Removing a ZERO from the price of amps

I mentioned a quote from Bruno on Computer Audiophile interview about a year ago saying the goal of Purifi is to remove a ZERO from the price of amps. Sounded very exciting a year ago and we are now getting close to getting this out to consumers.

A Benchmark AHB2 and one of these Purifi amps for me please.
I think that's true or should be. We've been working on a class D amp of our own for the last three years. We don't expect it to be particularly pricey- so far its looking like it might be the least expensive amp we make.
Smaller and more powerful, yet also more manageable and cost effective (but still top notch sound) is the unique value proposition of Class D technology.

Not bloating Class D into just another over-built or merely just uber expensive high end audio product......

Products that achieve this keep coming as the technology continues to gel.
Don't forget the Mytek Brooklyn Amp, among many other tiny, powerful Class D offerings.

I haven't heard it, but if Mytek wants to send me one for review... I'll be happy to write it up.
They can send me one too while they are at it.  :^)

I would compare to my current Bel Canto Ref1000m amps that have twice the juice but were also twice the cost retail.

Post removed 
Doug Schneider says:

I found that the Eigentakt was not only powerful enough to drive the A1s -- it sounded as good as the Constellations. As I wrote in my review, “almost nothing about the A1s’ sound had changed -- the tonal balance was the same, the highs were just as extended and the midrange just as pure, voices were equally robust, bass just as extended, and the soundstaging and imaging were exactly as before.” What’s more, I also thought that if there were any differences in the sounds, they “were at best slight and, surprisingly, favored the Purifi.”

Wow, when I read this it made me do a bunch of research on the PURIFI amplifier modules.    The Audio Science Review of them is here  and is also very positive.

It is very tempting to try these, although so far I only see mostly boutique brands selling them.   NAD has announced they plan to create a next generation amplifier platform using them.

The Purifi amps seem almost as good spec wise as the AHB2. However, based on Schneider’s description the Purifi seems to sound better than the AHB2 (which I will get).

When I heard Bruno et al say last year that their goal was to remove a zero from the price of an amp I made sure I kept my eye out for any amps with this Purifi module. I was disappointed that the only one I saw was the busy looking NAD. I heard a non-Purifi NAD amp last year that was simple, clean and sounding good for the price. I was hoping they would use the Purifi module in something like that instead of the jack of all trades version they put it in.

I would also be interested to see how Bruno’s new creation stacks up against the new-ish GAN amps.
While Class-D obviously brings the cost down by eliminating large heat sinks, the other big cost saver is using a switch-mode power supply as opposed to a big linear power supply. In these big A/AB amplifiers massive linear power suppliers are the majority of the cost.
Sucks they didn't just make a pure amp so we can see how it really competes against high end class A And AB amps.

Wondering if the A1’s big, weighty sound had anything to do with the huge and hugely expensive Constellation Revelation Taurus monoblocks, I switched to the Purifi evaluation amp, which offers less than half the power: 200Wpc into 8 ohms.

Thank you for the interest in our class-d amplifier technology.

There is a thread on audiosceincereview listing possible suppliers:

Bedst Regards

Kim Nordtorp Madsen
+45 50577994

Purifi ApS
Ledreborg Alle 118D
4000 Roskilde

I listened to the first part of Bruno’s interview. There is some truth to what he is saying........but, tons of things that affect sound cannot be measured. For instance, I just changed 4 inches of Hypex cable on the input of a Purifi based amp I have here to my own custom cable. The sound difference is huge, but the amp would not measure any different. Nord and Apollon claim their (not quite as good measuring) NC1200 based amps sound better than their Purifi based amps. A guy on Whats Best Forum has two amps from Nord done pretty much the same set of monos with the Purifi and the other with the NC500s.....he does say the Purifi is a little better but whatever op amp you put into the modules makes way more difference than the modules......and I bet swapping the input wire would be the same.

A great measuring amp is a good place to start.....but every Purifi based amp will sound different....because everyone will use different jacks, wire, solder, input stages, regulators for the input stages....passive parts in circuit, layout, AC jacks, fusing, infinity.

