I was in the audio signal processing design business for decades. I consulted on amp design with multiple big name companies, and finished my career designing products at Dolby Laboratories. Dolby had/has superb listening rooms. When we carefully blinded tests, even in a superb space with very highly regarded speakers and good source material, amplifiers of decent spec and power were indistinguishable. The key was double blinding the tests, so that neither the listeners or those running the test knew at any given moment which amp was in use. Listeners had a button that allowed them to (maybe) change amps. Sometimes it stayed on the same amp, sometimes it changed. Data collection was automatic - the system recorded the results which could only be seen at the end of the test. Almost without exception, listeners were no better than chance when trying to pick which amp they were listening to, or rank which sounded better.
Hi Paul. I'm so glad I "found" your RUclips channel. I have an EE and have worked with DC to daylight for almost 50 years. Just can't get enough. What I like about your presentations is that you explain even the most esoteric concept in plain old English terms; very clear. This is a great contribution to the human race. Can't thank you enough.
@Larry Niles Paul is at his place because he does something right. Half of the things are bullshit, some of the products aren't ideal but, they did something right. That's why they can still sound good. But to me, I prefer my own designs.
Its been said that the only spec that matters in stereo equipment is the shipping weight. Its pretty much just a numbers game. My way of being able to tell what an amp sounds like is to look at the parts it uses.
If you allow me Sir, it depends on the first order how your loud speakers designed , sealed or ported bass or passive radiator ,2nd the magnetic size , 3rd the coil impedance ( lower impedance generates more electricity according to moving rate as they louder in lower volume , 4 the matierials that made by driver cone * the heavier the more dumping factor needed , for example if plastic cone at 70% of your amplifier volume needs 70 dumping factor , the paper cone needs 30 and carbon fiber cone need 20 dumping factor , so it depends on how speakers reacting factors >> what are these factors >> inclouser type, impedance .material etc....
Thank you Paul, that summed it up well.The highest damping factors I have measured are on Crown amps, not the best amps for listening. They built one called the Power Line 4 that sounded better than the similar Crown DC300A and it had half the damping factor. The amps with the huge damping factors were good at driving passive subs though.
Would you say Bob Carver's Magnetic field coil power amplifier architecture design is an exception to the traditional damping factor theory ? I also noticed really expensive vintage audio amps (Sansui, Pioneer SX, McIntosh, etc.) have low damping factors. But these amps sound lovely.
I am going to take a shot at helping to answer the question. I will use an analogy of a car during discussion. Is a damping factor a good way to distinguish for the quality of an amp. Short answer yes. It is one of many. On its own, it does not predicate the quality of an amp. It is much like the shock on a car. The springs are the drivers. The car will be bouncy and out of control without the proper dampening of a shock. Another is the slew rate which is much like torque in a car. The faster a car can accelerate, the more "responsive" a car or amp can be seen to perform. All of this must follow a proper ability of an amp to be honest to frequency response. I also like to look at a square wave reproduction ability of an amp. If it can reproduce a square wave, then you can surmise that it can faithfully reproduce input signals. These items and more should be considered prerequisites when "spec'ing" out an amp.
Does this mean current model McIntosh solid state amplifiers, such as the MC452 or MC462, might have difficulties driving and controlling modern speakers?
A high damping factor is typically achieved by applying a lot of feedback around the output stage. This can smother the amplifier’s open and relaxed sound
It's in the name... "Factor". It describes how many times lower the output impedance of the amp is relative to the load. Yes, it's typically quoted for an 8 ohm load. So if the amp has an output impedance of 0.8 ohms.. then 8 ohms / 0.8 ohms = 10. Damping Factor has no units because it's ohms/ohms. It's a ratio. Medium sized tube amps will be around 10-30. Vintage amps & receivers like Pioneers/Yamaha will be around 40-60. Big beefy amps will be 100-400 or higher. Damping factor typically varies with frequency... being lower at high frequencies. This depends greatly on the output topology of the amp. NONE of this has anything to do with sound QUALITY. It can tell you a bit about how it will interact with your speakers. Typically, difficult speakers with complicated crossovers do better with high damping factor amps.... but even this is a generality.
