Technics SU-G700M2 integrated amplifier

When I reviewed Technics's SU-R1000 integrated amplifier for the December 2021 issue, I found its performance beyond my expectations. It practically rewrote the ritual of listening to music on my home hi-fi. With its wealth of technological advancements, significant user options, and clear, three-dimensional sound, it cast a large sonic shadow over the other integrated amplifiers in my possession.

What's more, joined to my reference system, the SU-R1000 upended my preconceived notions of what switching amplification sounds like and enlightened me about the sonic possibilities of those other innovations: Technics's super-speedy GaN FET switching transistors; JENO Engine jitter reduction; ADCT (Active Distortion Cancelling Technology, footnote 1); Intelligent Phono EQ; LAPC (Load Adaptive Phase Calibration, footnote 2); and the SU-R1000's practice of digitizing every signal that entered and departed its steel-encased frame. And then there was the SU-R1000's low noisefloor, credited to its Advanced Speed Silent Power Supply (footnote 3), which undoubtedly was at least partly responsible for the Reference Technics amplifier's surprising resolution.

I wasn't alone in my praise for the SU-R1000. Technical Editor John Atkinson found some things to crow about when measuring the amp, concluding, "As with the Technics SU-R1000's line-level analog inputs, this amplifier's digital and phono inputs offered excellent measured performance."

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I mentioned class-D, but Technics maintains that the SU-R1000 isn't a class-D amp. Most other class-D amplifier manufacturers claim, with justification, that "class-D isn't digital"; Technics says their approach to amplification is digital but isn't class-D. Whatever—I don't care. What I do care about is that it made me feel more at one with my beloved music collection and made listening to everything from FKA Twigs to the Beatles, from Marc Cary to the Bulgarian State Radio & Television Female Vocal Choir, pure joy.

So when Bill Voss, Technics's US business development manager, offered Editor Jim Austin and me a crack at the SU-R1000's less-expensive new sibling, I was all ears, limbs akimbo in anticipation.

The SU-G700M2 integrated amplifier
At $2699, the Technics SU-G700M2 costs slightly more than a quarter of the SU-R1000's $10,000 asking price. Part of Technics's Grand Class series, the SU-G700M2—G700M2 for short—retains several of the SU-R1000's essential features and adds new ones. Technics engineer Naohiro Mizumata-san designed both the SU-R1000 and the SU-G700M2.

An evolutionary upgrade from Technics's SU-G700 integrated, which was introduced in 2017, the M2 features several of the same technologies used in the SU-R1000, including the JENO Engine, LAPC, GaN FET transistors, and Advanced Speed Silent Power Supply.

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Nearly as robust in build quality as its more expensive sibling, the G700M2's two-layer bottom chassis is composed of 1.2mm- and 2mm-thick steel plates. Its top panel is a 1.6mm-thick steel plate. The 7mm-thick aluminum used in the front panel is said to improve vibration damping. The amplifier's sidewalls and back panel are constructed of 1.6mm-thick steel, and the unit's four footers are made of steel encased in plastic. The G700M2 stands a relatively compact 5 13/16" high × 16 15/16" wide × 16 27/32" deep and weighs a solid but manageable 28lb.

The G700M2 announces itself in bold yet subtle terms, making it clear that this is a Technics amplifier, but a contemporary one. My review sample arrived in Technics-vintage silver (it also comes in black) with classic Technics VU meters—updated of course—on its façade. Power button and headphone jack are positioned on the left side and above the large rectangular viewing window, behind which those two meters lurk, alongside the LAPC indicator and the remote-control sensor. On the right side, above the window, a small display indicates the input currently in use and the sampling frequency of the audio stream. To the right of that, a single knob allows input selection: Coax 1 and 2, Optical 1 and 2, PC (the USB input), Line 1 and 2, Phono MM and MC. The supplied remote repeats these functions and includes LAPC activation, power button (AMP), choice of MC or MM cart, attenuator, subsonic filter, and volume control, as well as setup menu, dimmer, and equipment selection. The amp's backside contains the usual options, including analog inputs (RCA), USB, Line Out (RCA), Pre Out (RCA), a pair of speaker binding posts, and IEC jack.

