Review and Measurements of Purifi 1ET400A Amplifier

[Julf]

Can we talk about who has the best designed 1ET400A case now?

And how the color of the case affects the sound quality?

 

[tensor9]

Does anyone lone when higher powered modules will be available?

 

[Julf]

Does anyone lone when higher powered modules will be available?

Has there actually been talk about higher powered modules? With the trend towards active speakers, there doesn't seem to be that much demand for more than 400-500W per module.

 

[Hayabusa]

Usually modding is another word for snake oil. I doubt the problem is anything other than audiophile hypochondria.

Then I appologise for using that term improperly ...

 

[boXem]

Can we talk about who has the best designed 1ET400A case now?

If this is not sarcasm, I guess you mean that the only difference between all the 1ET400 implementations will be the case.
That may not be right: like different implementations of the same ADC or DAC chip, they may measure differently. The integrator is not only responsible from the input buffer, but also from the supply to the control circuit. Noise and distortion will be impacted by these two factors.

 

[Julf]

- End off topic -

Oh, wish it was so...

 

[Thomas savage]

Can we keep to the op please , if you want to talk about phase shift outside of how it relates to this amp then please start a new thread.

Edit, I started the thread and moved @maty post out.Cheers

 

[tensor9]

Has there actually been talk about higher powered modules? With the trend towards active speakers, there doesn't seem to be that much demand for more than 400-500W per module.

I haven’t heard any.
But with my Maggies, 86 dB/m/2.63V (~83 dB/m/W), accounting for listening distance and headroom, the 450 W Purifi (300W of CLEAN power) is actually just on the edge of and maybe not enough power. I need a solid 500W of clean power. I’m being pushed towards the NC1200 because of this.

 

[ahofer]

But does it convey the emotion of the music?

 

[Julf]

I haven’t heard any.
But with my Maggies, 86 dB/m/2.63V (~83 dB/m/W), accounting for listening distance and headroom, the 450 W Purifi (300W of CLEAN power) is actually just on the edge of and maybe not enough power.

How have you determined that?

 

[tensor9]

https://www.crownaudio.com/en/tools/calculators

Handy little calculator. This is assuming 3dB of headroom.

 

[Julf]

https://www.crownaudio.com/en/tools/calculators

Handy little calculator. This is assuming 3dB of headroom.

Ah, so a theoretical calculation, not something you have verified? Keep in mind that that calculator assumes a free field (so outdoors or in an anechoic chamber). In a real room you need way less.

 

[tensor9]

Ah, so a theoretical calculation, not something you have verified? Keep in mind that that calculator assumes a free field (so outdoors or in an anechoic chamber). In a real room you need way less.

yeah I was wondering about room gain.

My first choice is would be an AHB2 (~190W), then a Purifi (260-300W), then a NC1200 (500W). I’m really a little concerned about the AHB having enough juice. (These power numbers are clean power, not rated.)

 

[Hayabusa]

yeah I was wondering about room gain.

My first choice is would be an AHB2 (~190W), then a Purifi (260-300W), then a NC1200 (500W). I’m really a little concerned about the AHB having enough juice. (These power numbers are clean power, not rated.)

I would first check your impedance minimum and check which amp would do best at that load.
I think maggies are around 4 ohm, and even lower at higher frequencies?

 

[tensor9]

I would first check your impedance minimum and check which amp would do best at that load.
I think maggies are around 4 ohm, and even lower at higher frequencies?

this is an impedance curve for the 3.7i I found on the web. Nor sure if it’s accurate.

there is a big dip to 2 Ohm around 500 Hz, and the higher frequencies are round 3 Ohm.

 

[maty]

Distance to the Magnepan 3.7i? To estimate the power you need at 2 Ohms.

 

[tensor9]

Distance to the Magnepan 3.7i? To estimate the power you need at 2 Ohms.

12 feet

 

[Hayabusa]

this is an impedance curve for the 3.7i I found on the web. Nor sure if it’s accurate.

there is a big dip to 2 Ohm around 500 Hz, and the higher frequencies are round 3 Ohm.

Ok, so at 2 ohm the 1ET400A current limits at 450watt, the AHB2 also current limited at 200watt and the NC1200 does 1200watt...

 

[maty]

12 feet (3.6 m).

https://www.magnepan.com/model_MG_37

Freq. Resp. 35Hz- 40 kHz
Rec Power Read Frequently Asked Questions
Sensitivity 86dB/500Hz /2.83v
Impedance 4 Ohm
Dimensions 24 x 71 x 1.625 inches

At 8 Ohms: dB/W/m = dB/2.83v/m

Calculations if they were 8 Ohms speakers.

80 dBSPL continuos is loud. If you listen to very good recordings with high/very high DR like me, at least DR15 -> You want 95 dBSPL at 3.6 m.

https://www.doctorproaudio.com/content.php?2273-calculators-proaudio-sound-dmx&langid=1#calc_spl

At 4 Ohms -> 100 watts.

At 2 Ohms -> 200 watts.


Problem, the amplifier will work near the limit so you need one that is well built and capable of supplying a large amount of current and, if possible, does not generate a huge amount of heat inside.

Using Hypex SMPS does not seem like the best idea for 2 Ohms loads. Better with forced cooling with very quiet fans like the very silent Noctua.

 

[maty]

NC500 with forced cooling (Noctua), from Norway:

https://www.diyaudio.com/forums/vendor-s-bazaar/281361-hypex-ncore-nc500-build-post5957553.html

-> https://www.vera-audio.com/product.php?product_id=1

If you want a class D, you can contact with Apollon Audio, Rouge Audio, ATM or Vera Audio... (better to avoid Nord, I think) to build a specific one for you, with Noctua. Hopefully, PURIFI 1ET400A Asian modules will be available in a short time, much cheaper than those used so far. $ 200 less by module than European.