Grandinote Shinai integrated amplifier Measurements

Sidebar 3: Measurements

I measured the Grandinote Shinai using my Audio Precision SYS2722 analyzer (see the January 2008 "As We See It." Before doing any testing I preconditioned the amplifier by following the CEA's recommendation of operating it at one-eighth the specified power into 8 ohms for 30 minutes. At the end of that time, while the black-finished chassis was warm, at 89°F (31.7°C), the chrome grille on the top panel that covers the internal heatsinks was very hot, at 125.8°F (52.1°C). I then performed the older FTC/IHF thermal stress test by running the amplifier at one-third the specified power into 8 ohms for an hour. At the end of that time, the chrome grille's temperature was a little cooler at 123.3°F (50.8°C). As the Shinai biases its output devices into class-A, it actually runs hottest with no signal and coolest at high powers. The amplifier has sufficient heatsinking capacity, but users should make sure it has plenty of ventilation.

The voltage gain at 1kHz into 8 ohms with the volume control set to its maximum setting ("33") was 31.6dB from the single-ended inputs and 6dB lower from the balanced inputs. The amplifier preserved absolute polarity (ie, was noninverting) with both input types. The volume control operated in accurate 1dB steps, and the Mute button applied a full mute. The single-ended input impedance was a usefully high 42.5k ohms at low and middle frequencies, dropping to 29.1k ohms at the top of the audioband. The balanced input impedance was twice these values at 20Hz and 1kHz but 68.8k ohms at 20kHz.

The Grandinote's output impedance, including the series impedance of 6' of loudspeaker cable, was relatively high for a solid-state design, at 0.24 ohm at 20Hz and 1kHz, increasing very slightly to 0.265 ohm at 20kHz. The modulation of the amplifier's frequency response, due to the Ohm's law interaction between this source impedance and the impedance of our standard simulated loudspeaker, reached ±0.25dB (fig.1, gray trace). The response into pure resistive loads, taken with the volume control set to its maximum, was flat to 20kHz and rolled off above the audioband, reaching –0.8dB at 200kHz into 8 ohms (fig.1, blue and red traces), –0.75dB at 100kHz into 4 ohms (cyan, magenta), and –2dB at 100kHz into 2 ohms (green). Note the excellent channel matching and that, commendably, the response didn't change appreciably at lower settings of the volume control. These responses were taken with the balanced inputs; the unbalanced inputs were also flat to 20kHz but started rolling off a little earlier at ultrasonic frequencies (fig.2). At the other end of the spectrum, the single-ended inputs' response was down by 1.4dB at 10Hz. The extended ultrasonic response was responsible for the amplifier's excellent reproduction of a 10kHz squarewave (fig.3).

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Fig.1 Grandinote Shinai, balanced inputs. frequency response at 2.83V into: simulated loudspeaker load (gray), 8 ohms (left channel blue, right red), 4 ohms (left cyan, right magenta), 2 ohms (green) (0.5dB/vertical div.).

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Fig.2 Grandinote Shinai, single-ended inputs, frequency response at 2.83V into 8 ohms (left channel gray, right green) (0.5dB/vertical div.).

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Fig.3 Grandinote Shinai, small-signal, 10kHz squarewave into 8 ohms.

As expected from the dual-mono construction, channel separation was excellent: >100dB in both directions below 3kHz. Measured with the unbalanced inputs shorted to ground and the volume control set to its maximum, the wideband, unweighted signal/noise ratio (ref. 2.83V into 8 ohms) measured a very good 79.4dB (average of both channels). Restricting the measurement bandwidth to 22kHz increased the ratios to 86.6dB, left, and 83.1dB, right, and an A-weighting filter increased them further, to 93.0dB, left, and 87.8dB, right. Spectral analysis of the Grandinote amplifier's low-frequency noise floor (fig.4) revealed that spuriae related to the AC power-line frequency were low in level; the 180Hz component was a little higher in the left channel (blue trace) than the right (red). The component at 880Hz (1000–120Hz) was the highest in level in both channels, at –90dB ref. 2.83V (0.003%).

