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Review and Measurements of Purifi 1ET400A Amplifier

Eidie

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Matias

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This is my primary motivator. I'm concerned that the standard 1ET400A doesn't quite provide enough juice to drive my B&W 804s to their full potential at high volumes.
Purifi is working on high power modules, although no specs, release date and price has been released.
 

JimB

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This is my primary motivator. I'm concerned that the standard 1ET400A doesn't quite provide enough juice to drive my B&W 804s to their full potential at high volumes.
What's your impedance frequency curve like? Bridging gets you more voltage swing, but not more current output. That is, it is a benefit for higher impedances, but not lower ones.
 

boXem | audio

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What's your impedance frequency curve like? Bridging gets you more voltage swing, but not more current output. That is, it is a benefit for higher impedances, but not lower ones.
913B804fig1.jpg

The non benefit for low impedances is both true and false.
True because when bridged, each amplifier sees half of the load. In the case of the 1ET400A, the current limit is reached before the voltage limit for impedance below 3.3 Ohm. So 6.6 Ohm when bridged.
False because the current limit is reached at a much higher voltage. So instead of voltage clipping at about 200 W in 6 Ohm for a standard configuration, current clipping occurs at about 750 W in 6 Ohm for a bridged configuration.
But the bridged power is droping quite fast with impedances lowering, and at the minimum of 3 Ohm that we see here, bridged is clipping at about 675 W and non bridged at about 400 W. At 2 Ohm both configurations have the same power before clipping.
 

Matias

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To me these graphs from Vera Audio are brilliant. Makes very simple to check the power difference between stereo/bridged 1ET400A, and where it is current or voltage limited.

https://www.audiosciencereview.com/...io-class-d-amp-build-quality.9895/post-655284

Bridging gets you more voltage swing, but not more current output. That is, it is a benefit for higher impedances, but not lower ones.
In my case, Thiel CS3.7 is 2.7 ohms, stereo puts out about 430W and bridged about 680W.

Yes we do. Through an external cable. Website communication sure needs an update. :facepalm:
You should definitely advertise this more, at least in your thread for followers to know. This makes me now interested in your amp! :) But maybe in 2022...
 
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JimB

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The non benefit for low impedances is both true and false.
True because when bridged, each amplifier sees half of the load. In the case of the 1ET400A, the current limit is reached before the voltage limit for impedance below 3.3 Ohm. So 6.6 Ohm when bridged.
False because the current limit is reached at a much higher voltage. So instead of voltage clipping at about 200 W in 6 Ohm for a standard configuration, current clipping occurs at about 750 W in 6 Ohm for a bridged configuration.
But the bridged power is dropping quite fast with impedances lowering, and at the minimum of 3 Ohm that we see here, bridged is clipping at about 675 W and non bridged at about 400 W. At 2 Ohm both configurations have the same power before clipping.
Yes. At 6 ohms, you are still voltage swing limited, right? Once you are current limited, there is little difference. I wondered about the curve for this particular speaker, because, if it was really about 8 ohms, the advantage of bridged would be quite substantial. But, if the impedance dipped to (for example 3 ohms) over a range where music power tended to be high, their should be relatively little advantage (but not none).

Since you have such an amp, and have characterized the actual performance, we can rely on your data for your case. The Purifi data suggests the maximum output current is 15A RMS (~21.2A peak for sine waves) in the power rating plot. Combined with nominal voltage swings, it appears 2.8 ohms is about the peak for bridged power at about 630W. And it does appear that 2 ohms is the equivalence point. That is, for >2 ohms, one starts to get some power advantage with two modules, bridged.
 

Ricku

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Long time reader, first time signing up and posting!

I was about to pull the trigger on 3 x P451 monoblocks from March Audio, but then I thought I'd just double check here first. Would I gain/lose anything by getting a VTV 3 channel Purifi with the "stock hypex factory buffer" instead? The VTV option is much cheaper.

edit: I'll be running some Arendal 1723 in LCR off an Arcam AVR20 via RCA.
 

goryu

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I was going to get 2 3 channel VTV purifi amps until I learned that they use the hypex buffer, instead of the purifi buffer.
 

Matias

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Long time reader, first time signing up and posting!

