So, from the previous thread about high-end class D the Purifi module was brought up. I decided to get a cheap example from VTV, a simple stereo unit with a single Purifi module and matching Hypex SMPS. Standard input buffer. I got it in yesterday. First impression wasn't what I was expecting: weak, congested dynamics is what stood out to me. I expected greater expression through my ProAc D30Rs. The other problems such as poor soundstage, thin / boring character, etc, I marked up to needing burn-in before evaluating. So it's been 24 hours, I would still expect to get at least the high control / damping of high end class D and dynamic power, but it's just not present.
Could it be an impedance mismatch? Other manufacturers selling the Purifi with their custom input buffers are reporting 47k Ohms. VTV doesn't say in the manual or on the site. I checked the Purifi data sheet which reports...2.2k Ohms on SE???? That can't be right?? That's absurdly low! Am I reading the right spec? My preamp has an output impedance of 230 Ohms. Can someone confirm that the stock Purifi has this ultra-low input impedance?
Most high end companies choose parts and execution by ear after they have done the measurement game. This is because they know that a ton of stuff that changes the sound cannot be measured.
Here is a list of companies that do this.....George would call them Snake oilers......but he won't: NONE of these companies shows measurements before and after changing parts and execution.....NONE.
1. Wilson Audio 2. Audio Research 3. Gryphon Audio 4, Constellation Audio 5. Parasound (designed by John Curl...who uses parts for their sound) 6. Magico 7. Kef 8. Odyssey 9. VAC 10. Von Schweikert Audio 11. Rowland Audio 12. Merrill Audio (used Synergistic fuses in older amp) 13. GR Research 14. Spatial Audio 15. etc. into infinity
Almost all tube manufacturers....they pick caps, etc. by ear....and they don't measure any different.
Almost all cable manufacturers
Most equipment stand manufacturers......I mean, can you measure a better stand?
There are companies that do little parts tweaking like Pass, Cherry Audio, Schitt, etc. However, there are more that tweak than do not....by far. Please George, call all these high end companies out. Let them know you will never listen to another Wilson speaker, etc. until they show measurements that confirm their sonic pickings......Go, George......do your duty.
Don’t try to flip this, to another direction, your the only one here on this thread.
I have the highest respect for those companies. (except for one that bridges his stereo amps into monoblocks and claims them as better performing amps), measurements/tests will call them out as lower performing, with one only plus of higher wattage.
BTW this statement of yours a couple of posts back, another bit of............? It flows forth like the Nile.
It is best just to ignore George. Let him have the last word or it will go on forever
Maybe we should use a new word for people like this. How about Anti Snake Oiler or ASO.
@ricevs , that is a good one :-). Assuming that george is the biggest ASO and he complains on fuses and other stuff like modding. But what surprises me is the -ve bias against Purifi and other class D modules that have come up recently. The folks on ASR have shown with measurements how good the Purifi module is and the potentials it has. Subjectivists and objectivists both agree on this one. It looks like he has "personal" agenda/motive against Class D. The only thing I could think of is that maybe Class D amps do not gel very well with his attenuators and hence is trying to discredit them? Not sure. Beats me.Well known designers still have to make a living and not run a charity. Why would they promote other designs over their own? And the quotes that they made, which george often mentions, are from "how long ago"? Technology changes, so we should see improvements in the new Class D amps, compared to the ones from a few years ago.
Almost all tube manufacturers....they pick caps, etc. by ear....and they don't measure any different.
This statement is false- they do indeed measure differently (whether some companies bother to measure the differences is a different matter). We use custom made resistors as well (made by Caddock); they sound better but they also measure better.
Most equipment stand manufacturers......I mean, can you measure a better stand?
Certainly! Sound Anchors was measuring the differences in performance of their stands 30 years ago. Its not hard.
