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

[boXem]

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.

This way of connecting RCA to XLR allows the XLR input to sense the reference of the signal, so that is the right way to do it. What could have a spectacularly detrimental effect on bass it that one of the cables connects pin 2 to the screen instead of pin 3. I have also seen RCA-XLR cables with pin 3 left floating...

 

[Soez]

This way of connecting RCA to XLR allows the XLR input to sense the reference of the signal, so that is the right way to do it. What could have a spectacularly detrimental effect on bass it that one of the cables connects pin 2 to the screen instead of pin 3. I have also seen RCA-XLR cables with pin 3 left floating...

Good points -- I was wondering if the issue might be something like this. I will soon have the intended fully balanced chain to feed the amp, so can avoid the potentially sketchy RCA-to-XLR step.

Further testing had to wait for now, as my wife's aunt is visiting us for a couple of days. (the setup is in our living room)

 

[Soez]

A quick update. For now just tested simply with the chain of WiiM Pro (which has volume control) --> Denafrips Ares 12th DAC --> boXem 4215/E2, as I have not gotten right the cables to connect through the miniDSP and get Dirac Live set up, yet.

Sound is definitely better than with the RCA-XLR cables from the I150. Of course the DAC is different, also.

Comparing to the setup with the speakers driven by the I150, there was still some difference in bass punchiness -- but this turned out to be simply due to the I150 having Room EQ in use. When I turned it off, the boXem was actually a bit stronger -- which is exactly what I would have expected. So, I'm quite confident now that once the full chain including miniDSP with Dirac Live is set up, the sound will be wonderful.

 

[mindcruncher]

I received it last week and have peeked in the box so everything looks good but i've not set it up yet. Does it still count as i'm an owner?

Need to clean up in my mediabench before I will set it up. It will happen in coming weekend or during the eastern. Been some busy weeks at work but I got some time to actually build my own (first ever) XLR-cables. Kind of proud of it!

 

[Sernyl]

Hi,
First read the manual several times.
....and learn how to do a "Factory reset" ;-)

I've set the amp gain to "Low"

Enjoy !

 

[Hifimayne]

Hi guys. Short question. Does the 4215/e2 board sense the voltage differential of the unused terminal in bridged configuration? Like on the Vera P150/600? Otherwise this would be against Purifys recommendation right? Im curious since boxem offers cables for a bridged setup.

Thanks in advance

 

[boXem]

Hi guys. Short question. Does the 4215/e2 board sense the voltage differential of the unused terminal in bridged configuration? Like on the Vera P150/600? Otherwise this would be against Purifys recommendation right? Im curious since boxem offers cables for a bridged setup.

Thanks in advance

Hi,
The negative out is always sensed. In our case, the negative output is left floating when bridging, like NAD do.
There are others ways to proceed, not sure if they are better.
BTW, there are no "official" recommendations from Purifi about bridging. The main issue when bridging is that one board is not aware of what the other board is doing, especially in case of failure. This can lead to serious problems if not handled properly. So bridging is officially not recommended to avoid "modules in a box slappers" to start playing with it.

 

[Hifimayne]

Hi,
The negative out is always sensed. In our case, the negative output is left floating when bridging, like NAD do.
There are others ways to proceed, not sure if they are better.
BTW, there are no "official" recommendations from Purifi about bridging. The main issue when bridging is that one board is not aware of what the other board is doing, especially in case of failure. This can lead to serious problems if not handled properly. So bridging is officially not recommended to avoid "modules in a box slappers" to start playing with it.

Thanks for your fast answer. Can you explain me how bridging can lead to performance degredation like stated in Purifi's Data sheet.
Page 15

Would be nice to have some sort of schematics of a setup with two 4215/e2 with calogrenant cables bridged. Havent found any.

And lastly. Are your Arthur 4215/e2 still identical to a 4215/e2 shipped in September 2022? (different color, ON Led, materials)

Thanks for your time. Love your products.

 

[boXem]

Thanks for your fast answer. Can you explain me how bridging can lead to performance degredation like stated in Purifi's Data sheet.
Page 15

Would be nice to have some sort of schematics of a setup with two 4215/e2 with calogrenant cables bridged. Havent found any.

And lastly. Are your Arthur 4215/e2 still identical to a 4215/e2 shipped in September 2022? (different color, ON Led, materials)

Thanks for your time. Love your products.

The fact that the two negative output sense are left floating leads to a slight increase in distortion. But the main issue is the one I described above: some diagnostics need special attention. And that is also a performance degradation.

The wiring is quite simple: red signal connector on channel A, positive speaker wire on positive binding A, black signal connector on channel B, negative speaker wire on positive binding channel B. A quick diagram would be a good idea indeed.

We are producing PN# A4215E22512 since 27th Sep. 22. We produced PN# A4215E22412 from March to September 22 but the differences do no impact audio nor visible stuff.
Since beginning of this year the LED is "darkened" and the feet are silver color but we can provide "old style" stuff for special cases.

 

[Hifimayne]

Add the Diagram to the bridge Y cable and theres nothing to get confused about. Interesting that I ordered right at the switch of these revisions Im considering getting a second one wouldnt be mad if my existing amp could get modified rather than modifying the new one to the old revision. Since the light is pretty intense in dark rooms. Otherwise a extremely modern and clean design.

 

[boXem]

Add the Diagram to the bridge Y cable and theres nothing to get confused about. Interesting that I ordered right at the switch of these revisions Im considering getting a second one wouldnt be mad if my existing amp could get modified rather than modifying the new one to the old revision. Since the light is pretty intense in dark rooms. Otherwise a extremely modern and clean design.

PM'd you.

 

[Timsonchin]

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.

