Rotel Michi P5 preamplifier
Before starting this review of Rotel’s Michi P5, the 60-year-old, Japan-based audio company’s recent preamplifier design, I thought it appropriate to consider “What is an audio preamplifier? What should it do?” There are plenty of opinions to be found at stereophile.com:
“What a preamp ought to do, apart from changing volume and switching sources, is as little as possible,” wrote Stereophile Editor Jim Austin in his 2017 review of the PS Audio BHK Signature preamplifier.
And yet “the preamplifier is the heart of a system,” noted Technical Editor John Atkinson in his 2013 review of Pass Labs’ XP-30 line preamplifier, “[in] that it colors and adds its own character to every signal that passes through it.”
Every preamplifier has features, from the most minimal (source selection and volume control) through, well, much more. Phono preamp? Balanced inputs, outputs, and circuits? Remote control? Balance control? A nice, big volume knob? A tape loop? A mono button? EQ? Digital room correction? Bluetooth?
And what are you looking for sonically? Straight wires with gain don’t exist, but some preamps aspire to that, while others imprint their sound on the music unabashedly. Buyers get to decide how much editorialization they want, and what flavor.
“More so than other hi-fi components,” the late Art Dudley wrote in a 2005 review of Lamm Industries’ LL2 Deluxe preamplifier, “a preamp is a personal choice: It will probably be your primary way of interacting with the system as a whole, and its selection depends a great deal on finding the balance you want between ergonomics and performance.”
“We may not know what we want from life,” Art noted the following year, in his Cary Audio Design SLP 05 preamplifier review, “but we damn well know what we want from an expensive preamplifier!” So, what about the Michi P5 from Rotel? Is it what you want in a preamplifier? Let’s find out.
Rotel’s Michi
Rotel has long specialized in high-value, minimalist electronics. Introduced more than a quarter-century ago—in 1993—Michi (in Japanese, “michi” means “road” or “path”) was the company’s line of statement electronics. The Michi RHCD-10 CD player, RHA-10 preamplifier, and RHB-10 power amplifier were finished in gun-metal gray with red-lacquered, wooden side panels.
Michi faded away (as Rotel continued on) until early 2020, when the Michi brand was revived. The new Michi line looks strikingly different from the original: The P5 Control Amplifier ($3999.99—the component under review), S5 Stereo Amplifier ($6999.99), and M8 Monoblock Power Amplifier ($6999.99) are all finished in a subtle, black matte coating with a glass front panel and a gorgeous, high-quality remote control.
The Michi P5 is big—19″ × 6″ × 17.75″ deep—and quite heavy at 50.5lb. It includes a moving coil/moving magnet phono stage, dual AKM-based DAC chips capable of 32-bit/768kHz and MQA support, Bluetooth with both aptX and AAC support, a headphone jack, balanced and unbalanced inputs and outputs, and fully balanced circuitry.
The P5’s design is minimalist: curved corners, sleek casing of anodized aluminum, a glass front panel, and two symmetric knobs. Left and right rotary dials are for input choice and setting volume, respectively; those functions and others are also supported by the remote control. A small, recessed on/ off button lies dead-center near the P5’s lower edge; its tiny center glows white when in use, red in standby mode.
The P5’s casework, including top and bottom plates, is constructed of anodized aluminum of thickness varying from 4mm to 4.5mm. Tempered glass covers the face of the unit, save its rounded corners, including the 2½” × 4¼” display. Slim heatsinks run down the sides of the P5’s case. “The chassis is powder-coated inside and outside, ensuring a clean, efficient design, but it’s also resistant to all elements,” Daren Orth, Rotel’s chief technology officer, wrote to me in an email.
Four custom-engineered, solid aluminum feet support the P5; the cushions are “of an anti-vibration material that has been tested and evaluated to provide an excellent balance of rigidity and malleability required for the preamplifier,” Orth told me.
The P5’s feature set, in contrast to the design aesthetics, is maximalist. There’s a built-in DAC and a phono preamp. There are even bass and treble controls resembling those in many car stereo systems. Accessible via the left button/knob, source options include analog choices labeled CD, Phono, Tuner, Aux 1 and 2, and XLR 1 and 2. Digital-input choices include S/PDIF in coaxial (RCA) and optical (TosLink) versions (three of each), as well as Ethernet, USB, and Bluetooth (the latter wirelessly of course). All inputs can be renamed. Each input and output has a corresponding rear-panel connection, as you would expect; these inputs are supplemented by a USB power source (for powering a compact streamer), a 3.5mm connection for an industry-standard IR remote receiver, a Bluetooth antenna, two 12V trigger connections, and an RS-232 port for integration with home-automation systems.