More like calling you out, on your snake oil mods, that you don’t backup
with any measurements, just a fusers "trust me it works"
Its easy enough to measure the effects of a fuse, and the different fuses. Its not rocket science either. All you need is a DVM. Having said that I'm personally not a fan of boutique fuses. At least one of them uses a Teflon tube to 'damp' the fuse element. The problem is the fuse actually has to blow in order to protect; this type of fuse can have the metal of the fuse element go liquid and finally to a plasma state simply because of that Teflon tubing in which its held. Such a fuse will not reliably fail at its rating, and thus we don't recommend them.
Its easy enough to measure the effects of a fuse, and the different
fuses. Its not rocket science either. All you need is a DVM.
Hi @atmasphere
Can you illuminate me on what types of differences, among equally rated and types of fuses you have encountered? How precise did the DVM have to be for you to measure it, and what qualities do you look for?
I am sure that changing a part here and there could change a measurement. However, this us not the usual case. You can take 10 different brands of normal metal film resistors and they will all measure the same.....and all sound different (I have done this).......maybe a non inductive Vishay or Caddock could change a measurement....but most things cannot.....and this includes brands of solder.....that also....all sound different. Yes, there are certain measurements you can do with a component stand that will be measurable.....However, there are no agreements as to which measurements mean what sonically and which component stand sounds best with which component. In fact, some people prefer to "add certain natural resonances.....to enhance the sound" Fuses all sound different and you cannot measure all the sonic differences with a meter of any kind. The only meter that matters is your ears. I have never seen anyone state that good film caps measure differently (certainly, ceramic,Tantalum and Electrolytics should never be used in the signal path).......yet all types and brands of film caps sound different. Please, use your ears.
Here is a good one. I bypassed a fuse with a 12 gauge wire soldered across the fuse solder on its inside bottom (fuse holder was a board mount fuse jobbie). It made an impressive improvement over the stock fuse. However, the tabs that normally would hold the fuse up slightly in the air were still sitting there......and I figured they might be adding some resonance. So I broke off these 4 tabs and the sound was noticeably improved. Measure that!!!!! This game is not simple....it is infinite....enjoy the infinite.....it is all there is......and it is infinite love and joy.
Here is another good one. Years ago it was said the Nichrome thin film surface mount resistors were the bomb. So, I bought 4 different one eight watt 75 ohm resistors from Mouser and tried them on the output of a low jitter clock. These things are so tiny you can hardly see them.....and they all look the same except for color. But all four brands sounded different.....one being way bad and one being way good. I still use the way good one today.....but now I use the quarter watt versions and parallel them for best sound. Did i say this game in infinite? Cannot say it enough.
I am sure that changing a part here and there could change a measurement. However, this us not the usual case.
What is it with people feeling its okay to pontificate and lecture about things they clearly haven't the foggiest about? To an audience chock full of people who do?
Ralph has more experience in his little finger but even I have enough to know its darn near the OPPOSITE of what this ricevs guy is saying. First swap I ever did was a diode, just a dumb little $8 hexfred, and the improvement was massive! Changed caps- huge. Fuse- ditto. On and on.
Actually did these things. Actually heard these differences. Just a suggestion ricevs, but I really do think what you should do for at least a while, every time you're all set to start blathering about that which you have no actual experience or knowledge of, type the words, "Of course I have no clue if this is right or not because I haven't done anything even close to this before but...." and then type away.
ricevs Almost all tube manufacturers....they pick caps, etc. by ear....and they don't measure any different.
atmasphere
This statement is false- they do indeed measure differently (whether some companies bother to measure the differences is a different matter). We use custom made resistors as well (made by Caddock); they sound better but they also measure better.
I couldn't agree more (wow that's one for the books) Any manufacturer/designer or modder worth his salt, will use all the EE laws at hand to design, then build/measure/bench-test and listen. And if they don't like it, they change things using all the EE laws/measure/bench-test again and listen once again till they get it right. Any fool that say otherwise is a hoax and a snake oiler.
Miller, I do not understand what you are saying to me. I am the one saying everything makes a difference and I have been doing listening tests for over 40 years. I do know what I am saying because I EXPERIENCED it, just like you did. Maybe you are confusing me with someone else. I am confused by your comments above......maybe you are confused. Check out my website...you will see how crazy I am..... he he.
