Class D amp fatigue

[@tunahead1126]

I love that Paul adds a little humor in his daily videos. I try and listen to them as often as i can. I have learnt quite a lot. Thanks

[@nicksnowbuildings]

I love the man, a true gem and a breath of fresh air in an audiophile community that is often so serious and lacking in self awareness. God bless him, I wish him all the best.

[@David-ik8wj]

definitely getting more smarter about hi fi technology.

[@jasonkillsformomy]

I had dilemma. I needed a new stove for my sauna and also a new amp, but only had money for one of them. I was torn. Until I tested a class A amp. Now have new stove and a new amp.

[@WalterReade]

Tosi hauska

[@marcbungener1877]

I’m the one who asked the question to Paul and before I had…tube monoblocs but actually it did not made living room a sauna 😂

[@johnpetrakis379]

@@marcbungener1877 Well, they just weren't big enough. Been toasted by some at shows, and your living room wasn't small enough

[@abecollins2266]

I had a Pass Labs Aleph 3 Class A amp that doubled as a room heater and stove to cook my fried egg breakfast. It pulled 250-watts from the AC mains to produce a meager 30-wpc of audio. It may have sounded decent if it weren't for my "real world" speakers and the power they required to come alive.

[@stLtBilko]

Lol

[@davidtyler3116]

Great explanation Paul. I would suggest, in general, for those people who fancy audio as a hobby, that they should get a hearing analysis to determine their individual loss issues. Many comments below - MIGHT - be somewhat related to their own ears. Especially in those above 40! I am above 60! I My eq and dampening and other room mods in my audio room are for me - specifically. I can listen for hours and not get fatigued. I would also say to others understand that some recordings are also less than optimal and can cause fatigue on any system. Unfortunately some of those recordings were made long ago and the artists have since passed, so it's what we have or nothing. Great channel, great advice from you as always!

[@Andrew-rc3vh]

You can use AI to improve imperfections in old recording equipment as long as the information is there in some form. For example if the tape machine recording it was not keeping a constant speed the AI will figure out the correction needed if the speed variations were non-random, e.g. a roller was very slightly elliptical.

[@natskar]

I agree! I can listen to my expensive class D amplifier I installed in my car allll day. Tune it correctly with a DSP and you get what you pay for (most the time). But it’s not always so broad, it is the smaller details such as the filtering and even quality of parts or wires how they’re ran and if the crossovers are wrong, the type of transformer, etc. all makes a difference to determine the company’s goal for how they want the sound or price of manufacturing

[@danabunner487]

I own several amplifiers, including a Class D, two solid state Class A/B, two tube single-ended and two tube push pull. I find my Class D amp to sound quite good. Very clear, very good imaging, great bass definition and power. I do not hesitate to use it for critical listening.

[@scottypalmer2158]

I agree. But some of the cheaper class D amps can sound sterile and lacking in dynamics, however I've never experienced fatigue.

[@Tamilpasanga664]

@@scottypalmer2158 Wat about TPA3251

[@scottypalmer2158]

@@Tamilpasanga664 : One of the best class D's for cheap. Get one with a removable Op Amp and install a Sparkos Labs Op amp...then a good power supply.

[@Tamilpasanga664]

@@scottypalmer2158 my swan hivi M50MKiii speaker sound worst, do need to add any external DAC

[@Tamilpasanga664]

@@scottypalmer2158 can change power supply board? will it make improve the sound quality

[@themastroiannis]

great explanation! thanks... Marantz Model 30...another absolute beauty, class D, not fatiguing, but extremely resolving! fantastic amp...

[@ScottGrammer]

Some of the earliest high-power Class-D amps were the Peavey DECA sound reinforcement amps made in the mid 1980's. They sounded great, and were even used in some recording studios for driving monitors. But part of their good sound might have been the fact that their pulse rate was 500kHz, much higher than most Class D amps. This allowed the reconstruction filters to be tuned to a much higher frequency, which reduced their phase shift in the top (audible) octave.

[@peteleoni9665]

I tried to play bass through one of those in the 80s. It would simply go "blank" for a second...Very clean for hifi though.

[@sonus289]

I still have a few of the deca's . Theye were lousy for low freq material, but decent for playback. I have one of the peavey digital power converters (dpc 1000) from the 90's that seem to have low efficiency from gain. 500w on it is weak compared to a 500w qsc of similar age. Seems like the manufacturers got the digital thing more stable than it used to be. I have a ashdown retroglide 750 that competes with my old carvin r1000 in bridge mode

[@wilsont1010]

Is it a typical issue for Class D amp that a drum beat can easily distort the smoothness of the vocal?

[@ScottGrammer]

@@wilsont1010 I've not heard of this. I can say, though, that Class D amps can do odd things when driven into clipping, depending on their design. This may be what you're referring to.

[@josepharchila1496]

I have a pair of M1200s and agree 100% no fatigue after DAYS of immersive listening! Bravo to PS Audio!

[@russmaleartist]

I have Crown Class D amps ... fou of them one for each frequency and one for my double subs. I had turned my speakers into active speakers and got rid of the passive crossovers, while using a DBX active crossover between my preamp and the Crowns ...I think they are detailed, focused with great accurate imaging...but to me, never fatiguing. I know everyone wants to say and are greatly convicted that theirs is the best;however, I just know I like mine and there are others who have listened and were impressed by them. The point is: if you like the way hopefully your system sounds...that is all that matters. Enjoy....

[@carltoncotter2614]

I remember a long conversation with Crown in Elkhart years ago, when I was switching away from Audio Research, Mark Levinson and Crown A/B amps. Their guy (who struck me as very knowledgeable) told me everything was changing and suggested I try one of their XLS amps if I was an "audiophile". I used it for years and it sounded pretty good but would love to know what might be better without paying "snake oil" prices?

