diyAudio Forums Archive > Top > Amplifiers > Solid State A cirucit to put Carlos anti-blameless stance to permanent rest. - Click HERE for Original Thread vynuhl.addict and hopefully that doubled barrel shotgun might be put aside for this one.I really encourage the inquisitive builder out there to try this circuit. Its essentially a blameless with some changes in error correction and current sourcing. If you have access to the same parts as listed all the merrier as the vas transistor is somewhat critical..You will be rewarded with effortless and music tones, with images that can often jump out at you with startling realism. The best part is that they comewith no ear fatigue at all over long listening. Graham Maynard Hi vynuhl.addict, That is a similar topolgy to Douglas Self's 'Blameless', but it does not follow Self's closed NFB loop stabilisation strategy. Your circuit does not have the single 100pF Miller connected C.dom which so slows VAS control of the output devices when driving real world loudspeakers. Good to hear that you have this genuinely useful topology sorted, as indeed Carlos has in his own Dx thread with a more simple design. Your 2SA1360 needs overcurrent protection though, because with an inadvertent fault condition it could conduct itself and the top half of the ouput stage into instantaneous self destruction with that Darlington drive. Cheers ......... Graham. destroyer X Mine was not good...maybe other one constructing....maybe i have made some mistakes...sounded without salt...i turn very nervous..really i am still nervous with that design. I was expecting beautifull sonic results...i felt myself stupid as a mule constructing that one and trying to make it sound fine. Grrrrrrr!....i cannot see that...i turn nervous once again! Kidding...Doctor Self is a nice guy with good designs...maybe i am deaf! C'a marche soldat...defense l'arrière! regards, Carlos Samuel Jayaraj vynuhl.addict, As pointed out correctly by Graham, the Vas transistor needs protection - you could take the cue from D.Self's many circuits. Taking the cue from Self a little further, why not use bootstrapping for the input like he did with his Load Invariant Amplifier? Your schematic does not show the transistor types for the Current Source and Vbe positions. The input stage decoupling resistor value is also not shown. (Can the same resistor not be replicated in the negative rail as well?) The 20K resistors to ground from the current sources on the negative rail can be split into 10K+10K and the junction can be decoupled with caps. Tell us more about the sound and to which amps did you compare. destroyer X But that one was terrible I leave in front of the beach ...and i have recorded that sound...the sound of waves when they are intense... a digital high quality recording was made. And i remember that i have reproduced that noise...and others too..but this one....result terrible!....the wave sound seemed to me to be air leakage from an automobile Gaz Station tire inflation machine. This is the reasons of my scandalous reaction to "that" amplifier. Observe my place....for sure i know the wave sounds quality... it is constantly playing inside my ears...and recording played with other amplifiers, as Symassym...GEM....mine and others sounded nice. regards, Carlos vynuhl.addict Graham, overcurrent potection such as a 10ohm resistor between emitter of vas and rail?. I took a hint in one of Hugh Deans posts to try out bare minimal lag, and secure with lead comp, needless to say this made a difference that was no less than stunning in sound quality differences, gone was that well documented solid state hardness. Even when I built the oiriginal blameless i used a 47pf cap instead of 100. Carlos, you points on the original blameless are very valid, It is clean, very clean but unable to allow long listening without breaks. The input stage decoupling resistor is 10ohms 1/4 watt. The VBE bjt in 2sd600k Sanyo, current source bjt are 2n5551 nos motorola. my goal was still aimed at simplicity while constructing, and in dougs designs he only decoupled one half with a resistor also but i am not sure of his reasoning. The original reason i did this was because i saw it done in the trimodal .. I suppose it could be replicated in the other rail but as far as tweaks go with this amp it sounds very finished. It is currently being run from a dual mono supply but using one 300va transformer and 24000uf per amplifier. The Rails sag very little at high levels(not ear bleeding), less than a volt +/- 500mv or less variation. Graham Maynard Hi vynuhl.addict, I would suggest half the value used in the opposite sink, which comes out closest to 33R, and use the voltage dropped across this to drive a current limit with emitter to rail and collector to the base of the 2SA1145. Use a very low capacitance PNP small signal transistor for this. Enjoy your listening. Cheers ........ Graham. Johan Potgieter Darn Carlos! I thought we had beautiful beaches in South Africa. :hot: :bawling: Regards. destroyer X result is possible...difference may be the constructions we have around...brazilian style...but the beach beauty, by itself is not a Brazilian Monopoly. Hawaii....Honolulu...Kaneohe....Waikiki is much better! regards, Carlos aguantesoda Forgive my ignorance, but... what does this circuit exactly? vynuhl.addict It is an amplifier, with a gain of 23 or 27db. Another question for Graham, for the the overcurrent bjt the smallest capacitance bjt i have on hand is 2sa1145 with a 50ma rating, would this suffice??. I want to use something that will have no detrimental effects on sonics at this point ..I originally blew a a1360 when first built after accidently shorting the vbe multiplier to the heatsink and subsequently ground (due to a very small shard of aluminum after drilling the heatsink), you are right in the respect of it will take it out instantly, but the output stage is very robust with mje15032/33 and mjl3281/1302.. Thanks Colin Graham Maynard 2SA1145 with a 50ma rating is fine. All this transistor needs to do is sink the differential tail current. Cheers ...... Graham. jmateus "Forgive my ignorance, but... what does this circuit exactly?" Nothing!.................. aguantesoda thanks vynuhl.addict! and sorry jmateus!.................. destroyer X reason why people do not came to answer you. To answer you, the whole circuit philosophy will need explanation..this is long and hard. Mateus is a nice guy...his answer could be just kidding...as the logical sequence, or the most possible answer... respecting the rithm of language.... could be this one. Say..some obvious answer that people use to give..depending of the culture, of course...for instance..the question...What to do with my finger?...well, the consequence is obvious..if i do not know what to do with it..people will say.. at least in my place: - Why don't you trow it.............inside you ears for instance (hehe) Tweaking something that may be problematic, circuit that is known by Mateus (deeply experience guy) as a problematic one...may still result a little problematic....so...result nothing related advantage, profit or happyness resulted of this work...this can be one of the possible meanings. He is nice..for sure he is..do not bother because, for sure, his aparently acid answer is result of our misunderstanding of his word's meaning. They are fine...good guys...circunstances were not so good...remember that ...even if they would not be so nice..they are few persons..our forum has more than 70 thousand folks...feel good with the others 69998 folks. But they are nice.... guaranteed they are nice. regards, Carlos aguantesoda ok carlos; I will be good. Saludos! vynuhl.addict J mateus is right, this circuit does nothing, that is nothing that it shouldnt do. It provides an avenue to amplify music in a very convincing and meaningful way, to cut through the BS and ley you sit back, relax and understand what is put forth both tonally, texturally and rythmically.. Those you frown upon and point fingers should first build it(with the same parts) then cast judegment beyond the obvious being a semi standard 3 stage design.. Colin destroyer X reference unit, in a fair A to B blind testings. The amplifier must be constructed following the designer instructions, the board have to be the one supplied by the designer, the parts have to be the ones suggested and the speakers used for testing need to be very good ones...and also, replaced by other good ones during A to B listening and comparing testings. I also think....alike you think...that, without those testings, people have not the rigth to say nothing about evaluation...or...at least... i will be entirelly sure that the one do not know what he is talking about. Without those kind of testings....in my personal judgement, words about every amplifier are "empty"...having no value to me. Also, it is not a responsable behavior. Unfortunattelly, for evaluation purposes, there are people that visit friends in House A....and next day visit another friend in House B....having space of time to fool himself...having listening environment different...having different social moments, different mood...well....a very bad conditions to compare something....and some guys deer to express evaluations having those kind of experiences.... non sense and not responsable way to judge things. Well...John Mateus told nothing....and this is all he said...we cannot know his meaning...but for sure was not a critic about....he was kiding for sure...the guy is nice. I am just supporting your idea and posting mine too. Thanks to let us know your ideas and your schematic. regards, Carlos vynuhl.addict Thanks Carlos, I wanted to be sure I could live harmoniously with this amplifier before I posted the schematics, a month has told me that it is possible. Secondly I became determined to do what I could to make the blameless topology a musical topology rather than an as you say"gas station air pump leak" when playing back the sounds of the ocean:o\), thanks for the inspiration Carlos..I believe this amplifier speaks very strongly against high value miller compensation and very strongly for phase lead and miller. What has really gotten me on this project is how some simple changes in the second stage makes the biggest differences, for a mere 20 cents more one SM cap and an extra transistor. Since I painstakingly drew out the original boards by hand and etched them I will have to make two new boards with some new ideas from Graham, I have 20 mje15032/33 on