BTW, what you quoted from me is true. I am not talking about changing a transistor or tube or making a circuit change. I am talking about changing a brand of solder, wire, resistor, cap, etc. to a different brand and measuring a difference. For the most part, you cannot measure the difference between different brands of solder/parts.....that is the truth. measurement wise.
Can you illuminate me on what types of differences, among equally rated
and types of fuses you have encountered? How precise did the DVM have
to be for you to measure it, and what qualities do you look for?
The voltage drop across the fuse varies. The better sounding fuses correspond with the least voltage drop ('better sounding' doesn't always correlate to 'boutique', just to be clear). I use a Fluke DVM that's 3 1/2 digits. Like I said, its not rocket science. I prefer to use Littlefuse or Bussman.
These are what I recommend and use, for those that don't know, these are quality fuses around 50cent. Not $150+🤦♂️
Remember change your old fuses that have see too many turn on cycles, especially on amps
Just change the fuse if old for a quality brand EE industry standard 50c fuse, as fuses (even the snake oil ones) do age after many turn on cycle surges.
I have never heard a Bussman or Littlefuse sound anywhere near as good as any boutique fuse. Please people use your ears. It is not just resistance that the fuse gives. There are non linearities in all materials and resonances. Fuses can measure exactly the same "voltage drop" and sound worlds different....please listen. Do not believe me or anyone....believe your own ears. Make up your own mind. Do not be a follower of people. Be a leader....a live...er....a knower.
One thing for sure you are right about: cheap OEM fuses are not anywhere near as good. But I fear your irrefutable info has run into an immovable object in George.
Greetings from New Zealand! Hope you're all keeping safe n well!
Seems like another derailed subject!
I'm extreamly happy with my March audio P451 Purifi class D monoblocks! They Definately blew away my Naim NAP250 amp by a huge margin. But hey, what do I know? We all hear differently and all have different preferences.
I can however back up lots of very positive reviews raving about modern class D power amplifiers. I'm a total convert, MERRY CHRISTMAS!
there are plenty of happy owners who trusted ricevs. GFi, is butthurt that ricevs continues to back him into corners with no way out, except to, well, be Gfi
In regards to the Naim, I have a Chinese clone of the NAP200. It doesn't sound as good as I recalled hearing from a dealer but that was a few years ago...and might have been one of the integrated now that I think of it...anyway I haven't tested that against the VTV yet. In fact the Purifi is due for another listen.
I’ve repaired a few Naim 250’s, the best was the first model with regulated rails back in the 80-90’s and they weren’t that good, they all oscillate at a drop of the hat, don’t think it would take much to beat them. If fact Naim dealers warned against putting them together with Quad ESL’s. And in the 80's Tocord speaker cable made them blow their guts.
The horrible midrange seems to have mostly solved itself. That's good. There is still a smearing / lack of resolution when things get busy. Midrange sounds -- instruments, voices -- still don't sound really convincing. Another troublesome aspect is that I don't seem particularly interested in long listening sessions. Lack of engagement. This could be a sign of a general lack of euphony which is the kiss of death of anything in my system.
Imaging and soundstage has improved since the early days, but it's still not really convincing.
Bass however has improved to the point that I'd usually associate with class D. Dynamics have also improved to a level I'd call satisfactory.
Next step I think I'll contact VTV and ask about what changes the input board and buffer options may have. Perhaps a double power supply model will help. If some combination can help midrange I may try that.
Since you went to great lengths in your other thread to dismiss ALL Class D amps as junk, why do you keep kicking yourself in the nuts by continually testing these devices?
Because I’m not a cultist who’s made up my mind forever. It’s not a religion to me. If someone with experiences I don’t have relates those experiences the only way I’ll know for sure is to try it myself. It IS true that some high-end manufacturers are making class D amps, so MAYBE there’s something to them afterall. Maybe all my experiences up until now didn’t cover what class D is capable of. That’s why I’m doing this.
Now, are YOU willing to admit that, perhaps, class D is inherently flawed and that is the reason why you’re not motivated to listen to your class D system? Would you be willing to try a good linear amp to find out?
