BOXEM Audio | Arthur 4215/E2 Purifi Amplifier | Owners' Thread

[n00brx]

I have received my Boxem Purifi last month and after 1 month of listening.
I really love the auto-sense on/off function. This is a life saver as I am using RME ADI-2 DAC which do not have any trigger out.
I also found the gain stage selector is much more useful then a jumper inside the box and I can play with the gain stage on-the-fly without any pops and noise.
Finishing of the case is way better than what I expected and the texture is unique to touch and feels really fancy. One minor thing regarding the LED indicator to be too bright can be improved by adding an option to dim it.
Finally about the sound quality which is very good sounding, as I found the IMD and SINAD is higher than my previous Hypex252 AMP.
I can subjectively tell (maybe placebo) there is less distortion from the purifi, I listen to music quite loud at 2M which is around 95db peak.

Anyway, this is one of the most satisfied HiFi purchasing experience and I really recommend anyone looking for the end game stereo speaker amp.

Please excuse my bad English as this is not my mother language

 

[boXem]

Wonderful! Any approximate figures for the crosstalk too? Thanks!

Quick and dirty measurement done this afternoon for you:

 

[JensenW]

Quick and dirty measurement done this afternoon for you:
View attachment 210032

Thank you very much!

 

[boXem]

While we are at the nice pictures:

 

[EdW]

While we are at the nice pictures:
View attachment 210033

With distortion figures at low power as good as any Purifi based amplifier and crosstalk better than any amplifier Amir has tested, along with auto power on/off and great build quality, we may have here the best class D amplifier to date?
Great if you could add some performance graphs on your webpage.

Longing to see Amir review this amp to see just how it compares

 

[Matias]

While we are at the nice pictures:
View attachment 210033

Wow, what is the SINAD of this?

 

[boXem]

Wow, what is the SINAD of this?

High gain 104.5 dB
Medium gain 107 dB
Low gain 108 dB

 

[EdW]

High gain 104.5 dB
Medium gain 107 dB
Low gain 108 dB

Flawless

 

[JensenW]

High gain 104.5 dB
Medium gain 107 dB
Low gain 108 dB

This is brilliant!

Will hot-switching between different gains while playing music cause any pops on the speakers or harm to the amp?

And how fast and sensitive is the auto sense? Some tracks inconveniently start with full afterburners right at 00:00:0000 while some tracks start with sounds that are quieter than whisper.

 

[boXem]

This is brilliant!

Will hot-switching between different gains while playing music cause any pops on the speakers or harm to the amp?

And how fast and sensitive is the auto sense? Some tracks inconveniently start with full afterburners right at 00:00:0000 while some tracks start with sounds that are quieter than whisper.

Gain changes are pop free.
Sensitivity of the audiosense is around -60 dBu, it takes about 2.5 seconds between detection and amplifier playing.

 

[JensenW]

Gain changes are pop free.
Sensitivity of the audiosense is around -60 dBu, it takes about 2.5 seconds between detection and amplifier playing.

The audiosense is very useful in most cases, it's definitely useful for me too, though I'm curious if there is a way to bypass it somewhat like when I'd like it to keep being on while I pause the music for the occassional short chat with a neighbor at my door?

 

[boXem]

The audiosense is very useful in most cases, it's definitely useful for me too, though I'm curious if there is a way to bypass it somewhat like when I'd like it to keep being on while I pause the music for the occassional short chat with a neighbor at my door?

If the short chat is less than 10 minutes, the amplifier will still be on when you are back.

 

[GiFi]

High gain 104.5 dB
Medium gain 107 dB
Low gain 108 dB

Wich are the values of impedances relative to the different gains?
Thanks

 

[boXem]

Wich are the values of impedances relative to the different gains?
Thanks

Input impedance is 94k (2*47k to GND), whatever the gain.

 

[GiFi]

Many thanks

 

[Zenek73]

@boXem | audio Any plans to offer preamp? I have dac without volume reg - I could buy RME but I'm not sure if I need such complex device

 

[boXem]

@boXem | audio Any plans to offer preamp? I have dac without volume reg - I could buy RME but I'm not sure if I need such complex device

It's in the works, I would like it to be ready for Q4.

 

[MCH]

Are you open to suggestions?

Multuchannel, stepped attenuator with remote and screen. Selectable balanced and unbalanced inputs and outputs. Small but with full size balanced connectors. And cheap, very cheap.

 

[boXem]

I try to be an open minded guy
- multichannel not really but a bit
- stepped attenuator yes
- remote yes
- screen probably (evaluating solutions right now)
- selectable IOs yes
- same case as the Arthur series
- made in EU

 

[MCH]

I try to be an open minded guy
- multichannel not really but a bit
- stepped attenuator yes
- remote yes
- screen probably (evaluating solutions right now)
- selectable IOs yes
- same case as the Arthur series
- made in EU

Looking good!

Don't know what other people think, but a sort of indication of where the volume is, is kind of necessary, isn't it? Be it screen or something like this