I am finishing up mods to Purifi based amps, right now. A part of my mod is to modify the Purifi module. No one has ever modded an NCore or Purifi module to my knowledge....they just add their own input stage. There are parts on the Ncore and Purifi modules that add audible distortion (not measurable). Putting lower audible distortion parts (and execution) here changes the sound to a more detailed and real sound. I will have more info shortly.....with very explicit details.
The Audiosciencereview cult......he he...believes in measurements only. They don’t think anything else know...wire is wire....stock fuses are fine.....any kind of connector is ok.....who cares about resonances....etc. etc.

I believe everything makes a sonic difference.......So I am in the "snake oil pusher" dept....according to them. According to me they are in the "Ostrich with head in I cannot hear anything" dept.

The old Objectivist versus Subjectivist game. Old as Audio itself. I just don’t understand why the objectivists don’t just get a 1977 Pioneer receiver and be done with it. Why do they even bother posting about anything....or investigating anything since they think nothing matters except numbers?......We humans are a hoot.

Every implementation of the Purifi module will sound different.....yet measure the same.....this is the truth.....truth is not what Audiosciencereview is about. They are about a point of view. Truth in audio is what you HEAR. Audiophile means lover of Measureitophile means lover of measurements. Two different kinds of points of view.

I think measurements are fine. They can indicate some audible differences......however, there are an infinite number of other things that determine audible differences. If you only measure, then you are not playing with the whole deck.  You are just playing with one card.  Really, not much fun!
Actually ricevs I do not only go by measurements. The AHB2 is something I owned before and know will sound good. The Purifi stuff is so new that I have no trust in it yet. I will wait and see what consensus is reached on what is considered good Purifi gear before I plunk money on it. The ASR site is helpful to learn about all the crappy Purifi builds that are out there at the moment. I am interested in a company out of Australia, who have a Purifi amp, called March Audio they maybe better than the pack.

Most of the people posting on the ASR link I shared recommended certain Purifi gear over the AHB2 based on better measurements (specifically watts) and better price of the Purifi. I am choosing the AHB2 today based on how it sounded to me when I owned it a few years ago. I posted the link because there are people like me comparing the Purifi amps with the Benchmark AHB2.

If Bruno were to sell his prototype Purifi amps I would be interested in those today but I will wait until version 2.0 before I look at other Purifi builds. In the specific case of Purifi, the ASR web site was very helpful in showing me why I am correct in this thinking (nothing to do with measurements).
I am glad you trust your ears. However, the March guy is a "nothing makes a difference except measurements" kind of guy. He argues against discrete op amps (those of us who listen know the OPA1612/LM4562 are good op amps but cannot compare SONICALLY to the best discrete op amps). IE....his amps are the worst sounding of the pack. The AudioScience guys go crazy over non meaning supposed wiring errors. They obsess over nothing because there is very little to look at because it is all measurements to them and other science based thoughts (like how pin one on an xlr is grounded). Meaningless drivel. They do not listen and compare. Every single mod I do to a Purifi based amp changes the sound (and to me, makes it sound better).

The measurements of the Benchmark and Purifi are so close it is a wash.  However, there are tons of things you could do to each amp to improve the sound.....non of which will change the measurements.  Check out 10 audio.  Jerry reviewed the Benchmark and loved it.  However, he put in a $135 Audio Horizon fuse in it and it became better (to his ears).  So was the amp perfect before or after the fuse?  Neither....if you gave me a Benchmark and I spent months tweaking would sound way, way, way better.......and that YOU could hear.    

It is nice to know which components measure the best....but as I said in the last post......there are infinite amounts of things that effect the sound.....and measurements is just is not infinity....except in spirit.
Hi Fi Critic did not think much of the Benchmark AHB2.[April-June 2016].."But it failed to to impress in terms of musical involvement,attaining an overall score of just 45 points".
I think the AHB2 is an awesome amp, especially for the KEF LS50's (bedroom system). I owned it for a few years so I am confident in my assessment. It was awful on an Magico A3 though, that speaker was more demanding. I also do not think Beryllium drivers are what I would pair with the AHB2.