the way and a couple rails of mjl3281/1302 left over fortunately so i wont have to pilfer from my present boards. Thanks Colin john_ellis Hi vynuhl.addict I agree with your objectives but wonder whether the circuit you posted really works as it says. First point I'd make is that the 10 pF is a lot smaller than Self's 100pF -as Graham already said. This puts the "Miller" effect ten times higher in frequency (i.e. less effect on audio) than in the blameless. Second point does it oscillate? Simulations using BD139/140 VAS, drivers says it does. Not badly (just a little, so maybe not noticed) Perhaps your 33pF can be made smaller....maybe only needs to be 15 pF with MJL3281 etc. Maybe the circuit is OK with the transistors you specify. I have not got models for those, but BD139/140 seem representative of many HF transistor types (ft ~100 MHz). If the VAS is slower, maybe already slows down the VAS without Miller capacitor ? cheers John vynuhl.addict Hi John, The devices i use for vas are 200mhz devices, The 33pf is lead compensation. From my limited understanding lead compensation wont annihilate the slew rate like strictly high miller would. As far as oscillations go, I have not tested for these with any test equipment, the output zobel resistor remains coolt at all times, bias current remains steady. When i laid out the copper board i have paid very close attention to high current traces/width, and signal path traces in my best effort to try and avoid parasitics by keeping the signal traces narrow/short and as direct as possible in a forward momentum. The global feedback loop is a mere 1cm, the length of a 1/4 wattresistor. The speaker lead terminates at the mouth of this resistor at a single point in a physical geometry. signal grounds and power grounds are sperate and take off from their individual points and flow into a vast singuar copper pool for signal and power from which i take off into the main star ground/centertap. judging by the computer pcb payouts this could not be done as i have with software. Very time consuming but sonically worth all the trouble. Ihavent tried a lower value lead, i have had no problems with sonics that have led me to believe that this could be any more beneficial at this point, could be, i will deifinately try, I have a couple 22pf silver micas hanging around. Just fi nishes 2 new boards with vas overcurrent protection, just need to wait for my drivers.. Colin jmateus Hi everybody I think an explanation is in order about the answer I gave some posts ago to a question from aquantesoda (funny name coming from Argentina). Very coincidental, my mother was born in Argentina, Buenos Aires and I kind of have some connection with this country... But let's go back to what I meant to say about that "acid" nothing I gave as a response to his question. I always loved this forum, I think it's a way of learning, always learning about this intricate world of diy audio. We learn and sort out what we like or dislike, we take advantage of the kindness of some very well versed people, a lot of knowledgeable people that so graciously give to all of us. It so happens that lately this forum is going to a status that is boring me so much that I thought I would give it up completely. That day was particularly bad for me, I was in such a bad mood that I was forced to say something drastic like "nothing".... Not in a despising tone, no, but as a disappointment because with so much rambling I get frustated of this resistor being 10 ohms instead of 12, that cap should 330uF as opposed to 220 and so on and on. I realize everybody has the right to say whatever they please, but com'on guys there are other more construtive ways to use this space that the forum gives us. I guess I should apologize for that "acid" answer...but my mood would be an excuse for that.... I'll probably get away fro this forum until it gets to be again a way to learn and discuss seriously the state of solid state audio.:smash: Conrad Hoffman Some fundamental "big picture" questions come to mind. Forgive me if these have already been beaten to death in times past. Where is it written that a "perfect" amplifier won't cause listener fatigue over time? In fact, if you had continuous live music in your living room for days on end, would it be wonderful, or would it become irritating? Worse, some mixes just are irritating. Noise is often added, and listener fatigue probably wasn't a consideration. So, how do you evaluate an amplifier alone? IMO, the best system may not have perfectly flat response, and may not exhibit zero compression. Since the system is made up of many components and interfaces, not to mention speaker drivers, how do you sort it out? More importantly, if the signal is to be modified, where's the best place to do it? My experience with Doug Self's design philosophy is that he comes as close to electrical perfection as anyone. Done properly, a nearly perfect signal can be reproduced, with any imperfections well below what can be heard, and almost below what can be measured. Note however, that using his guidelines is no guarantee of anything- you can still build a lousy amplifier if some subtlety is missed along the way. Personally, I go for flawless reproduction of electrical signals- what comes out has to mirror what goes in over a wide bandwidth and with as little addition of noise and phase shift as possible (though the audibility of phase shift is debatable). Then, because I like to fool with speakers, I match the sound to the room via adjustments to the active crossovers, and to the room itself. BTW, I believe there are problems with reverb times and standing waves that are more important than response, and cannot be fixed with any amount of fiddling with the system, only the room. Bottom line- if you want flat low distortion electrically excellent amps, Self's guidelines are the way to go. The question is, do you (and I don't mean anyone in particular) have the confidence and courage to say that isn't what you want, because the overall system sounds better with something different? destroyer X listen continuously this way....if the guy scape from the madness during this torture...at least..will have a flat B-- when finish. hehe Happy that i have found someone that can makes things more "extreme" than i usually can. BTW...as i have perceived from past posts...John Mateus is a very nice guy...so nice that he explained to us his reasons...nice from you Mr. Mateus. regards Conrad. Carlos Johan Potgieter Conrad and all, Now we have a discussion pending! (John might even linger a little). Conrad, yes, good point. But you supply the answer yourself a little later on in some way. The system listener fatigue you refer to initially is possible, of course - but to me that is different from what we are discussing here. A blameless amplifier will never give listener fatigue, simply per the definition of the term as I understand it, because an unlimited time element is included. (As one grows older :bawling: one's ears begin to provide the listener fatigue of course!) I (also) strive to make each component in the chain as good as possible. There are also some "audio philosophers" out there (mercifully so far not referring to members of this site/forum) who make pious sweeping statements regarding synergy. (Only they never seem to tell designers how to exactly achieve it and for whom, do they now - do we replace all our resistors with pots and twiddle until "it" sounds right? Sorry! :hot: :smash: ) So, to stay with amplifiers, one strives for inaudibility of all disturbances as much as possible - back to Douglas Self. For the rest: Ditto, each per itself. As far as the funny mixes on the market .... :smash: again. Regards unclejed613 ok.... here's my $0.02..... there's a few things i do in sim testing, and later in real testing, that tell me rather quickly whether a design is stable or will oscillate. first, i run a frequency response sweep. in the sim, i set the input amplitude to a level that produces nearly full undistorted output and sweep 10hz to 10Mhz. in real circuits, i run the sweep at 1 watt. the sim returns freq response and phase curves. pay attention to the rlationship between these. if the phase goes to or crosses 180 degrees below the unity gain frequency, you have a stability problem. the phase can be displayed on an o-scope by either comparing waveforms on a dual trace scope, or by x-y comparison on a scope. this is done with a purely resistive load. either an 8 ohm/2 watt carbon comp, or a dale noninductive load, with very short leads to minimize capacitance. most of the time, if you have instability, you will also notice a "hump" in the frequency response near the unstable frequency. second i run both the sim, and later the real circuit to clipping at 20khz with a capacitive load. if there's a tendency toward oscillation it usually shows up here. third (and this will sometimes reveal oscillation that gets missed by method two), i run the sim and the real circuit into a capacitive load at 1 watt 20khz, and go from no output bias to full bias. i have seen oscillation that begins at the crossover point and continues toward or beyond the waveform peak, and then extinguishes, leaving a clean waveform until the next zero crossing. vynuhl.addict In a sort of response to Mateus, I can agree to disagree with his staement partly. While I am at a great appreciation that this forum is full of so many audio gurus in my eyes and many others I also happen to know that it could be "some guy" with an idea of 10 or 12 ohms that could also have much to offer even though his degree may be simply soldering some parts on a weekend to experiment. I am of course no engineer or rocket scientist, I am a 28 year old finishing Carpenter by trade, and a musician by birth and at heart ,a drummer for 20+ years playing in two bands and doing session work and a father of two who enjoys everything on here whether mind numbingly insightful or off the wall in craziness and passion. Hey, it could always be worse, atleast we arent discussing the merits of cables :o). I am very glad to have this forum, because I can take comfort in knowing I can post any discovery of mine without being lambasted or I can ask a potentially stupid question without being flamed as a jack**s who has no idea what he is doing ;o). DIY audio is for everyone to learn, and there is always something to learn even in the most mundane of topics. Colin destroyer X And i apreciate very much the way you behave. Go ahead and thank you because