High end Class D amps?
Teo_Audio, This is not my experience. I have bought IcePower modules and sold amps using modified modules. I am now modding Purifi based amps. The only thing you lose when you modify is the warrantee from the manufacturer. Most audio companies don’t want to modify the modules.....instead rely on their own input stage or whatever to make themselves stand out from the crowd. The Mytek amps are modified Pascal modules. Most people reading this have no idea how complicated and infinite audio is. They have not played inside a component and therefore tend to talk in generalizations. They have no idea that all Purifi based amps will sound different from each other.....all IcePower amps will sound different and all Pascal, etc. etc. Every single thing you do changes the sound. There will be a review soon on the VTV Purifi stereo amp with the tube buffer. The reviewer will be swapping different discrete op amp in the discrete IV converter stage and describing the sound differences. This is just the tip of the iceberg. What I do to the Purifi module makes it sound way better. What I do to the power supplies, the input stages, the wiring, the jacks, the input circuitry, damping, fuses, etc. etc. all improves the sound. Measurements tell you little about the sound of an amp. Most things that make for a lower distortion SOUND cannot be measured. All metal film resistors have a sound.....yet, they all measure the same. All brands of solder have a SOUND......also not measureable.....all wires, jacks, foorters,,etc. etc..into infinity. |
As I keep saying.....everything makes a difference. There is no Class D sound. For instance.....every amp that uses the Purifi modules will sound different from each other. It is not just whether the power supply is linear or switching.....for a great switcher will beat a not so great linear. Every single thing has to be tweaked to the max. The input stages, the regulators, the wire, the connectors, the jacks, the fuses, all has a sound. By the way, if you are using a toroidal transformer and you use metal plates or bolts to secure it to the chassis....you are closing down the sound. You want your toroidal transformer off the chassis on a piece of wood an mounted using tie wraps and glue or a wooden plate on top and teflon screws......way better sound. Here is something really important: All Class D amps use a filter on the output to filter the around 500K switching frequency. Without this series coil and shunt capacitor your speaker would fry. It is common knowledge that you would never want your mids and highs in a speaker to go through a ferrite core coil. (Most speaker crossovers use coils, caps and resistors.......for coils the choice is either ferrite core or air core). No high end loudspeaker uses a ferrite core coil in the mids or highs......bass....yes.....everywhere else it degrades the sound noticeably..... So, why is it that all class D amps use a ferrite core coil on the output of their amps? Why would you want to mess up the sound with a ferrite core coil? You won’t if you value sonics. However, class D was made to be small and efficient and an air coil coil would be too large, and too expensive and possibly radiate more rf.......so, they are never used.......except for NOW. On the mods I do to the Purifi module I change the stock ferrite core coil to a custom made 12 gauge OFC copper coil. This sounds way more open and real then the stock coil......this is a breakthrough. You see, every class d amp that any of you has ever listened to has a ferrite core coil on the output. By the way, only the best air core coil will beat the stock coil. You have to listen and test and listen and test. I also use better sounding caps to ground on the output of the coil and orient these caps so that their outside foil is towards ground, for best sound. I also bypass the output stage power supply with my modified Wima caps for faster and cleaner sound. These caps are also oriented for best sound. No class D module is "pure" or has not sound. All are compromised. No class A amp is "pure" or has not sound. You start with the best circuit....and tweak it to the max. This is how you get great sound. Using regular integrated circuit op amps on the front end will not get you the best sound. I even modify the discrete circuits and regulators I use. This game in infinite. What is best today is tomorrows boat anchor. What I try to do is create products that are so good for the money......you can use them for years without finding a boat to mount it on. I just now thought of this. If you are building a Purifi class D amp and you want the mods I do to the output boards then I can do them for you. I will have to figure out the price. Call me if interested. |
Actually, you do not want any conductive material at all for a transformer bolt. Even a brass or non magnetic stainless steel bolt will degrade the sound compared to no bolt or plastic bolt. You want nothing conductive above, below or in the middle of a toroid. Again, mount the toroid off the chassis on wood and use glue and tie wraps or wooden plate on top with plastic nut and bolt. Likewise shielding a toroid with copper, etc. will close down the sound. If you want to shield then do it a couple of inches away from the toroid......let the toroid radiate its field. I also do not generally like shielded wires. |