Right. I use high damping factor amps for subs. The higher the damping factor the happier I am. It helps control overshoot of the driver and puts the breaks on. You get that nice punch. Cable length and gauge also matter. The shorter and thicker the better.
Hi Paul. Very interesting and this is a subject that I am working on. We have been in contact before and we have a mutual acquaintance that is known to Bascom King. Consider this, and it is thought provoking, make the amplifier draw the same current at _all_ frequencies and the amplifier's output impedance gets cancelled out. This basically means that we must EQ the current of the amplifier (the impedance plot is about current and nought about the voltage) inversionally proportional to the load on the amplifier and the alignment does not change with any source impedance. Then the output impedance of the amplifier does not matter. Way back in 1975 I had a discussion with Richard H. Small (of Thiele-Small Parameters) in Q2 of 1975 (he was not quite famous yet) and he basically said that the damping is entirely defined by the LF alignment and not by the output impedance. A better understanding of T-S Parameters actually confirms this. The idea of an amplifier having any 'damping factor' outright annoyed him. That is something I never forgot. I am now working on a paper that has been in the works for decades and I have a list compiled of whom I will send it to. The damping of an LF alignment can also be defined by _current versus frequency_ and includes maths that actually makes sense. The damping of an LF system is highest when the current is low. The list has some very well known names on it. Cheers, Joe
A very lucid comment. In 1975, broke and fresh outta military service I got my first "component " hifi budget system. I started reading about the Thiele/Small equations for venting loudspeakers. To my knowledge only two companies took advantage of this in those days; Electro/Voice and Ohm Acoustics. Acoustic Suspension ruled then as vented designs were trial & error and kinda sucked. Now, all Gods chillins got vented speakers. I purchased Ohm L's in 1978 and still use them. I used the L's with an SX-650 and output was enough to impress, if not annoy the neighbors. Damping Factor was 30. Got an SR-804 in 1979 and DF is 40. I thought DF was to tame the woofer excursions for cleaner bass and that higher was better. I've seen amps with DF of 10. Your narrative is technically a bit over my head. In plain talk (please), what IS a good amp DF???
Howdy. I like a lot the way you advocate modesty and comprehensive approaches in this field of high end audio. For myself I have a little bit of struggle breaking loose from the bandwidth, THD, slew rate and damping mania ... Regards.
Pauls explanation is quite accurate. The only thing I would add is a speaker is a motor generator and as such generates back EMF: en.wikipedia.org/wiki/Counter-electromotive_force A solid state amplifier that features a high damping factor not only can source current but can sink it ( consume the back EMF if you wish ). Paul used the word "control" which is a good choice of word. The bigger the speaker generally the larger the back EMF currents. If your driving a large subwoofer you may require an amplifier with a high damping factor. Tube amps with their large output transformers sink back EMF very poorly and should not be used to drive large coned loudspeakers.
Damping factor, high or low, does not correlate with how much current an amplifier can absorb. It only describes how much the current (in or out) alters the output voltage of the amp.
I've heard it described that matching an amplifier and speakers is like a marriage you have the two individuals and the combination makes a third personality.
Loudspeakers are just a particular type of microphone, and visa versa. No surprise that a loudspeaker also generates a voltage. Low dampening just means the output of the amp is not able to control the flow of current generated by the speaker moving on its own through the magnetic field as a result of, for example, the momentum of the speaker causing the speaker to not follow the output of the amp.
Hi Paul I've been watching your YT channel for some time now and find your videos pretty informative. I've posted questions to you a couple of times and received a reply on one regarding dacs. I have another that I'd greatly appreciate your opinion on. Being how in this video you touched on your upcoming speakers. I'd love to know if you have heard the Buchardt S400 speakers and your thoughts on them ?