you are turning this circuit better for our ears. regards, Carlos jacco vermeulen Carlos: you, you, you. :clown: Off topic: Geagte Johan, the MJL numbers are about $5 each in the US, up to $13 overhere. Ek weet nie of jy die email gelees het. Baie mense syn goed gewees vir my, ook die Suid Afrikaanse mense. Ek heb die transistore beskikbaar, vir jou geen koste verbonde nie. Allenig 'n persoonlik briefkaart vir dank. benodig wel 'n kontakadres vir ze an te stuur. vynuhl.addict Thank You very much for the kind words Carlos, I really enjoy the Charisma and kindness of yourself after all this stuff should be fun such as music itself. I have learned a great deal from these three stage models along with the intelligence and words on these forums, there are truly inspiring people here, I am gracious that I took Hugh Deans suggestion to visit and join here, another intelligent man with wisdom and words that always encourage. On the amplifier side, my new boards are done and ready to install, this time I have mounted the VBE multiplier bjt on top of one of the mjl3281 and increased the 100nf cap to 10uf, bias is much more stable. Added Grahams suggestion of current limiting and 10 ohm resistor on the negative rail also for the front end. will try 22pf lead cap next.. Time to go check the updates on the DX thred.. Colin destroyer X he is best designer..as he use his ears too...not only Mathematics...and he understand a lot of Maths too. I love him very much...he is alike a brother in my heart. Searching for his bad side i can only say that he has not time enougth to go talking with me all day long..he is very busy..his deffect is this one..works too much. regards, Carlos Johan Potgieter Hugh, What do you have that we do not have? Oops; don't reply! ;) destroyer X Retired from the Military Life he decided to go deep into audio...he bougth books and started to read them all... made contact with people that had deep understand about electronics and start his business... his beggining was more than 10 years ago. His first amplifier was published with that bootstrapped technologie...the same topologie i am using now..when he is using another one now a days...his Aksa has subcircuits and modifications not shown on my amplifier..as those things belongs to Mr. Hugh. He decided to understand deep the Mathematics involved into audio amplifier designs and have read all the famous designers books. The better is that he decided to join the instruments with his ear... circuits were tested by ear..by audition and parts substitution and sub circuits were tested..observing effects of waveshape, distortion and spectrum...so..each modern circuit was tested...many amplifiers types checked, built, listened, compared with his units...hardly researched each connection, to "listen" the best possible sound...of course friends have cooperate with him related those evaluations...not a lonely process. The result was an incredible amplifier, with some sub circuits used that increase sonics quality in a way no other amplifier could match....i have them here...i have compared...i have tested them...and no one could beat his Aksa 55 related sound stage and treble quality reproduction...focusing of instruments and voices quality...... others could be sligtly more powerfull with 35 volts....others had more dinamics....others had stronger bass...but the overall quality is unbeatable. He has something that i will never have....the patience to catalogue, to take notes of all steps he made.... evaluations about many circuits and subcircuits...effects using types of capacitor and transistors.... all those things he done is something i loose my track .. turning myself lost related the early begining of my researches..I have forgotten what happened with that "yellow" capacitor i have used last year....but Hugh Dean did not loose his track. He had everything organized...so....he could track the long travel back, to return watching all result of researches made, and joined them together in his amplifiers. Mathematics and theorical knowledge is, now a days, enougth to discuss with Engineers and to make himself be understood..also enougth to understand the experts.....but more than that...the qualities of a practical researcher he has...the real life experiences made.in the past and still beeing made... the years locked inside his laboratory, researching till he developed repetitive work disease in left arm.... 18 hours each day working years long..day after day.... spending all money he could, to pay parts, to use them till the limit (real limits) and to burn many parts to obtain the needed knowledge of real reliability for his products..... he made an excelent brand, with fidelity related all his customers....and also he is not lazy...to avoid misadjustments...to avoid that constructors make bad constructions...he is doing now a days by himself, soldering each part....constructing the entire unit to preserve quality and to preserve the secrets of knowledge, that costed so expensive to him...not only related money, but also related health and sacrifices he made related his family life. He is rich now a days...having many cars, motorcicles, enjoyning International travells, having employees and thousands of circuits sold and sounding wonderfull around this world...a humble man he is...even beeing the King of sonics That's what he have, and all that i do not have dear John regards, Carlos Johan Potgieter A question thus asked in lightheartedness leaves me humbled, Carlos. Thanks for the "introduction" - my loss not to have known the man, and my gain now. I do not find an emoticon for salute. jacco vermeulen Mr Dean is one of the rare species destroyer X last one. A comment to be made to Johan and Jacoo. He is so humble...really humble..that he complains when i do those things, those comments about him...also i have pictures of him and he never told me that i can use them. He use to say: "I am just a normal man Carlos...i do my best...working hard..but i am not that special guy you are thinking...i have many defects" He may be talking about our human food processing...well.... we all produce those things. He is special.... one of the 5 more respectable men i had the pleasure to know in those 56 years of life. And you cannot imagine how pretty are his daugthers...hehe regards, Carlos ................................................................................................... Nice smilies you found Jacco...final of off topic here....i will not do it again. .................................................................................................... Johan Potgieter Also then final on this, but ...... (Apology for temporarily hi-jacking your thread, Vynuhl.add.) I would suggest that on any thread it is never totally off-topic to give praise where praise is deserved. Those people shall not pass on unnnoticed - those from whom we learn or ought to learn if we are not stupid, so that they have not existed in vain. AKSA test destroyer X He tried to visit us and had problems. His damn provider was blocking messages i was sending him. He will return..for sure he will regards, Carlos destroyer X As i said...the man works too much. regards, Carlos Conrad Hoffman Johan- I went back and read Self's book last night concerning his definition of "blameless", since he did coin the term. As far as I can tell, it refers only to the reduction of his eight distortion mechanisms, and is purely electrical in nature. It says nothing about how the amplifier sounds, the point being that if those mechanisms are reduced to minuscule levels, there will be no sonic signature from the amplifier. Thus my belief that a "perfect" amplifier may or may not cause listener fatigue, depending on the program source. After all, if the program source were intended to produce listener fatigue, as so many of today's mixes do (see recent thread on bad CDs!), the amp should dutifully produce it. I guess we should agree on a program source that has no fatigue? Regards, CH vynuhl.addict Hi Conrad, I agree with what you are saying and do hold a certain belief in this approach. WHile self does great work in diminishing these common distortion problems I think this is a large part but only part of the picture. His concepts seem to be a great place to start and he gives some very solid foundations in which to build upon. I dont own his books but wonder if he goes farther into global and local feedback. Many into Selfs work like myself end up inevitably having more in common with the objectives of others who subjectively tune an amplifier as relying on strict electrical measurements can be sort of like eating processed cheese slices vs aged chedder :).. PS:Johan, no worries i enjoy reading the posts even if not 100% related.. Colin Johan Potgieter Thanks Colin. .... and agreeing with you and Conrad, further adding: The following does not necessarily refer to you guys, or anybody else that it does not refer to (now that is a profound statement! :cool: ). So preaching to the choir, but for completeness sake, some basic hearing philosophy: I have a problem with a certain view that in an almost derogatory way suggests that specs are allright, but there are still (as in must be) audible things that one cannot measure - ear so sensitive etc. This stance flatly ignores the multitude of tests done over decades at highly regarded centres (not by journalists) to try find out what is audible and what not. To the degree that this has resulted in reproduceable consistent results after using many thousands of subjects, I am really doubting that somewhere in some etherical spheres, something still lurks that we will discover or stand in awe of (re hearing, of course). Ergo, we have a useful "model" of the ear, even though we may not exactly be able to understand it from A - Z. This is not elevating science arbitrarily; it is about as simple as finding, after enough tests, that a normal person is considered too intoxicated to drive a motor vehicle with a blood-alcohol content above 0,05%, to use an example. It is not that medicos and psychologists claim to be superior (or engineers), it is simply using test results the way science has used it in a million other cases. Science do not know everything, but it knows certain things. In that way I believe one can define that an amplifier will be blameless or otherwise. As said by you, program sources are something else now ..:hot: It does become complex when one includes what was also found during the above tests, and that is the