@ricevs I believe mods can make a good piece sound incredible. Case in point is my Sony SCD-1 SACD player that was modified by $3K worth of mods 20 years ago by Vacuum State. I have recently put it back into my Bryston BHA-1 headphone system and it is phenomenal. Though the SCD-1 in stock form had "good bones" so that may have worked well with the mods.

I have 2 amps to get soon. A Purifi amp would be a nice cost saving way to achieve this. Like I said in my Original Post,

A Benchmark AHB2 and one of these Purifi amps for me please.

I want to find a Purifi amp with "good bones". Then modding that would be interesting.

Your counter arguments to the ASR Purfi build criticisms are understood. 

All the (good) companies that make the Purifi based amps use the same bones.....well, except the chassis.....which are all plain......but you might like one over the other.  The insides are all the same.....1200 watt Hypex power supply, Purifi module and input board all made almost identical to each other using Sparko labs regs and a choice of input op amps.  This is all I need to make a super thang.....because I change everything that matters.  VTV is cheapest in the US, offers a 30 day money back on their amps and has free shipping.   They can also do some custom stuff that no one else is currently offering.  I just talked to them today.  How about a 3000 watt power supply for a stereo or mono block?   They can do this.  Probably kick it up a notch......bigger power supplies are generally a good thing!

Had a chance to listen to Mikes (Mivera) new integrated amp yesterday which also uses the Purifi modules, absolutely stunning sound and will easily challenge separates in the 50K range, it's amazing what a no holds bar kit can do. I'm happy for the lucky few that are fortunate enough to own one.


I just received the latest Stereophile and Herb Reichert just reviewed a Purifi based amplifier built in North Conway NH.   After opening with how he generally dislikes the sound of class-D, he gives this LKV amplifier a very good review and the measurements are deemed excellent.   At 50lb it is ~1/2 the weight of my Pass amplifier and I'm hoping my next amplifier will be that weight or less :)   This amp's MSRP is still on par with my Pass but hopefully over time cheaper variants that still sound very good will be a common thing...
How much is this latest LKV amp?  The earlier version released last year was $8500 with NC500 modules....this is suppose to be better because of the Purifi modules and ?

Over time?......How about now! Modified VTV mono block amps using highly tweaked Purifi modules and 3000 watt power supplies, etc.....available for $3300+......15? lbs each.....or how about a !5 lb. stereo amp with single 1200 watt supply.....fully tweaked.....$2400. See my link above. We will have a tour of the cheaper one in about a month.....and then maybe a tour of a pair of 3000 watt power supply monos....a little later. Hearing is believing.
Why are people looking to Class D to “save” money on a power amp.  I have tried a dozen in the last twenty years and see value in all types.  For those who can afford zero feedback and tube output, there is no comparison.  Sorta separates the men from the boys.  Someday class D will rule, but class A is the king right now, like it should
Things change and move forward. We are talking about Purifi amps here and not the Class D you have heard. I am sure you have not heard these amps because almost no one else has. Here is a quote from someone who has and has reviewed a lot of amps.

I began evaluating the Eigentakt when I used it in May to review the Magico A1 minimonitors ($7400/pair). Before hooking up the Eigentakt, I’d been using a pair of Constellation Audio Revelation Taurus monoblocks -- massive amps that cost $40,000/pair, are specified to each output up to 500W into 8 ohms or 1000W into 4 ohms, and sound outstanding. The Eigentakt clearly wouldn’t be able to match that kind of power, but the Magico A1s don’t need it -- and don’t want it, unless you want to blow them up.

I also swapped out the Nirvana S-L speaker cables I use with the Constellations for the Neutrik speakON cables supplied by Purifi. Feeding the Eigentakt were an EMM Labs DA2 Reference DAC and Pre preamplifier, both via Crystal Cable Standard Diamond Balanced interconnects. My music server was an Asus ZenBook UX303U laptop computer, connected to the DAC with an AmazonBasics USB link.

