Review and Measurements of Purifi 1ET400A Amplifier

[Audiocrusader]

All class D amps from Purifi, Hypex and Icepower can drive any load there is. Even 0.2 ohms if need be. There's no minimum impedance like old class A and A/B amps of yesteryear. Instead they use current limiters. And only if these current limiters are triggered, the load is too much. And when these current limiters trigger, nothing bad happens. The amps just gently mute. So feel free to use any of these amps with any speaker on the market. And if the current limiters ever happen to trigger, it only means the amp is underpowered for the levels you listen at. But I've never heard a single report of anyone ever driving a modern class D amp from Hypex, Icepower or Purifi with a domestic speaker to the point of the current limiter triggering.

Please stop listening to the BS from the senior citizen audiophile forum community. 98% of what they say on audio forums is pulled directly from their asses.

 

[tensor9]

I think @March Audio posted a video of the NC going full power for 6 minutes and barely heating up. I haven’t tested it, but I think the “Class D can’t do low impedance” is a canard.

I get that, but I'm just referring to Purifi's own listed spec being less than what it can do.

 

[March Audio]

Is the 1ET400 a little under spec'ed (EDIT: manufacturer was overly conservative with the listed spec) into 2 Ohms? Do they only claim 450W into 2 Ohms because it just can't officially sustain that current for prolonged periods of time?

The 1Et is current limited at 25 amps. Long term power delivery is only thermally limited so as long as it stays cool enough then no issue. The Hypex have no issues with running high power levels and temperature but it should be noted the 1et has improved efficiency further. I have run them on the desk at normal volumes without any further heatsinking and they remained cool.

 

[Hayabusa]

The 1Et is current limited at 25 amps. Long term power delivery is only thermally limited so as long as it stays cool enough then no issue. The Hypex have no issues with running high power levels and temperature but it should be noted the 1et has improved efficiency further. I have run them on the desk at normal volumes without any further heatsinking and they remained cool.

Tensor9 has a point here. Why they spec so much less than the current limit could reach? Is the 25 amps RMS or peak? If it is peak, the power at 2 ohm whould be 625 watt and if 25A is RMS, its even 1250 watt.

 

[March Audio]

Tensor9 has a point here. Why they spec so much less than the current limit could reach? Is the 25 amps RMS or peak? If it is peak, the power at 2 ohm whould be 625 watt and if 25A is RMS, its even 1250 watt.

I would suggest, but this is only a guess, that it due to thermal limitations on specific components.

 

[Soniclife]

I would suggest, but this is only a guess, that it due to thermal limitations on specific components.

Do these modules monitor their own critical temps at the relevant points?

 

[DS23MAN]

I would suggest, but this is only a guess, that it due to thermal limitations on specific components.

The output coil is the thermal limiting factor.

 

[Hayabusa]

Do these modules monitor their own critical temps at the relevant points?

The documentation mentions overtemp protection of the heatsink set at 75c, but as far as I know the outputcoil temperature is not monitored.

 

[dkinric]

As we are awaiting reports of more amplifiers available with the Purifi modules, I was going down the Google hole and risked a click on 6moons. Usually entertaining for what it is, I thought it would be interesting to share a sample of the subjective impressions of this module from the other side of the fence.
In case you need a translation, the subjective impressions reflected the good measurements.

This sound was completely free from any exhibitionist explicitness of the detail uber-alles school. That slices and dices detail like a flamboyant TV chef who shows off his high-speed julienne technique in closeup. The bass was blessedly free of that cyborg gestalt which converts a redolent acoustic upright and percussion into hyper-damped synthetic bass and robotic drum machines. As such also the vital upper bass lacked that signature dry-yet-pinched feel to instead be properly rotund and texturally generous. The sound also missed any and all edge pixilation and surface gloss, the latter a routine artifact of excess airiness. Finally musical phrasing or flow wasn't hampered by even remnants of mechanical rigidity.

 

[Willem]

The verbal diarrhea is astounding. This is not only scientific nonsense, but also shows a gross disrespect for elegant literary style.

 

[ti33er]

Lol well I found this to be the case with my ex nc500 “The sound also missed any and all edge pixilation and surface gloss”

...I (and another) found that amp to sometimes exhibit a ‘plasticy’ sound, but let’s leave this before it starts another furious derailment off topic argument

Bring on the DIY modules; I’d like to hear it for myself

 

[digicidal]

The verbal diarrhea is astounding. This is not only scientific nonsense, but also shows a gross disrespect for elegant literary style.