inconsistency in hearing interpretation. This is again not derogatory. Palaeontologists say that our hearing facility evolved as a warning facility. Appreciation of melodius sounds and that sort of music only "arrived" a few seconds before 12:00, on a scale of creation starting at midnight and noon being now. Ears did not evolve as distortion detectors; what exists is the way hearing happens to be and that is not necessary consistent with our terms, in this minute increment in history. (One could illustrate this with regard to just about all our senses, not to bore folk with that now.) That to me explaines most of the so-called "conflicting" evidence in this field, and the weary bleat that science and subjectivism will never meet. They actually have long ago, it just requires doing homework followed by a realistic insight. Regards. Conrad Hoffman Colin, I think you've summed up one of the major sticking points between two philosophies. Some (me included) believe that electrical signals between two components are the whole story, and that if signals are identical (to some level that we can all happily argue about), the resulting sound *must* be identical. This is a really fundamental issue, because if identical signals produce different sounds, we have to resort to magic or unknown laws of physics to explain what's going on. I've simplified a bit, as the "signals" have to include what the ground level is doing, and things are never as easy as components floating in space, connected by exactly two wires, but the situation is still manageable. We have the means (if you have the $$) to measure signals to a handful of parts per million, and I've yet to hear any rational claim that the ear can resolve that. I've also never heard of a blind test that's even hinted that things are not as I've described. What those tests do confirm is that very minor differences in level and frequency response are audible as quality differences. IMO, cable interactions with component impedance's and component design (and, yes, capacitor choice) can easily alter those things. So, back to capacitors, if a particular type of cap (in a particular location) causes a tenth of a dB response difference (this is important- in the *system* that nobody ever seems to measure all at once) somewhere in the spectrum, you may well hear it. Worst, you'll (not you in particular) are apt to decide it's a difference in transparency, attack, smear, or some other emotion laden term that prevents getting at the truth of the matter. IMO, the proper way to look at it is not to attribute "goodness" or "badness" to the caps, but to understand how the properties of different types interact with the surrounding circuitry. Since the same circuits turn up again and again, it's only reasonable that certain types of cap will be considered optimal in certain situations. It's also expected that some situations will be a compromise when a lot of capacitance combined with good properties is needed- out-of-the-loop coupling caps and the large AC-to-ground shunt capacitor in the feedback paths of many SS amps come to mind ;) Understand that I toss this stuff out with a fair amount of good humor. I understand that not everybody shares my views. I wear flameproof undergarments, but am also perfectly willing to change my mind when presented with evidence that doesn't require me to invoke magic or unknown physics- thus my current construction project of pure silver and other conductors to compare sonic differences. Johan Potgieter I think Colin and I have posted at the same time (in forum sense), and said somewhat the same thing. So Colin, we can stand back-to-back; all the more difficult for folks to make an oblique attack! Just referring to an article series on capacitor tests by Dr Cyril Bateman in EW toward the end of 2002. I found them excellent and quite extensive, also debunking a few urban legends. Might be on the net; I bought the magazine copies. Regards. AKSA Carlos, Better late than never, I guess!! You humble me; I don't much like this praise, it creates absurd expectations and I am just an ordinary man with an extraordinary compulsion to produce a better amp. The world is made up of reasonable men and women. They work with what they have, and adapt to the world. Only the arrogant and overconfident will seek to change conventional thinking, and they generally work on ego or blind faith. They are the unreasonable ones, NP, JLH, Graham Maynard and Charles Ayre are amongst them. Conrad, You are absolutely right according to my research on Self. His amp reduces measureable distortion mechanisms and makes no pretensions about sonics. Yet sonics is where the focus clearly lies, with the gulf between objective measurements and subjective appreciation bigger than ever, even if the gap is measured in PERCEPTUAL terms. With so many low distortion amps sounding so ordinary in the market, I conclude that there are aspects of good sonic performance which are not yet being measured. I have heard the Blameless Self, and sadly it does not deliver as expected. Johan, Nothing that you don't all have, I assure you!! My private vision has always been of an amplifier that is musical and endearing, which makes a tear roll down your cheek...... This is hardly objective, and attracts howls of derision from the engineering dress circle..... BUT, it is necessary, as the finest engineering examples of good amplifiers leave much to be desired. If I have to stumble around in supernatural areas of the technology, mumbling incantations and groping for the ineffable, then so be it.... I do remain scientific and objective, however. I have had some success making engaging amps, so I feel pretty secure! You mention capacitors, and the sonic characteristics they bring to amplifiers. I certainly agree. Recently I heard some teflon input caps on one of my preamps, and was absolutely astonished. They do make a difference, chiefly in resolution and smoothness. They actually sound 'natural', whatever that means. The price of admission is ridiculous, of course, but this has driven me to redesign the circuit for much higher input impedance so I can use a much smaller teflon cap, reasonably priced for manufacturing and thus saving almost $US160 for two channels. I'm yet to test this circuit, but it looks very promising. Cheers, Hugh andy_c quote: Originally posted by AKSA They are the unreasonable ones, NP, JLH, Graham Maynard and Charles Ayre are amongst them. As we pause to pontificate, let us also not forget David Dynaco and Peter Quad. And as we grieve at the Tomb of the Unknown Marketer, Alfred E. Newman should be in our thoughts. G.Kleinschmidt quote: Originally posted by AKSA Carlos, Better late than never, I guess!! You humble me; I don't much like this praise, it creates absurd expectations and I am just an ordinary man with an extraordinary compulsion to produce a better amp. The world is made up of reasonable men and women. They work with what they have, and adapt to the world. Only the arrogant and overconfident will seek to change conventional thinking, and they generally work on ego or blind faith. They are the unreasonable ones, NP, JLH, Graham Maynard and Charles Ayre are amongst them. Conrad, You are absolutely right according to my research on Self. His amp reduces measureable distortion mechanisms and makes no pretensions about sonics. Yet sonics is where the focus clearly lies, with the gulf between objective measurements and subjective appreciation bigger than ever, even if the gap is measured in PERCEPTUAL terms. With so many low distortion amps sounding so ordinary in the market, I conclude that there are aspects of good sonic performance which are not yet being measured. I have heard the Blameless Self, and sadly it does not deliver as expected. Johan, Nothing that you don't all have, I assure you!! My private vision has always been of an amplifier that is musical and endearing, which makes a tear roll down your cheek...... This is hardly objective, and attracts howls of derision from the engineering dress circle..... BUT, it is necessary, as the finest engineering examples of good amplifiers leave much to be desired. If I have to stumble around in supernatural areas of the technology, mumbling incantations and groping for the ineffable, then so be it.... I do remain scientific and objective, however. I have had some success making engaging amps, so I feel pretty secure! You mention capacitors, and the sonic characteristics they bring to amplifiers. I certainly agree. Recently I heard some teflon input caps on one of my preamps, and was absolutely astonished. They do make a difference, chiefly in resolution and smoothness. They actually sound 'natural', whatever that means. The price of admission is ridiculous, of course, but this has driven me to redesign the circuit for much higher input impedance so I can use a much smaller teflon cap, reasonably priced for manufacturing and thus saving almost $US160 for two channels. I'm yet to test this circuit, but it looks very promising. Cheers, Hugh This is such ridiculous, self-congratulatory rubbish. A properly designed SS amplifier isn’t supposed to have a sound – it is supposed to faithfully reproduce the audio input signal without introducing perceptible coloration. A typical Douglas Self design (and those like it) satisfies this requirement by producing distortion well below perceptible limits. I never cease to be amazed at the ridiculousness of the pseudoscientific claptrap rife with suppositions of magical “non-measurable distortion mechanisms” concocted for the express purpose of unjustifiably deriding other peoples design efforts by those trying to flog off their magically performing amplifiers – Concoctions predictably proffered with a less-than-humble serve of contrived emotionality in a lame attempt to compensate for the distinct lack of scientific or technical rationale. Anyone out there who is reduced to tears by listening to their DIY amplifier suffers from a degree of emotional instability best treated by a professional. But I guess that all those who haven’t seen the light need to throw out their perfectly OK, but spiritually-barren amplifier designs and rush out to buy an Aspen amplifier and share in the religious experience, because all those impeccably performing SS amplifiers don’t sound right because Hugh says so. vynuhl.addict I used to own a Rotel and it didnt sound right, pretty basic low distortion 3 stage circuit,, the first 3 months I had it I thought it was the cats meow, but