Any ATI AT543NC user? How is your experience

[geek101]

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 close?. 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?.

 

[everettT]

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 close?. 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?.

The Hypex module is really good, ATI's implementation is very good. Take the wording as a little marketing as others have successfully used the modules with different implementations.

 

[AcuDefTechGuy]

ATI AT527NC
THD 0.001%
Crosstalk 116dB
SNR 118dBA

Power output 0.1%/1%
256/290W x 2Ch 8 ohms
213/250W x 5Ch 8 ohms
197/239W x 7Ch 8 ohms
377/475W x 2Ch 4 ohms

All excellent numbers.

 

[slipperybidness]

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 close?. 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?.

A differential amplifier is a type of electronic amplifier that amplifies the difference between two input voltages but suppresses any voltage common to the two inputs.[1] It is an analog circuit with two inputs in which the output is ideally proportional to the difference between the two voltages

In this case, it looks like the 2 inputs are an input on an individual amp module, but the outputs are bridged (1 amp drives the + cxn and the other amp drives the - cxn)

 

[geek101]

Do these amp work for 2 Ohm or 1 Ohm impedance swings?. The spec https://www.ati-amp.com/manuals/ATIpowerampspecs.pdf says safe between 4 and 16 Ohm only .

 

[everettT]

Do these amp work for 2 Ohm or 1 Ohm impedance swings?. The spec https://www.ati-amp.com/manuals/ATIpowerampspecs.pdf says safe between 4 and 16 Ohm only .

Most likely not. What are you powering?

 

[geek101]

Will be powering Legacy Aeris. It should be ok but a lot of cheaper class D are specd down to 2 Ohm

 

[PENG]

Will be powering Legacy Aeris. It should be ok but a lot of cheaper class D are specd down to 2 Ohm

Why worry if you speaker's minimum impedance is well above 2 ohm? Besides, you can use that ATI amp on 2 ohm loads for sure as long as you don't turn the volume up to damage your hearing first. The only exception is that some amps may have a low impedance detector that would shut down even if you turn the volume way down. I am not aware of any power amps that has such feature, but I think some do, because they want their amps to be more or less idiot proof. On the other hand, any 2 ohm rated amps will suffer from the same current limit issue if you turn the volume high enough. It is sort of (I mean to some extent) a silly game that fools mostly the technically uninformed.

 

[geek101]

@PENG what makes you so sure the speaker impedance of Legacy Aeris is going to be above or equal to 4 Ohm all the time?.

https://www.anthemav.com/products-current/model=m1/page=specs

https://www.apollonaudio.com/apollon-hypex-nc500-class-d-amplifier-nc800-sl/

https://www.nordacoustics.co.uk/product-page/nord-one-up-nc500mb-1

https://wyred4sound.com/products/power-amps/mono/sx-1000r (has min load)

Now so why should ATI AT54XNC not mention anything about 2 Ohm?

 

[geek101]

More specs that state 2 Ohm rating:
https://www.psaudio.com/products/stellar-s300-power-amplifier/#tab-specs
https://merrillaudio.net/element-116-power-amplifier-monoblocks/#1523170062166-5a2ff0e7-53cd

 

[AcuDefTechGuy]

Why worry if you speaker's minimum impedance is well above 2 ohm? Besides, you can use that ATI amp on 2 ohm loads for sure as long as you don't turn the volume up to damage your hearing first. The only exception is that some amps may have a low impedance detector that would shut down even if you turn the volume way down. I am not aware of any power amps that has such feature, but I think some do, because they want their amps to be more or less idiot proof. On the other hand, any 2 ohm rated amps will suffer from the same current limit issue if you turn the volume high enough. It is sort of (I mean to some extent) a silly game that fools mostly the technically uninformed.

Why do pro amps (Yamaha, Crown, QSC, etc.) show spec for 2 ohms, but consumer amps usually don't?

 

[AcuDefTechGuy]

More specs that state 2 Ohm rating:
https://www.psaudio.com/products/stellar-s300-power-amplifier/#tab-specs
https://merrillaudio.net/element-116-power-amplifier-monoblocks/#1523170062166-5a2ff0e7-53cd

The Audio Critic measured the 60 WPC ATI amp a long time ago and it was stable down to 1 ohm (I can't remember the actual power output at 1 ohm). So most of us aren't concerned with the ATI 200 WPC amps.

But if you are concerned with the 2-ohm published spec, look at the Pro Amps (Yamaha, Crown, QSC, etc.) because pretty much all these pro amps have published specs down to 2 ohms.

 

[PENG]

More specs that state 2 Ohm rating:
https://www.psaudio.com/products/stellar-s300-power-amplifier/#tab-specs
https://merrillaudio.net/element-116-power-amplifier-monoblocks/#1523170062166-5a2ff0e7-53cd

Didn't you notice that for the so called 2 ohm rating, there is caveat? You have to read between the lines...

2Ω Stable for musical transients

Stable for musical transients = not stable for continuous duties.

Most power amps, even many AVRs are "2Ω Stable for musical transients", instead of wording it this way, they normally use the term "Dynamic power....", or may even mention the IHF standard for such rating. As examples, NAD and Yamaha tend to emphasize dynamic rating more so than others. Others such as Denon/Marantz, Anthem etc., don't usually provide the 2 ohm dynamic ratings. Anthem does provide dynamic ratings down to 2 ohms for their power amps.