Take your Ncore amp and put a .1 ohm non inductive power resistor on the inside of the amp right at the binding post (in series with the post). Now the output impedance of the amp is at least .1 ohm.......so, listen to it again. Does it sound exactly like some other amp that has 80 damping factor? Not likely......there are so many factors that are probably part of the sonic equation. The measured damping factor of an amp could be realized by several things....including amount of feedback, amount of output devices, resistance of coils in series (if applicable), etc. I bet every amp with the same measured damping factor will sound different in bass quality. This game is way more complex than most people think. You can bypass the power supply with serious film caps and the bass will tighten, faster electrolytic caps in the power suppy will tighten bass....fi you damp certain things you will tighten the bass....or dry it up (over dampen)....on and on and on into infinity. Over simplification is usually done by those that do not do much actual hands on testing and A/Bing......mostly just guessing...and that includes manufactures, as well. I mean, how much time does anyone have to really research something? High end audio is mostly the blind leading the blind.....he he. In drag racing everyone knows what works......this is why dragsters all look the same, as if one person makes them all. This is because there are only 5 things to consider when making a dragster (performance wise).....horsepower, weight, drag, traction and gearing......and the performance can be measured by a clock. No one really knows why a certain piece of wire put in a certain direction would make a sonic change......and that is just one if the infinite possibilities of sonic change. This is why there are tons of amps, including class D and at every price point and they all sound different (and always will)......and sometimes the cheaper one is better. However, one thing is for sure. If you spend enough time doing serious listening tests than you can figure out a lot of ways to lower audible distortion. |
I brought my first proto of the mono IceEdge amps over to a guys house last year and we A/Bed it with his mono IceEdge amps from Mivera Audio. When we were listening to his amp the sound of the bass was rather "tubey" and I told him so. He said he liked that sound. However, when we put my super modded monsters in (same module with the same output stage with the same damping factor).....the bass now was way tighter and better and he remarked as such....he liked it much better with my amps. There were so many things different about the amps.....not just all my mods but different platform and feet. No one ever thought my super modded IceEdge amp was overdamped or dry sounding......espeically once I did the last 7 mods.......which is what I released and what Tweak 1 has. Not saying that it is as liquid as tubes or whatever.......just another perspective. Here is a link to a review by Herb Reichert......about his experience with the Harbeth 30.2.....He found no dry overdamped sound from the Bel-Canto amps Ncore based amps......though he did like the liquidity of tubes best. https://www.stereophile.com/content/harbeth-monitor-302-40th-anniversary-edition-loudspeaker-page-2 However, enter a zero feedback input stage Purifi amp and now Herb thinks the Bel-Canto is dry. https://www.stereophile.com/content/lkv-veros-pwr-power-amplifier-page-2 By the way, the Bel-Canto amps he has are simply stock NC500s with the stock switching supply from Hypex and an op amp for a buffer on the input....very basic...and way overpriced. You can buy a pair of mono blocks from VTV with the same configuration for $1300 delivered......Bel-Canto Ref 600s were $6K!!!!! https://www.audiosciencereview.com/forum/index.php?threads/review-and-measurements-of-purifi-1et400a... Scroll down a little and you will see the insides of the ref 600s Both the Bel Canto and the LKV use stock super low output impedance Ncore or Purifi modules. You should hear my modded Purifi modules with air core coils and super caps oriented correctly and modded Wima bypasses.....and with all the other mods too! So many ways to change things. Never ending fun! BTW, I can modifiy Purifi modules in your LKV or whatever amp.....and do other mods, as well. |
Thank you for sharing your experience. And thank you for realizing that you are just guessing. You actually have no idea.....that your theory about damping factor and class D has any meaning. You would have to get every class A amp that exists and every class d amp that exists and drive your subs and also your main speakers and see what you hear. Then you MIGHT have some actual real information. Every class D amp sounds different....including in the bass (my direct experience). Maybe adding great subs to any system will always get you better decay.....everywhere. Just as adding a supertweeter can make the bass better. So, what are you hearing? Without doing extensive experiments we are just a bunch of guessers. There is very little real information shared anywhere about how audio actually works. It is basically every man for himself. There are SOOOOOOOOOOOO many things that change the sound. Unless you account for every variable.....you know very little. I have spent over 40 years doing listening tests......and I know some things.....but really what I know....is that I know NOTHING! It is infinite. In drag racing there are only 5 things that make for performance......horsepower, weight, drag, traction and gearing. And all this can be measured by the clock. This is why dragsters all look the same......like the same person built them all. Everything is known in drag racing. Audio is the opposite. Nothing is known. All brands of solder sound different.....you cannot measure it....you have to listen....every wire, every resistor brand, on and on into infinity. Most things that make a sonic difference cannot be measured. I brought a proto of an amp I sold last year to someones house and A/Bed the amp versus his. Both his and my amps used IceEdge 1200as modules in mono blocks. Mine was modded....his was not. Both had the same damping factor and power as I did not change the feedback or output stage. His amp sounded "tubey" in the bass.....my amp sounded way faster, and cleaner and preferable by him and me. Damping factor is just one of tons of things that can affect bass performance. I am not saying that we should not share our guesses.....it is fun. The trouble is, that most state things like what you said but leave out the part that you have limited knowledge and its a guess. So, it is stated as "class d amps have zero decay in the bass....they are overdamped".......Then the rest of us just repeat this on other forums till everyone thinks the same thing. The blind leading the blind. Words are very powerful. Thank you for your intelligent use of words. The best words are those that uplift us. For we all want to be happy. Share uplifting words and deeds with everyone....we all win that way. May you all be happy and joyful this season and always. |