The low damping factor of Schiit products makes me worried that the wouldnt have the bass I like for Rock music, the new Ragnarok is only like 80 in the DF zone, but is that enough?
For me a high damping factor indicates the amp has a low output impedance which means that the speaker will have less of an impact on the amps amplitude or phase response
Any damping factor over about 10 is high enough that the speakers own dc resistance will dominate the amount that the motion that generates reverse EMF will be damped.
Good video. From my experience, with maybe a dozen or so different high-end speakers, they sound better (bigger soundstage mostly) when driven by a low damping factor. I have even gone so far as to take a high damping factor amplifier, such as my Bryston 4B, and put a 1Ω resistor in series. Maybe these speakers were simply voiced with tubes in mind.
It is entirely possible that tube amps are a consideration in high end speaker design these days. Going back a few decades when high DF was the norm among speaker designers, putting a resistor in series with the speaker put a bump or 2 in the bass response leading to an artificially warmer sound. If they had been designed with tube amps the designers would have voiced the speaker differently.
What was the link to the video you mentioned? Kudos, I enjoy your information on this channel very much. I wish I could support your company, but I haven’t worked in some time.
And the conclusion is: our ears are the best ''indicator'' of the performance of an amplifier = use your ears, folks! And they are on the head, we have a couple of them and they are bigger and bigger as we are older and older and we hear less and less... Mine are already quite large, either from listening or from age.
High damping factor means higher feedback, means better absorption of emf from the driver. But when output impedance is low enough it won't make difference because cable has much higher impedance in this case. And this is why cable also matters.
Low damping factor is never a good thing and one reason why tube amplifiers aren’t the best nowadays. But it’s a spec that doesn’t need to be more than around 30 and won’t matter if much higher. Like other traditional audio specifications, there is a good enough number that your ears can’t detect and anything better won’t matter. For example a THD of 0.1% vs 0.0001% might look like a huge difference but you won’t even notice the difference. When Paul doesn’t care the measurements it simply means the traditional measurements are good enough to not matter anymore for what humans can hear. However, you can still measure performance of an amplifier through an approach of comparing output to input mathematically using AD converters to save the wave forms and on a computer create the delta wave form (with the factor of amplification included). If you find no delta in such data above 80dB at all while playing real music...any talk of “audible effects” can be declared as snake oil and your amplifier is simply not contributing negatively to what you actually hear.
As usual with audio design it's a compromise. High damping factor does control woofers demonstrably better than valve amplifiers with their poor bass control and so with it's good damping it could be considered an extremely good thing for controlling overshot subwoofer (or woofer) excursions for instance, but a bad thing for high frequency performance as high damping factor is usually brought about by what might be considered by some an overdose of negative feedback, which can be a bad thing as loads of negative feedback usually accompanies an essentially non-linear circuit design (which is rightly considered undesirable). That much feedback will sort out the measured response, but not necessarily the heard response. So yes good for subwoofers, no for general use would be my answer.
Ahh ,,, Just because a Tube Amp has Tubes , is not what makes it lacking with respect to Damping Factor or not . It depends on the " Design of the Circuit " , that is , if it has Global Feedback , or not , in varying amounts .
Better is to have a class A amp - no crossover distortion, and staying entirely within the linear range of the amp. Ya just need a good transformer. And that amp is likely to have a low dampening factor, but you can't get better quality than a class A amp in its linear range. :)
Those little "D" class amps need speakers with at least 90+ sensitive, and not more than two drivers, then their not too bad, other wise poor. Nice video.
