and what about the source,same story .
when your DA converter is not very good everything you do hear is a waste of time.
I converter that puts out all the 16 bits (so very low noise level,low jitter etc) is rare.
when you have such a converter all your listening have to be redone.
gr Marius
when your DA converter is not very good everything you do hear is a waste of time.
I converter that puts out all the 16 bits (so very low noise level,low jitter etc) is rare.
when you have such a converter all your listening have to be redone.
gr Marius
Well, at the level of distortion we are talking about, 24 bit sources and 24 bit converters are preferable.
Hehe ;
With the few we know about the way our audition (ears + brain) is working, with our limited (or stupid) measurements methods, if any truth, it is somewhere between subjective feelings and scientific measurements... as we do 🙂
As hifi is a 'make believe' game, at the end, the best system is the one... who produces the best illusion ?
An amusing game where each string (supposed to be transparent) can ruin the show. Where each component's enhancement will reveal an evil somewhere else.
It is hard to explain how we can feel quasi unmeasurable distortions from amps, while, in the same time, we are using speakers with such a big amount of these with so little trouble.
Well, music is based on mathematics. Did guitarists make calculation when they improvise a solo ?
Because our reproducing systems are based on electricity, we have to be as scientific as we can, when it is about... but, there is a point where, if we rely only on this, we are just middle aged believers in an idol: Science.
https://www.youtube.com/watch?v=wDZFf0pm0SE
Of course, we have to master every aspects of electronic, but it is just the very first step, if we want to be a good audio designer. The second one is to educate our senses, including the one of the beauty. Understanding music, knowing the instruments.... Our accuracy will grow with experience, our success with talent... and endless love and efforts.
Yes the beauty of a printed board will help to hunt some demons... Yes, our reptilian brain helps us to find the right answer to a problem. The whole game is to educate our reptilian brain, as we can leave the calculations to a computer.
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Those of you who argue that these amps sound different have not built any of them let alone, two so you can compare. You sit at your computers and make suppositions based on simulations you have run. When you have built the amps and built a true A/B blind system then critize away. Most of you know far more about electronics than I will ever know but I have been a professional musician for nearly 50 years. I have worked as a sound tech for large churches and own a home recording setup. I know how music sounds. Not one of you has better "ears" than I do. Many guys continue to ask those of us who have actually built the amps, which one sounds best. Those of you who design don't want to accept the answer. I've said it before, if you want to hear a big change,buy different speakers. These ultra low distortion amps all sound so similar, you can just pick one and enjoy the build.
Don't be so contemptuous ;-)
It is BECAUSE we have some respect about your 'earing' ability that some of us had reacted such a way.
On my side, no simulation. Or preconception. But my long experience (i'm not young, was both pro electronic designer and sound engineer) has tell-me that no amp sound exactly the same that an other different one. Sometimes, it is on details, about instrument's separation, listening fatigue, details of transients, strength or lightness of basses, fluidity or sparkling of trebles... Some times it is obvious change of the whole landscape. Sometimes, it sound very close, but, magicaly, one makes-you 'feel the music', and the other not.
So, you can understand why i ask myself questions about your report ? ...or your way to compare ?
If i had found two different amplifiers with exactly the same reproduction and a different topology, i would chose any of those ones... and keep-it forever... stopping to search for better...
As some others, i ask myself questions about your sources and speakers. Is a link in your chain would be so colorful that it would take precedence over those subtle differences i *always* noticed ? Or your power supply (the same for all your builds ?) limiting the full amp's expressions of their dynamic?
If you are right, you just have several versions of perfect amps, you can stop to DIY and enjoy the music 🙂
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Can it be that adding the highpass cap to some of the designs can be a possibility not to let that design be as it is best and make them sound more the same. See in many pictures and schematics here that highpass caps are used even schematic show it as option. All it takes to omit this cap is source signal without (having cap at source by design) or around 0V DC, then a strait DC coupled amp have force of no timing error (group delay) from DC and up to xxx KHz lowpass filter.
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Terry,
I for one am not questioning your abilities or your knowledge of sound. I also have been around sound and music for most of my entire life. I practically lived in a recording studio when I was in high school rather than go to class when given the chance. I lugged around so much sound equipment that that got old, but I did get to hear much live music. I have sat in some of my friends living rooms and listened to them just play music or rehearse, and I am talking about well known musicians on the level of Stanley Clark and Airto Morera and Flora Purim and many others, not just some guys playing in a garage band. I;ve been on the other end and have been doing speaker and horn design for 37 years now, I understand how much speakers influence everything. I looked at the U-tube videos that Esperado / Christphe has just posted over on the Blowtorch thread and believe me I was laughed at until people listened when I brought back horn loaded speakers at the CES show in the early nineties before everyone else jumped on that bandwagon, it did open some peoples eyes. Setup is so important to comparing speakers and amplifiers.
I believe that in the case of the Slewmaster amplifiers we have reached into a very complex situation. We have a basic amplifier that is built on a very high level of electrical quality with the common output power section. The differences in input section are giving such high quality sound reproduction that to tell one from the other would be hard to tell apart, the distortion levels are at vanishingly low levels, to hear a difference is going to take some real effort. This I think says much about the basic concept of these amplifiers and there design. Actually I am impressed by your new found skills in solving some of the electrical problems you have tracked down, I have been watching you since the beginning of this thread and I can see the progress you have made. I do not question your hearing chops, I believe you are having difficulty hearing a difference between all these versons of amps. Perhaps as Christophe has said if you listen to two of these versions for more than a few minutes, could take weeks or hours you will notice very slight differences in presentation on some minor aspects of the sound, but who really can say without being in the room with you. I am close enough that I could drive out to your house and confirm to all that you got it right, or I could bring another set of speakers and we could hear something that with the present ones you never will hear? I can't say anything definitive from where I am sitting. I will just be happy to have an amplifier that is designed at such a high level, I hope when mine are complete they blow me away and I can get rid of some of the other amps I have lying around.I am here watching this thread and others for another reason, I was looking for an amplifier to use in a self powered speaker and I am not an electrical engineer so couldn't do the design myself. I think with almost any of the versions I have found my answer.