I'm assuming you've done your market research, but here's another demand for RCA input . I'm looking into purchasing a full setup: miniDSP SHD -> some Purifi amp -> Focal Aria 948. In the future I might add a home cinema receiver with center Aria CC900 and surround Aria 906, but would prefer to power the main speakers with the same Purifi amp. Most "affordable" receivers only have RCA output... Mainly thinking of marantz cinema 40/50.

That being said: one relevant differentiator between Arthur 4215 /E2 and other Purifi amps is the auto on/off feature. I'm curious, as my sleeping spouse sometimes significantly limits the position of the volume knob, how sensitive is the signal detection? Is it possible that at very low volume, the system won't turn on? And could I change the "detection level" if need be?

 

[boXem]

I'm assuming you've done your market research, but here's another demand for RCA input . I'm looking into purchasing a full setup: miniDSP SHD -> some Purifi amp -> Focal Aria 948. In the future I might add a home cinema receiver with center Aria CC900 and surround Aria 906, but would prefer to power the main speakers with the same Purifi amp. Most "affordable" receivers only have RCA output... Mainly thinking of marantz cinema 40/50.

If the idea is to have SHD -> amp via XLR and receiver -> amp via RCA, just keep in mind that you (or your spouse) would need to manually switch each of the two amp inputs when changing the source. Doesn't seem very practical. Since the SHD has analog inputs, I would do receiver -> SHD -> amplifier and use the SHD remote to choose the source from my couch.

That being said: one relevant differentiator between Arthur 4215 /E2 and other Purifi amps is the auto on/off feature. I'm curious, as my sleeping spouse sometimes significantly limits the position of the volume knob, how sensitive is the signal detection? Is it possible that at very low volume, the system won't turn on? And could I change the "detection level" if need be?

That's funny, I had one customer in the exact same situation as yours one year ago : a miniDSP SHD and a sleeping spouse. When in medium gain, the amp was powering down with volume button at -60 dB. He changed the gain to low and didn't complain anymore.

 

[Timsonchin]

If the idea is to have SHD -> amp via XLR and receiver -> amp via RCA, just keep in mind that you (or your spouse) would need to manually switch each of the two amp inputs when changing the source. Doesn't seem very practical. Since the SHD has analog inputs, I would do receiver -> SHD -> amplifier and use the SHD remote to choose the source from my couch.

That´s an interesting idea. The disadvantage would be to have additional delay (once from home cinema and another 25 ms from minidsp), which might be too much for gaming. I was thinking to get some kind of external switch box with both RCA and XLR I/O, but a good one seems hard to come by at first glance.

That's funny, I had one customer in the exact same situation as yours one year ago : a miniDSP SHD and a sleeping spouse. When in medium gain, the amp was powering down with volume button at -60 dB. He changed the gain to low and didn't complain anymore.

Smart, thx!

You built something very nice! And thanks for the quick reply.

 

[Victoria]

Man. Really jealous of everyone who has managed to pick up one of these beauties, especially with the flamboyant orange front-plate. I know this has probably been asked elsewhere but I'm a little lazy: any reason to pick two separate mono boxes up versus one stereo? I'd probably go dual mono just for the aesthetics, cost be damned.

Also any idea if boXem takes requests to change those binding posts though? Those ETI's really don't cut it for me. Yeah yeah I know they make zero difference in terms of anything but looks; but I do like my binding posts I'm rather vain what can I say.

I had these on my last power amplifiers (with ICEpower modules):

WBT 0763W Midline Binding Post Banana Jack White

WBT 0763W Midline Binding Post Banana Jack WhiteWBT's Crimping method is the preferred technique because it produces a physically and chemically optimum contact point with low transition resistance, which ensures pure signal transmission. For the procedure itself one must first strip the cable...

www.parts-express.com

Anyhow these amplifiers are right up there on my shopping list once I've settled down in a more permanent home and I don't have to keep moving every twelve months or so. Been on Class-D amplification since my ICEpower 125ASX2's from well over a decade ago and have always been itching to jump onto the Purifi bandwagon ever since they sent Amir one of their demo boards forever ago.

 

[boXem]

... I know this has probably been asked elsewhere but I'm a little lazy: any reason to pick two separate mono boxes up versus one stereo?...

Power in low loads, the mono-blocs are able to output 700W in 2 Ohm while the stereo is "limited" to 450W

Also any idea if boXem takes requests to change those binding posts though? Those ETI's really don't cut it for me. Yeah yeah I know they make zero difference in terms of anything but looks; but I do like my binding posts I'm rather vain what can I say.

I had these on my last power amplifiers (with ICEpower modules):

WBT 0763W Midline Binding Post Banana Jack White

WBT 0763W Midline Binding Post Banana Jack WhiteWBT's Crimping method is the preferred technique because it produces a physically and chemically optimum contact point with low transition resistance, which ensures pure signal transmission. For the procedure itself one must first strip the cable...

www.parts-express.com

...

We have nothing against changing components that are not safety/EMI related. So changing binding posts is OK in principle. We need to check the dimensions of the binding posts to determine the feasibility of the operation and then it is a matter of cost/delay. Will PM you.

 

[Ch#K]

Is there a chance that the grey housing will be available again? I would order a 4215 right away.

 

[boXem]

Is there a chance that the grey housing will be available again? I would order a 4215 right away.

Unfortunately no chance to see it back.

 

[Ch#K]

That’s a shame In case anyone owning this spec wants to sell it, please DM me.

 

[Hifimayne]

Unfortunately no chance to see it back.

Hey, I do have a grey body/black frontplate combo. Would it be possible to get two all black 4215/e2 and the grey unit as a trade in option? for @Ch#K

'Arthur Boxem 4215/E2
Grey Body / Black Frontplate
Revision: SEP 22