I was about to pull the trigger on 3 x P451 monoblocks from March Audio, but then I thought I'd just double check here first. Would I gain/lose anything by getting a VTV 3 channel Purifi with the "stock hypex factory buffer" instead? The VTV option is much cheaper.

edit: I'll be running some Arendal 1723 in LCR off an Arcam AVR20 via RCA.
Welcome. I would go March monos if I were you. Or maybe the new Apollon Pure multichannel amplifier.
https://www.apollonaudio.com/apollon-pure-5-system-purifi-1et400a-multichannel-amplifier/
 

boXem | audio

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Thanks for the report, I turned my eyes on the boxem 4215 with orange front (altough it seems to not being shipped until the end of august ordering now)
We managed to secure a few power supplies that were out of stock and will be able to build a few amplifiers by the end of July. :)
 

jdhiro

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Woohoo! After a two month wait, my Apollon Purifi Stereo Mini showed up today. Here are my thoughts after a hour or two of play.

The Experience
As I've mentioned before, I had to wait quite a bit longer than expected. The package was "stuck in customs" for a long time, but that's confusing to me because UPS didn't even have the package. The amp itself was double boxed very well, even if the packaging wasn't as professional as a big name manufacturer. The amp is wrapped in black plastic, presumably to protect the finish, but it did leave some residue/marks on the glossy finish. Wiping it down with a microfiber cloth didn't seem to help. You have to be close to the amp to see it, but it is there. There are also quite a few fingerprints on the back, so you know this was assembled by hand. Despite it's small size, the unit is quite dense and feels like it's built like a tank. I would absolutely give the build quality an A+. This amp is gorgeous in my opinion. I was a tad surprised that there seems to be no power button anywhere (update: found it, under the amp on the front-left!)

The Sound
I compared this back-to-back with my other stereo amp, an Emotive DR-2. That amp is rated at double the power, as is less expensive to boot. How would they stack up...

I'll start off by saying, whoever says "amps don't change the sound, they just make it louder" is dead wrong. I started off with Fleetwood Mac Dreams. It's... actually a different song between the two different amps, but I'm not sure I can say who the "winner" is. The Purifi is clean, pure, and very articulate. Passages that seem to be "behind the music" really come out. The sound has a certain "airy" character to it. I think that, especially considering the package size, this amp sounds incredible. Switching back to the Emo is confusing. The song is instantly more veiled, and complex passages seem to get just a little more "crashy". At the same time, drums kick harder, bass guitar strings have real presence to them, and the music just seems to have a bit more "crank it up" energy to it. The Purifi is like listening to your favorite band play live in the park, while the Emo is like standing in the front row of a rock concert.

There are also tracks like Daft Punk's Solar Sailer that are quiet bassy tracks that can be turned way up (+0) on the Emo, but with the Purifi mini I start to experience clipping around -5.

My instant reaction is that the Purifi is a better amp overall, but needs a lot more power for these big speakers.

What's my next move? Given the ergonomics of having a huge, heavy amp in my rack, I think I'll hold onto the Purifi and ponder a future with either Hypex 2kW or wait for Purifi to release higher power modules. Or maybe those bridged Purifi would be an option, it's still not clear to me!

64758134984__523002B0-2980-4B36-BDBF-5A5F6284A7A6.jpg
IMG_1670.jpg
 
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pLudio

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I was a tad surprised that there seems to be no power button anywhere, it seems that I can only turn it on with the trigger.
There's a hidden power button below the front, to the right of the left foot (if it hasn't been moved with the updated design).
 

chips666

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Woohoo! After a two month wait, my Apollon Purifi Stereo Mini showed up today. Here are my thoughts after a hour or two of play.

The Experience
As I've mentioned before, I had to wait quite a bit longer than expected. The package was "stuck in customs" for a long time, but that's confusing to me because UPS didn't even have the package. The amp itself was double boxed very well, even if the packaging wasn't as professional as a big name manufacturer. The amp is wrapped in black plastic, presumably to protect the finish, but it did leave some residue/marks on the glossy finish. Wiping it down with a microfiber cloth didn't seem to help. You have to be close to the amp to see it, but it is there. There are also quite a few fingerprints on the back, so you know this was assembled by hand. Despite it's small size, the unit is quite dense and feels like it's built like a tank. I would absolutely give the build quality an A+. I was a tad surprised that there seems to be no power button anywhere, it seems that I can only turn it on with the trigger.

The Sound
I compared this back-to-back with my other stereo amp, an Emotive DR-2. That amp is rated at double the power, as is less expensive to boot. How would they stack up...

