The issue is because the output impedance from the ASP is too low for the amp. The "solution" was the add 11k resistors on each of the ASP outputs so the amp doesn't cycle. ATI offered to make this modification on the amp side if I wished to get a new amp.
I still have a DC offset issue that was discovered with the ASP midrange output to fix next week, then I'll decide what to do.
I still have a DC offset issue that was discovered with the ASP midrange output to fix next week, then I'll decide what to do.
This is the same modification ATi was going to make on the amp side after Morris studied the ASP schematic...
Would 100k be more appropriate?
You are right, I took out the 11k on the tweeter and midrange and it opened up the top. I have it left on the woofers to avoid cycling, but this probably isn't ideal having it ONLY on the woofer outs
Would 100k be more appropriate?
You are right, I took out the 11k on the tweeter and midrange and it opened up the top. I have it left on the woofers to avoid cycling, but this probably isn't ideal having it ONLY on the woofer outs
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If all of these Ncore ATI amps are exhibiting this issue, then it's a design problem.
The ASP output resistance is a nominal 200 ohms, which is nearly perfect for any line-level type of device. If an amplifier can't work correctly with that output resistance from a source, then it doesn't have any business being sold to customers.
I suggest to request Morris revisit this. There is something else going here.
Dave.
The ASP output resistance is a nominal 200 ohms, which is nearly perfect for any line-level type of device. If an amplifier can't work correctly with that output resistance from a source, then it doesn't have any business being sold to customers.
I suggest to request Morris revisit this. There is something else going here.
Dave.
problem with AT528NC
Hello;
I am having a similar problem and wonder if anyone else has encountered it and what the solution was....
I am the happy owner of two AT6012’s. One I bought with my Linkwitz Orion 3.3 system and the other I bought to drive the Linkwitz 521.4's that I plan to build in the future for comparison. Then I noted that Linkwitz ultimately settled on the AT528NC as the best amp for the 521.4 system.So I bought one lightly used.
Unfortunately I’m having a little problem with it that is similar but not exactly the same as what is described in this thread. One channel from the OrionASP (right-midrange) causes the AT528NC to indicate peak by turning on thered light and clicking the mid-range driver. This problem occurs regardless of whether there is an input signal or not - just when connected to the ASP. It is also not specific to thechannel of the amplifier. I can plug in the midrange output from the ASP and tryto drive the speaker with any of the ampchannels and I get the clicking sound. Conversely I can use any other outputfrom the ASP into any channel of the amp and it works fine – music! It’s justthat one ASP channel that doesn’t work with any channel of the AT528NC. But the problem is only with the AT528NC, notany of the other two ATI amps. I can drive all speakers fine through any permutationof ASP or amplification channels on either of the AT6012's. Why would this happen? How could twoamplifiers from the same company (either of which is more than capable ofdriving the load) behave differently?
I have reached out to ATI for a solution. I will post the result but if anybody has any recommendations please let me know. I am not clear yet on whether the amp is covered by warranty. It was just manufactured and tested in April 2019 but the warranty may not be transferrable.
Thanks,
Marc (Alymere)
Hello;
I am having a similar problem and wonder if anyone else has encountered it and what the solution was....
I am the happy owner of two AT6012’s. One I bought with my Linkwitz Orion 3.3 system and the other I bought to drive the Linkwitz 521.4's that I plan to build in the future for comparison. Then I noted that Linkwitz ultimately settled on the AT528NC as the best amp for the 521.4 system.So I bought one lightly used.
Unfortunately I’m having a little problem with it that is similar but not exactly the same as what is described in this thread. One channel from the OrionASP (right-midrange) causes the AT528NC to indicate peak by turning on thered light and clicking the mid-range driver. This problem occurs regardless of whether there is an input signal or not - just when connected to the ASP. It is also not specific to thechannel of the amplifier. I can plug in the midrange output from the ASP and tryto drive the speaker with any of the ampchannels and I get the clicking sound. Conversely I can use any other outputfrom the ASP into any channel of the amp and it works fine – music! It’s justthat one ASP channel that doesn’t work with any channel of the AT528NC. But the problem is only with the AT528NC, notany of the other two ATI amps. I can drive all speakers fine through any permutationof ASP or amplification channels on either of the AT6012's. Why would this happen? How could twoamplifiers from the same company (either of which is more than capable ofdriving the load) behave differently?
I have reached out to ATI for a solution. I will post the result but if anybody has any recommendations please let me know. I am not clear yet on whether the amp is covered by warranty. It was just manufactured and tested in April 2019 but the warranty may not be transferrable.
