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Purifi EVAL1 EIGENTAKT Class D Amp Designs

mocenigo

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My own implementation of the Purifi modules was recently subjectively reviewed against two other amplifiers using different technologies, but also at different price points.
Very well written and documented, several pages, all sort of musics listened, nice to read.
Summary in half a line: the most expensive sounds the best, the least expensive sounds the worst. Bad luck for me, my amplifier was the least expensive :D. What was particularly hard to swallow was that I consider one of the two other amplifiers as "$hit packed in golden paper" and it was supposed to sound better.

What, you do not know that the performance of amplifiers is strictly related to price? ;-)
 

Phorize

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To me the NAD298 is outrageously priced. Can't imagine spending $2300 on a Purifi amp when you can buy one for half that price that does the job. Or you can spend $1700 on the March Audio P452, which seems high to me too. People can argue it's more expensive because it has "features" but most users just need an amp that turns on. You don't need variable gain, auto sensing, line out, bridge or other gizmo's that simply offer more parts to break. A simple build with quality Purifi components is best for most. Save the other $1000 toward a great pair of speakers.
Perceived value is highly subjective. If you breakdown the cost of parts and the value added merely by proper execution of the build for something like the p452, the $1700 looks fair. You can obviously get cheaper, but no small or medium size business can survive, let alone invest time in the sort of R and D that it takes to develop a state of the art loudspeaker on the sorts of margins that I’d imagine the cheapest manufacturers will be on.
 

MaxBuck

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I have no problem with good companies making a good profit. Radical concept, I know.

The NAD C298 is an excellent product that I believe represents a bargain in the amplifier marketplace. I feel sure that many other amplifiers employing Hypex or Purifi modules similarly offer great value.
 

stren

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I have no problem with good companies making a good profit. Radical concept, I know.

The NAD C298 is an excellent product that I believe represents a bargain in the amplifier marketplace. I feel sure that many other amplifiers employing Hypex or Purifi modules similarly offer great value.
More like average buck then? JK ;)
 

pogo

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NAD C298 (similar to NAD M33 in theory)
In practice, the NAD M23 is very similar and the recommended upgrade for the M33. Usable in bi-amping mode or in bridge mode, where the M33 takes over one channel also in bridge mode. In a first test, the bi-amping was preferred with Dali Epicon 6, which is probably related to the higher DF.
 

SIY

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In practice, the NAD M23 is very similar and the recommended upgrade for the M33. Usable in bi-amping mode or in bridge mode, where the M33 takes over one channel also in bridge mode. In a first test, the bi-amping was preferred with Dali Epicon 6, which is probably related to the higher DF.
Your repeated attempts to infect others with your utter lack of understanding of source impedance effects are once again noted.
 

pogo

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Have any of you been able to hear the T+A A200 (Purifi) with switchable DF on the AXPONA?:
Link1
Link2
 

SIY

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Have any of you been able to hear the T+A A200 (Purifi) with switchable DF on the AXPONA?:
Link1
Link2
This nonsense seems to be an obsession. Still haven't bothered doing the basic calculation yet?
 

pogo

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Here we go to the next round and again with switchable DF like in the A200 (stereo version): T+A M200
The new purifi design may already be installed there!?
 
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pogo

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The new purifi design may already be installed there!?
It is not the new Purifi design and it is not bridged. It will probably continue to use the same Purifi design, but with a differently designed input stage and PSU.
 

pogo

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I have the amp in question here (T+A A200), the damping factor setting noticeably changes how...
I had the opportunity to listen to the B&W 702 S2 on the T+A A200.
As soon as you switch to DF LO, the reproduction becomes more bulbous and the area above now seems to be behind a thin curtain. Bass beats themselves are reproduced more fully with DF LO, but lack contour.
If I had simply had an amplifier swap done there on site, i.e. had an AMP with a lower DF replaced by one with a higher one, I would most likely have preferred the lower one and would not have noticed the advantages of the higher DF in the higher ranges at all, i.e. less curtain. If you want to run the 702 without a sub, another option would be to bi-amp it. I think with a low DF for the lower part and for the rest a high DF one would be able to get the most coherent without sub.
 

SIY

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I had the opportunity to listen to the B&W 702 S2 on the T+A A200.
As soon as you switch to DF LO, the reproduction becomes more bulbous and the area above now seems to be behind a thin curtain. Bass beats themselves are reproduced more fully with DF LO, but lack contour.
If I had simply had an amplifier swap done there on site, i.e. had an AMP with a lower DF replaced by one with a higher one, I would most likely have preferred the lower one and would not have noticed the advantages of the higher DF in the higher ranges at all, i.e. less curtain. If you want to run the 702 without a sub, another option would be to bi-amp it. I think with a low DF for the lower part and for the rest a high DF one would be able to get the most coherent without sub.
More storytelling?

Or did you actually use basic controls? Haha, I crack myself up.
 

stren

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I had the opportunity to listen to the B&W 702 S2 on the T+A A200.
As soon as you switch to DF LO, the reproduction becomes more bulbous and the area above now seems to be behind a thin curtain. Bass beats themselves are reproduced more fully with DF LO, but lack contour.
If I had simply had an amplifier swap done there on site, i.e. had an AMP with a lower DF replaced by one with a higher one, I would most likely have preferred the lower one and would not have noticed the advantages of the higher DF in the higher ranges at all, i.e. less curtain. If you want to run the 702 without a sub, another option would be to bi-amp it. I think with a low DF for the lower part and for the rest a high DF one would be able to get the most coherent without sub.
Fast and bulbous?
 

pogo

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did you actually use basic controls?
Yes, my ears as well as the thing in between ran flawlessly ;)
Moreover, I was not alone and the fascinating thing about pressing the DF button is that immediately the low frequency range moves forward and the range above it recedes.
 

SIY

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Yes, my ears as well as the thing in between ran flawlessly ;)
Moreover, I was not alone and the fascinating thing about pressing the DF button is that immediately the low frequency range moves forward and the range above it recedes.
More story-telling.

Have the ABX logs? Hahahaha, I crack myself up.
 

pogo

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Here is the assembly of a T+A M200: Link
Near the output section of the Purifi 'module', you can clearly see the additional switchable DF circuit.
 
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pogo

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Here is another test report that describes the DF switching on different speakers and their audible differences well: Link
 
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