I'll start off by saying, whoever says "amps don't change the sound, they just make it louder" is dead wrong. I started off with Fleetwood Mac Dreams. It's... actually a different song between the two different amps, but I'm not sure I can say who the "winner" is. The Purifi is clean, pure, and very articulate. Passages that seem to be "behind the music" really come out. The sound has a certain "airy" character to it. I think that, especially considering the package size, this amp sounds incredible. Switching back to the Emo is confusing. The song is instantly more veiled, and complex passages seem to get just a little more "crashy". At the same time, drums kick harder, bass guitar strings have real presence to them, and the music just seems to have a bit more "crank it up" energy to it. The Purifi is like listening to your favorite band play live in the park, while the Emo is like standing in the front row of a rock concert.

There are also tracks like Daft Punk's Solar Sailer that are quiet bassy tracks that can be turned way up (+0) on the Emo, but with the Purifi mini I start to experience clipping around -5.

My instant reaction is that the Purifi is a better amp overall, but needs a lot more power for these big speakers.

What's my next move? Given the ergonomics of having a huge, heavy amp in my rack, I think I'll hold onto the Purifi and ponder a future with either Hypex 2kW or wait for Purifi to release higher power modules. Or maybe those bridged Purifi would be an option, it's still not clear to me!

View attachment 140228View attachment 140232
Hi
Nice amp
The power button sits on the bottom
Enjoy...
 

JHC

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Thanks for the report, I turned my eyes on the boxem 4215 with orange front .

The 4215/E2 in orange looks great and sounds amazing!

Arthur is my main amp now, kindly disregard all non-ASR approved items u see.

DSC_0024.JPG
 

AudioJester

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Woohoo! After a two month wait, my Apollon Purifi Stereo Mini showed up today. Here are my thoughts after a hour or two of play.

The Experience
As I've mentioned before, I had to wait quite a bit longer than expected. The package was "stuck in customs" for a long time, but that's confusing to me because UPS didn't even have the package. The amp itself was double boxed very well, even if the packaging wasn't as professional as a big name manufacturer. The amp is wrapped in black plastic, presumably to protect the finish, but it did leave some residue/marks on the glossy finish. Wiping it down with a microfiber cloth didn't seem to help. You have to be close to the amp to see it, but it is there. There are also quite a few fingerprints on the back, so you know this was assembled by hand. Despite it's small size, the unit is quite dense and feels like it's built like a tank. I would absolutely give the build quality an A+. I was a tad surprised that there seems to be no power button anywhere, it seems that I can only turn it on with the trigger.

The Sound
I compared this back-to-back with my other stereo amp, an Emotive DR-2. That amp is rated at double the power, as is less expensive to boot. How would they stack up...

I'll start off by saying, whoever says "amps don't change the sound, they just make it louder" is dead wrong. I started off with Fleetwood Mac Dreams. It's... actually a different song between the two different amps, but I'm not sure I can say who the "winner" is. The Purifi is clean, pure, and very articulate. Passages that seem to be "behind the music" really come out. The sound has a certain "airy" character to it. I think that, especially considering the package size, this amp sounds incredible. Switching back to the Emo is confusing. The song is instantly more veiled, and complex passages seem to get just a little more "crashy". At the same time, drums kick harder, bass guitar strings have real presence to them, and the music just seems to have a bit more "crank it up" energy to it. The Purifi is like listening to your favorite band play live in the park, while the Emo is like standing in the front row of a rock concert.

There are also tracks like Daft Punk's Solar Sailer that are quiet bassy tracks that can be turned way up (+0) on the Emo, but with the Purifi mini I start to experience clipping around -5.

My instant reaction is that the Purifi is a better amp overall, but needs a lot more power for these big speakers.

What's my next move? Given the ergonomics of having a huge, heavy amp in my rack, I think I'll hold onto the Purifi and ponder a future with either Hypex 2kW or wait for Purifi to release higher power modules. Or maybe those bridged Purifi would be an option, it's still not clear to me!

View attachment 140228View attachment 140232

Biamp?
 

ezra_s

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We managed to secure a few power supplies that were out of stock and will be able to build a few amplifiers by the end of July. :)
..aaaand ordered one.
 

AudioJester

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That Apollon amp is beautiful, best finish I have seen on a ncore/purifi amp.
If your going to biamp, for simplicity maybe get a 4 channel version and sell the stereo amp?
I was going to pull the trigger on a Nad c298, but now that amp has me thinking. It has adjustable gain as well?
 

Matias

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