I don't have a Class D system so I would not dismiss them out of hand. I left the high end 25 years ago, Meitner, Audible Illusions 3A etc.because none of it sounded close to the Symphonic band I played in for five years.
So, at the mention of the brand Purifi in the beginning of this thread I thought for sure the poster would be discussing this...
”Specifically, HybridDigital Purifi Eigentakt amplification, a game-changing Class D technology (Eigentakt means “self-clocking” in German) that produces ultra-low distortion regardless of frequency or load.”
I’m admittedly very new to this hobby, but it seems like the poster purposely choose the lowest common (Purifi) denominator to speak about, as opposed to their newest and best.
Anotherbob is confused. The Purifi module has a nickname of Eigentakt. That is all. They are one in the same. Bruno’s last version of his amp circuit was called Ncore and is manufactured by Hypex. When he formed his own company he needed a new name for his latest version of his amp (so he used this German word for his new circuit).....therefore Purifi is the name of his company and Eigentakt is the nickname or name of the Purifi module that this thread is about. Most people, including myself, refer to the Purifi module as the "Purifi module" (no Eigens mentioned).....hence some peoples confusion. https://purifi-audio.com/eigentakt/
I keep repeating that all Purifi based amps will sound different. It is not a magic bullet.....no one thing is. Just another class D circuit that sounds slightly better than the NC500 but can be tweaked to sound really fantastic.
There is a more powerful Purifi module under development. After it comes out we will probably then be saying ET400 or ET700 or 1200 or whatever it is to differentiate between the two. Right now there is just the one and only Purifi module (1ET400A......which stands for Eikentakt circuit with 400 watts/mono amp).
Hi: I am the top 3 in the list, ¡¡¡ Just retired general thoraxic surgeon,with 77 years old.And where are the other old people? Only alcohol,drugs,sex or ,,, Thanks for all yours input and questions
ricevs: In further reading on this subject it appears that there is no “nickname” for the amp under discussion, it is THE name, as it is referred to that everywhere I’ve looked. You sir, are the one confused on this point. Why you conveniently left the actual name of the amp out is anyone’s guess.
In reading the test reports on this amp it is consistently rated very high, some calling it revolutionary or a game changer. Inaudible distortion and zero amp coloration of the sound, pretty much what most would consider a perfect amp to be. Clearly there’s more versions with higher power on the way.
Maybe I should have put "nickname" in quotes....I was just letting you know that the Purifi module and the Eigentakt module are one in the same. You notice the name of this thread.....does not say Eigentakt. No biggie.
What is important and that most don’t realize.....and I am repeating....is that the Purifi module is not perfect....it has a sound.....it does have a color....it does not have zero amp coloration.....nothing does. I modifiy the Purifi module and my mods allow much better sound.......I am not talking about a different input buffer, etc. I actually modify the module by changing the output coil, the caps to ground on the output and bypassing the main high voltage power supply with modified Wima caps. These mods do not change the circuit, nor any measurement worth noting. The Purifi module is not the Golden Goose, Golden Egg, silver bullet or whatever, just another step better than the NC500....the last Bruno circuit. There will be plenty of better circuits down the line....sorry guys....this is what is real. However, the Purifi module modded along with the whole amp modded will blow your mind. But next year, there will be something better.....as always. There is no "End Game" in audio......audio is infinite.
I communicated with the owner of VTV about what I've experienced so far and about the upgrade options. He said that he hasn't experienced what I have -- that tells me that his standards for audio quality may be lower than mine. He did mention that the tubed input board makes a big difference to sound stage and so can different opamp options. It seems that the various discrete opamps are more about coloration / tone, is that true? The worst problems I described at the start of this evaluation have mostly solved themselves with burn-in. Improved dynamics and soundstage won't make or break the sound, but the midrange is problematic. What do I mean by this?