I get that the desire to drive page views and banner impressions on the site basically requires long-winded prose fests... but I have to agree with you. There is a point at which verbosity becomes obstructive to the purpose of communication... and that review crossed that line early and at a high rate of speed.

Edit: New favorite reason for going with a Purifi amp... it avoids shorting things out and apparently damps reflections as well:

On textures, the DC-coupled class AB amps acted shinier and wetter. The Purifi amp played it more matte and dry.

I can think of literally nothing worse than a soggy, highly reflective listening room... luckily my AB's seem to just amplify signals so far... but why risk running them when you can be safe with the Purifi amps?

 

[murraycamp]

This sound was completely free from any exhibitionist explicitness of the detail uber-alles school. That slices and dices detail like a flamboyant TV chef who shows off his high-speed julienne technique in closeup. The bass was blessedly free of that cyborg gestalt which converts a redolent acoustic upright and percussion into hyper-damped synthetic bass and robotic drum machines. As such also the vital upper bass lacked that signature dry-yet-pinched feel to instead be properly rotund and texturally generous. The sound also missed any and all edge pixilation and surface gloss, the latter a routine artifact of excess airiness. Finally musical phrasing or flow wasn't hampered by even remnants of mechanical rigidity.

Before the Purifi modules were developed, I couldn't really enjoy the music because of all the "exhibitionist explicitness," "cyborg gestalt," "dry-yet-pinched feel," and most of all the "edge pixilation and surface gloss." I just didn't know it at the time. Man, I'm sure glad all that has been taken care of. Like a giant weight lifted off my ass ears.

Now I just have worry about electrosmog.

 

[digicidal]

Now I just have worry about electrosmog.

I'm pretty sure that's the one of the reasons why exotic power conditioners seem to be required in audiophile circles. (BS filters decidedly less so unfortunately).

 

[murraycamp]

I'm pretty sure that's the one of the reasons why exotic power conditioners seem to be required in audiophile circles. (BS filters decidedly less so unfortunately).

Yes, because there is an inverse correlation between electrosmog and PRAT, and maybe bloom too. I mean, everyone knows this to be true. Because they read it on the internet.

 

[ti33er]

I’ve never heard an improvement with my mains conditioner. It is only there to make me feel more secure with potential dodgy power in my flat. I don’t use on my power amp anyway

 

[JimB]

...
Edit: New favorite reason for going with a Purifi amp... it avoids shorting things out and apparently damps reflections as well:


I can think of literally nothing worse than a soggy, highly reflective listening room... luckily my AB's seem to just amplify signals so far... but why risk running them when you can be safe with the Purifi amps?

Well, I can actually relate to this one. I once described the primary difference in listening experience between two models of speaker as like the difference in glossy, vs matte photofinishing. The 'glossy' experience felt more critically detailed (and satisfying in that way), but the 'matte' experience felt a bit more real-world. What to choose, what to choose. Speakers, in real rooms, vary, tremendously (unlike DACS and most amps).

 

[digicidal]

Well, I can actually relate to this one. I once described the primary difference in listening experience between two models of speaker as like the difference in glossy, vs matte photofinishing. The 'glossy' experience felt more critically detailed (and satisfying in that way), but the 'matte' experience felt a bit more real-world. What to choose, what to choose. Speakers, in real rooms, vary, tremendously (unlike DACS and most amps).

I have no problem with this being a description of loudspeakers. The idea that the character of the speaker in room changed from one to the other based solely on the switching of amplification I find laughable. Even many of my speakers that are very close to each other in measurements still are very different in listening (mostly because of differing dispersion characteristics).

So many subjective reviews (that one in particular) read like more of an analysis of the musical content itself first, and speakers second - than the gear the review is supposed to be considering. This makes sense, as those are much more audible than the amp/DAC/cable/etc. - but to me it also exposes the fact that even those with supposedly golden ears can't actually hear a significant difference, and must therefore resort to describing the artist/recording/instruments as somehow indicative of the devices in the signal chain.

 

[Willem]

+1

 

[dkinric]

Hi

I'm currently at the Melbourne Hifi show. I was hoping to have the final release product ready for the show but the enclosures only arrived yesterday afternoon. So it doesn't look like we are going to be demoing them.

However this does mean the amps will be good to go in a couple of weeks (it's going to take us 3 1/2 days to drive back . Purifi are ready for orders.

@amirm , given the interest in these amps, the availability now of top measuring DACs, and the upcoming holiday sales, can this review be a priority? When can we expect to see a production model review?