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Fig.4 Grandinote Shinai, spectrum of 1kHz sinewave, DC–1kHz, at 1W into 8 ohms (left channel blue, right red; linear frequency scale).

The Grandinote Shinai is specified as delivering 37Wpc, with no load impedance or distortion level mentioned (footnote 1). At our usual definition of clipping, which is when the THD+noise reaches 1%, with both channels driven the Grandinote delivered 30Wpc into 8 ohms (fig.5, 14.8dBW) and 36Wpc into 4 ohms (fig.6, 12.55dBW). Relaxing the criteria to 3% THD+N, the Shinai clipped at 34Wpc into 8 ohms (15.3dBW) and at 54Wpc into 4 ohms (14.3dBW). Into 2 ohms (fig.7), even with just one channel driven, it reached 1% THD+N at 15W (5.75dBW), and though actual waveform clipping was relatively mild below 70W into 2 ohms, the THD+N remained between 2% and 3% between 20W and 70W.

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Fig.5 Grandinote Shinai, distortion (%) vs 1kHz continuous output power into 8 ohms.

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Fig.6 Grandinote Shinai, distortion (%) vs 1kHz continuous output power into 4 ohms.

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Fig.7 Grandinote Shinai, distortion (%) vs 1kHz continuous output power into 2 ohms.

I measured how the THD+N percentage changed with frequency at 6.33V, which is equivalent to 5W into 8 ohms, 10W into 4 ohms, and 20W into 2 ohms. Other than in the low bass, the distortion levels were consistent with frequency (fig.8) but increased significantly as the load impedance halved. The gray trace in this graph shows the behavior into 2 ohms; I would not recommend using this amplifier into such a demanding load.

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Fig.8 Grandinote Shinai, THD+N (%) vs frequency at 6.33V into: 8 ohms (left channel blue, right red), 4 ohms (left cyan, right magenta), and 2 ohms (gray).

The shape of the THD+N spuriae waveform at moderate power into 8 ohms (fig.9, bottom trace) suggests that the distortion signature predominantly consists of the subjectively innocuous second and third harmonics. This was confirmed by spectral analysis (fig.10), though higher-order harmonics can be seen at or below –80dB (0.01%). At the same power into 4 ohms (fig.11), the third harmonic dominates, though the higher-order harmonics don't get any higher in level. With its bent transfer function, the Shinai did only okay with an equal mix of 19kHz and 20kHz tones, the combined waveform peaking at 10W into 8 ohms (fig.12). The second-order difference product lay at –70dB (0.03%) with higher-order intermodulation products a little higher in level.

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Fig.9 Grandinote Shinai, 1kHz waveform at 10W into 8 ohms, 0.14% THD+N (top); distortion and noise waveform with fundamental notched out (bottom, not to scale).

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Fig.10 Grandinote Shinai, spectrum of 50Hz sinewave, DC–1kHz, at 10Wpc into 8 ohms (left channel blue, right red; linear frequency scale).

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Fig.11 Grandinote Shinai, spectrum of 50Hz sinewave, DC–1kHz, at 10Wpc into 4 ohms (left channel blue, right red; linear frequency scale).

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Fig.12 Grandinote Shinai, HF intermodulation spectrum, DC–30kHz, 19+20kHz at 10Wpc peak into 8 ohms (left channel blue, right red; linear frequency scale).

The Grandinote Shinai's measured performance is dominated by the designer's decision not to use negative feedback. I would expect the Shinai's sonic character therefore to be similar to that of a typical tube amplifier. I don't recommend using this amplifier with loudspeakers whose impedance drops much below 4 ohms.—John Atkinson


Footnote 1: In an interview, designer Massimiliano Magri told Rob Schryer that the maximum output power is the same—37W—into 8 or 4 ohms.—Editor
COMPANY INFO
Grandinote S.R.L.S.
North American distributor: Goerner Audio
91 18th Ave.
Deux-Montagnes, Quebec, J7R 4A6, Canada
(514) 833-1977
ARTICLE CONTENTS

COMMENTS
JHL's picture

A measured, positive review of what looks to be a superb product artistically engineered with deliberation and care that sounds tremendous. And if you look closely, the reasons for this sound are in there too.