I found that the Eigentakt was not only powerful enough to drive the A1s -- it sounded as good as the Constellations. As I wrote in my review, “almost nothing about the A1s’ sound had changed -- the tonal balance was the same, the highs were just as extended and the midrange just as pure, voices were equally robust, bass just as extended, and the soundstaging and imaging were exactly as before.” What’s more, I also thought that if there were any differences in the sounds, they “were at best slight and, surprisingly, favored the Purifi.” I played “Hope Is a Dangerous Thing for a Woman Like Me to Have -- But I Have It,” from Lana Del Rey’s Norman ***** Rockwell! (16-bit/44.1kHz FLAC, Interscope). As I also said in the review, “the subtle sounds of her lips moving as she sings softly into the microphone were more apparent through the Purifi.” Ever since the arrival of the Revelation Taurus monos, I’ve loved their combination of smoothness, detail, and effortlessness -- for the Eigentakt to turn in the same performance, at a fraction of the price, was incredible. I was impressed. Granted, if I’d needed more power than the Eigentakt could provide, the Constellations would have easily walked away with the prize -- but in this first test, and within the Eigentakt’s power limitations, its sound quality had proved extraordinary.

I've heard a Purifi amp and it had a very neutral sound which is good in my book. Nice power and grip on the woofers. Clear vocals and acoustic in the mids and highs. I returned the one I had as the build quality was less than optimal. If you're looking for a stereo version Apollon Audio have them as well as monos. March also looks like good build quality and I think he's coming out with a stereo version as well. 
The March Audio guy emailed me and said his stereo version comes out in the end of August 2020.

I bought the Benchmark AHB2 last week and looking to buy a second AHB2 for mono block setup. I need a 3rd amp for my orphaned KEF LS50s and a Purifi amp is in the cards. 

I want to wait and see what NAD has in the cards. The should soon release a simple Purifi amp. I am not interested in the Master Series M33.
NAD just announced their Purifi based 2-chan amplifier.

I just purchased a Benchmark AHB2 yesterday to compare with my Pass X250.8; if I don't take to it, maybe the C298 will be the next amp I try :)
@ddafoe  That c-298 is what I have been waiting for the second system. I wonder what the sonic sacrifices are in mono block form.

I also have a new AHB2 and love it. Your comparison with the PASS X250.8 seems like comparing 2 totally different sonic profiles.

I will be getting another AHB2 to run in mono. If you do not like yours and looking to sell hit me up with a PM. I am looking for the black version.
Here is a comparison of the Purifi based 2 channel stereo amps from VTV and NAD:

Cost: The C-298 NAD is $2K plus shipping and maybe tax.  The VTV stereo amp is $979 with free shipping (30 day money back) with the stock Hypex single dual op amp per channel.  If you want the Pro Sparko Labs discrete op amps with Sparko Labs regulators on each channel then it is $1350 with free shipping.  Mono blocks using the Sparko labs combo are $1800.

Warranty:  Same for both....2 years.

Sound:  I would think the basic $979 VTV and the $2K NAD would sound close. NAD does not say what kind of buffers are used in their amp but says there are separate regulators for the "op amps" in more than one.  You only need one buffer on the input of the Purifi module....that is what VTV uses in all their versions.  The simpler and purer the signal path the more pure the sound.  There is also a gain setting pot on the NAD and it is common knowledge that cheap pots are not pure sounding.  Look at what serious manufacturers do to make a serious pot. The Sparko labs version of the VTV would have just one better sounding discrete op amp in the signal path in front of the Purifi module.  No doubt this version would sound better than the NAD.

Versatility: The NAD has RCA as well as XLR inputs.  However, you can simply get a pair of RCA to XLR adapters and plug them into the VTV.  You do realize that balanced sounds better.  The NAD has a bridging switch.  Really, how many people are going to use this?  Bridging is best for higher impedance speakers.  If you really need to drive low impedance, hard to drive speakers then it is best to use a more powerful amp that is not bridged.  VTV makes mono blocks using the NC1200 for that very purpose.  

