Just a reminder that /we Purité Audio have BoXem ‘Arthur’ demonstration units available.
Below a super testimonial from a Boxem customer.
‘Boxem Arthur 4215/E2 arrived recently. It offers a nice looking external chassis. The package was double boxed and DHL took good care of it. DHL is an amazing service. Delivering the unit to the United States within 48 hours of shipping from Luxembourg at about the same shipping cost as an 8 pound package via Fedex within the USA. I was impressed.
The chassis is 8 7/8" wide by 11 1/8" deep by 3 1/8" tall (binding posts excluded). This Stereo PURIFI 1ET400A based chassis design is the smallest by volume when compared against the March Audio P452 or the Buckeye 1ET400A amps. On a looks basis, the rounded aluminum March Audio case is a bit more visually appealing but the Boxem case is a big step up from the bare bones Buckeye Purifi chassis. The Arthur 4215/E2 chassis design reminds me a little bit of a high quality hard drive case from the 1990's when hard drives were all 5.25" in size. The finish is a matte dark gray with a slight texture on the sides while the front panel is jet black. Once out of the box, the chassis weighs 6 lbs 9 ounces. For its size, the 4215/E2 has a feeling of weight. It doesn't come with a USA type power cord so I found a nice one in my box of spare power cords.
A 3-way toggle gain switch is available on the back. It supports 12.8, 20.8 and 27.2dB gain settings. The switch is located beneath the high quality ETI binding posts. After trying all three gain positions with the RME ADI-2 DAC FS, I settled on the medium setting which offers 73dB volume levels with the Revel F328Be speakers when the ADI-2 volume setting is at 19.5. Fred at Boxem Audio is flexible with amp builds which allowed me to upgrade to the ETI KRYO Silver Plated Tellurium Copper binding posts. (
https://eti-research.com/kryo-connectors/) These binding posts are finely crafted and a joy to use with my silver Viborg VB401S Banana Plugs.
According to Kill-a-watt, the Boxem Arthur 4215/E2 uses 14W while idle. Even with the RME ADI-2 DAC FS set at 19.5 using the middle Boxem gain setting of 20.8dB, the reading never exceed 14W while the F328Be speakers were playing at 73dB levels in a large room. The Purifi design offers the best power efficiency I have tested for an amp in this class. (Compare that to the NCx500 model 5519/N2 which idles at 26W). Boxem takes it even further with circuitry on board that reduces power use after approximately 9 minutes of inactivity from 14W idle to 0.5W in standby mode. Once music is detected on the XLR input "B" the amp turns back on within approx. 3 seconds. If you don't typically turn the amp off when not playing music, this is a nice feature to limit phantom power consumption.
The Boxem Arthur 4215/E2 design incorporates Texas Instruments OPA1656 Burr-Brown op amps designed specifically for uses where audio fidelity is crucial.
https://www.ti.com/lit/ds/symlink/opa1656.pdf?ts=1712286380724&ref_url=https%3A%2F%2Fwww.mouser.com%2F
In a recent Bruno Putzeys video interview he shared a preference for the OPA1656 with the Purifi amp. This was interesting as both the March Audio and the Buckeye Purifi amps were being built with the OPA1612. One difference between the 1612 vs 1656 is the 1656 has higher output current availability. While technically the 1612 should be powerful enough to drive the Purifi modules, it does appear to be pushing pretty close to its maximum levels for output voltage (considering +/- 12 VDC rails). Perhaps the greater headroom of the OPA1656 could be responsible for a subjectively better sound quality alluded to by Bruno? I still need to spend time with the Boxem 4215/E2 before I can consider whether I have a preference between the OPA1656 vs OPA1612.
Thank you Fred for all of your hard work. I appreciate your attention to detail and the quality amp builds you are producing at Boxem.’
Keith
www.puriteaudio.co.uk
