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ATI AT522NC Stereo Amplifier Review

RichB

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The rear switches are hard power switches and that is not what we are discussion here.

The AT4000/AT6000 when initially produced would power on with the trigger after powering on. However, when the power was removed using the rear power switches or loss of power, they did not response to the trigger until the front touch capacitive power button was engaged.

Here is my 2018 article on the AT6000s:
https://www.audioholics.com/amplifier-reviews/ati-at6000

The article included this editorial note:

EDIITORIAL NOTE ON TRIGGERING

When I first received the AT6000’s the trigger functionality required pressing the power button to complete the power cycle. If the power ever went out the amps would not turn on until the power button was pressed. This is not “family friendly.” Updated control boards unconditionally power-on from the trigger, eliminating instances of pops on power up, and also improving the soft power-up process.

At the time, I also tested an AT4000 which had the same trigger issue.

In 2019, I wrote this article comparing the AT4002 and AT522NC amplifiers:
https://www.audioholics.com/amplifier-reviews/ati-at4002

It included this editorial note on the Auto-Off function that had to be disabled:
EDIITORIAL NOTE ON AT500NC Auto-Power Off
My AT522NC auto-power off features was not functioning properly. Whether manually or trigger power-on, the amp powers off after 10 minutes. Apparently, an EU feature gone awry. Thankfully, ATI has a procedure that involves pressing the power button while plugging-in the power cable that disables the inactivity power-off function. Once disabled, the manual and trigger power-on works properly.

The AT4002 supplied for this review, did not have the trigger issue. It triggered on after a hard power cycle.

If you have an issue with triggers not working on an AT6000/AT4000 amp, I recommend contacting ATI to have it repaired.

Them's the facts. :)

- Rich
 

RichB

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I never heard of any defect that needed fixing on the 4000 6000. The 4000 and 6000 series use a powered on off switch which resets if it loses power. I am the person who designed that control system and wrote the software for it and I've never heard of anything being wrong with it. From what you say it seems to be working normally but when I get a chance I will look at the source code and double check.

There's nothing that can be done about that. The switch requires power to work and if it loses power it has no other choice but to reset. It's just the nature of a solid state switch. The software could be rewritten to override the power switch with the trigger cable but that's not my call to make.

It was fixed years ago.

Contact Sanjay at ATI and they should send you a programmer with newer firmware.

I know very intimately how all of the power amplifier control works because I'm the person who writes the firmware. I know there was a lot of back-and-forth on the trigger on the 4000 6000 amplifiers because they used an electronic power switch on the front panel. Electronic switches lose their state when power is lost where mechanical switches do not.

The issues was that after a loss of power, the trigger ceased to work. State need not be an issue because the amp is off and the trigger is ON. That's all that is needed to determine to power the amp.

That was the stated problem and it was corrected with a hardware change (possible for popping issues) and two rounds with the programmer. Not only did I, but also two friends had to apply fixes moving some very heavy amps and reprogramming. I don't remember if we all replaced the logic board.

ATI was given the text of the review and Sanjay and other are fully aware of the issues.

Personally, I have a very bad reaction to this statement you made: "I never heard of any defect that needed fixing on the 4000 6000.". Perhaps, you do not mean to be deceptive but the original response lead to the impression that this was not an issue and was not correctable. It was an issue and it was corrected.

Going forward, please do not confuse customers by stating your credentials and denying the issue.
This is not in the best interest of ATI nor does it help the customer.

- Rich
 
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RichB

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Actually what I said was completely true; I had no idea of any problems with the 4000 / 6000 trigger or power switching. Sometimes I'm asked to "change this so it works this way", and I do - I don't necessarily know the reason for the change. In this instance I wasn't trying to cover up anything, I was just going from what I knew of how the power switch worked when I originally wrote the firmware. No grand conspiracy here. ;)

Thank goodness somebody told someone: Please change the trigger logic so the amp turns on, even from a cold power on :p

- Rich
 

RichB

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FWIW, I first emailed Sanjay about this defect in May 2017. That’s not to presume everyone in the company was made aware of it at that time.

I assure you ATI can resolve the issue. If you are comfortable removing the cover and using a programmer sent by ATI, that is by far the preferred solution.

- Rich
 

jhaider

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I assure you ATI can resolve the issue. If you are comfortable removing the cover and using a programmer sent by ATI, that is by far the preferred solution.

- Rich

I know. I appreciate you mentioning that when I first brought up the issue here, and @MakeMineVinyl for indirectly reminding me of the fix. I finally fired off the email. I’m fine removing the cover. Lifting it out of the cabinet is what I’m not looking forward to!
 

RichB

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I don't under stand what you mean about the trigger logic and cold power on. Could you explain more; perhaps this can be made so if OK'd by higher ups.

Here is the old behavior:

- Turn off, the rear power rockers and turn them on after a few seconds (to simulate loss of power).
- Power is presented on the Trigger to turn on the amp.
- The AT6000/AT4000 do not power on.
- Press the front power electronic switch and the amp powers on.
- Subsequent trigger ON/OFF work until power is lost.

The result of this design is that in the event of a power loss, the amps does not power using the trigger until they are manually powered on from the front switch. Many customers have non-technical family members and to them, the system ceases to work. I have owned many amps, including other ATI models and ATI OEM models and no other amplifier with trigger support behaves this way. Thus, it is broken since the clear requirement for an amp with trigger voltage must always turn on.