quickly I grew to realise it really sucked at playing music. Hugh has gone on to the next stage of aspen in designing an amplifier (lifeforce) which is apparently far more neutral but still sounds good. It seems to use concepts which are not found in your run of the mill HI-FI store offerings that should be used but unfortunately for our ears arent. Dougs Blameless is not plug and play and enjoy, instead it can be a beast thats needs a little taming so you can listen to it for more than 20 minute intervals. I guess the human ear can be a funny thing, a screen can tell you there is no fear, all should sound like magic, or atleast magic all above the vvanishing low distortion and noise floor but somehow it isnt so, atleast my ears dont tell me so, otherwise I would have loved the blameless right off the bat. Hugh speaks of capacitors and the sonic differences, doug self wrote very clearly on capacitor distortions namely electrolytic, but it applies to many others, which really comes down to dieletric absorbtion in signal coupling, no black magicl but pure fact that teflon has the lowest absorbtion of them all, aside from air..People like hugh spend years building with passion an amplifier that they can proudly release for the public to buy, most companies will just throw something together, pass it through accounting, and hope its approved by the penny watchers for the most part. Colin AKSA Glen, Andy, Howls of derision indeed...... :D Why does this alleged 'claptrap' threaten you? You haven't heard my amps, you have not studied the schemat/layout, you won't be buying one, why does this distress you when there are dozens of blatant conjobs in this (and other) consumer fields? If you knew the market, you would realise that specification on its own is not enough. Sound quality counts. Engagement is much talked about by audiophiles; clearly it matters. I don't believe you guys actually design and market amps into this market, so you are afforded the luxury of contempt for the commercial realities. Glen, you highlight measurements which bear little relationship to the extraordinary complexity of music, no consumer listens to test tones, and music can only be subjectively analysed. In any event, you do not know the distortion figures of my products, and I'm not about to go on about them anyway even though they are very good. There is a necessary balance here which from your ivory tower you choose to ignore. Glen, if you should come to Melbourne, I would like to meet you. In fact, come to lunch on my ticket. I would like to hear your story, your outburst is interesting. If not, say so here and demonstrate your adversarial attitude for what it is. Cheers, Hugh destroyer X People use hard agressive words to call atention...i think they can make a better work painting themselves red, holding a watter mellow over the head...dancing with bananas, and crossing some big street nude. I use to put them into ignore list..as not kind enougth to listen them...noises...i prefer sound! This means..he can jump and scream... i will not be reading..so..will not bother me....no chance for those guys! regards, Carlos Conrad Hoffman Hey, this is an easy one. Put Crummycap in both channels. Feed both channels with music of your choice (parallel-mono). Feed output to speakers. Also feed outputs to matched pads and into something like an E-mu or other decent interface. Record a while at 96 or better khz and 24 bits. Match the levels. Compare waveforms. If they aren't close to identical go back to the drawing board because the channels aren't matched. You have bigger problems than capacitor types. If they are matched, put Teflon cap in one channel only. Run same test. If you see a difference in signals, you now have something legitimate to investigate. If not, the difference resides somewhere above the neck, below the hair, and between the ears, not in them. I don't know the answer here, but am quite confident it isn't magic, and it isn't some unknown signal property yet to be discovered (Nobel prize probably awaits you if it is). Hardware is hardware. It doesn't care about you, and you shouldn't get emotionally involved with it unless you want to get hurt :devilr: destroyer X People love strikes...friends already sending mail telling that Dx had a frontal crash against that "german"...ahahahaha Dear Vinyl..you will have more ideas and more friends will come. this is good. regards, Carlos AKSA Conrad, I agree with you. BUT, the cost in time and effort of getting to the bottom of this conundrum is considerable. As a manufacturer, I'm only concerned with what sounds better, how to offer a competitive product, and how to trim costs. I actually can't afford to do this rather expensive research, and leave that to the academics with grants!! I've heard the teflon caps, I can hear a profound improvement in resolution, I perceive there is a marketing advantage in having them, so I minimise their cost with optimal design and put 'em in the circuit. I note that the dielectric constant is lower than most anything else except air. That seems to compute in terms of 'memory', and might explain the sonic differences. Nuff said..... On your last comment, above the neck/between the ears, I am bemused by the notion that different people hear different things, and a lot of people are suggestible. This is inescapable, and suggests that audio is like food, and automobiles. Not everyone likes the same thing; cf. tubes v. SS. Thus, we can identify a subjective, perceptual component as well as an objective measurement issue. Furthermore, testing in present technology (and specifically for the purpose of measuring THD) is only possible with either single or dual tones, and this is not a particularly valid facsimile of music, which is the definitive consumer working medium. Cheers, Hugh Conrad Hoffman Hugh, you're a businessman first, and that's the key to survival in a competitive market- my compliments! This is a guess, but there's probably a better market with better margins when amplifiers are sold using the language of poets, rather than the cold harsh realities of engineering. If you can lower the cost of using Teflon, you get the benefits of Teflon along with the bragging rights of using it. BTW, there's certainly nothing wrong with Teflon in technical terms :D Now, looking at it from the technical end, I suggested the test routine I did because it's incredibly cheap and fast. No expensive gear beyond a $130 interface and the computer you probably already have. If you did the same thing with a scope, it would require an expensive differential front end, because the bare inputs probably don't have enough sensitivity or CM range for the gain you need. From a business perspective, and this should be a good lesson for many people here, having that technical information as to why the Teflon cap is better (if, in fact, it is), doesn't offer you any benefit. It cost money to get the info and then what? It won't help sales. It won't drive the design. The measurement has a poor ROI. Thus my happy situation of being a hobbyist. I don't have to worry about ROI, how to pay the employees, where to advertise, what the competition is doing. No expensive CE conducted and radiated emission tests. No vendors late with parts. I just worry about whether my wife approves of how much I spend and do what I like! Johan Potgieter quote: Originally posted by Johan Potgieter I have a problem with a certain view that in an almost derogatory way suggests that specs are allright, but there are still (as in must be) audible things that one cannot measure - ear so sensitive etc. This stance flatly ignores the multitude of tests done over decades at highly regarded centres (not by journalists) to try find out what is audible and what not. To the degree that this has resulted in reproduceable consistent results after using many thousands of subjects, I am really doubting that somewhere in some etherical spheres, something still lurks that we will discover or stand in awe of (re hearing, of course). Ergo, we have a useful "model" of the ear, even though we may not exactly be able to understand it from A - Z. Not sure that it is kosher to quote one's own stuff, but I feel somewhat like the angler suddenly washed off the rock, boots, fishing tackle, present scientific situation (I am only the messenger here, not the originator!), dignity and all. So pardon me for retrieving a wet paragraph or so in case someone did not notice before the wave came ...... I was carefully lifting my head above the speaker box after the previous salvo's (not seemed to have been aimed at me specifically - thanks for the consideration) - but: Any over-selective argument in this business of audio is bound to run adry. Is it so difficult to understand that when e.g. Doug Self's amplifier does not sound right, that does not mean that there are things that scientists cannot yet measure? Why is it taboo to accept that natural, honest-to-life hearing perceptions can differ from one person to the next?? At least, I am confused; the previous sentence was in fact acknowledged during the salvo - why then is the immediate assumption (at least the way I "heard" it) that science still cannot account for all? I find those two truths contradictory - in fact, my above quote shows that science can account for this, that is why some folks will dislike the same setup that others prefer! Hugh (and I stand by my earlier recognition of your achievements among that of many others) you say that some amplifiers with good specs sound poor - well ordinary, whatever. What "good" specs? I will now rear up my whole person from behind my loudspeaker box (as you know, the present sizes do not provide as much protection as did the Klipsch's of old anyway!) and say: Indeed no! One is in fact able to explain most of an amplifier's audible shortcomings by looking at proper specs - only those must include at least also a spectrum analysis into a resistor as well as into a (again proper) loudspeaker simulated load. We are a little starved re magazines down here in South Africa, but in the only mag we find here with analyses viz. Stereophile, I see that correlation most of the times. I make amplifiers for a "market" - i.e. not large production runs, but at least for a variety of clients - all with different hearing (and loudspeakers and CD players and ... and....). For whose "taste" must I design? Perhaps so far I was fortunate in that nobody was disappointed. But either I must have a singular talent thataway (and I don't believe that), or I must have done something right by simply following basics plus what little experience several decades (5 of them) have earned me. I am trying to make the point that one cannot justifiably condemn something because it did not sound right to someone - or 2 or 3 or even 10 people. My minimum requirement for such a claim would be a proper blind test. (And that is another sticky toffee of a whole new argument. For now, listening to unknown entities repeatedly does not constitute a valid blind test; not on one occasion or in one day or two.) Similarly it does not mean that you are hearing challenged if you are incapable of hearing what the next man does (sorry, that one is too easy!). Coming to a valid conclusion with hearing tests is a technology in itself, involving knowledge of hearing physiology and psychology. The tests and pronouncements of the studies quoted above involved all of that, which is why they are considered representative. This does of course not mean that one cannot step into a shop and prefer something - it is your ears, time and money and it (mostly) works. It does mean that one must be careful of elevating that to dogma. Thanks for attention. Conrad Hoffman Johan, I feel your pain, as our standards appear the same, as do our decades :xeye: Hugh, however, is selling sizzle, not steak. Hopefully his steak lives up to the advertising, but he's astute enough to realize that selling sizzle is more profitable, gives him more control over the customers perception, and avoids the need for academic research that he'll never get a return out of. I don't see this as a terrible thing, only a choice in priorities. IMO, most of the high-end makers use a similar business model, whether they'll admit it or not. If customers believe in magic, and buying this stuff makes them happy, great. For those of us that understand how various bits and pieces of varying impedance interact, and accept the absolute equivalence of the time and frequency domain viewpoints, not to mention decades of properly conducted audio tests, and who want designs backed up by science, diy is probably the best choice. AKSA HI Johan, Hmmm. Tough questions. I don't have a lot of time to spend answering this kind of rigor, because there's no ROI and I'm kinda busy at present, but here goes. Any amp with 20Hz-20KHz +/-1dB and THD of less than 0.05% at full power into 8R would classify as good specs. THD takes no account of spectral distribution of that distortion, of course, and there's the rub. Frequency response is clearly important for anything with wide bandwidth pretensions. Yet, most of Japanese amps of the last twenty years meet these specs, and more, but sound, well, a little lifeless, lacking somehow in vitality. Lux is better than most, but even the big Denon monoblocs were dull, at least to me. Same for the Self Blameless I heard at an audio club. There was none of this lifeless sound with the single ended triodes I've heard. I attribute this lifeless sound to over compensation, in an attempt to make the amp unconditionally stable into any load, no matter how nasty. I would not blame any designer for this approach; there are some truly horrible crossovers out there which dip below two ohms and create huge phase shift. It turns out that designing for any load is one of the reasons why many Class AB SS amps don't sound so good, but I won't comment further on this; the topic is complicated and consumes a lot of time. Johan, you ask for chapter and verse on the proof of this argument. I can't give it to you. It's an ingrained hunch I have based on my work with amps over many decades. I'm no longer much interested in a formal proof now, I just know what works and what does not. I do like single ended design, don't much go for full complementary input stages or voltage amps. Amongst the designs I see which show conventional engineering rigor I do notice the same old approach which has not changed in decades, and only masters like NP and Charles Hansen, of Ayre amps, seem to have it right. Tube amps are very different, and the conventional designs I see plastered all over the web mostly sound very good. I also think that NFB is just fine, and gets a very bad rap. It's difficult to design a good amp without it, though the Dartzeil seems pretty good from all reports. I hear your comment that this is all very hit and miss. But so is the choice of a good restaurant, or digital camera, or automobile. They are all products of perception; taste varies, and there's no accounting for it. Some love the surgical, dry, high impact of SS, others prefer the organic mellow sound of tubes. Why? Heck, I dunno, but it does represent a legitimate choice, and there will be quite measureable portions of the consuming audiophile public who choose them, and that's really all there is to it. Psycho-acoustics can give us some of the answers, but not all...... and there is the psychology of the marketing to consider - what ageing, wealthy audiophile can resist a picture of the patrician Dan standing next to his Testarossa with his technically perfect amp at his feet? It's a very comely image, and it sells a lot of amps. In closing, don't forget fashion. One year it's zero global feedback, the next it's tubes, the next it's teflon couplers, and so it goes on. An impassioned, even feverish audio press can whip up a frenzy of excitement over the latest gadget, we would all be cynical if we sat in the planning rooms of the advertising agencies and editorial discussions at the audiophile magazines! But that's all normal in a sophisticated consumer world. Every dog has his day, but only a very small number really do know the truth, and they are not generally the contemporary buying public. Example: I drive a 15 year old car in very good condition, a Cressida, because they represent the best Toyota could make back then and even the newest models, with the exception of the Lexus range, can't compete with the excellence available in the early nineties in what was a very expensive car but which is now dirt cheap. I mention this because I represent an insignificant portion of the auto market and my decision to keep this very old model is not important to the present market, but it is an informed choice, and it represents - to me anyway - the truth. The same could be said of say the JLH 10W Class A amplifier. An oldy, but a goody..... Cheers, Hugh Conrad Hoffman IMO, two amps that met 20-20k +/- 1 dB, would be perceived very differently if the response curves had opposite slopes or some other peculiar mismatch- a 2 dB wide window allows for a lot of creativity in giving an amp a particular sound- something the wise high-end designer would take subtle advantage of. Like him or hate him, remember that Carver was able to successfully match the sound of any amp in blind tests using a few (or a lot of) tweeks. Regards, CH AKSA Conrad, You mentioned that I sell sizzle, not steak. A fetching metaphor, but I cannot let it go as it is wide of the mark. Have a look at my forum and read some of the unsolicited reviews and critiques of my gear (I am assuming you've not heard or seen it!) and understand that I distinctly am NOT selling sizzle. I am selling performance, in fact, but while my techniques for achieving this performance do not necessarily correspond to your research oriented approach, it would be inappropriate to dismiss it as wrong, or failing to deliver results. As I've said before, you do have an obligation to listen before making judgements.... Cheers, Hugh destroyer X And that behavior... the interest of audio started even earlier, around 1960 when i started to construct everything people published ....and the most strange thing, is that the most sophisticated ones, usually sounds worst.....with exceptions of course.... this is the conclusion of many years testing...not empty words...experienced words. More than 4000 amplifiers were constructed, compared and then dismounted to use the parts to another one....even the parts were the same...i had not too much problems with parts...as they were sounding in many amplifiers...so...sonics came from the design only, not because parts....components were out from the game.... and this is a good argument to the ones that believe transistor sounds different...i do not think this way...only capacitors sounds different, and circuits, and topologies. That Blameless was the biggest scandall in my life....i turn very nervous... the one received shots....maybe a perfect amplifier..i do not discuss this...it may be very good if people instead of listening go watching waveforms into scopes...those visionphiles may be happy. I think many people had not the chance to listen to Hugh Dean amplifiers... the ones that have listened loved his amplifiers. Thank you Hugh, that you came here loosing your time trying to say things we both know very well...but hard to prove using numbers.... people need to listen to believe. I am sorry, also, that i have called you here writing something about you....as this calls, usually, result not so good reactions...people use to attack you because envy, others wants to know ....and because of that they put you against the wall...pushing you hard.... trying to receive key informs to answer their own doubts...well...some questions and discussions are fair but extremelly hard to you....i always perceive those things, in our forum, alike Jesus Christ judgement..when people had already decided to kill him...because he deer to say he come from the skies...i feel myself very bad watching those things...and this is a constant. Some guys, alike my young daugther, behave very strange....my daugther, for instance, even never have tasted banana with sugar and cynamon always reacted not to touch... not to eat... those things were awfull to her....not pretty...i do not know... she was "hating without taste"...and the same way...there are people that "hate simple designs without listen to them".....not very scientific minds...not a good scientific behavior in my point of view. You really do not need to convince people about your amplifiers quality...you have more sales than you need...thousands of customers that do not think twice to have your last models...and they are in Audio Circle confirming your words..showing proudly their constructions...and they are people that can buy the most expensive gear...and they still prefere your unit....because it is extremely good. It is hard for audiophiles, to accept quality without numbers...and they usually believe