Review and Measurements of Purifi 1ET400A Amplifier

[Sieniek]

Hello to all of you, I am a new member over here and have joined the forum with the hope that you can help me to find the answers on my questions.

First of all I am really grateful for all the people’s like all of you over here because thanks to passion you all have we can move forward in audio quality at our homes. I really appreciate the work and all the measurements that Amir is doing even if I do not understand more than half of these measurement. At least I can understand which amplifier is ranked as number 1 or 2.

I am trying to build my audio system. I already have some Audio Nirvana full range drivers and have some Audio Lii W-15‘s as for bass drivers. After I have seen the measurements of Devialet Expert done by Amir I have decided to sell my Devialet Expert Pro 220 and I have just bought a minidsp SHD by which I will be doing the active crossover between the full range drivers and bass drivers. My plan for future is to buy a Benchmark AHB2 for stereo for my Audio Nirvana drivers but I cannot afford the cost of the brand new unit so here I hope for any kind of a good deal of used one sometime in a future.

The Lii bass drivers, W-15’s are rated in their specification from 50W up to 150W. I am trying to figure out how much of power would I need to drive them well enough if I have 2 units or even 3 units of these per channel ? (I am deciding between 3 units per channel or 2 units per channel).
Also, which amplifier would be the best ? From what I have researched it looks like the Purifi 1ET400A which have 227W in 8ohm or Hypex NC400 are the best, which one would be better or should I look for anything different ? I am thinking about driving these bass drivers with one of these amps but there is a possibility I would buy another set of these amps to drive the full rangers as well. Should I buy them in mono blocks for the best results or as a stereo amp ? Which version should I look after ? There are so many different versions that I am lost to be honest.

Also with the Purifi 1ET400 I can see there is an MK1 version and MK2 version which is much more expensive, is MK2 version really better ? In which shop, from which website would be the best to buy them ? I am based in UK.

I really apologise for asking for so much of help but I cannot find definite answers on all of my questions by doing a research and I am not knowledgeable enough (I do not want to do any mistake as it looks like I will need to spend some serious money for everything) so I hope we can discuss it together and I hope you can help me as a more experienced and more knowledgeable members over here.

ps. I have also 2x Rythmik F18 which about I am thinking of how could I connect them together with AN full range and W-15 drivers together with a Minidsp SHD, is there any possibility to do this ?

Before when I still been an owner of a Devialet Expert Pro 220 (was using them as 440 in mono blocks, still have second one with me) I was using my AN full range speakers with 2x Rythmik F18 with each of these on each side. It was easy to set up system as with active crossover done on Devialet between the full range and subs it was quick and simple to make it work. I was using a windows Dirac with it as well. Now I have W-15’s also and would like to expand the system with them and going seperates because I know that with minidsp SHD and a great amp like these from Hypex, Purifi or Benchmark I will get a much better sound than ever before.

Amir measurements made me to rethink my audio system and I have made a decision of selling my Devialet and going with separates.

All in all this forum is the real thing and I am glad that such a great and informative places like this exists. For me this is the best audio forum I know with the truth in audio.

My perfect sound quality is always the one where I can hear exactly what was recorded in the studio.

Thank you for all of your help and input just in advance. And really sorry for such a long post.

Best Regards,

Rafael

 

[nerdoldnerdith]

You can't go wrong with the Purifi to drive them. The greater power of the Purifi will make a more significant difference than the few extra inaudible dB of performance of the Benchmark. I'd personally say that something this clean for bass is overkill, but what the hell do I know... It's not like it could hurt.

 

[JimB]

... with the Purifi 1ET400 I can see there is an MK1 version and MK2 version which is much more expensive, is MK2 version really better ? ...

I am unaware of this. Do you have more information? If you mean EVAL1 (single channel) vs EVAL2 (two channels), I believe the distinction will be that TWO EVAL2 cost more than ONE EVAL1. As far as I understand, both EVAL products use the same amp modules (1ET400A).

 

[Julf]

The Lii bass drivers, W-15’s are rated in their specification from 50W up to 150W. I am trying to figure out how much of power would I need to drive them well enough if I have 2 units or even 3 units of these per channel ? (I am deciding between 3 units per channel or 2 units per channel).

Remember that the difference between 50W and 100W is only 3 dB in SPL.

Are you going to connect the 2 or 3 units in parallel?

 

[mSpot]

Also with the Purifi 1ET400 I can see there is an MK1 version and MK2 version which is much more expensive, is MK2 version really better ?

Purifi produce only one version of the 1ET400 amp module.

Nord created their own MK1 and MK2 versions of Hypex and Purifi amps, where the MK2 versions are dual mono (dual power supplies) and have upgraded buffer boards. The cost of components is in fact higher for MK2 and is reflected in the higher price but whether MK2 has better sound quality is an entirely separate question.

 

[Aardappel]

Hi everyone,

I am new here and in the process of buying a complete new system. The speakers I have selected after listening to 20+ different floor standers are the Klipsch RP-8000f, and based on a whole lot of research I have also settled for a Purifi amp with the EVAL1 buffer which I still need to order. I am really struggling with how to drive the amp without losing the benefits of it (low noise, clean and excellent SQ).