Hi Paul, After all those years in audio and even working at a loudspeaker manufacturer, and still telling that a HIGH damping factor is something good? (Is this part of the 1 % that isn’t true?) I think this is utter nonsense, I think it is quite the opposite… Damping factor is an important element in a power amplifier's ability to control a loudspeaker. Yes, but the LOWER the better! Damping factor is the root cause of the current distortion in loudspeaker drivers. If an amplifier has a high output impedance (more than 100 times the load) and thus a very LOW damping factor it is not sensitive to impedances (reactive or resistive) in the loudspeaker. So it is not sensitive to (changes in) the inductance (which is current and excursion dependent), not to voice coil resistance (dependent on temperature, known as power compression) and not to generated voltages (back emf). So with a very LOW damping factor the (current) distortion is much lower, especially in the small signal domain. However a HIGH damping factor lowers the quality (Q) of the resonance. So, when you dampen the resonance in another way than with electrical damping the distortion in the loudspeaker is much lower. And there are other ways: mechanical, acoustical, electronically (EQ) and probably more… So, maybe a HIGH damping factor 'controls' the resonance, but certainly not the driver. A LOW damping (a high output impedance) improves the control of the amplifier over the driver, makes it less sensitive to influences (temperature, excursion, current, cone motion, sounds!, …) and results in lower distortion. Afterall, like all electromotors, drivers are current driven devices, not voltage driven.
That's an interesting take on the subject though not one I would agree with. But, thank you for sharing a different viewpoint! There's always room to learn and be accepting of new ideas even if we don't agree.
@@Paulmcgowanpsaudio And on which part don't you agree? Electromotors, current distortion, high output impedance eliminating impedance dependencies? (I'm also open for an off-line discussion. Give me a sign and I email you.)
@@Paulmcgowanpsaudio Okay, … So, we agree that a driver is an electromoter. And that the current through the voice coil creates a force (F = Bl x I), which creates acceleration. And that velocity of the voice coil creates an electromotive force (a voltage) over the voice coil. With a very low output impedance (much lower than the load) the current through the voice coil is very dependent on the impedance in the driver. And with a very high output impedance (much higher than the load) the current through the voice coil is not dependent on the impedance in the driver. In this way the temperature of the voice coil, the inductance of the voice coil (changing with current and excursion) and motion of the voice coil (by the created sound, but also by unwanted vibrations and by external sounds) all has influence on the conversion from the output voltage of the amplifier to the current through the driver, and thus the SPL output of the driver. So, in my opinion, a low output impedance amplifies the influence of varying impedance of the load and a high output impedance attenuates the influence of a varying load impedance. Where exactly do we disagree?
@@JerryRutten By attenuating the influence of the amplifier it has the tendency to change the sonics of the driver in ways the designer did not intend (for the most part) and certainly cannot control (since "high impedance" is different for almost any amplifier because it varies with frequency). While I agree with your electrical analysis, I do not agree on the usefulness of the results. High impedance amplifiers generally do not sound as controlled or authoritative on speakers as lower impedance amplifiers do.
I was in the audio signal processing design business for decades. I consulted on amp design with multiple big name companies, and finished my career designing products at Dolby Laboratories. Dolby had/has superb listening rooms. When we carefully blinded tests, even in a superb space with very highly regarded speakers and good source material, amplifiers of decent spec and power were indistinguishable. The key was double blinding the tests, so that neither the listeners or those running the test knew at any given moment which amp was in use. Listeners had a button that allowed them to (maybe) change amps. Sometimes it stayed on the same amp, sometimes it changed. Data collection was automatic - the system recorded the results which could only be seen at the end of the test. Almost without exception, listeners were no better than chance when trying to pick which amp they were listening to, or rank which sounded better.
Hi Paul. I'm so glad I "found" your RUclips channel. I have an EE and have worked with DC to daylight for almost 50 years. Just can't get enough. What I like about your presentations is that you explain even the most esoteric concept in plain old English terms; very clear. This is a great contribution to the human race. Can't thank you enough.
@Larry Niles Paul is at his place because he does something right. Half of the things are bullshit, some of the products aren't ideal but, they did something right. That's why they can still sound good. But to me, I prefer my own designs.
Its been said that the only spec that matters in stereo equipment is the shipping weight. Its pretty much just a numbers game. My way of being able to tell what an amp sounds like is to look at the parts it uses.