[@ericelliott227]

In my opinion: The class D amps of today are not the evil many make them out to be. Sure, back in the early days, they could be nasty, but now, most all the issues have been licked. I'd say that 99% of fatigue comes from the speakers used with the amp and not so much the amps themselves. The fault of the amps in the grand scheme is what side of neutral they tend to lean towards. Pairing up lively speakers with a class D amp will cause fatigue because class D amps are lively. Pairing up lively speakers with a class A or A/B amp balances things out and will not be fatiguing. Example: Wilsons are lively speakers (I personally don't care for them, but that is just my taste). Wilsons are better paired with class A or A/B and even then, they can be fatiguing if not dialed in well. Speakers that lean towards the warm side of neutral (tilted down) pair well with class D amps. It is not limited to "commercial" class D amps (in this case "commercial" means big names like Marantz, etc. I assume and most of Marantz's two channel amps are class A/B actually), one can make a PS Audio class D amp fatiguing by pairing up speakers that emphasize the output, although putting a tube in the input path greatly helps to diminish said fatigue. I also think it is not brand specific.

[@scottypalmer2158]

My experience mirrors yours. If the intended speakers have a naturally warm character then class D without fatigue. Pair a class D amp with bright speakers and you might develop problems. In my experience the class D amps generally present more detail but less dynamics than A or A/B.

[@doctormidnight]

My Focals sound just "meh" on my digital amp, almost annoyingly analytical and detailed. I really prefer it with my OG PSB Alphas, ProAc response, and Wharfedale Rubiance 27s. In that order. Sorry Tarun, I just think the PSBs sound a bit flatter!

[@jdlech]

I agree, it took 40 years for engineers to master class A and AB. It's taking 40 years to master class D. But we're getting to the point where class D can surpass even the best A and AB amps ever designed. 50 years from now, everything will be class D, and all other classes will be relegated to the esoteric. Not necessarily better, just different. I've already seen measurements of a class D amp that forced the lab to get new test equipment precise enough to measure the THD and S/N ratio. It was so low their standard test equipment couldn't measure it. Couple that with power efficiency over 90% in some cases, and the other class amps start to look antiquated.

[@Thomas..Anderson]

I guess class D- amps are evil. They take the oil away from snake oil sellers.

[@davidperry4013]

I have pioneer A-9 amp from 1981 and Q Acoustic 3020i and it has a nice homely sound. The sound just feels like home. Q Acoustics speaker have a tendency to sound homely.

[@airwood99]

I designed and built my first class D amplifier in 1979, agree the filters are the hardest to get right

[@fabieneldridge3414]

Paul is so knowledgeable when talking about music reproduction. Things are becoming so good that they are by passing our ears ability to hear. There are so many choices today of Great systems it makes it hard to decide what to buy. I guess people just need to find what they like to hear and not worry about what others like. I’m happy with my system and will probably die with it. I built my stereo room for the speakers and stereo that I installed. Everything was built to suit my speakers so they could breathe properly. In my opinion the speakers are your music. Lots of amps ect can push the speakers and so many are Great that the sound is really relies on the speakers and room than anything else. Just my opinion but I would always invest in speakers before anything else ! They are the Soul, Heart of any Great stereo system !

[@jdlech]

Everyone in the audiophile community laughed at the pioneers of psychoacoustics. But now look where we are - surround sound everything.

[@lgude]

Ah, clarity re class D. I have a Chinese SMSL class D, but listen at low levels. Now I understand why I have no problem with fatigue listening to detailed classical like string quartets, piano solos and the like. The detailed rendition of the class D amp feeds me for the same reason Earle Scruggs playing country banjo does. But I notice that at higher volumes my beloved details sound harsh. Bingo, you nailed it Paul.

[@UndyingShadow83]

Unless you're doing blind A/B testing, its probably bunk. And I've never felt "nervously exhausted" after listening to 2 hours of music. Has Mark tried weed?

[@kaypee1972]

I don’t have any PS audio gear but I have same power drill you guys use. Step by step, I’ll get there 😂

[@geddylee501]

Lol

[@rolandevans5894]

A thoughtful and informative expert opinion which counters some of the irrational anti class D prejudice. I have March Audio mono blocks which use Bruno Butzeys class D modules which I find very engaging and not at all fatiguing.

[@RamoLasiaf]

Thanks for the information. I build my own class d amp. Yes.. 30 years still strong. The filters are propriety (simple and effective). It never gets fatigues. The only problem with class d is that you never get to do anything except enjoy the beauty of music. 😑 And if you have a weak heart NEVER put the volume high. Just enough to hear the sheet music pages being flipped. 🤷‍♂️ Or the seats squeaks.

[@MarkSWilliams27]

I'd love to talk with you about building me one! Is there a way to contact me I wonder? Does youtube block emails?

[@thomascollins7932]

I have an early Class D integrated from Cary Audio (20 years old). It is generally on a 2nd small system. Cary is most well known for their tube gear that is the polar opposite of fatiguing. However, while the Cary has amazing power and grip with my Volti horns, after a while, I do tend to notice that fatigue factor that the writer mentioned. I am glad to know there are more class D options as I like much about the format, especially lighter weight and less heat.

[@johnreardon4944]

I'm an audiophile at home. AND I own a live blues music venue in Gifu, Japan. My speakers are all Class D QSC. K12.2, KS118, and CP12. No problems with them, as some people might know. Anyway, live music is not fatiguing if the band is exciting. I have endless compliments on our sound from both the audience and musicians alike. I find that the Class D amps along with our LED ADJ lights are very efficient powerwise. Can anybody here comment on the quality of the amps in my powered QSC speakers? I know that they're having quality control issues on some parts, but the design itself seems to be very well made. Again, it's not home audio, but relevant to Class D amps. Personally, I'm beyond impressed with the live sound quality. Our source gear is high end as well and doesn't need to be addressed unless one thinks so. Thanks!

