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

[groovybassist]

Have spent 10 days now with the Arthur 4215 and have the following to share:

1) The variable gain setting allows me to pair my Matrix Audio Element X with the 4215 set to Low gain. In this configuration, the 4215 is utterly silent - pressing your ear nearly on a tweeter there’s zero noise. Nice. As you would expect, this very low noise configuration yields very transparent playback.
2) I like the Audio Sense feature more than I thought I would. Having the amp take care of itself is great, especially for my wife.
3) I’m using stand-mounted speakers (PSB B600 - easier to manage as I age) to fill a large space and the 4215 has plenty of power to take charge of the B600s. Increasing the volume just makes things louder - no sense of strain at all.
4) Fred was responsive to my questions, built the amp quickly, had it ready/shipped when he said he would and the fit/finish is very well done. While those seem like things that should be expected in every purchase, I’m amazed at how often these simple expectations aren’t met, so I commend Fred for making the process quick and easy.

All in all, I’m very happy with this purchase!

 

[Extreme_Boky]

Dare I ask the obvious... how does it sound?

 

[groovybassist]

Dare I ask the obvious... how does it sound?

Like it simply plays whatever signal it’s fed. Rightly or wrongly, one of my arbiters of how faithful to the recording a component is, is how well it differentiates each piece of music played through it. If every piece of music takes on a certain characteristic, I consider that component as coloring the signal it’s fed. With the 4215, it’s very clear the vast differences between recordings - to me, that’s a sign that the 4215 is simply passing on what it’s fed.

 

[Extreme_Boky]

Thank you, that seems like a great amp you have there.

 

[bbforce]

Have spent 10 days now with the Arthur 4215 and have the following to share [...]

I have mine in use now for almost one year and I could not be happier - the unit works without any flaws and drives my Klipsch Palladium P-37F with ease. Simply a great product!

 

[Garlic]

hello,

What is the dept total depth including the binding posts and with XLR cable plugged in ?
I'm quite interested in this model but have a size (depth) limit on my bookshelf (33,5 cm)

any known issues with using a RCA source and therfore a RCA to XLR cable ?

I'll be using a NAD C700 as my source.

thanks

 

[bbforce]

Fred (boXem | audio) answered this for me as follows:
31.8 cm of amplifier + about 4 cm of banana + about 5 cm of cable radius = about 41 cm.

 

[Garlic]

Fred (boXem | audio) answered this for me as follows:
31.8 cm of amplifier + about 4 cm of banana + about 5 cm of cable radius = about 41 cm.

Thanks !

too big for my shelf

 

[ivo.f.doma]

Is a variant with cinch connectors also possible? And would the same sensitivity of up to 27dB remain with unbalanced power supply?

 

[boXem]

There is no real demand for RCA, and having both XLR and RCA is difficult due to lack of space.
The gain would not change anyhow.

 

[ivo.f.doma]

Well thank you. So if I use an RCA to XLR cable, what output voltage from the AVR will I need at the highest gain setting of the amplifier to reach its rated maximum power? (up to 8 ohms)

 

[boXem]

Well thank you. So if I use an RCA to XLR cable, what output voltage from the AVR will I need at the highest gain setting of the amplifier to reach its rated maximum power? (up to 8 ohms)

Somewhere between 1.8 and 1.9V

 

[ivo.f.doma]

Well thank you.

 

[Sernyl]

Remains the "problem" : absolute no mercy for technically poor recordings (or further alchemy) and they are a lot...
But is it the music or the technic you are listenig to, right ?

 

[Soez]

I got the boXem 4215/E2 ultimately to be used as the power amp in a chain of WiiM Pro -> Denafrips Ares 12th -> miniDSP Flex Balanced -> boXem 4215/E2, but have not gotten the miniDSP or the DAC yet.

As I couldn't wait, I tried plugging the 4215 into the pre-outs of the Buchardt I150 that's been the workhorse so far with the S400 MK IIs, but it doesn't sound quite right. The biggest difference is a significant drop in the 'punch' of bass, be that kick drum, double bass, or something more electronic. As this should not be the case -- frankly I was expecting the effect to be the opposite -- I'm trying to figure out what the issue is. I would blame the cheap Stagg RCA-to-XLR cables, but I guess on this forum the consensus is that cables shouldn't sound different. Anyway, I'm also getting proper Mogami cables with Neutrik connectors, and of course want to get the miniDSP and the Ares hooked up -- but I have understood the I150 should also be a rather high quality pre-amp, so would be surprised if the issue lies there.

Having said all this, I'm by no means a professional and can't do proper measurements at home, other than what e.g. Dirac will enable with the UMIK-1. But the difference is very audible, I am sure most if not all of the people here would hear it very quickly on certain tracks.