My main concerns are volume control, balanced input (or not) and avoiding blowing up my speakers because of the input Voltage/gain of the EVAL1 input buffer. As you all know the Purifi EVAL1 power amp has max volume at an input Voltage of 1.5V. Ideally, one would hook the amp up to a balanced XLR DAC for a fully balanced connection but I wouldn't rely on just the volume control of a balanced DAC as I am reading online that some DACs sometimes revert to 100% volume after a power outage for example. That would blow my new speakers/ears (and amp?) and is an unacceptable risk. I would therefore need to add a passive volume control (like this JBL Nano Patch+) which may or may not add distortion/noise. How have you guys solved this problem? It also just seems silly to use a balanced DAC with a 4V RMS output to then limit that gain before it goes into another gain stage (EVAL1) and then into the Purifi modules.

An alternative is to go with an unbalanced DAC and use a modified RCA to balanced XLR cable (like the one from March Audio) just because that opens up a whole lot more DACs (at lower prices, such as the E30) to choose from, do you see any issues with that approach? However, if you then add a passive inline attenuator such as the Schiit Sys passive preamp (which adds noise at reduced volume) to make sure that the E30 can run at a higher volume (with lower distortion, right?) and for the aforementioned speaker/amp safety reason, won't you lose all the benefits of using the March Audio 'balanced' RCA to XLR cable? With this setup [E30 DAC - RCA to Schiit Sys - March Audio 'balanced' RCA/XLR to Purifi EVAL1 amp] there would be an unbalanced RCA connection from the DAC to the Schiit, followed by the 'balanced' RCA/XLR connection to the amp.

Furthermore, does the EVAL1 contain the necessary RF filters to stop the issues as recently raised by March Audio in this Purifi thread?

Apologies for all the text, but how can I best drive a Purifi EVAL1 power amp and how do you guys drive the amp? I just want to hook it up via Toslink and computer via USB whilst having remote volume control without running the risk of blowing up my speakers and ears!

Cheers

 

[Matias]

Hi everyone,

I am new here and in the process of buying a complete new system. The speakers I have selected after listening to 20+ different floor standers are the Klipsch RP-8000f, and based on a whole lot of research I have also settled for a Purifi amp with the EVAL1 buffer which I still need to order. I am really struggling with how to drive the amp without losing the benefits of it (low noise, clean and excellent SQ).

My main concerns are volume control, balanced input (or not) and avoiding blowing up my speakers because of the input Voltage/gain of the EVAL1 input buffer. As you all know the Purifi EVAL1 power amp has max volume at an input Voltage of 1.5V. Ideally, one would hook the amp up to a balanced XLR DAC for a fully balanced connection but I wouldn't rely on just the volume control of a balanced DAC as I am reading online that some DACs sometimes revert to 100% volume after a power outage for example. That would blow my new speakers/ears (and amp?) and is an unacceptable risk. I would therefore need to add a passive volume control (like this JBL Nano Patch+) which may or may not add distortion/noise. How have you guys solved this problem? It also just seems silly to use a balanced DAC with a 4V RMS output to then limit that gain before it goes into another gain stage (EVAL1) and then into the Purifi modules.

An alternative is to go with an unbalanced DAC and use a modified RCA to balanced XLR cable (like the one from March Audio) just because that opens up a whole lot more DACs (at lower prices, such as the E30) to choose from, do you see any issues with that approach? However, if you then add a passive inline attenuator such as the Schiit Sys passive preamp (which adds noise at reduced volume) to make sure that the E30 can run at a higher volume (with lower distortion, right?) and for the aforementioned speaker/amp safety reason, won't you lose all the benefits of using the March Audio 'balanced' RCA to XLR cable? With this setup [E30 DAC - RCA to Schiit Sys - March Audio 'balanced' RCA/XLR to Purifi EVAL1 amp] there would be an unbalanced RCA connection from the DAC to the Schiit, followed by the 'balanced' RCA/XLR connection to the amp.

Furthermore, does the EVAL1 contain the necessary RF filters to stop the issues as recently raised by March Audio in this Purifi thread?

Apologies for all the text, but how can I best drive a Purifi EVAL1 power amp and how do you guys drive the amp? I just want to hook it up via Toslink and computer via USB whilst having remote volume control without running the risk of blowing up my speakers and ears!

Cheers

Hi get an RME ADI-2 DAC fs and it has the AutoRef feature of variable gain and the highest SINAD after volume change. For 1.2k usd it is a steal.

 

[Aardappel]

Hi get an RME ADI-2 DAC fs and it has the AutoRef feature of variable gain and the highest SINAD after volume change. For 1.2k usd it is a steal.

Hi Matias - I appreciate your help! I have looked into that DAC however it really is out of my budget... At that point it might almost be better going for a NAD M33 as it has everything built in plus room correction. I am trying to get the best bang for my buck, hence the Purifi EVAL1 however I just need to find a sensible way to drive it

What would be a good solution at a lower price and how have others solved this?

