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Technics SU-R1000 - Good but not the king of switching amps

Was looking at the measurements for the Technics SU-R1000 Integrated published by Stereophile. I never bother with the reviews of the sound quality as there’s 1 reviewer there whose ears I trust and it’s not this reviewer.

To be clear, this IS a digital amplifier, and is not a Class D amplifier. Atmasphere will always disagree with me, but given Technics nomenclature and the use of an A/D converter, and PWM output I think if any amplifier qualifies as digital this one does.

What I find kind of interesting here is that the measurements are OK but not absolute Class D killing results. I am particularly unimpressed by the performance of the impedance compensation circuit, LAPC, which at the end of the day does not seem to have performed significantly better than actual, non GaNFET amplifiers, particularly in removing the effects of the output filters Class D amps require. I really hoped to see a huge win here... but it’s not. It’s just making the PWM perform almost as good as a true Class D amplifier.

I have not heard this integrated, but the claims and expectations laid out for the technology seem to not be proven in the measurements. This is a very expensive integrated that does everything differently, and measures about the same as previous generation, also excellent sounding, Class D engines I’ve seen measured.

My stance that Class D was already very good and that new, faster switching amps would have to be truly spectacularly better to unseat them remains, in my mind, uncontested.

Can’t wait to see everyone trashing Class D on the measurements suddenly decide that this amp should be heard and not measured.

erik_squires
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nonoise's avatar
nonoise
10,883 posts
 

Some companies that make class-D amplifiers are content to have their technology labeled class-D—just don't call it digital. Technics is happy to have the amplification technology in the SU-R1000 called digital—in fact they insist on it—just don't call it class-D!"

Technics' digital amplifier is often mistaken as class-D, but strictly speaking, Technics' digital amplifier is not class-D," company CTO Tetsuya Itani writes in a Technics white paper. "Class-D ... is a ... method that applies analog signal technology such as sawtooth wave generation and comparator, so it has the drawbacks of conventional analog amplifiers, such as the possibility of distortion and noise mixing, depending on the accuracy of parts, etc. Further, since the input is an analog sound signal, it is necessary to [perform] D/A conversion on the digital signal, and there is a limit to accuracy in handling a high-precision signal such as high-res sound. Technics' full digital amplifier processes digital input as it is with high precision, so it is advantageous, especially when handling high-res signals. When dealing with analog signals, a 192kHz/24bit high precision A/D converter is used to ensure high performance." To perform this task, the SU-R1000 utilizes the AK5572EN 1740EAC ADC chip from AKM.

So it's not class D but a fully digital amp. Who cares what ASR says about it?

All the best,
Nonoise

jerryg123's avatar
jerryg123
3,429 posts
 

Agreed who cares what ASR say’s 

From what I have read of their Pie Eyed data based reviews they have zero interest in how a product really sounds.

Spec sheet pirates is what they are.

erik_squires OP
16,126 posts
 

I'm also not really interested in ASR blessing an amp or not.


I guess what I'm disappointed in is that yes, Class D amps have minor but measureable issues with speaker impedance and absolute response at the top octaves.  The Technics system was a really interesting take on how to correct for this.  Mind you, you could do this yourself with DSP, but still, I thought the idea was really progressive and leveraging of modern DSP capabilities and reduced cost to solve a problem.

The results, at least measurably, were meh.  After all that hype you end up with a switching amp which measures sometimes as good as, sometimes worse than 2  or 3 generation old Class D.  And I am a fan of these Class D designs, I just wanted to see something spectacularly better.

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