and listening to hot jazz instead.

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Thursday January 4, 2024

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David Mellor

David Mellor

David Mellor is CEO and Course Director of Audio Masterclass. David has designed courses in audio education and training since 1986 and is the publisher and principal writer of Adventures In Audio.

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