If you allow me Sir, it depends on the first order how your loud speakers designed , sealed or ported bass or passive radiator ,2nd the magnetic size , 3rd the coil impedance ( lower impedance generates more electricity according to moving rate as they louder in lower volume , 4 the matierials that made by driver cone * the heavier the more dumping factor needed , for example if plastic cone at 70% of your amplifier volume needs 70 dumping factor , the paper cone needs 30 and carbon fiber cone need 20 dumping factor , so it depends on how speakers reacting factors >> what are these factors >> inclouser type, impedance .material etc....
Thank you Paul, that summed it up well.The highest damping factors I have measured are on Crown amps, not the best amps for listening. They built one called the Power Line 4 that sounded better than the similar Crown DC300A and it had half the damping factor. The amps with the huge damping factors were good at driving passive subs though.
What does "highest" and "huge" mean in numbers?
Would you say Bob Carver's Magnetic field coil power amplifier architecture design is an exception to the traditional damping factor theory ? I also noticed really expensive vintage audio amps (Sansui, Pioneer SX, McIntosh, etc.) have low damping factors. But these amps sound lovely.
I am going to take a shot at helping to answer the question. I will use an analogy of a car during discussion. Is a damping factor a good way to distinguish for the quality of an amp. Short answer yes. It is one of many. On its own, it does not predicate the quality of an amp. It is much like the shock on a car. The springs are the drivers. The car will be bouncy and out of control without the proper dampening of a shock. Another is the slew rate which is much like torque in a car. The faster a car can accelerate, the more "responsive" a car or amp can be seen to perform. All of this must follow a proper ability of an amp to be honest to frequency response. I also like to look at a square wave reproduction ability of an amp. If it can reproduce a square wave, then you can surmise that it can faithfully reproduce input signals. These items and more should be considered prerequisites when "spec'ing" out an amp.
So a Peachtree Nova150 is "better" than a Pass Labs Xs 150 because the damping factor is greater and the distortion % is lower?
@@Koru-Health Let me help answer by using a quote from my previous post.
"On its own, it does not predicate the quality of an amp."
Does this mean current model McIntosh solid state amplifiers, such as the MC452 or MC462, might have difficulties driving and controlling modern speakers?
A high damping factor is typically achieved by applying a lot of feedback around the output stage. This can smother the amplifier’s open and relaxed sound
A little feedback goes a long way..anything more than a touch is too much and ruins the fidelity
Muy bien explicado!!!! Gracias Paul!!!!
So what number is regarded as a high damping factor number? And does it change depending on what ohm speaker your using?
It's in the name... "Factor". It describes how many times lower the output impedance of the amp is relative to the load. Yes, it's typically quoted for an 8 ohm load. So if the amp has an output impedance of 0.8 ohms.. then 8 ohms / 0.8 ohms = 10. Damping Factor has no units because it's ohms/ohms. It's a ratio. Medium sized tube amps will be around 10-30. Vintage amps & receivers like Pioneers/Yamaha will be around 40-60. Big beefy amps will be 100-400 or higher. Damping factor typically varies with frequency... being lower at high frequencies. This depends greatly on the output topology of the amp. NONE of this has anything to do with sound QUALITY. It can tell you a bit about how it will interact with your speakers. Typically, difficult speakers with complicated crossovers do better with high damping factor amps.... but even this is a generality.
Majority of the stuff you can purchase at Best Buy or wherever is 200, most high-end brands are rated at a 1000
Right. I use high damping factor amps for subs. The higher the damping factor the happier I am. It helps control overshoot of the driver and puts the breaks on. You get that nice punch. Cable length and gauge also matter. The shorter and thicker the better.
