ATI AT543NC recent user feedback?


There are measurements for the AT524NC model from here : https://www.soundandvision.com/content/ati-at527nc-and-at524nc-amplifiers-review-test-bench

Quoting: 
"Into 4 ohms, the amplifier reaches 0.1% distortion at 377.2 watts and 1% distortion at 475.5 watts."

This seems very good to me. I am guessing AT543 will be very similar if not very different. The AT54XNC amplifiers use two N-Core modules per channel in a differential bridged output configuration delivering 500W RMS per channel at 8 ohms and 900W RMS at 4 ohms.

What is differential bridge output is that better for THD or does it make it worse?.
geek101
The specs do not indicate any change in THD between 54x and 52x models.  I would not pay too much attention to THD and distortion because that doesn't really dictate how well an amp sounds.
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The AT52x amps are single-ended and use a single board per channel, but you can have up to 8 channels.
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The AT54x amps are balanced differential and use two amp boards per channel, but you are limited to 4 channels total because of this.  Each channel will have more power capability (500 watts vs 200 watts) and have more power supply current per channel.  Also, since each channel with have two current sources doing push/pull, you will get better control of the speaker.  It may sound better than the 52x single ended amps.