I thank you and OS and Jason and Thimios and a few others for your hard work and think you have all solved my quest. Is this the best amplifier in the world, I can't say that, but I do believe that you are playing at a SOTA level here and that is good enough for me.
Blessing to you and I respect your opinion,
Steven
I for one am not questioning your abilities or your knowledge of sound. I also have been around sound and music for most of my entire life. I practically lived in a recording studio when I was in high school rather than go to class when given the chance. I lugged around so much sound equipment that that got old, but I did get to hear much live music. I have sat in some of my friends living rooms and listened to them just play music or rehearse, and I am talking about well known musicians on the level of Stanley Clark and Airto Morera and Flora Purim and many others, not just some guys playing in a garage band. I;ve been on the other end and have been doing speaker and horn design for 37 years now, I understand how much speakers influence everything. I looked at the U-tube videos that Esperado / Christphe has just posted over on the Blowtorch thread and believe me I was laughed at until people listened when I brought back horn loaded speakers at the CES show in the early nineties before everyone else jumped on that bandwagon, it did open some peoples eyes. Setup is so important to comparing speakers and amplifiers.
I believe that in the case of the Slewmaster amplifiers we have reached into a very complex situation. We have a basic amplifier that is built on a very high level of electrical quality with the common output power section. The differences in input section are giving such high quality sound reproduction that to tell one from the other would be hard to tell apart, the distortion levels are at vanishingly low levels, to hear a difference is going to take some real effort. This I think says much about the basic concept of these amplifiers and there design. Actually I am impressed by your new found skills in solving some of the electrical problems you have tracked down, I have been watching you since the beginning of this thread and I can see the progress you have made. I do not question your hearing chops, I believe you are having difficulty hearing a difference between all these versons of amps. Perhaps as Christophe has said if you listen to two of these versions for more than a few minutes, could take weeks or hours you will notice very slight differences in presentation on some minor aspects of the sound, but who really can say without being in the room with you. I am close enough that I could drive out to your house and confirm to all that you got it right, or I could bring another set of speakers and we could hear something that with the present ones you never will hear? I can't say anything definitive from where I am sitting. I will just be happy to have an amplifier that is designed at such a high level, I hope when mine are complete they blow me away and I can get rid of some of the other amps I have lying around.I am here watching this thread and others for another reason, I was looking for an amplifier to use in a self powered speaker and I am not an electrical engineer so couldn't do the design myself. I think with almost any of the versions I have found my answer.
I thank you and OS and Jason and Thimios and a few others for your hard work and think you have all solved my quest. Is this the best amplifier in the world, I can't say that, but I do believe that you are playing at a SOTA level here and that is good enough for me.
Blessing to you and I respect your opinion,
Steven
A Vertical MOSFET SlewBaby almost ready to test. I just want to check out with a simulation the best values for R103 and R107 to try and get the temperature compensation about right.
I'm using the single EF (the TO-220 driver rather than the TO-126 pre-driver, as suggested by Valery) with some 2SA1306 / 2SC3298 I had on hand. The outputs are some Vishay IRFP240 / IPFP9140 pairs since they are actually better compliments to one another than the 240/9240 or 140/9140 are together.
I'm using the single EF (the TO-220 driver rather than the TO-126 pre-driver, as suggested by Valery) with some 2SA1306 / 2SC3298 I had on hand. The outputs are some Vishay IRFP240 / IPFP9140 pairs since they are actually better compliments to one another than the 240/9240 or 140/9140 are together.
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Nice! 😎
Your opinion on the sound would be interesting 🙄
Heatsinks look rather compact - vertical FETs like to run hot, but also like good dissipation, keeping them stable hot... just be careful 😉
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Nice.
Worry about emitter resistances on power FETs. It is clever to avoid wired (inductive) ones for stability.
Yes !
Yes, here is my example - I started with the heatsink, marked by yellow frame. Then I noticed - though the spreader works fine, the temperature sometimes raises too high.
After mounting a bigger aluminium section at the bottom, temperature became very stable...
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How would you know?😀
Suggestions?
Valery,
I have boards and MOSFETs coming. I had planned to copy your build but with 5 pair of outputs. Do you think three pair would be better? Have you made any changes since you last posted it?
Thanks, Terry
I strongly believe it will work with 5 pairs smoothly (15 mA of the EF idle current is enough for driving input capacitance of 5 pairs).
Cheers,
Valery
Metal oxyde ones (single or //) or this kind of things:
http://www.selectronic.fr/media/pdf/3427.pdf
Good. What do you think of the suggestion to avoid wire wound emitter resistors? Do you think the 0R22 emitters need a change in value?
Blessings, Terry
Well, I also use these cement SQP 5W (or, in some cases, 10W) resistors - don't have any better option at the moment. 0R22 is fine (with rather high NFB loop gain we normally have in this series of amplifiers).
Cheers,
Valery
thread reopened....posts that disappears are either deleted by the poster or by the moderators, several posts have been pulled here for commenting on moderation.suggest that you cary on the discussion on the superiority of the CFA here: http://www.diyaudio.com/forums/solid-state/240712-cfa-topology-audio-amplifiers-127.html