Hi Paul. Very interesting and this is a subject that I am working on. We have been in contact before and we have a mutual acquaintance that is known to Bascom King. Consider this, and it is thought provoking, make the amplifier draw the same current at _all_ frequencies and the amplifier's output impedance gets cancelled out. This basically means that we must EQ the current of the amplifier (the impedance plot is about current and nought about the voltage) inversionally proportional to the load on the amplifier and the alignment does not change with any source impedance. Then the output impedance of the amplifier does not matter. Way back in 1975 I had a discussion with Richard H. Small (of Thiele-Small Parameters) in Q2 of 1975 (he was not quite famous yet) and he basically said that the damping is entirely defined by the LF alignment and not by the output impedance. A better understanding of T-S Parameters actually confirms this. The idea of an amplifier having any 'damping factor' outright annoyed him. That is something I never forgot. I am now working on a paper that has been in the works for decades and I have a list compiled of whom I will send it to. The damping of an LF alignment can also be defined by _current versus frequency_ and includes maths that actually makes sense. The damping of an LF system is highest when the current is low. The list has some very well known names on it. Cheers, Joe
A very lucid comment. In 1975, broke and fresh outta military service I got my first "component " hifi budget system. I started reading about the Thiele/Small equations for venting loudspeakers. To my knowledge only two companies took advantage of this in those days; Electro/Voice and Ohm Acoustics. Acoustic Suspension ruled then as vented designs were trial & error and kinda sucked. Now, all Gods chillins got vented speakers. I purchased Ohm L's in 1978 and still use them. I used the L's with an SX-650 and output was enough to impress, if not annoy the neighbors. Damping Factor was 30. Got an SR-804 in 1979 and DF is 40. I thought DF was to tame the woofer excursions for cleaner bass and that higher was better. I've seen amps with DF of 10.
Your narrative is technically a bit over my head. In plain talk (please), what IS a good amp DF???
Howdy.
I like a lot the way you advocate modesty and comprehensive approaches in this field of high end audio. For myself I have a little bit of struggle breaking loose from the bandwidth, THD, slew rate and damping mania ...
Regards.
Pauls explanation is quite accurate. The only thing I would add is a speaker is a motor generator and as such generates back EMF:
en.wikipedia.org/wiki/Counter-electromotive_force
A solid state amplifier that features a high damping factor not only can source current but can sink it ( consume the back EMF if you wish ). Paul used the word "control" which is a good choice of word.
The bigger the speaker generally the larger the back EMF currents. If your driving a large subwoofer you may require an amplifier with a high damping factor. Tube amps with their large output transformers sink back EMF very poorly and should not be used to drive large coned loudspeakers.
Damping factor, high or low, does not correlate with how much current an amplifier can absorb. It only describes how much the current (in or out) alters the output voltage of the amp.
I've heard it described that matching an amplifier and speakers is like a marriage you have the two individuals and the combination makes a third personality.
Very good explanation on this topic .Thanks
the sound experience is actually the baby
Loudspeakers are just a particular type of microphone, and visa versa. No surprise that a loudspeaker also generates a voltage. Low dampening just means the output of the amp is not able to control the flow of current generated by the speaker moving on its own through the magnetic field as a result of, for example, the momentum of the speaker causing the speaker to not follow the output of the amp.
Hi Paul I've been watching your YT channel for some time now and find your videos pretty informative. I've posted questions to you a couple of times and received a reply on one regarding dacs. I have another that I'd greatly appreciate your opinion on. Being how in this video you touched on your upcoming speakers. I'd love to know if you have heard the Buchardt S400 speakers and your thoughts on them ?
In general does class D or class ab have better damping factor?
Excellent video, high-end companies use that spec as selling point because most likely you have to purchase online
The low damping factor of Schiit products makes me worried that the wouldnt have the bass I like for Rock music, the new Ragnarok is only like 80 in the DF zone, but is that enough?
For me a high damping factor indicates the amp has a low output impedance which means that the speaker will have less of an impact on the amps amplitude or phase response
Any damping factor over about 10 is high enough that the speakers own dc resistance will dominate the amount that the motion that generates reverse EMF will be damped.