And yet it doesn't impress the bench.

Is the ear's fault or the bench's fault?

Ortofan's picture

... the sound quality of an amplifier with a "bent transfer function" that exhibits relatively higher levels of distortion dominated by "subjectively innocuous second and third harmonics".

So much for a "straight wire with gain" being the paradigm for the ideal amplifier.

JHL's picture

...cant and dogma is consistently exposed as an obsession with assuming cause and effect, co-opting whatever "science" may exist thereby, and browbeating the nearest pair of ears with what they're hearing and especially, what motivates the stuff between them. This we call the scientific method and/or real musical fidelity. Or if we're not, we make assumptions, cast aspersions, frame narratives, and draw conclusions.

Speaking of feedback, it's a lot like fallacy: It always sounds worse when you nest it in complexity.

Archimago's picture

That JS likes the sound in his room, with his speakers (don't know about the WLM Diva, but the LS50 and Totem are small speakers), using his playback gear, that's great. If he likes them and feels they're worth $15,000 for 37Wpc into 8-ohms (manufacturer specs), I hope he keeps them...

Subjective reviews are simply opinions based on the reviewer's system, ears, and mental preferences anyway. IMO, too many variables in there for it to necessarily tell me if anyone else might really like them or would put up 15-grand to own these. Of course, nothing wrong with gathering these opinions and listening for oneself.

On the objective side, no they won't win any awards for resolution and definitely no awards for power with low distortion. Nor are they great with demanding loads. These are just the facts and would be useful if you're thinking about buying these considering your room size and type of speakers. That's useful information, right?

Given the fact that distortions can be high with speakers and human perception has its limits as well, the objective results suggest that these should sound good at normal power output; as with most decent gear these days whether tube/solid state, with or without feedback...

Doesn't seem like there's anything here all that controversial.

Ortofan's picture

... speaker testing, you state that "many audiophiles dismiss controlled blind testing when in fact this is in all likelihood the most powerful tool available for honest research - just as it is for every scientific discipline involving human subjects!"

If that is indeed your viewpoint, what value do you place on the results of subjective evaluations (of any type of sound reproduction equipment) which are not the result of controlled blind tests?

If you've not read them already, you may wish to review back issues of the Audio Critic magazine. Before employing controlled blind testing, they were wont to recommend the latest "amplifier of the month".
After instituting a controlled blind testing protocol, they determined that the $500 price of a Yamaha integrated amplifier under evaluation "will purchase as much electronics as most of us will ever need." (A comparable model from the current line-up would cost no more than $900.)
The review concluded with the comment "as to those of you who want to know 'how it sounds' - well, we must not be getting our point across."

Anton's picture

Job well done. I liked how perfectly you placed that piece into your life for the time it was on hand. Thank you.

Something in review reminded me of something I have been 'believing' of late:

I think we are going through a sort of "punk" era in Hi Fi.

I am of a certain age and recall the 'excesses' of rock as the prog infestation occurred.

Back then, there came a point where it took the London Philharmonic to make rock records. (Moody Blues, etc.)

Tours made Spinal Tap shows seem humbly intended.

Rock music became a sort of quagmire (to me.)

Then, punk came and shook the barnacles off again.

I think I see some punk ethos hiding in Hi Fi these days: integrated amps that require less of us...fewer wires, shelves, tiny little feets, etc. Speakers with more manageable impedance and are less 'fussy' to drive. Speakers like the DeVore Orangutans, the Zu line, the re-emergence of the credibility of Klipsch, and others I am forgetting.

I am lately liking the idea of 'less stuff' to deal with.

This integrated fits this newer paradigm, I like it.

Imagine a room with a nice streamer, an integrated amp, speakers, and done!

Uh, oh, maybe I am starting to think 'exit level!'