[@jordanmetcalfe8302]

QSC build quality isn't fantastic, they're on the lower end as far as PA goes. There's a reason systems from the like of L'Acoustics, Coda Audio and D&B Audiotechnik use external amplification.

[@johnreardon4944]

@@jordanmetcalfe8302 I'm not familiar with those brands. I'll check them out. Thank you! I'm using powered speakers because space in my venue is extremely limited. It's in Japan. However, I'm wanting to buy a much larger building soon so your suggestion is very helpful. Availability and cost of imported gear is another factor for me too. QSC was my best option when I opened two years ago. The new RCF speakers are just now becoming available here I saw recently.

[@raybin6873]

@@johnreardon4944 I've seen many powered speaker systems not hold up well when driven hard. I've had amplifiers with cracked circuit boards...went back to using external amp system. I've been doing live stage sound since 1980's. I think the powered speaker stuff is more of a marketing ploy. 👍

[@johnreardon4944]

@@raybin6873 I understand your point. Thank you. That's what I've been worrying about with QSC's latest problems. I'm not positive, but because I bought my K12.2s and KS118 early on, I'm hoping to be safe from the problems with their later batches. My saving grace might be that I don't play my speakers loud. At all. My K12.2s are at unity and my KS118 sub is at minus 7. For real. Headroom is what has been successful for me thus far, not volume. So if I do get a bigger venue, I could sell my speakers and invest in separates. Your advice is taken seriously. I will say this though. The QSC CP12 speakers are phenomenal as monitors. I've never heard anything bad about them having any problems. They are very underated for what they are. Reviews and forums speak ultra highly of them. So at first, I will definitely keep those and try to invest in your knowledge of separates for at least my PAs and subs. Pros and cons of powered speakers vs separates are not to be overlooked lightly in my case. But sound quality is always my priority. Headroom is also a big factor, I know. And so overkill on wattage is a plus for quality speakers. Just last weekend, even with my current QSC system, our rare acoustic gig with vocals were heard with ease and without any stress from the speakers. I'm guessing that you're on to something higher quality than what what I've already been impressed with. I'm looking forward to discovering something new to ensure that my venue stays number one in my area. I'm already getting high end talent playing there so....

[@EthanWiner]

Fatigue is a function of overall volume and frequency distribution. It has nothing to do with amplifier class.

[@thd9041]

I was disappointed reading all the comments until i read yours Mr Winer

[@ianwilliams5915]

"our products, our class d products - never fatiguing never" - bold statement that cannot be true as every person's hearing is different. - I'm tired myself of the class A, AB, D 'battle'.

[@AzimuthAviation]

I've gone from the big house flagship system as an electronics engineer to a medium sized 2.1 class D amp based on a TI chipset development board powered with a Meanwell SMPS. I enjoy beautiful detail and find that a little 6j5 preamp adds just a little sugar to the mix.

[@HobbesJunior]

i¨ve often wondered what a decent tube preamp could do, (and ordered faulty tube amps home, so never got around to it ,,, since analog input via e.g. records, smacks any digital input, in regards to bandwidth and thus bass performance ,,,, could a simple preamp solution mimmic this , or is it more just a bit nice colouring it gives ,,, ,,, i will have to test it again, ith upcoming setup ,,, :)

[@HobbesJunior]

ps pascal audio sell d modules with near 130 db dynamic range,,, they run cold at full loads, since they pass on nearly all the power, to the speaker,,, big plus for class d ... and good powersupplies resonate at upwards ½ million hz, thus able to reproduce one order of magnitude lower freq. up to 50 khz ,,, new class "d" tech power supplies, came from medical scanners, as most or some of you probably know :) ...

[@scottypalmer2158]

I totally agree. My $800 15lb Hafler amp barely gets used. Changing Op Amps when permitted can be sonically rewarding too. I really like the Sparkos Labs Op Amps.

[@_944audiophile]

John Urlick’s Spectron Musician iI Amplifier was truly a breakthrough in Class D technology some 20+years ago. Might even compete in today’s world favorably!

[@nathanvanstralendorff2405]

Hi Paul, thsnk you again for the explanations on fatique. A few tubes in front will make music sing more, have more "soul" as we say here. I've updated tweaked and adjusted some things in my and others setup through your tips and tricks, , so it sounds a lot better. Thanks again 👌

[@marcbungener1877]

Many thanks for answering the question. Much appreciated.

[@peteleoni9665]

Stay tuned for "perfect" class d amp from PS Audio, which will sound exactly the same as the other decent class d amps but will be utterly "non fatiguing" And so it goes.

[@peteleoni9665]

Oil de snake' Oui Oui!

[@merakrut]

I bought mono-blocks with Purifi 1et400a modules in them. At first I was impressed by the clean detailed sound, however after a few days I noticed something strange with my hearing. When I washed my hands the water sounding like ice crystals a very high frequency noise added to the water coming from the tap. Then I noticed the sound was in everything, like when I read a physical news paper it sounded like it was printed on tinfoil. I stopped listening to the amplifiers for a week, and the hearing problem slowly disapered. Then I started using to the amplifiers again and after about one hour the strange hearing problem was back. I now have a class-AB amplifier with equally good sound as the class-D amplifiers. Fortunately no more problems with my hearing. I'm so happy it did not get chronical.

[@AdamsOlympia]

I’ve been thinking about getting my first 400 or 500 watt stereo amp; so I have the option to drive any speakers I throw at it … I’m only worried about the potential to blow my expensive speakers with so much power on tap, especially being a relative newbie to high end audio. How do you mitigate that danger, short of wiring up fuses before the speakers?

[@Tarodenaro]

Mark Levinson does makes a pretty decent class D as well (53?) i think; sounds weird but it's okay. I did tried coupling a transformer on the output of a 3-watt chip amp and it does sounds interesting, but not that great. I think the problem with class D is that you need a really clean power section; a direct box or tube input will help, but a clean DC rail is still required otherwise the amp sounds different on silent and loud recording, just like you said! good response.