 

[Matias]

I would (and did) choose the ADI-2, buy once and forget it. I don't know alternatives to it.

 

[Sieniek]

Remember that the difference between 50W and 100W is only 3 dB in SPL.

Are you going to connect the 2 or 3 units in parallel?

Yes, the difference isn’t big at all and I believe that for two units per channel it would be enough. What about three units per channel as here I am not sure. I have three 6 units altogether and the choice to go with two or three per channel. If three units would be too much for one 1ET400 then I would go with two units. What do you think ?

Thank you for your input Julf !

 

[Sieniek]

Purifi produce only one version of the 1ET400 amp module.

Nord created their own MK1 and MK2 versions of Hypex and Purifi amps, where the MK2 versions are dual mono (dual power supplies) and have upgraded buffer boards. The cost of components is in fact higher for MK2 and is reflected in the higher price but whether MK2 has better sound quality is an entirely separate question.

Achh I see now, thank you for clarification. I have thought that Nord is the one to buy from. Where should I buy them best then ? I believe the MK1 would be the one to buy then, but I am not sure where should I look for them.

Thank you for your input !

 

[Sieniek]

I am unaware of this. Do you have more information? If you mean EVAL1 (single channel) vs EVAL2 (two channels), I believe the distinction will be that TWO EVAL2 cost more than ONE EVAL1. As far as I understand, both EVAL products use the same amp modules (1ET400A).

I was thinking about MKI and MKII versions from Nord acoustic but now I understand that MKII is their own modified and supposedly “better” sounding 1ET400. If it is sounding better I do not know but as mSpot has explained the difference between them to me I would prefer to go with the one created by Purifi and not modified further by anyone. MKI is the one I would choose.

Thank you for your input also !

 

[Sieniek]

You can't go wrong with the Purifi to drive them. The greater power of the Purifi will make a more significant difference than the few extra inaudible dB of performance of the Benchmark. I'd personally say that something this clean for bass is overkill, but what the hell do I know... It's not like it could hurt.

Thanks for your reply nerdoldnerdith ! I think that in this case maybe you have right. If I would choose between the 227W of Purifi 1ET400 and 100W of Benchmark AHB2 I would go with Purifi for driving my full range but my dream plan someday is to have two Benchmarks in mono bridge, hopefully someday I will be lucky enough.

 

[Julf]

Yes, the difference isn’t big at all and I believe that for two units per channel it would be enough. What about three units per channel as here I am not sure. I have three 6 units altogether and the choice to go with two or three per channel. If three units would be too much for one 1ET400 then I would go with two units. What do you think ?

I am pretty sure the 1ET400 is fine driving three units.

 

[Sieniek]

I am pretty sure the 1ET400 is fine driving three units.

This is what I believe as well. Do you know where is the best place to buy them ?

Is 1ET400 better than NC400 overall ? Because I can see that in SINAD the NC400 is higher.

 

[Julf]

This is what I believe as well. Do you know where is the best place to buy them?

I would get them straight from Purifi, but it all depends on where you live.

Is 1ET400 better than NC400 overall ? Because I can see that in SINAD the NC400 is higher.

I have not seen any double blind listening tests. Both measure so well that I would be surprised if there were audible differences, but you never know...

 

[Sieniek]

I would get them straight from Purifi, but it all depends on where you live.


I have not seen any double blind listening tests. Both measure so well that I would be surprised if there were audible differences, but you never know...

Yeah, most probably there is no audible difference between them. I live in UK.

 

[Sieniek]

I would get them straight from Purifi, but it all depends on where you live.



I have not seen any double blind listening tests. Both measure so well that I would be surprised if there were audible differences, but you never know...

Julf, I have checked the https://purifi-audio.com/vare/eval1/ - Purifi website and there are options to buy:

1ET400A

or

Eval1

I can understand that the 1ET400A is for mono blocks right ? But it is not a complete kit ? What else would I need to buy to make this kit a complete working mono block ?

or is it better to buy Eval1 ? I understand that Eval1 is a complete stereo kit, is that right ?

is it hard to install these kits overall ?

Is there any description of how to do it somewhere ?

Please let me understand these differences as I am not sure which one should I buy and how to install the kit later on.

 

[Julf]

Julf, I have checked the https://purifi-audio.com/vare/eval1/ - Purifi website and there are options to buy:

1ET400A

or

Eval1

I can understand that the 1ET400A is for mono blocks right ? But it is not a complete kit ? What else would I need to buy to make this kit a complete working mono block ?

or is it better to buy Eval1 ? I understand that Eval1 is a complete stereo kit, is that right ?

is it hard to install these kits overall ?

Is there any description of how to do it somewhere ?

Please let me understand these differences as I am not sure which one should I buy and how to install the kit later on.

The Eval1 is much more complete, pretty much just plug in the power supply, put everything in a box and off you go. The bare 1ET400A is more of a component, and you have to supply much more yourself.

 

[Matias]

is it hard to install these kits overall ?

Is there any description of how to do it somewhere ?

Lots of reading in this topic:
https://www.audiosciencereview.com/forum/index.php?threads/diy-purifi-amp-builds.10478/