Hypex ncore nc1200 doubles the output at 2 ohm. Georgehifi builds the Lightspeed Attenuator that measures poorly but sounds decent. He has this obsession of GANs that have one metric pumped up, cost more, but do not perform better than ncores or Purifi. Getting into technicals with him is a waste of time, because he then inundates with irrelevant links and/or retreats to subjectivist positions. " Many, me included, prefer scotch to bourbon".
new GAN amplifier
LSA Voyager GAN 200.
https://www.underwoodhifi.com/products/lsa-electronics
200w into 8 ohms
400w into 4 ohms
???w into 2 ohms
Showing 9 responses by pirad
arty_vandelay, Please compare data for your favorite top A/B amp U-LD Mk4, given by the creators at www.siliconchip.com.au (August 2015) and the newest D-class from Bruno Putzeys - Purifi 1ET400A (www.purifi-audio.com). The D-class beats the A/B in all major categories. THD+N 20-20kHz is better with Purifi at 10W (ten) than with U-LD at 100W. From your coveted 5kHz, Purifi stays at 0.00029% (up to 20kHz) at 10 (ten) WATT and U-LD reaches 0.0008-0.001% at 100 WATT! The tough 18kHz+19 kHz intermodulation figures are given only by Purifi, AFAIK. But this is all academic. Both amps are an overachievement for the human listener, appreciated mostly by AudioPrecision analyzers which are not precise enough for some of their metrics. PS. The U-LD amps are not on offer any more, are they discontinued? |
>100kHz response? Some species of bats indeed can detect 200kHz but they can't hear the human range sounds. Then there is the question of transducers, I think I came across once a lab specimen that goes high ultrasonic. Then there is the problem of mics, top studio Telefunken U47 (9k $) goes only up to 20kHz. So, other than Batman music recorded with lab mics and played by lab transducers it might be a tall horse to climb. |
arty_vandelay You wrote: "Distortion (IMD) is still higher than a decent classic blameless AB design above 10kHz." Do you mean this part of Amirm's test: "I was surprised to see the rise in distortion with frequency. I had hoped that the super high gain-bandwidth of the 1ET400A would do away with this. Not an audible concern though as the distortion products here are all in ultrasonic range. [...]The Benchmark AHB2 does a lot better since it has much cleaner ultrasonic spectrum.". Well, ASR is known for measuring audio phenomena that no human can hear. A concern for bats, perhaps. As for the 18khz+19kHz IMD, Purifi is absolutely tops, not to say that no other manufacturer provides those data. Amirm writes: "Bruno had encouraged me to run intermodulation test with 19 and 20 kHz tones. I matched levels with Benchmark AHB2. I was surprised to see so much lower intermodulation distortion with 1ET400A. The first pair of sidebands is more than 10 dB cleaner and the rest almost don’t exist!". The Benchmark AHB2 is Amirm’s/ASR reference A/B amp. "The cleanest amp on the planet". As for subjective perceptions of audio, to paraphrase the local classic, "there are many, me including, who like tubes best". |
All digital audio is built around the sampling theorem, not the other way round. There are places in the signal chain where high sampling rates make sense. The final reproduction stage is not one of them. Why, and how it can be harmful is well explained here: https://people.xiph.org/~xiphmont/demo/neil-young.html |
https://www.audiosciencereview.com/forum/index.php?threads/review-and-measurements-of-purifi-1et400a... The above was explained ad nauseam from post #558 in this thread at ASR |
Is it not demonstrated that a true flying machine, self-raising, self-sustaining, self-propelling, is physically impossible? It is apparent to me that the possibilities of the aeroplane, which two or three years ago were thought to hold the solution to the [flying machine] problem, have been exhausted, and that we must turn elsewhere. I can state flatly that heavier than air flying machines are impossible. I have not the smallest molecule of faith in aerial navigation other than ballooning, or of the expectation of good results from any of the trials we heard of. So you will understand that I would not care to be a member of the Aeronautical Society. The present generation will not [fly in the next century], and no practical engineer would devote himself to the problem now. There is no basis for the ardent hopes and positive statements made as to the safe and successful use of the dirigible balloon or flying machine, or both, for commercial transportation or as weapons of war. The demonstration that no possible combination of known substances, known forms of machinery and known forms of force, can be united in a practical machine by which men shall fly along distances through the air, seems to the writer as complete as it is possible for the demonstration to be. Flight by machines heavier than air is unpractical and insignificant, if not utterly impossible. — Stanley Mosley, 1905 The aeroplane will never fly. 1920 “No flying machine will ever fly from New York to Paris.” — Orville Wright, inventor of the airplane. |