[@ericberger6966]

Unfortunately, often it depends on the recording. Especially with a new setup revealing more details and better dynamic I discoverd, that some of my recordings start to fatique me, and some came to life.

[@Chiroman527]

Hi Paul, I am a subscriber. I have a unrelated to Class D Amp question. I have a Denon DRA-800H Receiver rated to 4 -16 Ohms. It has 2 Channels for Stereo (and video connections which I do not use at this time). I have connected 1 Pair of Elac Debut 6.2 speakers to Channel A , and 1 pair of Elac Debut Reference 6.2s to channel B. The Elacs are 6 Ohms nominally rated. They sound terrific played simultaneously or separately. However, as a Student of Audiophilism (at 71 YO), I learned that the Ohms ratings have an impact on the Receiver /Amp. I use 14 gauge copper speaker wire running perhaps 12-18 feet form the Receiver. At first, due to my laziness and ignorance, I wired the two speakers in parallel to one channel. That overheated the Receiver at 60 volume levels. It shut down with its Protective Circuitry. Then I wired the channels separately : 1 pair to Channel A and the other pair to Channel B. The Denon still gets Hot (has not shut down, but it is getting hot). Is there anything other than getting rid of the Elacs that i can use to "boost" the Ohms handling of the Denon? If I connect 2 other pairs of dislike speakers But with 8 Ohms ratings, it's fine. No Overheating to this extent. Appreciate your advice . THX for your terrific work.

[@ncironhorse8367]

I really like how Paul doesn't bash the competition and even acknowledges another brand of speaker.

[@ArlenMoulton2]

Class D amps themselves don't have a colour to their sound, that's the best part, as long as the output filter is made with decent components it should be absolutely fine! The hardest part is pairing speakers with them, as most speaker manufacturers do their R&D with AB amps, so they colour the sound of the speakers based off amps with a completely different tone to class D

[@hubbsllc]

I appreciate this video, Paul - thank you for posting it. Last year I bought a Crown XLS 1000 class D amp to use for amplifying a keyboard rig through a pair of vintage Acoustic 807 three-way cabinets just because my 1980s QSC amplifier is just so heavy and is a 3U as opposed to the Crown's 2U. I really appreciate the flexibility of having the built-in digital filters so that you can implement biamping, use a subwoofer, etc. more easily. But it does have more of a noise floor than the QSC has which isn't that big a deal on a gig but if I'm working with the rig at low volumes at home it's more noticeable.

[@zeusapollo8688]

I do like some acoustic cabs

[@hubbsllc]

@@zeusapollo8688 Sadly the pair of 807s I bought had one blown original 4"x10" horn (implemented as a midrange) that I was able to at least get back from the previous owner in trade for the replacement that was in there. There seem to be only two drop-in replacements for sale in the US; one has a plastic horn and one has a metal horn. The metal-horned one has a very peaky response and the whole cab sounds off with it installed. I put the one working original in its place and that improved things a lot.

[@zeusapollo8688]

@@hubbsllc I have some big acoustic horns. Wood front. I will look at the model number when I get home. 4 inch driver sounds about right

[@zeusapollo8688]

824

[@mrpmj00]

Yep, I have great Class A/B (Parasound 2125v2, Arcam AVR5) and shitty Class A/B (Emotiva BasX-A3, Denon x3700H). I also have great Class D (NAD C298 which is similar to NAD M23, Parasound Zonemaster 2)...no ear fatigue with a quality Class D. Apple Music lossless

[@therealmitch-a-palooza7262]

Purifi is the first class D amp module that really addresses the key issues that cause class D amp fatigue. There are a few things. One, most class D amps have not historically been load invariant, and they have tended to have better response up too than down low under load. This means they’re often quite bright. Second, the iron core inductors used for output filtering tend to cause distortion in the upper frequencies, which humans find very fatiguing. Purifi is both load invariant, and has a special feedback loop around the inductor to reduce that distortion to sub-audible levels.

[@sebastianjaramillo5049]

the first one was the Ncore by bruno putzeys, the purifi is the refined one by bruno too, the latest nilay is the best one so far by bruno of course

[@richardramorino3319]

I had an early class d amp, the Bel Canto Evo. I now have the Nad M33 with the Bruno Putzeys output stage. I hate to say it, but class D ain't there yet. There is something lifeless about the mid range and highs. They are great at dynamics, bass and clarity, but something is definitely missing. Manufacturers have many tricks to hide the deficiencies, but..

[@abecollins2266]

What amp are you comparing the modern class D NAD M33 to when you say "class D ain't there yet"?

[@richardramorino3319]

@@abecollins2266 in what I would call "the big and meaty" category I would include my McCormack DNA 500, Musical Fidelity, Harman Kardon HK 990, and BAT. In the "just the facts please" category various Benchmark Media stuff, and due to my second hand connections to the music/music management industry, various professional amps going all the way back to the now defunct Uni-sync brand in the 1980's. I generally like Italian speakers ( Sonus Faber Cremona) and am now eyeing a pair of Van Alstine mono blocks for my Rosso Fiorentino floorstanders.

[@simplereef4854]

I agree. I never any class D amp. Class D amp tends to have 3 rd order harmonic distortion that make the sound brittle and bright. Not my taste!

[@bradatherton9369]

@R L What are you talking about, a 'perfectly amplified input'? No amplifier is perfect, every amplifier has some amount of distortion. If you learned that in school then I want to sign up for that class ;)

[@bradatherton9369]

@R L If that's what you want to believe you are free to believe it, but that doesn't make it right. You're obviously convinced of your belief so I'll not try to sway you.

[@spacemissing]

Of course the cure for this trouble will be found in an all-tube class D circuit. Can't wait for the product announcement. Thanks for laughing along.