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I asked Voss how Technics created a pared-down version of the SU-R1000—was that the goal?

"As in the past, it has often been our practice to apply the advanced technology of our flagship models to more affordable models in the product line," Voss replied by email. "When Technics introduced the R1 Reference Class system at IFA in 2014, much of the key technology was appropriated to the C700 Premium Class system: things like Digital Amplification, LAPC, JENO Engine, state-of-the-art digital processing, and of course the classic power meters."

To hit a price below $5000—indeed, below $3000—Technics must make sacrifices, yes?

"JENO Engine and LAPC are the same on the SU-R1000 and SU-G700M2," stated Technics CTO Tetsuya Itani in an email. "In terms of the power supply, the SU-R1000 has two separate power supply circuits, independent left channel and right channel circuits, while the SU-G700M2 has one."

Other differences: The output-stage transistor in the SU-R1000 is a GaN FET; in the SU-G700M2, it's a MOSFET. (The G700M2 uses GaN FETs in its power supply circuit.) The SU-R1000 has Active Distortion Cancelling Technology; the SU-G700M2 doesn't. The SU-R1000's Intelligent Phono EQ is a digital/analog hybrid with DSP, while the SU-G700M2 has a standard analog phono stage.

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About that power supply: "The SU-G700M2 is equipped with the same GaN FET and SiC SBD as those mounted in the SU-R1000, to deliver maximum performance from the high-speed switching power supply system," notes the Technics website. "The power supply unit for the amplifier features Technics's exclusive block electrolytic capacitor, optimized through scrupulous tuning, which was also installed in the SU-R1000. The screws used for securing the wires sending audio signals to the speaker terminals are made of nonmagnetic brass. The large ground terminal accommodates a thick, large-diameter ground wire. What's more, a super low noise regulator is provided in the later stage. It prevents the decrease of regulation due to fixed switching frequency and impedes the mixing of noise into high frequencies. The result is a low-noise and high-response power supply that maximizes the performance of the digital amplifier."

The G700M2's Advanced Speed Silent Power Supply "improve[s] speaker drive power [with] a greater feel of energy," states the Technics website. GaN FET switching frequencies have been "increased from the conventional 100kHz band to the 400kHz band to ensure stable supply of voltage and current and to reduce adverse effects of modulation noise on the audio quality; additionally, a Phase Invert switch has been added, which is unique to the SU-G700M2," cited Voss.

In place of the SU-R1000's Intelligent Phono EQ with its multiple conversion topographies (translating analog to digital as smoothly as Rudy Van Gelder sipping a martini), the G700M2 includes a more standard MM/MC phono stage—an upgrade from the original SU-G700's MM-only phono stage.

The G700M2's phono stage "achieves low noise by using a differential parallel connection configuration of a first-stage, low-noise FET. In addition, four-level gain adjustment enables selection of the best gain according to the cartridge output. This enables optimal playback of high-grade analog recorded sound sources tailored to the user's environment."

The G700M2 incorporates the same headphone amplifier found in the original G700 model. The M2's innards are laid out in three sections, similar to the SU-R1000, which is said to shield interference better than the original G700 did.

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A clear stream
Streaming from Qobuz and Tidal via Roon, the G700M2 ticked nearly every box. I bathed in the G700M2's warm glow of good tone, ample soundstage, forward flow, and solid dynamics allied to copious low-end and detailed treble.

I compared the Technics's digital conversion to that of the Denafrips Ares II DAC, using a Sonore opticalRendu to convert the Ethernet stream to USB, the external DAC's output connected to one of the Technics's line inputs.