Good video. From my experience, with maybe a dozen or so different high-end speakers, they sound better (bigger soundstage mostly) when driven by a low damping factor. I have even gone so far as to take a high damping factor amplifier, such as my Bryston 4B, and put a 1Ω resistor in series. Maybe these speakers were simply voiced with tubes in mind.
It is entirely possible that tube amps are a consideration in high end speaker design these days. Going back a few decades when high DF was the norm among speaker designers, putting a resistor in series with the speaker put a bump or 2 in the bass response leading to an artificially warmer sound. If they had been designed with tube amps the designers would have voiced the speaker differently.
Learned something again. Thank you.
What was the link to the video you mentioned? Kudos, I enjoy your information on this channel very much. I wish I could support your company, but I haven’t worked in some time.
There are good used PS Audio gears out there! Good luck!
And the conclusion is: our ears are the best ''indicator'' of the performance of an amplifier = use your ears, folks! And they are on the head, we have a couple of them and they are bigger and bigger as we are older and older and we hear less and less... Mine are already quite large, either from listening or from age.
Good one. May i repost this?
Check out the video from The Hans Beekhuyzen channel covering the same topic, but in greater detail.
The only way to tell from specs if an amp is any good is when the manufacturers stop cherry picking the results (some even just making them up)
A high damping factor generally means that you will have tight bass.
High damping factor means higher feedback, means better absorption of emf from the driver. But when output impedance is low enough it won't make difference because cable has much higher impedance in this case. And this is why cable also matters.
The amp I have has a damping factor of 2000 and I can say it is the best sounding amplifier I've ever had.
I have one too, but is it because of the damping factor? Or it sounds that good because it is finished in black 😉
No but that it is a healthy constructed one
A very heavy amp generally lets you know it should be at least decent. You are listening to your power supplies.
As i think , increase the DF meant lower the musicality .
No single specification is an indication of a good amplifier, but it can be an indication of a bad one... 🤔
There was a question years ago in the Absolute Sound magazine as to why an amp can sound great but have bad specs.
@@andershammer9307 no they can't
Low damping factor is never a good thing and one reason why tube amplifiers aren’t the best nowadays. But it’s a spec that doesn’t need to be more than around 30 and won’t matter if much higher. Like other traditional audio specifications, there is a good enough number that your ears can’t detect and anything better won’t matter. For example a THD of 0.1% vs 0.0001% might look like a huge difference but you won’t even notice the difference. When Paul doesn’t care the measurements it simply means the traditional measurements are good enough to not matter anymore for what humans can hear. However, you can still measure performance of an amplifier through an approach of comparing output to input mathematically using AD converters to save the wave forms and on a computer create the delta wave form (with the factor of amplification included). If you find no delta in such data above 80dB at all while playing real music...any talk of “audible effects” can be declared as snake oil and your amplifier is simply not contributing negatively to what you actually hear.
I have no idea how much damping factor does my amp (Jadis DA50 S) has and never cared, just sit and listen and you know if it's for you. :)
As usual with audio design it's a compromise. High damping factor does control woofers demonstrably better than valve amplifiers with their poor bass control and so with it's good damping it could be considered an extremely good thing for controlling overshot subwoofer (or woofer) excursions for instance, but a bad thing for high frequency performance as high damping factor is usually brought about by what might be considered by some an overdose of negative feedback, which can be a bad thing as loads of negative feedback usually accompanies an essentially non-linear circuit design (which is rightly considered undesirable). That much feedback will sort out the measured response, but not necessarily the heard response. So yes good for subwoofers, no for general use would be my answer.
Last thing I look at is " spec " for performance .
Ahh ,,, Just because a Tube Amp has Tubes , is not what makes it lacking with respect to Damping Factor or not . It depends on the " Design of the Circuit " , that is , if it has Global Feedback , or not , in varying amounts .