[@analoghardwaretops3976]

No you Don't have to laugh..... Much earlier.. (60- 80 years ago) most transmitter towers of AM / FM / SW ( 500KHz - 150 MHz) broadcast used tube output power stages ( that too in KW/MW ranges ) ...so it's NOT difficult to design & build one...even if just for experimental purposes...

[@spacemissing]

@@analoghardwaretops3976 And they still do. You're dealing with a ham here (KJ6QKV).

[@analoghardwaretops3976]

@@spacemissing good for you 👍 maybe you can give an idea of complexity & cost in building a class D tube amp..

[@johnmcclure4983]

Great video Paul! Very informative.

[@keithmorgan6498]

For those using inexpensive class D amps place a HIGH value resistor say between 330 Ohms and 560 Ohms across the speaker terminals. You will need to experiment to find what you like. It has very little effect on the speaker impedance and won't overload the amp.

[@user-xg6zz8qs3q]

Tripath fixed that problem decades ago. Those class T amps really sing. And they're dirt cheap. Please bring T amps back.

[@user-xg6zz8qs3q]

@Douglas Blake Gosh darn! That's why nobody speaks of Tripath? So everything circles back to the TPA3255 and the Aiyima A07? This also makes me more intrigued about the Octavio Amp. It's like a Bluesound Powernode copycat product from France and it uses the TPA3250. The specs seem so underwhelming but Octavio made some mods to the circuit boards.

[@user-xg6zz8qs3q]

@Douglas Blake Wondom still sells Tripath boards and finished amps. I have one of those amps. It's dirt cheap but only 10W. And it powers my fullrange drivers just fine.

[@stefanweilhartner4415]

good coils for the output filter cost a lot of money. low inner resistance makes the coil bigger and it needs the right core material so that it does not get into magnetic saturation when you go over 10W output. my aiyima 07 max has a 240W power supply that means 2*100W output is possible. i guess they do not have the best coil from coilcraft or würth inside because they are expensive and the aiyima 07 max costs only 95€. but i think below 2*20W they probably do not go into saturation. and i guess i did not go beyond that so far. when the coils go into saturation at a certain power level, the audio signal gets distorted and that probably contributes to the listening fatigue

[@mikepxg6406]

As I and my ears get older I prefer more revealing.

[@Santos.Sarmento]

Bruno Putzeys and Lars Risbo at Purify.

[@machone539]

This sounds a lot like when CDs first came out. A lot of folks said the sound was "harsh". All my amps are AB connected to JBLs and Jamo. But I do have a desktop amp that is class D to a pair of Triad bookshelf. I think they are fine. Maybe swapping for a more "mellow" speaker would make the class D amps less fatiguing?

[@beornthebear.8220]

I love class D for my 5 string bass guitar amp. It has a choice of tube or solid state input stages (which can be combined) but I love that an 8 pound amp putting out 800 watts RMS is the size of a the size of a 2" thick book. I started bass in the late 70s. and a 300 watt tube or solid state bass amp then were huge, heavy, and hot. I marvel at how little heat this generates at such a small size and light weight.

[@miguellogistics984]

Well understood why you like it. I just do not get the mids that I like out of the Shuttle Max 12.0 and the Shuttle Max 12.2 was just Double Violin/Flat Wound Dark Tube Modeled Power Section. I ended up leaning on the Copper Toroidal Power Transformers of the NEOX400, GBE600 and the GBE1200. They are all laying about me right now, yes even the ShuttleMaxs. I really need to sell those.

[@clemmcguinness1087]

What is this amplifier please?

[@tmdillon1969]

I have a pair of Bel Canto M300 monoblocs that I simply love. They pair perfectly with my upgraded CSS 1-TDX. However, I'm not sure I'd put them on my Cornwalls or JBL L100s. I have a Marantz 2330 set up with those and the synergy seems spot on. Personally, I believe the published specs on the 1-TDX are generous and they actually are less sensitive than reported and really came alive when I put the Bel Canto's on them.

[@iankemp73]

Over 10 years with a Lyngdorf SDA2175 Power. Only just returned to Class A\B. Rotel RB991 which is driving Spendor S8E.

[@johnchild61]

I would say that it’s all about your ears! I own a Technics SUV-3 class AB Whilst a good Amp when I first owned it it was in my view to much top end and low on bass now I am some what older it sounds better as my hearing has changed , I have always had big speakers , much better Bass response , I have recently built my own Mono block 100w class AB and it performs better than a commercial unit by comparison, with a good music uncompressed source it , can produce 1khz square wave at full power indefinitely into an 8 ohm load , and at 10khz and is still square very little rounding would no normally test at that frequency but just tried to see how good it was , do the same to a commercial amp it just cuts out protection circuit kicks in ! Overall my home brew is great very pleased with the results, the first amp I built was a 3 watt stereo class A valve amp EF86 EL84 I was 14 years old at the time . The 100W amp is a MOSFET using industrial MOSFETs I had access too,

[@Justwantahover]

I bought a $200 clsass D amp 3 years ago and it sounds really "scratchy" in the upper treble. Now I just recently bought a $50 class D amp and it's treble compares well with my AU $1,800 class AB amp! (But not in bass, unfortuneately.) So in the last 3 years, class D seems to have improved a LOT! Better chips, I reckon, and more affordable better chips.

[@stpd1957]

Brilliant response Paul. Thank you. Seán

[@necrodh]

Class T was ultra superior but all brands of transistors copyated the Tripath technology and Tripath went to bankruptcy, I have a 2000's Sony class T and it sounds "high end" very acurate, holographic, tube-like sounding, no ear fatige, also I use a tube preamp to feed it, and the result is so vivid sounding, Adya Tripathi is a genius, now he works developing car computers and electronics to create more eficient cars.