Gotta keep my vinyl, though!

JRT's picture

The Plitron PAT-4152 toroidal output transformer was designed by Menno van der Veen for use in power amplifiers with a solid state output stage.

In any amplifier utilizing an output transformer, the qualities of the output transformer are critical to the resulting performance, and the easiest way to avoid the problem is to do just that by avoiding use of the output transformer in the design of the low impedance solid state output.

Good as it was, I don't think that the PAT-4152 attracted much demand, as it lags in benefit/cost in the analysis of alternatives in comparison to designs not using an output transformer, and more so as copper became increasingly more expensive.

The data sheet for that PAT-4152 OPT is available at the following link.

http://www.tec-sol.com/products/elec/plitron/spec/PAT-4152.pdf

Audiophon's picture

I am happy that Robert Schryer liked the Grandinote in his system. Over the last 16 years I had some really great sounding amps in my system: Classé CAM 350, Parasound JC1, Pass XA 100.5 and now the Grandinote Demone with the matching preamp Domino. When I heard the Grandinote amps for the first time in my system in direct comparison to my beloved Pass amps, it be became soon clear that concerning three dimensionality, naturalness and bass they outperformed the Pass be far.

They might not fit into every system due to their limited power, but they sound much more powerful than their power rating might suggest.

Just listen for yourself!

tonykaz's picture

Nice reading your work and thoughts, you seem to possess a refreshing everyman's perspective about our hobby's philosophies.

Might I request a series about today's phono cartridges.

Nice work, thanks.

Tony in earthly Paradise. ( an Incubator for Old people, wish you were here )

rschryer's picture

Are you asking me to write a series you won't read?

:-)

tonykaz's picture

I read EVERYthing you write!

besides,

I'm a transducer guy.

I own and invest in phono transducers.

I span from the ending years of 78 thru to todays formats, I'm eclectic and even esoteric.

Phono cartridges are the largest contributors to the Singing voice of a Vinyl system and it's most fragile component.

So I ask you, for instance, who is actively reviewing the Grado Series so that interested persons could understand the wide range of cartridges they offer?

If 33.3 vinyl is so important, the ongoing Phono Cartridge reporting is very much missing from the most important Audiophile Journal in the entire world.

Of course, I've advanced into the 21st. Century gear and enjoy the freedom of not having to curate a vast collection of that vintage stuff.

and...

I don't consider the $15,000 Phono Cartridges ( that the Planet guy reports on ) as valid or appropriate for our mainstream 33.3 vinyl lovers.

You could have a tonearm with the SME Bayonette headshell mounting system, a handfull or more of headshells filled with samples from every cartridge manufacturer. You would create the most read Monthly ( or weekly ) Stereophile feature. You would become another Tyll like giant in this tiny industry.

Wether I would read your reporting, or not, your work would gradually be positioned towards the front of the published monthly, everyone would read your stuff anddddddd buy more phono cartridges.

Tony in Venice

Glotz's picture

It would be great if more lower-priced carts get attention in the main review section of the magazine. Richard would be awesome for that! Please include comparisons in that price point, as well as some cost-no-object designs for reference.

I do think MF's reporting is spot-on all of the time, but one man can only do so much every month. HR does review great carts, but again, both of these men have a lot on their screens.

$15k cartridges are the Ford GT's of the audio world, and always have a place for anyone that digs the state of the art. The same goes with $15k integrateds!

@Richard - A truthful and funny response to Tony. Perhaps he is not done with turntables yet? It all depends how well you write! (Lol- and kudos to your writing.) A series may not be necessary, but coming back to new carts a twice a year would be very welcome.

rschryer's picture

...Robert, right? :-)

Thanks for the kind words, Glotz.

Glotz's picture

I am so sorry Robert!

rschryer's picture

That would be nice.

Btw, Tony, I agree with you. In our current political climate, supporting China's economy (and military) feels yucky.

At the same time, are we willing to pay substantially more for audiophile gear made entirely in N.A?

I'd like to think so, but...

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