Also around back are four main outputs—two pairs each of unbalanced (RCA) and balanced (XLR)—a mono subwoofer output, and an unbalanced (RCA) line-level output, which bypasses the P5’s volume control.
Popping the lid on the P5 revealed—unsurprisingly, given all those features—a large, densely populated PCB. Also visible are the most conspicuous pieces of the power supply: four large capacitors and two transformers, one for each channel. “The outputs of the audio transformers feed [two] 63V 4700µF (each) high-efficiency, low ESR slit-foil smoothing capacitors for the [a]nalog power supply,” Orth told me. “A separate output winding feeds another bank of [two] 63V 4700µF slit-foil capacitors for the digital power supply.” Michi transformers are designed and manufactured at the Rotel factory in Zuhai, China. “The bank of four high-efficiency, T-Network, slit-foil, low-noise capacitors, 4700µF, each, [add up to] 18,000µF. The T-Network capacitors in the P5 have 2 sets of positive and negative terminals, allowing the capacitors to charge and discharge more efficiently.”
The P5’s moving-magnet phono stage amplifies the incoming signal by 52dB, according to the specifications, and the moving coil phono stage by 70dB. There’s plenty of headroom: MM input sensitivity is 2.5mV, MC is 250µV, and “the MM stage will reach overload at 199mV and MC at 22mV,” Orth noted.
The P5’s headphone amplifier, Orth wrote, utilizes an “independent, isolated + and – 15V DC power supply to ensure wide dynamic range and separation of the circuit from all other analog and digital circuits. The dedicated voltage regulators feed only the headphone amplifier. The circuit has been tuned with high-quality components including mylar capacitors and metalized resistors to ensure [that] temperature and output levels deliver a consistent frequency response.”
While all Michi products are hand-assembled in a factory within Rotel’s Zuhai, China, plant, the mechanical design of the P5 was outsourced to a UK-based industrial design firm, and sonic tuning was performed by Rotel’s engineering and design team with support from Bowers & Wilkins in the UK. (Rotel and B&W have had a partnership since the early 1980s.)
Setup
“For Windows computers, [the] PC-USB [input] can drive 24/96k audio with the built-in Windows audio driver,” Orth explained. “To achieve audio sample rates above 96kHz, the Michi audio driver must be loaded.” No driver is needed for Apple computers. “The current PC-USB audio supports up to 24-bit/192k; that may increase with a software update that’s scheduled for October [2020].” I loaded the Michi driver to my Asus laptop PC, set laptop and Tidal to “Rotel Audio” for playback, and set the P5’s source to “USB Audio Class 2.0,” as directed by the manual. At first, I got no sound for files with a bit rate and/or sampling rate above 16/44.1, but this was easily fixed. With help from Orth, I enabled the maximum sample rate in the Advanced tab under Sound in Windows setup on my computer.
In what some will consider an odd pairing—they could hardly be more different, despite their shared Japanese heritage—I used the P5 preamplifier with one of my most treasured components, the Shindo Haut-Brion power amplifier ($11,000, footnote 1). A 6′ pair of Auditorium 23 speaker cables carried signal to my DeVore Fidelity O/93 loudspeakers ($8400/pair). I screwed my EMT TSD 15 N Super Fineline stereo cartridge ($1950) to my Kuzma 4Point tonearm ($7090), which is mounted to my Kuzma Stabi R turntable ($7465), which sat atop the Kuzma Platis 65 isolation platform ($3267). A 2m pair of Shindo XLR-to-RCA interconnects connected the P5 and the Haut Brion and, briefly, the Mytek Brooklyn AMP+ ($2495). For digital-source comparisons, a pair of Shindo RCA interconnects connected the BorderPatrol DAC SE ($1925) to the P5’s Aux input. A 3.6m run of Furutech GT2 Pro USB cable connected my PC to the PC-USB port of the P5, for streaming.
Footnote 1: My Haut-Brion used to be Art Dudley’s Haut-Brion. One day in 2019, Art and I exchanged amplifiers for a trial, my older unit for his newer one. He preferred the richness of my older unit; I preferred the enhanced resolution of his newer one, so we made the swap permanent.
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COMPANY INFO
The Rotel Co. Ltd.
US distributor: Sumiko
6655 Wedgwood Rd. N, Suite 115
Maple Grove, MN 55311-2814
(510) 843-4500
sumikoaudio.net
ARTICLE CONTENTS
Page 1
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Specifications
Associated Equipment
Measurements
Jason Victor Serinus September 2022
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