[@PSA78]

I heard that they overproduced them or the market didn't respond. There's still a ton of those chips available so they are still used in new products. It was other chips made after that got a bad reputation, oddly enough. 😄

[@necrodh]

@@PSA78 there is a small cult of that transistors, im curious of how the 100w version sounds, mine is the 20w and it fullfills my room better than my olschool Onkyo or modern Yamaha amp both are 100w but they sound like a childs toy the Onkyo has Sanken mosfets and Nichicon caps

[@PSA78]

@@necrodh They are cheap enough to try out. Some of those cheap boards outperform really expensive amplifier from not that long ago. Just look at the price difference between a really good board today (ICE, Hypex etc) and one of the "brand name" amplifiers that use them, it's a steep price for a box, cables and some connectors.

[@brendanhoffmann8402]

I used to listen at way higher volumes when I had smaller speakers but now have literal towers of speakers (almost as tall as me) and only ever need to turn it up to 1/4 volume for it to be at a good level, (I have a class D amp), it is quite loud at that level. If I'm emotional and need to get that feeling of power from loud music I might turn it up to 1/3 volume. I listen to music for most of the day usually (I'm disabled so don't have much else to do most of the time)

[@geddylee501]

Never had a fatiguing amp,,, , for me the culprit has always been cd players that sound harsh, brittle and glassy and in the end fatiguing,,, so good luck out there with the class d amps, didn't even know of this problem

[@barrypatterson1154]

I don’t personally care for class D amps but Bryson amps are the most fatiguing amps I have ever heard. They are so bright and harsh sounding I have to leave the room after a few minutes. Doesn’t matter what speaker is being used. In a previous video Paul mentioned this as well.

[@chriscuthbertson]

I find that the more detailed the sound the more fatiguing it is due to my brain having to deal with more sound information coming into my ears. I cannot let the sound just 'wash over' me.

[@BB..........]

I own Wyred 4 Sound ST-1000 mk II and ST-500 mk II amps, and a pair of PS Audio M700 monos, and none of them are fatiguing. They sound incredibly clean, are dead-silent, have tons of power, and run barely warm to the touch. My speakers are Dunlavy SC-Vs, which are incredibly accurate and revealing, so if Class D was an issue, I'd hear it.

[@billymartin3160]

I have wyred 4 sound STI-500-v2 and i'm having issues at higher volumes. Did a direct comparison to my 40 year old Sansui AU-717 class AB. The sti 500 cannot handle a busy sound at high volumes. I feel like if there is a lot happening in the music, the sound gets very jumbled and almost muddy. I can crank on the Sansui waaaay louder than the wyred 4 sound without the sound falling apart. Tekton speakers. Any ideas?

[@TheNLHAZE]

Hi Paul as usual is the glass half full are is the glass half empty you remind me of my grandfather with Alzheimer's thanks Paul and have a great day🤣🤣😎

[@7.12_am]

I saw that title and my mind was blown

[@g0fvt]

Many years ago I did play with some Harrison Class D amplifiers, a lot of RFI from them but great sound. I realise that is subjective though.

[@tjerkeikmans4561]

Dear Paul, I'm Tjerk from The Netherlands. I love your videos, the way you explain things is very educating and fun to listen to. My question for you is: I used to have a separate pre amp and power amp. But I upgraded to a new all in one amp with separate power supplie for the pre amp. Do you think separate pre and power amps have a big future? Or is development catching up and is the need for that less and less ? Hope to hear from you :) lot's of love Tjerk

[@connorduke4619]

He has answered this question before somewhere.

[@daniellesmith1059]

I have done some work with independent amps. Had coupling problems, like the power amp clips early. So I like the integrated system. I do not like class D.

[@techcafe0]

same for me, listener fatigue sets in early for me when listening to music thru my (admittedly, low-class) Class D Fosi V3 amplifier from Amazon. i'm not sure if the bright & shouty, in-your-face, sound is typical of Class D amplifiers, since I've only had a real good listen to the Fosi V3, which is a rather impressive-sounding amp for its size, but it can also be like nails on a chalkboard after listening for a while. Maybe the higher end Class D amps are better sounding, similar to Class AB? There's just something about using PWM to 'chop up' the music (waveform) before delivering it to the speakers that I think makes Class D sound decidedly discordant, to my ears.

[@PH-gm2qe]

Tube preamp could really help in such case. I also solved it by tube preamp.

[@KenTeel]

Trying to explain pulse width modulation/amplification to non technical people, now there is a challenge. To understand how this works one needs to understand what a duty cycle is. A duty cycle is how long the high state is, vs the low state, for a wave that looks like a square wave. For instance if we look at a duty cycle of 50%, half the time the high voltage would be on, and half the time the voltage would be zero. For a 30% duty cycle, a high voltage would be on for 30% of the time, and 70% of the time the voltage would be zero. The output of a class D amp would be a series of pulses, that is a train of pulses the swich between fully on and fully off. The output of the amp has a series of duty cycles (a pulse train.) When the duty cycle is long, that is the voltage is high for a longer period than it is low, for instance, a capacitor that is hooked to this output, has a longer time to charge. So across the capacitor the voltage can rise. If the duty cycle that is charging the capacity is short, then the capacitor won't charge, and will dissipate voltage. The capacitor is hooked the load (your speakers) so as the pulses charge or allow discharge of the capacitor, your speakers will see a rising and falling voltage. I think that this is the basic idea of how a class D amp works. If I'm wrong, somebody correct me on this description. PS: So you can see that the output capacitor is being fed by ones and zeros (digital) but the capacitor is charging and discharging at a rate that makes an de facto analog signal comming from it (to the speaker.)

[@stLtBilko]

Yeah you make great videos my man, they're very informative thank you, What about class D amplification using discreet outputs?, I feel that would give a decent sound & without the fatigue if you don't use over bright components

[@David-ik8wj]

I own a set of Krell Monoblocks FBP 350 MC. after some research i want to listen to the 1200's I hope they will charm my ears as the big Krells have done for 23 years. My main motivation is I need something lighter in weight and does not run up my electric bill. I'm getting too old to be lugging these around. The Krells are linear class A 100 percent. It will be interesting to compare these technologies and hopefully the 1200"s will be keepers.