Thanks,
Marc (Alymere)
All ATI AT500NC Series amplifiers are covered by ATI’s 7-year transferrable warranty
AT52XNC Amplifiers
AT52XNC Amplifiers
Marc,
I suspect ATI will tell you the problem is with your source (ASP.)
The way you're describing the issue, it very well could be. I think I would check the output of your ASP for excessive DC voltage on the midrange output in question. If significant DC is present, the AT528 amplifier might have an issue with this whereas the AT6012 amplifier doesn't.
Dave.
I suspect ATI will tell you the problem is with your source (ASP.)
The way you're describing the issue, it very well could be. I think I would check the output of your ASP for excessive DC voltage on the midrange output in question. If significant DC is present, the AT528 amplifier might have an issue with this whereas the AT6012 amplifier doesn't.
Dave.
update
Update
ATI responded with exactly the point Davey raised, namely that the 6012 has more DC protection than the 528NC. I measured the mid-range outputs (all of the outputs actually) and there is no DC present on any ASP output channel with or without program material playing. And no hum or any other sonic issues. I let ATI know this result but they haven’t responded yet.
These particular Orion 3.3’s I picked up a couple of months ago from Psutton (you may know him on audio science review and other audio forums) in Austin – drove from San Francisco to retrieve them. So I know that he built the speakers from a Wood Artistry kit and bought the kit along with the pre-made ASP from WA. It sounds great with the 6012 so that combined with no measured DC suggests that the ASP is not the problem. Also, moophone above says ATI solved the problem by sending him a new 528NC amp. So it’s not the amp design in general, just his amp, and just my amp.
Turbowatch2, I hope you are correct about the 7-year warranty. I did submit the required information to transfer the warranty but the factory manual I received with the amp suggests that the warranty can only be transferred following a sale by an authorized reseller, not a private party. We’ll see.
Any other measurements I can do in the meantime to help ATI figure out the problem?
Update
ATI responded with exactly the point Davey raised, namely that the 6012 has more DC protection than the 528NC. I measured the mid-range outputs (all of the outputs actually) and there is no DC present on any ASP output channel with or without program material playing. And no hum or any other sonic issues. I let ATI know this result but they haven’t responded yet.
These particular Orion 3.3’s I picked up a couple of months ago from Psutton (you may know him on audio science review and other audio forums) in Austin – drove from San Francisco to retrieve them. So I know that he built the speakers from a Wood Artistry kit and bought the kit along with the pre-made ASP from WA. It sounds great with the 6012 so that combined with no measured DC suggests that the ASP is not the problem. Also, moophone above says ATI solved the problem by sending him a new 528NC amp. So it’s not the amp design in general, just his amp, and just my amp.
Turbowatch2, I hope you are correct about the 7-year warranty. I did submit the required information to transfer the warranty but the factory manual I received with the amp suggests that the warranty can only be transferred following a sale by an authorized reseller, not a private party. We’ll see.
Any other measurements I can do in the meantime to help ATI figure out the problem?
If they do not mention the "not transferable" transferable warranty on their web site, they intentionally conceal this. You could tell it a trade lie, so customers are mislead about the value of the product after they bought it. It is a huge difference if you buy electronics with or without such a warranty. I do not think they want to discuss this openly.
Technically I would put a capacitor (about 4.7uF) between source and amp, this way the "DC tale" is of the table or they are right...
Technically I would put a capacitor (about 4.7uF) between source and amp, this way the "DC tale" is of the table or they are right...
Update.
I decided to double-check my DC offset measurements between the ASP and theAT528NC and it turns out that I was careless and not looking for the right orderof magnitude effect. When I switched to the mV scale from the volt scale I discovered that there isan offset of approximately 60 mV on the problematic midrange channel while theother channels are all below 10mV. I didn’t realize that such a low DC voltagecould trigger the protection circuit of the amp. As suggested, an in-line capacitor fixed theproblem. I only had a 100uF sitting around but I was thinking that even that valuemight be too low. Thanks setting me on the right track to solve the problem.
I decided to double-check my DC offset measurements between the ASP and theAT528NC and it turns out that I was careless and not looking for the right orderof magnitude effect. When I switched to the mV scale from the volt scale I discovered that there isan offset of approximately 60 mV on the problematic midrange channel while theother channels are all below 10mV. I didn’t realize that such a low DC voltagecould trigger the protection circuit of the amp. As suggested, an in-line capacitor fixed theproblem. I only had a 100uF sitting around but I was thinking that even that valuemight be too low. Thanks setting me on the right track to solve the problem.
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