So what are people drooling over most? Hypex or Purifi?

[Hdale85]

I may build one of these at some point, kind of curios is the Purifi stuff that much better? Hypex doesn't have their nCore modules anymore, but they do have the Nilai I think it's called which from what I understand is based on nCore. A while back I wanted to build a Hypex amp based on the UCD180 or 400 modules I feel like it used to be more expensive. Hypex's kits are really nice though, if I went that route I'd likely grab their preamp at some point too.

[JonMarsh]

At the core of any discussion of Hypex and PuriFi should be an understanding of Bruno Putzeys and his contributions at Philips, Hypex, and PuriFi.

I started "following" him (yeah, I think he's an influencer) when he was back at Philips, but well after a burst of work I did in Class D architecture to further the development and release of 250V MOSFETs by Siemens back in the late 80's and early 90's.

Interestingly, Hypex still has this PDF from Bruno's 2007 AES convention presentation linked on the Hypex site- but it's a set of presentation foils, and without his exposition (speech) might be hard to follow for someone not already skilled in the arts, so to speak. (would be like getting my foils for the 1990 AES presentation I did on Class D development for Siemens, which did results in an invited paper for 1991.) (a lot changes in our understanding and approach to problem solving for Class D between 1990 and 2007 in the intervening 17 years!!)

https://www.hypex.nl/media/fe/01/90/1682341944/A%20universal%20grammar%20of%20class%20D.pdf

I have worked with the nCore modules, and put together system configurations for folks. I do own an Audio Precision APx555 analyzer, as used in my "On the bench" posts. I have a set of the PuriFi modules and compatible power supply, and have planned a modified front end to use with them, but certain speaker projects have had higher priority. Some day...

The key innovation for PuriFi over nCore is the change in the feedback architecture and the considerable reduction in distortion projects generated in the output filter. The new Hypex architecture addresses some of these issues also, and I'd hazard a surmise that they are running somewhat neck and neck these days, but not having tested them, I can't really say with certainty.

It's funny seeing semiconductor companies like EPC promoting their GaN transistors and putting a fair amount of effort into developing a demonstrator- but lacking knowledge of how to implement a good overall architecture, the end result is out performed by silicon transistors in PuriFi.

https://epc-co.com/epc/markets/consu.../class-d-audio


OTOH, I can say with certainty that though Hypex and PuriFi being the best of the CLASS D solutions and being a very high value proposition approach, they are not the best performing audio amplifiers- they don't stand up on the bench to my Halcro D68 or my Cambridge Audio Edge W's, which is why the "pressure" to test the newest Class D modules is not so high for me.

I was often recruited by HQ or NA management to test new Class D products that Infineon has acquired, usually by buying small companies, because all the AEs only had experience with switching power supplies, and didn't have theoretical or hands on knowledge of Class D, and didn't have a top of the line Audio Precision analyzer. I could tell some stories, but shouldn't, out of circumspect regard for my former employer of 35 years (Distinguished Engineer long before I retired)

you may not realize, but apart from one pin, the interface connectivity of nCore and PuriFi modules is the same, It's pretty easy to work with either one, and I do want to get back to that when the 3 or so speaker projects in the queue are complete. PuriFi has an excellent engineering team, but I wouldn't count Hypex and their long business experience out.

[Hdale85]

So you think other amp technologies still sound better then? I have some PCB's for Class A amps, but the money needed for just the heatsinks and chassis alone would be rather big. I haven't checked the prices on that stuff recently but it wasn't cheap 10 years ago when I got the PCB's lol. They are Pass Labs Aleph X boards. I want to build that out someday regardless but it seemed like people were gravitating towards Class D now days because it's getting on par with A/B or A stuff but maybe not?


Edit: Just looked up the 2 amps you mentioned and yeah they are WAY outside of my budget lol. What exactly is class XA?

[technodanvan]

What about something like the Benchmark AHB2? While still expensive, it is my understanding that it is very highly regarded in some circles. I had researched Purifi quite extensively a while back and concluded it probably wasn't worth the expense at the time. Granted I would probably not be making them myself. I think it was March Audio that made some 'affordable' prebuilts that can be more affordable than the Benchmark.

For the record, I have a Ncore-based NAD (not Nilai) that drives my Wavecor Ardents rather well. Personally I don't see any reason to upgrade at this point. While both Benchmark and Purifi have caught my eye I think I'd go for something with more convenience next time - something that Jon will probably gasp over - an all-in-one DAC/amp/media player. Something like a NAD M33, or even the M10 for compactness. Granted, I think they both come with Purifi too...

[theSven]

What about something like the Benchmark AHB2? While still expensive, it is my understanding that it is very highly regarded in some circles. I had researched Purifi quite extensively a while back and concluded it probably wasn't worth the expense at the time. Granted I would probably not be making them myself. I think it was March Audio that made some 'affordable' prebuilts that can be more affordable than the Benchmark.