[@glenngutheil9950]

Great video, though on a budget, I'll stay with a class a-b amps, but refurbished

[@everkief8365]

I was having covid symptoms. I went to see my doctor and he diagnosed me with ""Class D amp fatigue."" He sent me home with some Vitamin D! I was confused but VERY relieved and spent the remainder of the day listening to Led Zeppelin on my $250 JVC mini-system manufactured in the mid 90s, with 25 watts per channel! This mega 25 watt system really blasts out the dbs! My other mini-system only has 12.5 watts per channel: how embarrassing! 12.5 watts... ROFL!!! I feel much better now and have no fatigue but am a bit exhausted trying to figure out why my 25 watt per-channel sounds so damn good. Must be cause its 4 ohms, right!? Also those massive 2.5 inch woofers really blast out the bass! WOW!!!

[@lazzer408]

HCA-2 was 2002? There has been retail class D since 1978. I believe that's when Sony released theirs.

[@graxav]

Great vid! BTW - what does that input tube do the famed 90++% efficiency?

[@milesdufourny4813]

For me the only Class D amps that sound good use the Purifi module. I find the B&O ICE module based amplifiers unlistenable.

[@anthonymartino9917]

Listen to what I GOT. The Legacy iV2 it will blow you away in every way.

[@olhoTron]

In a nutshell: dont overload your Class D

[@alholdway2003]

I'm used to technics SUV-85 integrated amplifier class AA with JBL 4312 speakers. It weighs alot but sounds excellent.

[@johnpick8336]

Some musicians are great to listen to once or twice at a listening session, listen to them anymore and you may feel like everything in your system is wrong. One of those Musicians for me is Steve Morse solo and with his Dregs Band. Steve Morse is a Fabulous Musician who surrounds himself with other Fabulous Musicians, but I listen to him more than 2x a day, Boom,, at first I blamed my system too, but I noticed that I felt the same way listening to Steve Morse's Music thru a Boom Box . Lol

[@0M9H4X_Neckbeard]

Class D reputation suffered because of the cheap, badly made ones commonly found in mini-systems or Chi-Fi.

[@xinjinping8113]

Only Class A and A/B for me.... Anything that uses filters is bad.... That goes for DACs as well.

[@BH4x0r]

the TAS6424-Q1 might be an interesting chip, it's an automotive class d amplifier chip switching at 2.1MHz, i believe that this can have really minimal filtering and thus minimal phase shift? now ofcourse automotive, and 75W don't scream performance or SQ but it'd be interesting to see more amplifiers reach higher switching speeds, because that will eventually eliminate the need for a low pass filter at all as in the end the inductance of the speaker cables themselves will act as the filters (when it reaches a high enough frequency)

[@kartinosurodipo4520]

I understand that problem. I am class D designer. That is typical problem for class D designed with only single feedback taken before LPF. So it is not true that sound is only waveform. Try post LPF feedback like Hypex UcD, Purify or double feedback like Ice Power. Sure Bruno is the god of class D. Try that product. Dont use cheap consumer like TPA, TDA, etc. Those are pre LPF feedback. Yes, fatique in 1-2 hours.

[@nicktaylor7680]

I'm guessing he is listening to 10yo+ class D - the latest Hypex amps are both smoother and lower distortion than most class AB amps out there at a fraction of the cost.

[@brianbob7514]

What makes them fatiguing ? Especially if they sound good at first?

[@WXSTANG]

Very well said. The reality is that eliminating high order noise (I forget the name of the exact harmonics), is extremely difficult in a class D because of its switching. Often times the circuit is creating harmonics in the 20-200kHz range which subconciously is annoying (especially to animals that can hear it). We can't hear it, but it is there. Tweeters while not rated for past 20kHz, can reproduce those frequencies, just like subwoofers can reach below 10Hz (think about when the subwoofer is moving, but we hear nothing). This is more easily dealt with because the output filtering on the class D is also responsible for shaping the music waveform (smoothing it out) so it is not a digital mess. The end result is a compromise for an "analogue like" output, but is completely incapable of eliminating high order harmonics without some trickery to create a "dual" output stage with who filters, which requires some kind of extra load. One resource for filtering... www.maximintegrated.com/en/design/technical-documents/app-notes/6/624.html

[@ConnorDylan]

It's not difficult. All it takes is basically an inductor.

[@nearchd504]

I have used tpa3110 tpa3118. They were okay, but the similar 3110 had different gains. I have used tpa 3116d2 , and mosfet class d power amps with regular components non smd components. These class d don't last long like the class ab types, class AB are robust.

[@Smog104]

Bang and Olufsen ICE power class D we’re at the forefront we’re they not ? I use a Beogram 3300 turntable Soundsmith cartridge with a Project DS2 valve pre amp with a Bang and Olufsen Beocenter 2 with a Beolab 19 sub with Beolab 8000 mk2 with a pair of Townshend audio super tweeters. Class D sounds fine by me ???

[@Stephen-nd1sx]

My N.A.D. C388. is great. I think I've never heard anything else. But I listen to it all day with great pleasure. I'm new to all this but can someone answer this question. I switched from a single pair of speaker wires to bi wiring a+b channels into speakers. This greatly improved output volume and clarity. Why? And is the power split 50/50. Or is there something else going on?

[@Stephen-nd1sx]

SVS SoundPath Ultra Speaker Cable - Banana-Banana - 10ft (3.1m) 12 gauge I went from one pair to two. If you can suggest a better option for cables I'd like to hear your opinion. What would be significantly better without being hundreds and hundreds of dollars!

[@Stephen-nd1sx]

I hope the package is new speaker cables. Lol.

[@Roof_Pizza]

Tell me why we want a class D again? Judging by the rest of his gear he bought a 'good one', and yet.....