The standalone Denafrips converter had a slight edge over the Technics's: larger soundstage, improved texture and resolution of instruments and voices. But the Technics's rendering of digital files was pleasing, warm, full-sounding, and nearly as capable as the Denafrips—a close-run thing. While digital through the G700M2 didn't measure up to its SU-R1000 big brother in terms of scale, transparency, depth, and resolution, it readily revealed differences in recordings and ancillary components, loudly and clearly.


Footnote 1: "The Active Distortion Cancelling Technology accurately extracts distortion by determining the difference between the speaker terminal output and JENO output and then applies correction to the output digital signal, thus correcting the conventional digital amp system." Technics's website.

Footnote 2: "We thus developed a speaker impedance adaptive optimisation algorithm that performs correction to the ideal impulse response through digital signal processing by measuring the frequency amplitude-phase characteristics of the amplifier with the speakers connected." Technics's website.

Footnote 3: "The Advanced Speed Silent Power Supply has eliminated this noise by fixing the switching frequency in the 400kHz band." Technics's website.

COMPANY INFO
Technics, Panasonic Consumer Electronics Corporation
Two Riverfront Plaza
Newark, NJ 07102
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COMMENTS
georgehifi's picture

JA, can you remember or have filed away what that measurement was on the Technics GaN flagship SU-R1 or the SU-R1000?

Cheers George

John Atkinson's picture
georgehifi wrote:
JA, can you remember what that measurement was on the Technics GaN flagship SU-R1 or the SU-R1000?

The SU-R1000 had 316mV of ultrasonic noise present at the loudspeaker outputs without the auxiliary Audio Precision low-pass filter. I didn't note the center frequency.

John Atkinson
Technical Editor, Stereophile

georgehifi's picture

J.A.:"the three DC voltage levels described by the data are completely obscured by high-frequency noise, presumably radiated from the switching output stage. With undithered 24-bit data (fig.17), what should have been a relatively clean sinewave was again obscured by high-frequency noise. It should be noted however that the noise is above the audioband."

I would think that if the reviewer listen close he would have heard "artifacts" of this almost 1v noise through such efficient speakers as the 96dB DeVore Fidelity Orangutan O/96??

Cheers George

michelesurdi's picture

this is really depressing

ken mac's picture

Listen to what the man, JA, said.

georgehifi's picture

I said "artefacts" of the fundamental.
(disappointing was used by him, not me)

Cheers George

Mike Rubin's picture

“I compared the Technics's digital conversion to that of the Denafrips Ares II DAC, using a Sonore opticalRendu to convert the Ethernet stream to USB, the external DAC's output connected to one of the Technics's line inputs.”

Did you have occasion to play DSD files from the opticalRendu over the USB input? If so, did they play natively or did they play as DoP? I ask because I am having a tough time finding integrated amp USB inputs that can play native DSD without an ASIO driver, which Linux-based renderers like the Rendus cannot use.

Sonore has added some DAC IDs to its kernel, which is supposed to be the workaround, but I have found the implementation to be hit-or-miss. (For example, my ultraRendu is supposed to have the DAC ID for the NuPrime IDA-8’s DAC, but I can’t get dsf’s to play natively at all. That’s not necessarily an issue with DLNA players such as JRiver, Audirvāna, or MinimServer, but, with the expensive HQPlayer, I not only can’t upsample PCM to DSD, I end up with DSD downsampled to PCM.)

I know I can get external DACs that do just fine with USB and DSD from Linux, but, due to cabinet space considerations, I am in the market for an integrated that can handle these files natively.

Bontius's picture

I love reading all the reviews of Stereophile, it's a joy.

In al reviews this sentence in this review is one of the weirdest, puzzling and original ones I came across in years:

" translating analog to digital as smoothly as Rudy Van Gelder sipping a martini"

Haha, it should be added to the audiophile dictionary I suggest. But before that, shouldn't it be between quote signs because it is by Technics ? And what does it mean ?

Thank you

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