ATI AT522NC Stereo Amplifier Review

[amirm]

Why not just ignore it? I don't think you need to defend yourself and the site constantly: the overall quality of the exchanges here speaks for itself. There's an infinite supply of trolls and this could turn into a game of whack a mole with an unavoidable emotional toll. And for us, mere mortals who aren't familiar with all the backstage stories, it is sometimes hard to tell the differences between genuine healthy disagreements and subtle trolling...

It is good advice but he goes after everyone's pant leg. And will keep changing aliases so you don't know to ignore him.

 

[amirm]

This amp will be shipping out folks. Hope you have all the data you need....

 

[jhaider]

ATI still makes class A/B amps - the Morris Kessler Signature AT4000 and AT6000:

https://www.ati-amp.com/AT4000.php

Perhaps it would be possible to compare one of their Hypex-sourced amps to a Signature amp and see if the huge difference in price is justified from a performance point of view.

We should have some respect for our host's back! We have an AT4007 in our media cabinet. It will come out only (a) when we move, and a professional mover packs it up, or (b) if it dies. The thing weighs over 100lbs.

I guess it's too late, but I am interested in one thing: if power is interrupted, will an ATI NC model turn back on from the 12V trigger, or do you have to press the front sensor?

After a power outage the AT4007 defaults to standby, and you can only turn it on from the front button. The trigger is effectively disabled. That's my only functional complaint about the AT4007. This quirk has led to angry phone calls from my wife while I was abroad on client matters, because the TV would turn on but no sound would come on. ATI asserted this behavior is for safety reasons, but my old AT2007 would come back on from the trigger after a power outage. Then again, I replaced the AT2007 because the trigger circuit went bad after ~7 years of use. So maybe they're saving the trigger circuit with this behavior?

 

[pma]

This is HYPEX NC400 large signal step response, measured into 10 ohm load. I assume NC500 module would behave similarly?

 

[amirm]

I guess it's too late, but I am interested in one thing: if power is interrupted, will an ATI NC model turn back on from the 12V trigger, or do you have to press the front sensor?

I just packed the heavy thing. It is actually going back to ATI because of faulty design of the trigger. So testing wouldn't have done any good.

 

[amirm]

This is HYPEX NC400 large signal step response, measured into 10 ohm load. I assume NC500 module would behave similarly?

I measured slew rate of 8 usec with AP which is likely due to low bandwidth of AP itself. Spec is 60 volts/microseconds.

 

[BDWoody]

Why not just ignore it? I don't think you need to defend yourself and the site constantly: the overall quality of the exchanges here speaks for itself. There's an infinite supply of trolls and this could turn into a game of whack a mole with an unavoidable emotional toll. And for us, mere mortals who aren't familiar with all the backstage stories, it is sometimes hard to tell the differences between genuine healthy disagreements and subtle trolling...

I would also say it is different when it is your standard troll with a chip on his shoulder and three posts...and someone who is a significant regular contributor.

For those of us who make this place a regular part of our day, someone like that just becomes like a diaper rash that won't go away.

Plenty of regular contributors have frequent and heartfelt disagreements with our host, but they don't go from thread to thread denigrating him or the site as part of some personal crusade, nor do they throw passive aggressive shade at every chance.

 

[TomJ]

I own an AT522NC and AHB2... I found the AT522NC to be brighter and prefer the AHB2 that is more natural to my ears.

I bought a new AT522NC earlier this year expecting good build and sound quality. I was disappointed with both. It sounded bright as reported by Rich and others (perhaps because of the IC op amp on the buffer board?) and had intermittent transformer buzz, intermittent 60Hz hum, and unexpected protection circuit shutdowns with clean XLR input (Mytek) in a reference system that was 100% stable and reliable before the ATI arrived. Bummer...

 

[Thomas savage]

Constructive criticism, data analysis is great ..

Obsessively Tearing everything down because it dose not suit your ideals is not.

Some just seem to be in some inane trip to deride things seemingly with no ambition beyond trying to look like a smart arse.

Oh well.

 

[RichB]

We should have some respect for our host's back! We have an AT4007 in our media cabinet. It will come out only (a) when we move, and a professional mover packs it up, or (b) if it dies. The thing weighs over 100lbs.

I guess it's too late, but I am interested in one thing: if power is interrupted, will an ATI NC model turn back on from the 12V trigger, or do you have to press the front sensor?

