Review and Measurements of Purifi 1ET400A Amplifier

[elberoth]

Just got the new Purified Nords. I did not get a chance to listen (and with my current work load it may take a while ...) but I did manage to open them up and take some pictures.

What is most interesting, is that the Purifi modules show some 20 deg celsius lower working temps than the Ncore ones. They still run hot at idle, but not just as hot.

Here are two amps side to side:

Purifi top
NCore NC 500 bottom

This pic doesn't is not accurate enough, but the NCore modules get as hot as 68'C (154 degrees Fahrenheit). By far the hottest component is the coil:

Purifi on the other hand maxes out at 50'C (all temps at idle with the tops open), with the hottest components beeing that vertical daughterboard an a chip next to it.

PSU transformer, Sparkos discrete voltage regulators on the input board also reach 50'C.

Purified Nord inside:

Purifi board (here you can see the vertical doughterboard that gets so hot and the long chip next to it; the coil on the other hand is warm, but not hot to the touch):

 

[Labjr]

So the heatsinks are for looks?

 

[elberoth]

Yes and no. Both the PSU and Purifi module are heatsinked to the bottom of the case, which connects to the heatsinks. It is not a direct connection, which is less than ideal, but some of the heat is certainly dissapated by the heatsinks on the sides as well. Basicly the whole aluminium case acts as a heatsink.

 

[Sir Sanders Zingmore]

How about sending a "lightspeed attenuator" to Amir to have thoroughly tested

Speaking of LDRs what happened to the one that @stereo coffee was going to send

Received thanks, and working on building one up for you to send as soon as I can

 

[georgehifi]

This is why I would like to see from amirm the same phase graph and 10k square wave on the Purifi without any external A.P. HF filtering.

It gives me an idea where the output filter is set, which is in direct relation ship to any phase shift into the audio band, and also how intense the residual switching frequency noise is that on the output terminals.

Now please everyone, let my questions be answered by the OP and man I asked, who is doing the measuring on this Class-D module, I didn't ask anyone else, just him.

Cheers George

 

[restorer-john]

Now please everyone, let my questions be answered by the OP and man I asked, who is doing the measuring on this Class-D module, I didn't ask anyone else, just him.

Again George, this is a forum. You don't roll in here and tell us not to comment in an open thread.

If you want a super secret, private one-on-one conversation with Amir and don't want member's input, use the private messages. I'm sure he'll accommodate you.

 

[VintageFlanker]

All that I have asked is specifically directed at @amirm because he is the one doing these independent measurements no one else, and what I ask seem to get other backs up around here,

Did you ever heard about Private Message?

Edit: Ooops... What @restorer-john just said!

 

[Labjr]

Yes and no. Both the PSU and Purifi module are heatsinked to the bottom of the case, which connects to the heatsinks. It is not a direct connection, which is less than ideal, but some of the heat is certainly dissapated by the heatsinks on the sides as well. Basicly the whole aluminium case acts as a heatsink.

Seems like yes to me. If the heatsinks are just bolted to the bottom of the case, they would seem to be of little benefit. Would be better off with thin aluminum sides.

 

[restorer-john]

Seems like yes to me. If the heatsinks are just bolted to the bottom of the case, they would seem to be of little benefit. Would be better off with thin aluminum sides.

It's an off-the-shelf box with heatsinks. They serve no purpose other than cosmetic in this situation.

Rotel were the kings of cosmetic heatsinks back in the day.

 

[Labjr]

It's an off-the-shelf box with heatsinks. They serve no purpose other than cosmetic in this situation.

Rotel were the kings of cosmetic heatsinks back in the day.

They add weight if that's considered a purpose.

 

[March Audio]

It gives me an idea where the output filter is set, which is in direct relation ship to any phase shift into the audio band, and also how intense the residual switching frequency noise is that on the output terminals.

Now please everyone, let my questions be answered by the OP and man I asked, who is doing the measuring on this Class-D module, I didn't ask anyone else, just him.