Better is to have a class A amp - no crossover distortion, and staying entirely within the linear range of the amp. Ya just need a good transformer. And that amp is likely to have a low dampening factor, but you can't get better quality than a class A amp in its linear range. :)
Yes, Class-Amps sound amazing, but are notorious for getting very hot to the touch, because of as the scenes heat they put out🤦🏻
@@albertelazar4069 But what is a little quibble over energy efficiency when the goal is pure quality of sound? Good, efficient, cheap. Pick any two.
Those little "D" class amps need speakers with at least 90+ sensitive, and not more than two drivers, then their not too bad, other wise poor. Nice video.
paul says "I'm getting excited " and you look and see a big bulge in his pants ! LOL
😅no.😊
I can tell you the specs on this thing are irrelevant: dandagostino.com/products/relentless-monoblock.php It is the most amazing I've ever heard!!
Hi Paul,
After all those years in audio and even working at a loudspeaker manufacturer, and still telling that a HIGH damping factor is something good? (Is this part of the 1 % that isn’t true?) I think this is utter nonsense, I think it is quite the opposite…
Damping factor is an important element in a power amplifier's ability to control a loudspeaker. Yes, but the LOWER the better! Damping factor is the root cause of the current distortion in loudspeaker drivers.
If an amplifier has a high output impedance (more than 100 times the load) and thus a very LOW damping factor it is not sensitive to impedances (reactive or resistive) in the loudspeaker. So it is not sensitive to (changes in) the inductance (which is current and excursion dependent), not to voice coil resistance (dependent on temperature, known as power compression) and not to generated voltages (back emf). So with a very LOW damping factor the (current) distortion is much lower, especially in the small signal domain.
However a HIGH damping factor lowers the quality (Q) of the resonance. So, when you dampen the resonance in another way than with electrical damping the distortion in the loudspeaker is much lower. And there are other ways: mechanical, acoustical, electronically (EQ) and probably more…
So, maybe a HIGH damping factor 'controls' the resonance, but certainly not the driver. A LOW damping (a high output impedance) improves the control of the amplifier over the driver, makes it less sensitive to influences (temperature, excursion, current, cone motion, sounds!, …) and results in lower distortion. Afterall, like all electromotors, drivers are current driven devices, not voltage driven.
That's an interesting take on the subject though not one I would agree with. But, thank you for sharing a different viewpoint! There's always room to learn and be accepting of new ideas even if we don't agree.
@@Paulmcgowanpsaudio And on which part don't you agree? Electromotors, current distortion, high output impedance eliminating impedance dependencies? (I'm also open for an off-line discussion. Give me a sign and I email you.)
@@JerryRutten The latter. A lower output impedance is best to control varying higher impedances.
@@Paulmcgowanpsaudio Okay, …
So, we agree that a driver is an electromoter. And that the current through the voice coil creates a force (F = Bl x I), which creates acceleration. And that velocity of the voice coil creates an electromotive force (a voltage) over the voice coil.
With a very low output impedance (much lower than the load) the current through the voice coil is very dependent on the impedance in the driver. And with a very high output impedance (much higher than the load) the current through the voice coil is not dependent on the impedance in the driver. In this way the temperature of the voice coil, the inductance of the voice coil (changing with current and excursion) and motion of the voice coil (by the created sound, but also by unwanted vibrations and by external sounds) all has influence on the conversion from the output voltage of the amplifier to the current through the driver, and thus the SPL output of the driver.
So, in my opinion, a low output impedance amplifies the influence of varying impedance of the load and a high output impedance attenuates the influence of a varying load impedance.
Where exactly do we disagree?
@@JerryRutten By attenuating the influence of the amplifier it has the tendency to change the sonics of the driver in ways the designer did not intend (for the most part) and certainly cannot control (since "high impedance" is different for almost any amplifier because it varies with frequency). While I agree with your electrical analysis, I do not agree on the usefulness of the results. High impedance amplifiers generally do not sound as controlled or authoritative on speakers as lower impedance amplifiers do.