For the record, I have a Ncore-based NAD (not Nilai) that drives my Wavecor Ardents rather well. Personally I don't see any reason to upgrade at this point. While both Benchmark and Purifi have caught my eye I think I'd go for something with more convenience next time - something that Jon will probably gasp over - an all-in-one DAC/amp/media player. Something like a NAD M33, or even the M10 for compactness. Granted, I think they both come with Purifi too...

The Benchmark is price I paid for a refurbished Cambridge Audio Edge W amp on eBay, not sure how they compare though. That's outside of my expertise. Once I get on the queue with Steve for the SMJ 40 build I will need another amp... I really would like to do a DIY amp build...

[Hdale85]

My goal was always to eventually have a 2 channel system that I built all the components of, speakers, amps, dac, maybe even a turntable.

[theSven]

A turntable is on my list to purchase. When you start the amp project I will be following and budget pending may tag along to build one as well.

[Hdale85]

The Purifi and the Hypex are very easy builds they are essentially just a set of modules you’re assembling into a case.

[theSven]

The Purifi and the Hypex are very easy builds they are essentially just a set of modules you’re assembling into a case.

Would you add any filters? There was another member here that was trying different filters with the Purifi.

[Hdale85]

There’s a front end stage someone has that I’d probably use, he has a video up let me grab it but his build was really nice.

[Hdale85]

[ergo]

I did a Purifi build some years ago and documented punch of it in this thread

https://www.htguide.com/forum/mission-possible-diy/class-d-projects/43067-purifi-class-d-amplifiers?p=829843#post829843

Mine was based on EVAL1 Stereo 1ET400A Evaluation Kit
Now they have some more options for the input board, but at least for EVAL1 me and my friends listening experience did not rate it very high. Especially the depth of the sound field was lacking even though measurements were ok.

So we iterated on my unit while keeping my friends original for A/B comparison.

After many experiments it's now running the "Whammy headphone amp" as the first stage.

*****
Coincidentally I'm currently thinking of going exact opposite - I ordered the parts kits for Nelson Pass's F5m and will try to build a class-A amp for a change. I have big heat sinks sitting idle for years, I also have power transformers, so the main high cost items are all there.... so hopefully after coming DIY season (meaning autumn/winter time in Estonia) I will have a comparison.

[Hdale85]

Not sure if you know of the Amp Camp Kit from diyaudio store. Supposed to be really good and based on a nelson pass design. I've thought about building a couple of those in a monoblock config but idk. The Aleph X's would be very large, very hot amps lol. Maybe I could just do the 50wpc variant of them.

[JonMarsh]

I have a couple of those... in the queue, other projects with regards to speakers for SMJ and forum members take higher priority.

[JonMarsh]

The Benchmark is price I paid for a refurbished Cambridge Audio Edge W amp on eBay, not sure how they compare though. That's outside of my expertise. Once I get on the queue with Steve for the SMJ 40 build I will need another amp... I really would like to do a DIY amp build...

Remember, guys, there is a bench review of the ABH2 online here...

https://www.htguide.com/forum/forum/...ahb2-amplifier

Subjectively, it's pretty clean, doesn't have the bass control and extension subjectively of my best amps. Treble with complex material is not as focused as I would like. It's better than a lot of stuff out there, but not in the same class as a Cambridge Edge W or a Halcro, IMO, and that of a good friend and former colleague who has auditioned the ABH2 at home, but mostly goes with Halcros.

[Steve Manning]

My goal was always to eventually have a 2 channel system that I built all the components of, speakers, amps, dac, maybe even a turntable.

If you guys have a turntable design in mind let me know .... I can certainly knock out some bodies for those that are interested.

[Hdale85]

Once upon a time I was trying to workout how to do a magnetic levitating table, but I'm not sure I have the knowledge to pull that off effectively.

[ehampshire]

I know you were asking about DIY and I've contemplated builds with both Hypex and Purifi modules. However, after pricing them out I find the $50 extra to just buy it built from VTV hard to overcome. Would be fun! I have this VTV driving my B&W 801s, it is a very nice amp (sounds as good as my Bryston's) and *very* cost effective: https://vtvamplifier.com/product/vtv...ifier-1000wx2/

Another option I've heard good things about are Buckeye, but they cost more than the VTV: https://www.buckeyeamp.com/

[Scareurpasenger]

I have been tempted by some of the audio phonics offerings. Great pricing and I like the cases. Buckeye looks solid but the cases are quite basic. https://www.audiophonics.fr/en/power...rs-c-6306.html

I have seen some of the nc400 and nc500 oem modules on ebay which might make it that much more affordable.