Any ideas at this point what the issue could be if not cables?

I will also get a chance to test with the Audiophonics HPA-S400ET Sparkos edition in a couple of weeks, if I haven't figured out the issue otherwise by then.

 

[boXem]

I got the boXem 4215/E2 ultimately to be used as the power amp in a chain of WiiM Pro -> Denafrips Ares 12th -> miniDSP Flex Balanced -> boXem 4215/E2, but have not gotten the miniDSP or the DAC yet.

As I couldn't wait, I tried plugging the 4215 into the pre-outs of the Buchardt I150 that's been the workhorse so far with the S400 MK IIs, but it doesn't sound quite right. The biggest difference is a significant drop in the 'punch' of bass, be that kick drum, double bass, or something more electronic. As this should not be the case -- frankly I was expecting the effect to be the opposite -- I'm trying to figure out what the issue is. I would blame the cheap Stagg RCA-to-XLR cables, but I guess on this forum the consensus is that cables shouldn't sound different. Anyway, I'm also getting proper Mogami cables with Neutrik connectors, and of course want to get the miniDSP and the Ares hooked up -- but I have understood the I150 should also be a rather high quality pre-amp, so would be surprised if the issue lies there.

Having said all this, I'm by no means a professional and can't do proper measurements at home, other than what e.g. Dirac will enable with the UMIK-1. But the difference is very audible, I am sure most if not all of the people here would hear it very quickly on certain tracks.

Any ideas at this point what the issue could be if not cables?

Did you try different gain settings?

 

[Soez]

Did you try different gain settings?

Yes, at first it was on Low, and the difference was very significant. Then I switched it to High, and then the difference is narrow, but still audible. As a power amp the 4215 should of course be clearly above the built-in NCore of the I150 both in terms of power and overall quality, so something gives. My first reaction was "my god, these cables sound terrible", but I know that would not be the first hypothesis on this forum.

Anyway, I will get more data points as I get to try with high quality cables and get the other components in place. Just sourcing for ideas on what might explain the difference.

 

[boXem]

Yes, at first it was on Low, and the difference was very significant. Then I switched it to High, and then the difference is narrow, but still audible. As a power amp the 4215 should of course be clearly above the built-in NCore of the I150 both in terms of power and overall quality, so something gives. My first reaction was "my god, these cables sound terrible", but I know that would not be the first hypothesis on this forum.

Anyway, I will get more data points as I get to try with high quality cables and get the other components in place. Just sourcing for ideas on what might explain the difference.

From your description, I wonder if the gain structure of the Buchard makes it playing louder than the boXem, even in high gain. Did you try to raise the volume setting by a few dB when playing the boXem?

 

[Soez]

From your description, I wonder if the gain structure of the Buchard makes it playing louder than the boXem, even in high gain. Did you try to raise the volume setting by a few dB when playing the boXem?

Will test tomorrow.

FWIW, my experience is a bit similar to what 'Thomas & Stereo' on Youtube described talking about his experience with the Purifi DYI kit, video here. He addressed it by using another input buffer board (from Neurochrome).

Now, I've read so much good stuff about the 4215/E2 that I'm expecting to find a more straightforward explanation/solution that will bring the sound at least on par with the I150, and ideally above. Of course, some things are also a matter of taste, but I really really like the 4215 as a product overall and I want to get it to sound the best it can. I find the looks (to my taste) and build quality superior compared e.g. to the Audiophonics, which ultimately was the decisive factor as I expected the amps to be almost identical otherwise.

Interestingly, as the Audiophonics is more widely reviewed, some have described bass as its strongest points, e.g. here. As I will get to test also the Audiophonics (the Sparkos edition) in a couple of weeks, we should ultimately get to the bottom of this. Just wanted to open up the discussion if someone else might find this interesting also.

P.S. Not sure if this is also in some ways an unfair comparison, as the I150 has been designed specifically for the Buchard passives.

 

[theREALdotnet]

As I couldn't wait, I tried plugging the 4215 into the pre-outs of the Buchardt I150 that's been the workhorse so far with the S400 MK IIs, but it doesn't sound quite right. The biggest difference is a significant drop in the 'punch' of bass, be that kick drum, double bass, or something more electronic. As this should not be the case -- frankly I was expecting the effect to be the opposite -- I'm trying to figure out what the issue is. I would blame the cheap Stagg RCA-to-XLR cables

I wonder whether shorting the (3) pins of the left and right inputs of the boXem could have that effect, because that’s what you’re doing when using RCA-to-XLR cables. The screen (cold) contacts of the left and right RCA pre-out sockets are almost certainly connected on the Buchardt side.