About the IceEdge 1200 AS1 modules in the PS Audio and the amps I made last year: I measured them at 2 ohms of 1000 watts......200 watts below what it does into 4 ohms......yet Michael Fremer says it drives the Wilson’s very well? I have not read the review yet. OH NO, this cannot be. George will never talk to us again. Michael just destroyed his "class D cannot drive Wilsons" nonsense that he as been spouting for years. He screams.....but it does not double its power into 2 ohms......it cannot possibly drive a Wilson......ha ha ha......So, i guess 1000 watts into 2 ohms is enough after all. |
If all you have heard is a stock Bel Canto Ref 600.....then you have no idea how good the latest class D is. The Ref 600s use a stock Hypex power supply, a stock Hypex NC500 module and an input buffer that is an integrated circuit powered by two three pin regulators.......and this is for $6K per pair. Now, Bel Canto has updated this amp (now called an e1x)) to make it a stereo amp using the same stock NC500 modules and a single Hypex power supply but finally they made their own discrete front end buffer for the amp......this amp is also $6K and you can read a review (that is completely worthless) on Stereophile. Let’s look at what VTV does....They will sell you a stereo amp with two Purifi modules (slightly better than the NC500s), a single Hypex power supply and their own discrete input buffer board with say Sparko Labs discrete buffers.........basically the same configuration as Bel Canto and the cost is $1500 delivered (including shipping) and 30 day money back. One quarter the price!!!! My modifications to the VTV amp cost $1050 bringing a totally tweaked Purifi based amp to $2600......less than half of Bel Cantos latest thang. The mods completely transform the amp. I actually mod the Purifi board (change the output coils to super OFC air core coils, use better caps on the output filter and bypass the power supply with modified Wima caps). Bruno is just one of many people who are pushing class D further. The Merrill amps, the AGD amps, the new Technics amps ($10K pure digital integrated coming early next year...OMG!...check it out!), the Cherry amps, New Class D amps, etc. etc. are all fantastic sounding and completely designed by other people. The Purifi module is not "pure" sounding. My mods make it way more "pure". This game goes on and on. As these latest amps (and about to be released amps) get out for more people to hear then the reality of what class D is doing now will finally be known. I will be sending out one of my modded VTV/Purifi amps on tour......so get in line to see what is possible. Class D is coming of age. Some are still too expensive for most (like the Merrill and AGD amps).......but my modded Purifi and soon others at $3K or less is what we need. The (to be released in Feb.) pure digital class D Technics integrated at $10K...is a preamp, amp, DAC and phono stage with wild distortion reducing stuff in it......so, it is really not that expensive (and you save space, have only one power cord, and no interconnects). |
"Real Audiophiles?" Who is to judge that? Audio is every man for himself. There is no criteria for who has the best sound, or how to achieve it.....as it is all subjective.......the opposite of drag racing.....where most everything is known by everyone and tested by clocks. Best to not rely on ANY one persons opinion.......but base your truth on your own direct experience. All amps that measure the same sound different....all speakers that measure the same sound different......which do YOU prefer? That is what matters....... |
There is no perfect "Class". All amps sound different....no matter what the class of amplification is. All classes are imperfect. All need tweaking. If this were not true then we would be all using 1977 Pioneer receivers. Everything has gotten better.....all classes are improving. A great class A is great......a great class D is great. A not so good class A is not so good. A not so good class D is not so good. Every single thing needs to be done at a super level. I have never seen an amp that I could not improve. Just the binding post bypass system will improve any amp. There is no end. We have only just begun....enjoy the ride! |
Usually statements like these are made by people who do not like tweaking. So they make something silly up. The power supply in that amp is way away from the back panel. The power supply (a switching one) is completely self protecting......it shuts off if there is over current/over voltage, too high of temperature, DC offset, etc.. Also there is a fuse on the power supply. There is no "fire hazard".....same with having cotton covered wires inside. If you don't understand or like something....then attack it......the ego says. The heart says....what does this do? Maybe I don't know everything. Maybe I should keep my mind open till I have tested this with my ears. |
A catastrophic event ..he he... is when you win the super duper lotto. That is about the same odds as a wooden backed amp has catching fire. When have you heard of an amp that caught on fire? (I have read about 2 in over 50 years....and no bodies house burned down).. And if it did.......did it have wood on it? The answer to the above is practically never and never. We worry about silly things. By the way, fuses do not help with lightning.....the fuse blows and so does your component. Maybe you mean putting a bomb in the amp? That certainly would be catastrophic. Maybe we can get back to how various amps sound instead of worrying about a wooden back plate. People have different philosophies about what is safe.......some would never do anything without someone else telling them it was safe. Some rely on their own intelligence. Some hide in caves.....some dance in the light. Fear and ignorance is what keeps people from being happy. Trust your self....and dance in joy! |