Cheers George

Maty has already told you what the phase shift is.

I will tell you later what the Purifi risidual voltage is but the Hypex is about 350mV RMS.

Again, why do you think it is of importance? Are you still having this misconception that seeing the switching frequency on a high bandwidth plot relates to in band audible noise?

Why do you think Amir is going to tell you anything different?

 

[georgehifi]

If you want a super secret,

Again I specifically ask questions to the @amirm who's doing these bench tests about his bench tests, and who is the OP, and you guys attempting to speak for him in a not too calm manner.
Too angry for me, Ignored. And if it bugs you so much you to can use the ignore button also.

Why do you think Amirm is going to tell you anything different?

I didn't ask him to tell me I asked him to show me graphs and pics if he has them, give up please, Ignored also, And if it bugs you so much you to can use the ignore button also.

 

[amirm]

Let's calm down. What is the question?

 

[March Audio]

Let's calm down. What is the question?

What is the phase shift of the Purifi at 10kHz?
Do you have a plot of a 10kHz square wave without AES input filter?

I have discussed this at length with George in another forum.

 

[March Audio]

Again I specifically ask questions to the @amirm who's doing these bench tests about his bench tests, and who is the OP, and you guys attempting to speak for him in a not too calm manner.
Too angry for me, Ignored. And if it bugs you so much you to can use the ignore button also.


I didn't ask him to tell me I asked him to show me graphs and pics if he has them, give up please, Ignored also, And if it bugs you so much you to can use the ignore button also.

As has been pointed out by others already George, that is not how this forum works. Everyone is free to comment on your posts.

Considering you have already been given the answers to your questions I think you should lose the attitude.

 

[amirm]

What is the phase shift of the Purifi at 10kHz?
Do you have a plot of a 10kHz square wave without AES input filter?

Thanks. I don't have either measurement.

 

[georgehifi]

Let's calm down. What is the question?

Thanks amirm, requests 1: 2: and 3" from here, if you have them saved as screen shots.
https://www.audiosciencereview.com/...-of-purifi-1et400a-amplifier.7984/post-237856

Without A.P.'s passive low-pass filter.
As the output (without AP filtering) to me has a direct relationship to the amount of residual switching frequency noise seen on the 10k square wave, and also a direct relationship to the amount of shift down into the audio band if you've graphed that, and gives an idea where the amps output filter is set also.
These are hidden when the A.P.'s passive low-pass filter is used, I like to see it warts and all.


Don't know why it caused such bristling from some. Stereophile show both with and without A.P.'s AUX-0025 passive low-pass filter.

And the graph of phase shift figures, from this module.

Cheers George

 

[amirm]

Without A.P.'s passive low-pass filter.
As the output (without AP filtering) to me has a direct relationship to the amount of residual switching frequency noise seen on the 10k square wave, and also a direct relationship to the amount of shift down into the audio band if you've graphed that, and gives an idea where the amps output filter is set also.
These are hidden when the A.P.'s passive low-pass filter is used, I like to see it warts and all.

The 1 Khz spectrum in the review is without the filter:

You can clearly see the noise shaping and the switching frequency. Is there something extra you want to understand about this?

 

[georgehifi]

The 1 Khz spectrum in the review is without the filter:

Sorry, but I'd like to see how much is riding on the 10k square wave as in the Stereophile square wave shots above to me, more informative.
If you don't have it that's fine.

What about 1 and 3
1: Which are a phase response graph from 50khz down to 5khz without A.P. filter inline.
2: A screen shot of a 10khz square wave without the A.P. filter inline.
3: Now that it's been mentioned rms wattage all just before clipping at 8ohms, 4ohms, and 2ohms without any understating of the 8 or 4 to make the 2 look good, that seems to be getting more popular to do with manufacturers own specs.

Cheers George

 

[Audiocrusader]

George is a well known "anti-class-D crusader" on Audiogon forum... Straight to the ignore list.

That's quite a noble crusade. Industry member I'm guessing?