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.
Only some of class D amps have speaker impedance issues. If you use a lot of feedback.....like Purifi does, then you have flat frequency response into any load. Purifi has a new higher powered module that according to one person whom I trust....has even better sound than the current one. And all Purifi amps measure superbly in other ways, as well. Yes, ASR does not listen, so they know nothing that is important in audio (the sound) Listening tests are what is real. |
Depends how you define it. Lots of Class D can handle low (~ 2 Ohm) loads, but response with simulated speaker loads (as opposed to simple resistors) usually shows them to behave a little differently. That's what I was focusing on, but maybe wasn't saying it quite well.
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Lol!! I won't always disagree, unless you say something like this- on the one hand, its a digital amplifier; on the other you discuss class D amps- including Pulse Width Modulation, which is an analog process found in most class D amps. I'm puzzled by the idea of a 'digital amplifier' since the bits in a digital word represent a voltage, whereas in a switching amplifier the on and off states have no such meaning. At some point the digital signal has to be converted to analog; as best I can make out this might describe a class D amp with a DAC driving it directly. I've puzzled over their claims about this amp. I think a lot of it is marketing. I've seen claims that the amp is zero feedback and there is also evidence to suggest that there is feedback. The output impedance of the amp should be very low even if its zero feedback and so should behave as a voltage source even into 2 Ohms. But that means that the output filter will introduce phase shift; to get around it they have a very high switching frequency and thus also a high filter frequency. At least that's my take on it. Its quite a tour de force of engineering- too bad it didn't bring home the bacon for you.
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@ricevs : On November 27 Amir tested and listened to the new Topping PA5 class D amp. It placed second to the Benchmark AHB2. Speakers used were the Infinity R253's. PA5 had 40/80 wpc for $349! Sonically second to the AHB2! All you ASR haters should pay attention!
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