After a power outage the AT4007 defaults to standby, and you can only turn it on from the front button. The trigger is effectively disabled. That's my only functional complaint about the AT4007. This quirk has led to angry phone calls from my wife while I was abroad on client matters, because the TV would turn on but no sound would come on. ATI asserted this behavior is for safety reasons, but my old AT2007 would come back on from the trigger after a power outage. Then again, I replaced the AT2007 because the trigger circuit went bad after ~7 years of use. So maybe they're saving the trigger circuit with this behavior?

If memory serves, I tested this on the AT4002 last spring and it worked properly, triggering on after power was removed.

This was also original trigger functionality of the AT6000's, requiring manual power on after a power outage. ATI fixed it for the AT6000 and for the AT4000.

Contact ATI support and they should be able to send you a programmer to update the trigger logic. However, you will need to get some help to remove it from the cabinet/rack and remove the cover to access to logic board to reprogram it.

Please PM me if you want to discuss it further or need contact info.

- Rich

 

[oivavoi]

You were banned for a week trying to be insulting. It is also annoying to read your negative posts in thread after thread. Like this one I responded to:


I do all this work to measure this gear and this is the nonsense I wind up dealing with. Not in one thread, but multiple. The data is presented to you for free. Use it if you like. Ignore if you don't. It gets tiring to take so much time to keep defending myself and the site. You took advantage of our gentle moderation by piling on and on. Learn to be respectful. It is not much to ask.

TBH I didn't perceive this as an attack on you Amir. I read that post as saying that the interpretation of measurement data by "many people" (to quote the current leader of the free world), even on this forum, can be influenced by bias - but in this case bias in favor of products that are regarded as being science-driven. I agree with that assessment, and I think that he was correct in pointing out that a hf slope and less power in high frequencies is an objective breach with the high fidelity ideal, whether it's audible or not.

I for one have greatly enjoyed Audimus' postings around here, and have found them to frequently be enlightening and illuminating. I have also perceived his postings as questioning/criticism, not as negativity for negativity's sake (unlike that Audiocrusader guy). I think that level of criticism and questioning is healthy for a forum, as long as it doesn't get outright trollish and hostile. I have not perceived Audimus to getting close to something like that. I wonder whether you got so fed up - and rightly so - with Audiocrusader, that Audimus' more valid and gentle critical postings somehow became lumped into the same category. So I would encourage you to revisit your decision in this case.

 

[SegaCD]

Can you tell me which tweeters have response well beyond the 100kHz flat bandwidth of Amir's input filter?

Many ultra-lightweight tweeter diaphragms like the Pioneer/TAD ribbon tweeters reach beyond 100kHz (even the 1970's-era Pioneer HPM-series speakers that used said tweeters could). They're out there. Not common, but they are.

 

[March Audio]

Many ultra-lightweight tweeter diaphragms like the Pioneer/TAD ribbon tweeters reach beyond 100kHz (even the 1970's-era Pioneer HPM-series speakers that used said tweeters could). They're out there. Not common, but they are.

Many? At what level?

Having performed some research work with bat's (seriously, I really have ) I know the challenges of trying to get past 100kHz.

In any case the lowxlevels of distortion in the ultrasonic band still won't be of any issue.

 

[waynel]

I am referring to mechanical hum from the transformers that was audible from my seated position in a quiet room.

I don't believe there is an established solution for blocking DC.
I had a Panamax MX500 and not only did it not remove the hum it seemed to limit amplifier performance.
I was not about to buy an amplifiers (power regenerators) for my amplifiers.

The Benchmark engineers (and others) have found the best way to combat transformer hum is to eliminate the source

- Rich

This worked well for me:
https://avahifi.com/products/humdinger-dc-line-blocker

 

[RichB]

This worked well for me:
https://avahifi.com/products/humdinger-dc-line-blocker

I no longer have these issues with the AHB2's but thanks for the link.
If effective, I wonder why manufacturers don't include this in their designs.

- Rich

 

[Labjr]

I no longer have these issues with the AHB2's but thanks for the link.
If effective, I wonder why manufacturers don't include this in their designs.

- Rich

Because not everyone has the problem.

 

[RichB]

Because not everyone has the problem.

I suppose, that and not everyone cares about the problem.
Also, the issue varies from amp to amp and from design to design.

- Rich

 

[Labjr]

I suppose, that and not everyone cares about the problem.
Also, the issue varies from amp to amp and from design to design.

- Rich

DC blocking circuits are fairly simple. There's probably a circuit at diyaudio.com.

 

[pma]

This forum cares about SINAD

 

[HammerSandwich]

DC blocking circuits are fairly simple. There's probably a circuit at diyaudio.com.

Rod Elliott certainly does.