Lumin P1 streaming D/A preamplifier

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I start this review with a confession. I have consistently found that when I play CDs on a transport and feed the digital data via AES3 (AES/EBU) to a D/A processor, the music has more drive, particularly at low frequencies, than it does when I send the same 16/44.1 data to the same D/A processor via my network. However, these days I almost always stream my music rather than playing physical discs. Not only is it much more convenient; the wealth of metadata available with Roon 1.8 is addictive. I also have convenient access to much more music: my growing library of hi-rez files and hi-rez music streamed from Qobuz.

I don’t understand why there should be an audible difference between AES3 and network audio. The data are the same in both cases, and the reclocking of those data when fed to the processor’s DAC chips should be identical. And if the reclocking isn’t identical, the timing accuracy should favor the network connection, where the clock doesn’t have to be extracted from the datastream, as it does with AES3. In any case, for the reasons stated above, I always keep my ears open when I try new streaming D/A processors, like the one under review here, the $10,000 Lumin P1 from Hong Kong–based Pixel Magic Systems.

The P1
The elegant-looking P1 offers a complete set of digital inputs—AES3, S/PDIF (coaxial and TosLink), plus USB and Ethernet (electrical and optical) with full MQA decoding—adding to that balanced and unbalanced analog inputs, one HDMI 2.0 input, and three ARC-enabled HDMI 2.0 outputs with 4K video passthrough. The P1 offers balanced and single-ended analog outputs and S/PDIF (BNC) and USB digital outputs. The P1’s gently curved front panel displays the volume setting or metadata for streamed music being played, including bit depth and sample rate, though not the album cover. The Roon Ready P1 can be controlled with Roon or with Lumin’s own app for iOS and Android devices. It comes with a slim, solid remote control.

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The elegance continues inside the case. The linear power supply for the analog circuitry is based on a shielded toroidal transformer. The digital and analog input circuitry is housed on one printed circuit board; the dual-mono, solid state output circuitry (balanced and unbalanced) and the D/A converter chips—a pair of ES9028PROs capable of processing PCM data up to 384kHz and DSD data up to DSD512—are on a second board. The analog outputs are coupled to the outside world with a pair of premium-quality Lundahl transformers.

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The USB input uses an XMOS controller, and the DAC chips are clocked with what Lumin refers to as “Femto Crystal Oscillators” with “precision FPGA distribution.” The P1 has a volume control based on Leedh processing (footnote 1), which was invented by Gilles Millot of Acoustical Beauty, a French high-end loudspeaker manufacturer. Leedh minimizes the number of additional bits introduced in mathematical operations to reduce or eliminate the truncation-related loss of information. The P1’s Leedh volume control operates with 32-bit precision. Leedh processing is the P1’s default setting; it can be disabled with the Lumin app for with/without comparisons.

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Installation
When I connected the P1 to my network, it was recognized by Roon 1.8 as “Lumin X1.” (The X1 is the P1’s bigger brother.) The small image of the P1 on Roon’s Audio Settings page confirmed that it was a legitimate Roon Ready device. I enabled the P1 as a Roon endpoint, setting the volume control to “Device control” and MQA decoding to “Decoder and renderer.” Lumin recommends burning in the P1 for 400–500 hours; with outputs not connected, I streamed audio to it for five days. At the end of that time, I connected the P1’s balanced outputs to my Parasound Halo JC 1+ monoblocks, reduced the volume control to a relatively low value, selected a file with Roon, and pressed “play.”

Nothing.

I told Lumin and Source Systems, the company’s US distributor, about the problem (footnote 2), and a second sample was shipped tout de suite. I set up the new P1, made sure its firmware was the current version, and made the necessary connections. Success! I had sound via both digital and analog connections. I repeated the burn-in and started my critical listening.

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The L1
Along with the second sample of the P1, Source Systems sent this diminutive, network-attached UPnP server, styled to match the P1 and powered by a 12V wall wart. The L1 is priced at $1400 for the 5TB version; a 2TB version is also available. The L1 is a network-attached storage device, but not a conventional one. To load it up, you must copy files from a computer via a USB 3.0 port. Once it’s loaded up, the L1’s network port can be connected to the user’s router and the P1 can see it and access music files.

One wrinkle for this Mac user was that the L1’s 5TB hard drive is NTFS-formatted “due to drive size and Windows recognition,” and Macs don’t recognize NTFS drives. Lumin says that the L1 was intended to be populated by simply dragging-and-dropping files from a PC—”it’s not designed for anything else.” To copy files from a Mac, the L1 can be reformatted as a FAT32 drive (for the 2TB version) or exFAT (for the 5TB), or third-party apps could be used to allow the drive to be recognized by a Mac. For simplicity’s sake, I copied my music library onto the L1 using a USB connection from a Windows 10 PC that lives in the test lab.

Once the L1 has been populated and connected to the network, it scans the files to create the metadata it displays with the Lumin app. During scanning, its status LED blinks blue. 100 albums take approximately two minutes to scan.

Footnote 1: See processing-leedh.com/, especially this AES paper.

Footnote 2: After this first sample had been returned to Pixel, they discovered that the linear power supply had been wired for 220V operation instead of 115V.

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