Upgradability:  None with the NAD and extreme with the VTV (serious mods by myself.....EVS).  My mods can take stock VTV, Nord and Apollon amps to sonic levels that few have ever heard.

So, why would you buy a stock NAD?  Some do not know what goes on inside a component so buying from a conservative company like NAD seems safer.  Most have never had a component modded so they do not know the value of mods.  This is why I will be sending out amps on tour with the mods done so people can really hear what all the TWEAKING fuss is will have your mind blown.
just like chefs and cooking

they can all start with the same ingredients, end of the day, it is about how the end product is seasoned and whether it tastes right to the head chef

measurements measure what can be measured, often it is what cannot be measured that really matters
Anything as stupid as comparing warranties then advertising tweaks that would void warranties? Stick with the NAD, Apollon,March avoid the cheap VTV above all avoid useless tweaks.
I have been manufacturing products and modifying products for over 42 years. I have less than 1% unhappy customers. This includes over 100 modified CD, DVD, SACD and Blue Ray players (most of which were stock players that were sent in to mod so the customer got to hear the improvement), 100 Millennium DACs (see reviews in Audio Review), 15 Hand Made DACs, a dozen amps make last year using highly modified IceEdge modules, hundreds of passive preamps including the Ultimate Attenuators (class A rated in Stereophile for 7 years), hundreds of Ground Enhancers (ear tuned litz wire ground enhancer for amplifier), etc. etc.

So, those that have heard what I do love it and know that I improve their product or that the product is a superior product. Then there are others with no direct experience with my products (listening tests) who think what I do is "useless tweaks". Is it useful to believe someone with no experience? Or is it more useful to believe those that actually tried something? You can look at a pile of apples and decide that a particular apple you would never want......then someone comes up to the vendor and buys that apple and takes a bite and right in front of you says....Man, this is the best apple I have ever tasted. Are you willing to expand your state of experience? Taste it, you might like it. Way over 1000 customers say my apples are seriously good.....and that is after tasting them.

90% of what makes sound different (and better sometimes) cannot be least, not at this time.  This factoid freaks out the measurement people.  I believe some measurements are needed (especially with regard to speakers).....however, most things that lower audible distortion need to be discovered and implemented by careful listening tests.  Most of the techniques I use are ideas I got from reading or talking to others.  Some things I have discovered on my own.  Once you realize that "everything makes a difference".......then you have an infinity of possibilities.  This is what makes this game fun.  It never ends, you are always learning and growing and the sound just keeps getting better.  I wish you all an ever expanding joy.
My big beefy 50Lb Roksan power amp died (120W a channel, about 9k new with its preamp). I had bought it second hand, and did not have car type money for a replacement. I was keen not to downgrade myself. I plucked up the courage and went class D. I mean it might work, maybe - this from someone who hated the early CD players. 

So I bought a 2K NAD C298. Well, I bought 2, for no good reason other than they seemed a bit small and weedy compared with what I had lost. I have come to love the big slam one can get from a powerful amp. 

Then life throws me a curve. Only one NAD turns up. I tried it anyway, not expecting much. Its gain (with pot bypassed) was the same as the Roksan. 

Well, long story short, I was impressed. There was no loss of slam or low bass. The music sounded as fun as before. But there was a lovely delicacy about the top end. Things sounded very "clean", sort of brand new. Even my technophobe other half noticed and started waffling on unprompted about lots of spaces between the instruments. I was pleased, and decided that the second unit, when it turned up, was going to be returned. So definitely a cost efficient purchase. 

Well, of course when NAD number 2 turned up I had to try it. I mean, you would, wouldn't you? I was sort of expecting to either hear nothing, or maybe hear more bass (the power output per channel goes waaay up when you bridge them, even though the gain stays the same). 

Well, there was no more bass, and I could really hear a difference. Stereo improved (no idea why), the treble got sweeter (and it was nice before) but the big difference was that everything just got more exciting. I think with 2 I was playing louder, as there was none, or much less, of that shouty, fatiguing sound that makes me turn the volume down. Jeez it would dance. 

I kept the second unit. 

My speakers do dip down to 4 ohms, but the amps have never hit protection.