Take a piano or a horn. Does it sound like an acoustic piano or could you mistake it for a synth? Does a horn sound like a believable, real horn? Would the better opamps fix this? Why does the standard Purifi opamp which is supposedly very low distortion fail to handle this? The Odyssey I'm comparing this to is by no means an especially high-end amp. It has a lot of current delivery and bandwidth, uses the good Symphonic Line parts, but otherwise appears to be pretty simple design. I busted the newer Stratos even further trying to fix it, now one channel doesn't work at all. The old Stratos I have is too inferior. I went and bought another used Odessey, a high-end Kismet that's only 3 years old. This should out-perform my Stratos and it'll be interesting to compare it with the VTV.
So how bad IS the standard Purifi in the VTV? Will the upgraded input board and discrete opamps move it to another level? Obviously the manufacturer won't say "yeah the base model sucks".
Another interesting finding. I decided to swap out my reference power delivery to the amp: LessLoss level 1 power filtering cable + Firewall 64x from a Furutech GTX-D(r) NCF outlet to a standard black 14-guage power chord from a standard outlet. The difference on one test track was...almost nothing. Maybe the it was a touch muted / muffled on the standard cable, but nothing you couldn't chalk up to audio memory effects. This hasn't been my experience with my linear amps. I wonder if the switching power supply is just agnostic to mains quality -- or it's already so messed up the mains quality won't make a difference?
Okay...I'm done with this amp. I tried listening to King Crimson's Larks' Tongues in Aspic, and right on the first track the part with the rattler/shaker percussion thing...it doesn't sound like an actual instrument but like a diffuse low-resolution jumble of tones, like the percussions were blurred beyond recognition. It's been plenty burned in at this point. Earlier I had emailed VTV asking about this poor midrange performance and the response basically said he hasn't experienced that problem.
I mean...look. If you don't think THAT'S a problem, if THAT sounds fine to you, then I have no business considering this amp any further...right? If it was "oh yes this or that option improves things" than okay maybe it would be still worth considering. New opamps aren't going to fix it, there's no reason to believe they will. Besides this...the almost complete lack of engagement and boredom with the sound isn't going away. It's not about harmonics, I think the Purifi does a "good" job with returning the normal even order harmonic information you'd expect to hear. Is it the trashy midrange which is doing this and my mind is simply rejecting it? Class D distortion?
I'm told that this isn't a real trial because...I'm not using the little custom input board with discrete opamp? Really? Will that REALLY have such a major impact on the sound to transform it from awful to good? Why would Purifi release a bad-sounding input stage? Are they deaf? I think I've given it an ample chance. Any disagreement?
My thought is the following. At $979, the VTV Purifi with Hypex buffers is by far the lowest price Purifi stereo amp on the market. Everybody else is selling Purifi stereo amps in the range of $1400 and above, and only with custom buffers. Presumably nobody else wants to offer the Hypex buffer because it is a poor match for Purifi. If you upgrade the VTV with custom buffers, then the price jumps up to $1400 and more, making it similar to the rest of the market. So the $979 price is only there to attract attention and bargain hunters, even if the Hypex board doesn't work well with Purifi.
It's a little surprising that Purifi would release a compromised product to the public to represent their brand. I guess I'll look into a input upgrade then. It's just there's no way anyone with any kind of good amp experience would think this is fine, forget about great.
To be fair, Purifi does not sell their module with this input buffer. In fact, they don't sell their products to the public at all except to the DIY community. The amp you bought includes a buffer that wasn't even designed with the Purifi module in mind.
Purifi expects that their OEM customers will add value to their module by designing proprietary power supplies, input buffers, and other logic and circuitry. The NAD M33 or the LKV Veros are more the kind of products they envision, or at least the VTV with their tube input buffer.
Amplifiers built with the Purifi module are only going to be as good as the sum of its parts, like any other electronic product. If you build the amp with an entry-level power supply and the cheapest possible input buffer, it's not going to be an good indicator of what the module is capable of.
Yes, to echo the above. The input board you have in your VTV is the Hypex eval board that was originally for the NC500 module. Purifi has also made an input buffer board (both stereo and mono) that uses different regulators, op amps, etc. Warren at VTV is now going to sell those, as well. However, the Purifi one won’t sound as good as the VTV custom input board with discrete op amps......but, of course, there is lots of other things you can do to improve the sound. What you have is the least good sounding Purifi version that anyone can buy.