Here is the new behavior (that has been there fixed for years):

- Turn off, the rear power rockers and turn them on after a few seconds (to simulate loss of power).
- Power is presented on the Trigger to turn on the amp.
- The AT6000/AT4000 amps power on.

Honestly, this is not even remotely complicated.

If you read my articles, you will know that I have great respect for ATI and their products.
But trigger logic has, in the past, be problematic.

- Rich
 
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RichB

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You're right, it isn't complicated...but

No other ATI amplifier has ever had the touch ON/OFF switch which itself relies on power, so the behavior is different than the previous (and current) amplifiers which have a latching front panel power switch. In the original design of this amplifier, it was stressed to me that the front panel switch must always be able to turn the amp OFF in case of emergency. The only way to make this so is to make it so that both the trigger and front panel power switch be actively ON. Something was obviously changed so this is not the requirement, and the hardware was changed to make it so.

The new logic always turns the amp on, even after a rear power switch power cycle or loss of power.
Once on, even when by trigger, the front power switch always powers off the amp.

The requirement has not changed and it behaves exactly as expected in all cases.
Apparently, you are the designer and I am the field tester. Nice to meet you. :)

- Rich
 

MakeMineVinyl

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Apparently, you are the designer and I am the field tester. Nice to meet you. :)

- Rich

Oh, I test massively, but I can only test for behavior which is consistent with the directions I've been given. ;)
 

RichB

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Oh, I test massively, but I can only test for behavior which is consistent with the directions I've been given. ;)

Field test provides the customer perspective: the trigger should always turn on and off the amp.
Internal requirements add: the front panel switch should turn off the amp.

Thankfully, ATI support was excellent and supplied a fix.

The new logic works properly:
  • Trigger plugged-in and voltage present: Turn amp on (front panel switch is irrelevant).
  • Trigger plugged-in and voltage absent: Turn amp off (front panel switch is irrelevant).
  • Power-on process complete and front panel switch off: Turn amp off (the trigger is irrelevant).
Perhaps, the implementation is complicated but the requirements are not.

- Rich

P.S. I'd have PM'ed you long ago but you don't permit it.
 

nick-v

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I'm using the 3-channel version of this amp in my media room fed from the pre-outs of a Denon AVR-X3700H.

I'm curious if there's any performance advantage either way between going RCA-RCA or using RCA-XLR cables into the amp?
 
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RichB

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I'm using the 3-channel version of this amp in my media room fed from the pre-outs of a Denon AVR-X3700H.

I'm curious if there's any performance advantage either way between going RCA-RCA or using RCA-XLR cables into the amp?

There will be no common noise reduction and could be worse SN. RCA's were not measured here so we cannot say for sure.
There appears to be a slight improvement with the balanced inputs measure here with 1kHz signals:

THD+N from the amplifier was less than 0.002% at 1 kHz when driving 2.83 volts into an 8-ohm load using the RCA input. When using the XLR input under the same conditions, THD+N was less than 0.001%. Crosstalk at 1 kHz driving 2.83 volts into an 8-ohm load was –116.09 dB channel 1 to channel 7 and –114.57 dB channel 7 to channel 1 using the RCA inputs and –115.67 dB channel 1-to-channel 7 and –115.92 dB channel 7-to-channel 1 using the XLR inputs. The signal-to-noise ratio with an 8-ohm load from 10 Hz to 24 kHz with “A” weighting was –115.17 dBrA using the RCA input and –118.06 using the XLR input.

ATI AT527NC and AT524NC Amplifiers Review Test Bench | Sound & Vision (soundandvision.com)

If you were had a balanced source, then yes, if not, it's not worth trying.

- Rich
 
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DonH56

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Silly question-there is then a cord (maybe not included) to connect this to a 20A outlet, if you had that wired in?

It ships with a standard 15-A power cord per their web site: The supplied power cord will have either: a NEMA 5-15 plug (Type B) for use in the USA, a BS 1363 (Type G) plug for use in the UK, or a Schuko (Type F) plug for use in the EU and the rest of the world.

Note a 20-A outlet (in the USA) will accommodate standard 15-A and 20-A plugs so the standard cord will fit either one. A 30-A outlet (and thus plug) is a different configuration.
 
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Head_Unit

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20-A outlet (in the USA) will accommodate standard 15-A and 20-A plugs so the standard cord will fit either one.
What I should have asked is, can you get a 20A cable and connect it AND is there any advantage to that? (And if not, then why do they use a 20A connector...)
 

DonH56

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What I should have asked is, can you get a 20A cable and connect it AND is there any advantage to that? (And if not, then why do they use a 20A connector...)

The only advantage would be if the 20-A cord has heavier wire gauge (lower AWG number) and you need the (likely very small) additional voltage that would provide at maximum power due to the lower resistance.

So, yes to the first if you have a 20-A outlet, and to the second, I really doubt it...
 

HammerSandwich

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Or you have enough channels to stress a 15A breaker. Seems highly unlikely, unless you have a ton of channels running subs with boosted VLF. Seems even less likely with ATI Ncore.
 

Head_Unit

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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.
You don't have the internal TV speakers enabled? Or it's not possible? My default is the TV runs internal speakers, NOT the stereo, because of fear of just such phone calls. The horror! The horror!
 

RichB

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You don't have the internal TV speakers enabled? Or it's not possible? My default is the TV runs internal speakers, NOT the stereo, because of fear of just such phone calls. The horror! The horror!
The auto turn off logic was broken and can be corrected by ATI, it can also be disabled.

- Rich
 
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