[@stephenstevens6573]

Class D, in some form, is the future of HiFi

[@Roof_Pizza]

@Douglas Blake Who cares? Sounds worse, fails, doesn't have decades of history of flawless performance. The on;y ;good ones' are apparently just as expensive as other designs. The only reason why class D is such a hot topic is the manufacturers want to save money.

[@Roof_Pizza]

@@stephenstevens6573 On the Space Station maybe.

[@wa2368]

@Douglas Blake better dynamic range?! Bullsh

[@FastGuy5]

@@wa2368 yes better by a lot.

[@bearchow1929]

Apparently they now have Class D vibrators and my wife recently tested one for a while. While the batteries lasted longer she really didn't feel that it was in any way more satisfying than a standard vibrator. But it did cost more. And she didn't really notice any difference with regard to fatigue.

[@analoghardwaretops3976]

That's exactly the advantage of class D .over the A / AB ... it's higher efficiency...a.k.a. lower power wastage for same power input when compared to other ( linear ) amp. classes..

[@disco_ltk]

Your wife should consider making some unboxing videos.

[@BTW...]

I bet she prefers any vibe than you.

[@sbwlearning1372]

Gotta agree here I'm using ice power as1200 boards 2x600 watts with a valve preamp. Bliss !!! and both together cost maybe the price of one audiofools RCA cable ( yeah one )

[@faludabutt8253]

My question to Paul is “ why do I need 1200watts @ 4 ohms by using M1200”? I am using his S300 with a tube pre-amp and I rarely turn the knob over 10 or 11 o’ clock. I can EQ the sound via tone controls on the pre-amp. S300 was a tad fatiguing & dry ( at higher volumes) with XP10. Now, sound has altered. I am sticking with class D as I cannot compromise on bass

[@microcolonel]

There are pdm direct amplifying modulators as well.

[@jaakko200987654321]

almost all my amps are class d. what i like about them is the power density. 4000w out of a amp that weighs like 5kg! (behringer inuke nu6000). in my car i have soundigital amps (sd400.4d evo4 and sd3000.1 evo4) and they are very efficient and have a ton of power and the amps are SUPER small! (the 3kw amp is the size of 2 monster cans!)

[@jaakko200987654321]

forgot to add: the behringer has very good sound but its a little fatiguing. the SD's are not fatiguing at all

[@Resorob]

I can relate to the listening fatigue, I have heard a lot of class D amps and finally decided on Hypex NCore400 units. I tried them with passive preamp, they were very detailed, strong on delivering a very tight bass and very much in your face, I did not like what I bought very much. And then as luck would have it, I found a preamplifier by MM Audio a division once part of Hypex and designed to be used with their class D amps. The misery was gone and enjoyment started, it gave the NCores more body, more meat on the bones and shaved off bright edges. My personal experience, feel free to disagree, is that class D amps are best enjoyed over a preamp designed for them, or one with a tube stage as Paul mentioned and not over a passive preamp.

[@guyboisvert66]

Disagree. Just get the most linear and low distortion preamp you can, period. Il you like harmonic distortion added by tubes, then go for it. In my case, it's a no go, i want to get as close as possible as the recorded audio material.

[@user-dh7lt4we2t]

I'm also using icepower 1200AS2. I'm quite satisfied with the sound I got

[@KiiAudio]

Hi Paul, Bruno Putzeys is with Kii Audio and Purifi for the last 8 years now.

[@WimHulpia]

Tried Audiophonics hpa-T400et (class D 3 channel purifi!!!) and sent it back. Treble was too harsh with most songs on my focal electra 926s... bass was wonderfull though. The stereo amp version (hpa-S400et) was tested on asr and came out as one of the best ever. Now I am scared to try other class D amps.

[@AbsoluteFidelity]

Thats because the electra is harsh on the top end. You would never have a problem with current day Class D if your speakers were neutral.

[@WimHulpia]

Thank you Mark. Yes this also came to my mind. I own Sopra No1s now and these are definetily better at the top end. But I since I sent the HPA-T400ET back, I cannot check. I do consider to give it another try next year. Thanks for your feedback@@AbsoluteFidelity

[@FastGuy5]

No phase shift in the audible band with class d done properly

[@AndMakrid]

Lovely as always!

Like 2000 from Murten - Switzerland.

[@LeRoySL-q5q]

I'll take Class AB all day long.

[@Exgol2005]

My class D experience: bass and shimmers very good. Lacking in mids. Some vocals rendered nasal. Used a few. Linn Akurate best of the bunch. Sounds like my preferred high biased AB amps But for all its good bass, i find Class D not as tight/controlled a gain clone bass.

[@miguellogistics984]

From your message you seem to be elaborating on something I noticed when working with Digital and Solid State Amplifiers for the Bass Guitar. I walked away from this long ago and had to read to remember that the Digital ultra light amps were Class-D. In my work with two models. one modeled to sound as a tube amp, and the other a straight forward design, I did not enjoy the Tube Model on the Power System (the PreAmp shared the 12AX7 tube, so the Power Sections were the difference,) and I preferred the First Issue Class-D. BUT! Weight being no object, and the tone being far more inspiring, I was very excited with the Toroidal Power Sections of 425W@4Ohms and 1200W@2Ohms of the same companies other amps. Copper made the instrument sing and inspiring. It was a Mid range clearly missing from the Original Class-D and High Clarity that the Tube Modeler just did not give. So some of us hear things, others hear other things. But at my performances, people tended to gather on my side of the stage. Maybe what you hear is real?

[@Exgol2005]

@@miguellogistics984 good to hear some affirmation that my ears still good for this hobby ;)

[@paulstubbs7678]

Maybe we have to wait for the PWM freq to get up into the MHz so the filters can be simplified so they don't have any musical effect.

[@theoracleprodigy]

All I know is the last class d I dealt with was a Denon av. It was both the clearest and most distorted amplifier I've ever heard. Some music just couldn't help but distort all over with it. Mostly heavy mid sounds it just couldn't deal with.