Even a dual mono VTV with the VTV custom input buffer boards using the best buffers will not give the best sound. There is much more to be gotten from tweaking everywhere. You cannot do this at this price point. It is all plug and play at the $1500/$2000 level.
I do not believe that VTV offers the Eval 1 and 2 buffers, and nor have I seen any other vendors offer amplifiers with Purifi Eval buffers. On Purifi's order pages, they do not sell the Eval boards separately (only in kits combined with 1ET400A modules).
This thread is a great example of why I chose many years ago to avoid DIY. How many ways does one wish to swim in the quicksand of slippery standards of sound quality, with no assurance of a result with actual great sound? I'll give the manufacturers their due; it's a lot better than wasting my life/time/money building a mediocre components that are not worth hearing.
It didn't take genius to see that the amp, speaker, etc. kits all have fundamental caveats. You don't get superb on the cheap. The odds you will make huge mistakes are very high, as evidenced in the thread here. So, you spend your days slaving over a build that ends up an also ran. Not my idea of how I want to spend my audiophile life. Maybe if I was thrilled to look at circuits, it would be fun. But, what fun is it when the sound is so-so? I'm not into this to see how good I can make cheap audio. That's all but assurance that one plays in the shallower end of the pool.
Kudos to those who want to play in DIY for the learning, for the fun of it. But, that's not me. I can't stand compromised sound, and I won't accept it long term. If it can't perform at a high level, then pride of build/DIY doesn't matter. Same with vintage; can't take it, as the sound quality is just not there typically. It's cheaper, it's nostalgic, but it's nowhere near great.
What's interesting here, too, is how many times people have tried to tell the OP that he's missing things, but the self-confidence and skepticism is off the charts. No wonder he'll not build a superior amp. Having used discrete opamps rolling into the EE Minimax DACS, I know firsthand how they can contour everything related to the sound, not only tonality. The OP is hard core skeptical, so it's not surprising to me he can't get the amp to work great. This should be a cautionary tale for those who tend to "think" what should or should not work. This is a perfect example of how theory on the cheap doesn't build great components - or systems.
This site has become rife with people like this; really proud of their objectivist perspective, and declarative of what should or should not work. Only one problem; it doesn't build superior systems, it builds average systems, nothing worth writing home about.
It reminds me of some of the industry members, manufacturers, with the same attitude, very skeptical of anything other than what they consider to be supported by theory. They tend to build to spec, with the cheapest parts that should do the job competently. These are not the best components on the market. They serve a purpose for the lower cost audiophile, but there is significant compromise to them sonically. These components over many iterations of systems never rise to the top; they never best superior gear with higher quality build and methods.
@douglas_schroeder - I don't think you read this thread very carefully. This isn't about DIY (although I don't personally share your skepticism about DIY). The OP purchased a commercial product using the Purifi module, a basic SMPS and cheap input buffer, and is blaming the Purifi module for its disappointing sound quality instead of the surrounding parts and overall design.
That's like saying all DACs that use the ESS9038 are crap because a $79 AliExpress special sounded mediocre.
I talked to Warren at VTV last week and he told me he has the Purifi eval boards coming in. He told me that he would sell it even cheaper than the Hypex boards because he was not going to use any input or output connectors.....just what is on the eval board. He will have a smaller chassis that will fit the eval board perfectly. The Purifi eval board version would be something like $50 less than what the Hypex board one is. A lot of people told him they wanted the Purifi input board....so that is why he is doing this. This "Purifi input buffer board" version will never be able to be upgraded to the custom VTV input buffer boards (that use discrete op amps).....Again, this is for people who want the cheapest thing possible and do not want to upgrade, ever. Basically, this will be very close to the eval. amps that Purifi sent out.....but for way less money than you can even assemble them yourself by buying the parts from Purifi, Hypex and chassis from China, etc.
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