small distortion numbers means sound quality....this is wrong.... real life is full of reverberations, distortions and strange sounds...a violine playing near you is awfull...sounds alike a cracked bamboo...we need some distance not to capture those lower level spikes of sound. High fidelity...low distortion will give you that original sound...i do not think people will really prefer that only to force numbers to make sense. We are analogical beeings.... bio chemical machines...our audio transference is awfull...inside ear you have bonds moving and heating a diafragm....for sure..we are not having perfect square waves entering our brain.... bio chemical reactions are slow...you cannot perceive too big slew rate.... you "system" will not hold that....we need sounds that can be detected by humans. We do not listen 100 Kilohertz..and there are amplifiers trying to reproduce 100 kilohertz....speakers do not reproduce 100 kilohertz too...so...there are a lot of non sense things and people accept without discuss...but they have problems to accept experienced people words...old folks informations....this is a pitty. I have invited you here dear Hugh...but i will ask you to leave us...i think you do not deserve to face things you are facing....not fair to you. Yes, there are educated people here,...there are folks making questions and discussing in a very high level or respect and good educations...some fair questions and some clever arguments...but we both know the bricks will come...and one already arrived with extremelly ignorance of behavior. Sorry...i have started that...making comments about you. regards, Carlos vynuhl.addict I apologize to Hugh, this is not the thread I had hoped it might turn into, I do not support the attacks againgst Mr Dean that seem to be quite baseless and coming from those who dont own his amplifiers. If ou read between the lines and even "the lines" you will notice that he points very strongly towards the VAS stage and its lack of investigation by the general crowd. I share his belief in the fact that it is a major sonic sticking point in audio reproduction as i have heard it with my own ears. The reason why the Blameless sounds so lousy has alot to do with the second stage "as is". as the output is a conventional emitter follower, similar of which the aksa used, and the LTP is pretty common, emitter degeneration, current mirror and active current source. Just dont be cheap and spend an extra few cents to separate the ltp and vas current sources. I am thinking I might have to build a couple of extra furnished boards and send them to Carlos to ake up for his bad experiences with the original :). Colin destroyer X to learn more...there's not closed doors in my life....i am always open to change my mind...i love to do that...as i perceive mind changes as evolution. You will be kind sending me one board.....keept it hidden inside card paper and send it as a letter...just one board...i will try it..for sure. I have any doubts that your intention was not that one...i was the fool, as i know how people react against Hugh....many guys do that trying to shake Hugh till unstabilize him to make him talk too much....and it is intersting, since 2004, slowly, he passed all important informs about his amplifier....but people did not perceived that...hehe VAS is the most important circuit to sonics...people thinks that differential is...negative! My personal adress is: Carlos Eugênio Mergulhão Rua Dona Balbina Menelau 56 -1601 Candeias - Jaboatão dos Guararapes Pernambuco - Brasil South America 54440-331 regards all folks. Carlos vynuhl.addict Its a deal then Carlos, the board will post as of next week. I am hoping that you might do something I have no access to and provide some measurements out of curiosity if possible on performance, I am curious to see how it may of may not relate to perceived sonics. Thanks Colin SY quote: Any amp with 20Hz-20KHz +/-1dB and THD of less than 0.05% at full power into 8R would classify as good specs. By whom? I'm as non-voodoo and measurement-oriented as anyone, and I would find that "spec" laughably inadequate. Don't conflate "specs on an ad sheet as outlined by the FTC" with "proper and reasonably complete measurements." AKSA Carlos, Colin, When you have an uneducated novice in any area of knowledge claiming the sorts of things I claim then there will always be cries of 'impostor' from those who make their living from conventional pursuits. I accept that, it amuses me because it only redoubles my determination to walk away from the crowd. I stress that nothing I have done is particularly original. It's all there for those who are prepared to do the hard yards, and keep an open mind. Insight is 99% repetitious hard work; we all have the brains to do just about anything we choose. History is littered with 'shooting the messenger' stories. A farmer who shears his sheep off season; a fisherman who trawls in a known barren area; a painter who insists on cubism; a computer scientist who gives his life to open source software; a conservationist who chains himself to a dozer - these people are all treated as fools, but this is just human behaviour. At my age I no longer care what others think. It's actually a huge relief - by their abuse and rhetoric you can spot the followers. Yes, to a minor degree I am self-congratulatory, but I seek out and carefully listen to those who offer a contrary view, as the result of listening to the conventional view is always, by definition, more of same....... No progress is possible without a 'what if' mentality, and that only comes from those with a contrary view. And I love a little conflict. Glen, how about that lunch? I can recommend the salmon foccacia! Cheers, Hugh AKSA Stuart, I particularly enjoyed the quote from the source of modern Islamic fundamentalism - who was very badly treated in his native Egypt by Nasser. How about 30Hz - 18KHz and 4% THD into 8R at full power? Is this a good spec? Please explain this to me, I'm confused......:confused: Cheers, Hugh :clown: destroyer X Scope lover..hehe About your avatar, ..this nose is really big...has some connection with the old tale...Pinocchio? ahahahha Carlos lumanauw The most expensive picture in the world is hand painted and not even close to the object being painted. It doesn't have the super detail or superb technical spec of modern photography, but why people willing to pay so much for something that is blurry, distorted, and certainly not having as good specs as modern photograph standards? AKSA Human Perception, perhaps?? Hugh lumanauw Maybe? :D The point is, there is something those people enjoy much more than accuracy or distortionless. Sometimes a very accurate and distortionless picture makes the brain exhausted by thinking harder (looking for the mistakes) and the eyes are focussing to the details, not seeing the whole picture. Loosing the entertainment aspect. G.Kleinschmidt quote: Originally posted by AKSA Glen, you highlight measurements which bear little relationship to the extraordinary complexity of music, no consumer listens to test tones, and music can only be subjectively analysed. This is utterly ridiculous. If you think that such things as an amplifiers THD, IMD and TIM performance has little relationship to an amplifiers sonic performance, then you obviously don’t know what you are talking about. Also, I never said that consumer’s listen to test tones or that subjective evaluation has no place. If you think that such is necessarily implied by drawing attention to the above mentioned, measurable distortion mechanisms, then you’re full of baloney. quote: In any event, you do not know the distortion figures of my products, and I'm not about to go on about them anyway even though they are very good. There is a necessary balance here which from your ivory tower you choose to ignore. So what? I didn’t make a single comment on the performance of your products, I criticised the completely unsubstantiated pseudoscientific hokum you use to market them, which you also use to deride other peoples products, with basless utterances such as this: quote: ….This is hardly objective, and attracts howls of derision from the engineering dress circle..... BUT, it is necessary, as the finest engineering examples of good amplifiers leave much to be desired. That latter is contemptible. The one sitting in the ivory tower here isn’t me, but it is you with your golden pair of ears with an amazing ability to build audio products that even engineers responsible for the “finest engineering examples of good amplifiers” cannot match. And what of substance do you have to offer to substantiate such a grandiose claim? Nada! Just a paragraph of twaddle about how you are personally driven to develop amplifiers that cause you to cry. Give me a break! quote: Glen, if you should come to Melbourne, I would like to meet you. In fact, come to lunch on my ticket. I would like to hear your story, your outburst is interesting. If not, say so here and demonstrate your adversarial attitude for what it is. I have absolutely no intention of driving over 1000 kilometres for a free lunch, and what on earth does my “story” have to do with your unsubstantiated, pseudo-scientific musings on the performance of other peoples amplifier designs? BTW, contrary to your claims designed to make you position look less untenable, nobody here is howling derision, but instead putting in plain words why what you have posted is baloney. I have a tendancy to be a little less subtle than most, but that's just me. G.Kleinschmidt quote: Originally posted by AKSA Carlos, Colin, When you have an uneducated novice in any area of knowledge claiming the sorts of things I claim then there will always be cries of 'impostor' from those who make their living from conventional pursuits. I accept that, it amuses me because it only redoubles my determination to walk away from the crowd. I stress that nothing I have done is particularly original. It's all there for those who are prepared to do the hard yards, and keep an open mind. Insight is 99% repetitious hard work; we all have the brains to do just about anything we choose. History is littered with 'shooting the messenger' stories. A farmer who shears his sheep off season; a fisherman who trawls in a known barren area; a painter who insists on cubism; a computer scientist who gives his life to open source software; a conservationist who chains himself to a dozer - these people are all treated as fools, but this is just human behaviour. At my age I no longer care what others think. It's actually a huge relief - by their abuse and rhetoric you can spot the followers. Yes, to a minor degree I am self-congratulatory, but I seek out and carefully listen to those who offer a contrary view, as the result of listening to the conventional view is always, by definition, more of same....... No progress is possible without a 'what if' mentality, and that only comes from those with a contrary view. And I love a little conflict. Glen, how about that lunch? I can recommend the salmon foccacia! Cheers, Hugh Sorry, but I don't like salmon and I steer clear of most foccacia breads because most contain obscene amounts of sodium. PS I see that since you have now steered this thread to a discussion on salmon, focaccia bread, cubism, farmers and people who chain themselves to bulldozers :rolleyes: you really don't have any technical arguments of substance to support your claims about the sonic inadequacy of “the finest engineering examples of good amplifiers”. That figures. Cheers, Glen Greg Erskine Hi Glen, What is your motive? You reaction seems way out of proportion. You seem very angry for a man that likes large breasts. :D I find it very hard to read your posts, my eyes keep getting distracted. :o Have you found the audio forum: http://www.diyhifi.org/ regards AKSA Glen, You have made my day!! A man with your obvious cachet doubtless travels; I had expected you'd occasionally come to Melbourne, the invitation, Sir, stands. Then you can be really rude to me! You are adept behind a keyboard, what are you like in person? Again, I ask the question, why are you so threatened? Did I really insult you with my baseless opinions? Are you such a conventionalist, or do you have an MEng? Cheers, Hugh pinkmouse :cop: Let's not go down the personal insult route folks. Keep it clean and no punching below the belt...Ding-ding, round two ;) Conrad Hoffman Hugh, I'd be happy to buy you lunch, as I find this whole topic extremely interesting, including the business aspects that are so real, but rarely acknowledged. Unfortunately, we're half a world apart, so just have a beer for me. Let me try to summarize my point of view and see if you agree or disagree- 1) Identical signals sound identical. If you hear a difference in sound, it's because something is physically different, or it's because of mood, weather, biorhythms, etc. 2) Any *physical* difference that results in an audible difference can be measured and quantified using well known electronic methods. That's it. I don't have your amps, don't know whether they are good or bad. When I say you sell sizzle, I say nothing about your amps, only about the need to generate interest and excitement in the customer so he/she will buy the product. Pure engineering talk won't do that, and you'd be out of business quickly if that was the only thing you relied on. I will speculate that if you have a lot of happy customers, the amps must be reasonably good, but that's not the issue here. The issue is how one goes about achieving a certain engineering goal, and many of us have strong beliefs that trial and error should be backed up with tests and proofs, otherwise the final claims of how it sounds must be classified as hype and marketing, not claims that can be verified by a third party. I'll toss out one additional belief, totally unsupported by science. Just consider it the ravings of some nut on the web- Perfect flat response doesn't sound good. You don't want it in your living room. It's an easy engineering goal for each component- nice ruler flat graph, but somewhere in the system response needs to be altered to please the ear. It can be done anywhere between the music and the ear- the mic, the mix, the CD player, the amp, or the speakers. Probably the room too. The blameless amplifier is, in fact, blameless. Unhappiness with it is the result of expecting perfect flat wideband response to sound good. That seems reasonable on the surface, but the same logic led men to think the earth was the center of the solar system. It just made sense. It was just wrong. One has to view the sound of a system as a system level problem, not in terms of tweeks to individual components, as that makes the problem unmanagable and unsolvable. [trivia question- why do performance microphones advertise non-flat response as a benefit, with no sense of shame or guilt?] Regards, CH destroyer X And it is something that you may know..but good to remember. We can measure everything till it enter into human perception...maybe you can measure the internal ear mechanical parts...maybe timpanus ( ear membrane) can be checked using ultrasound or laser techniques. But what goes after that is very complicated..will enter brain and we do not even know how brain processes those data. Brain is connected to person character, personal tastes, live experiences the guy had, mood, health and references the guy had learned in this life. The same signal can be "felt" by one different than other... and evaluation as good and bad will depend of subjective values.... Sound can be understood objectivelly as electrons and wave forms..air pressure and those things...but sound perceived are matter of subjectivity....this is not something measurable....metering are made to scopes and to produce a good communication language, a common language between enginneers...listening is made for humans... and even it's expression..it's translation in words will depends from the one is talking and perceiving things...his language can have signs we do not understand clearly. Women listen some frequencies better than others...because of babies crying maybe....audition system is adapted, tuned to this ancient job to take care of children..to listen distant cries of children...they hate scratching sounds and hi frequencies steady tones...we do not behave the same way...we males. And there are differences from person to person. To know if an amplifier is good for humans..they have to listen...the simple observations and analisis of data will not guarantee good results. That amplifier a lot of people loves...that one may be good for humans. Entering inside people's brain...subjective things appear and those things are not measurable now a days...at least i have no idea how to measure those things.....i would be happy to know. regards, Carlos Johan Potgieter Hugh, I appreciate your stance, and your time. My question about "good specs" was not a challenge to you personally, and you did acknowledge the important thing, that the usual THD stuff etc. has become totally inadequate especially for SS. That is my (our!) whole point! Folks keep on saying that amps sound awful despite "good" specs, when the particular stated specs are really following fashion and little else. Ergo, the criticism of specs per se, as soon as something sounds plain, lifeless or whatever, is really rather unfair (to be more truthful, I should have said uninformed). In general to all: With that I was not elevating specs to more than they should be, just trying to indicate why designers must look at the same and are following a particular route. Indeed, specs need not be quoted at all to non-understanding men-in-the-street. (In fact - see all the rubbish that that had caused mostly because of unscrupulous promotion yellers. Specs should be banned!) I do sadly notice a misunderstanding of what the hi-fi system is there for. Honourable members mentioned that a well-liked painting need not necessarily be photographically accurate, etc. Quite so! But what about a photo of that painting, usually to show what the original is like? Would one, especially art connoisseurs, put up with that being not an exact copy of the original, i.e. distorted? I think not! Our sound systems are (or should be) not there to generate sound. They are there to re-produce; like the photo of the original. (Just for the record, I am naturally not talking of effects systems e.g. guitar amps, etc.) That is generally what many of these arguments can be reduced to. I do not condemn the right of music-making systems - staying with amplifiers, just give the right amount of 2nd and 3rd harmonic generation etc. and au voila! Been there, done that and surprised listeners. Only that is not what I aim at as a designer of hi fidelity amplifiers. It is as simple as looking up the dictionary definition of fidelity. the flawless photo (record) of the original, not a new original. Let us in the broader sense give both of these the right to exist. But with that comes the obligation to acknowledge as well the ability to recognise the difference, failing which is often the cause of unnecessary and unproductive debate. Hugh (back to you), A few posts ago (did not note the number) you gave one of the better dissertations of your kind of stance that I have read. It makes sense and I respect it - Thanks. May I just add, if necessary, that I "argued" your arguments and not yourself; if the latter perception arose I apologise. Though we are both down under (now, now, let us not start a "who is the underest" argument!), I am still remote, otherwise would have liked to meet with you. Regards. vynuhl.addict Gee, I almost cried when I could sit it front of the Blameless for more than 20 minutes at louder levels, and not want to run from the room for breathers. My ultimate test scope and measuring equipment is my wife, especially for high frequencies because she couldnt sit in front of the original blameless either, it would give her a "headache" in her words. Now she can and does perceive major differences and benefits and high frequency that is softer and not etched and hard sounding, in other words she gets no headaches aka ear fatigue. She has no qualms with telling me it sounds like excrement if she thinks so.Perhaps if you know precisely what to look for, in which I dont, you could design this using measuring equipment through the entire process solely but it is far more personal to do with a set of ears or two provided you arent clinically deaf. My older brother is deaf since birth but still even he can sense and perceive certain changes from desgns being alot more in tune with other senses then us with hearing take for granted. My guitarist has 6 years in robotics engineering, he open admits he can do all the math, run any test out there but when it comes to audio designs he finds he needs to take 6 steps back (figuratively speaking) to come out 12 steps ahead..Why do many finest engineering examples drown and put a choke hold on the VAS with miller compen