Hi everyone,
I’m hoping to get some insights on an issue I’m experiencing with my center speaker amp. Yesterday, while using my home theater, the amp started producing a strange noise. I was able to record it, and the noise persists regardless of whether an input is connected or not.
The amp in question is the AUDIOPHONICS AP300-M450ET with a Purifi 1ET400A module. It uses an LM4562 op-amp in its buffer circuit. Interestingly, after powering it off for a while and then turning it back on, the noise disappeared; but after about 30 minutes of use, the same noise returned.
I have an OPA1656 on hand, which I believe is compatible, and I’m planning to swap out the LM4562 tonight to see if that resolves the issue.
If the op-amp swap doesn’t work, I’m wondering if there’s a straightforward way to diagnose the problem further. I’d prefer to avoid sending the amp in for repair, as it could take 2-3 weeks. Alternatively, I’m considering just purchasing a replacement Purifi 1ET400A module and swapping it in.
Has anyone experienced something similar or have any predictions on what might be causing this? Any advice on diagnosing the issue or potential fixes would be greatly appreciated!
Thanks in advance for your help!
I’m hoping to get some insights on an issue I’m experiencing with my center speaker amp. Yesterday, while using my home theater, the amp started producing a strange noise. I was able to record it, and the noise persists regardless of whether an input is connected or not.
The amp in question is the AUDIOPHONICS AP300-M450ET with a Purifi 1ET400A module. It uses an LM4562 op-amp in its buffer circuit. Interestingly, after powering it off for a while and then turning it back on, the noise disappeared; but after about 30 minutes of use, the same noise returned.
I have an OPA1656 on hand, which I believe is compatible, and I’m planning to swap out the LM4562 tonight to see if that resolves the issue.
If the op-amp swap doesn’t work, I’m wondering if there’s a straightforward way to diagnose the problem further. I’d prefer to avoid sending the amp in for repair, as it could take 2-3 weeks. Alternatively, I’m considering just purchasing a replacement Purifi 1ET400A module and swapping it in.
Has anyone experienced something similar or have any predictions on what might be causing this? Any advice on diagnosing the issue or potential fixes would be greatly appreciated!
Thanks in advance for your help!
Does audiophonics buffer have bypass option? So you can deduct it is from the buffer itself/components on it.
It does, I somehow forgot that. Now testing it with the bypass option, no noise for the last 20 mins. I am waiting for the amp to heat up, thinking that it might be an issue trigerred by the heat. After some more time, I will insert the new opamp and try that.
Thanks!
I tried it with bypass for a while, it didn't make that noise. Then I put on the new OPA 1656 opamp, and again, it didn't make that noise for around 20 mins of use. However, then it started making a different kind of noise.
I am assuming that it needs to go in for repairs.
I am assuming that it needs to go in for repairs.
It seems that it indeed is an issue with their buffer board. Write to them if it's under warranty.
I wrote to them already, now that it is weekend, will need to wait until Monday for a response.
This morning, I tried the amp once again. I get completely different kind of noise now, as can be seen in the video below. When I put the amp to bypass mode, it doesn't make any noise. I started suspecting the voltage regulators in the buffer circuit. I guess they are there to feed the correct voltage to the opamp? Is there any way for me to check their state? I have a multi-meter. If I can confidently spot the problem to be caused by the buffer circuit, would be much easier to get a new buffer circuit from audiophonics and replace it myself instead of shipping it in for repairs.
Thanks!
This morning, I tried the amp once again. I get completely different kind of noise now, as can be seen in the video below. When I put the amp to bypass mode, it doesn't make any noise. I started suspecting the voltage regulators in the buffer circuit. I guess they are there to feed the correct voltage to the opamp? Is there any way for me to check their state? I have a multi-meter. If I can confidently spot the problem to be caused by the buffer circuit, would be much easier to get a new buffer circuit from audiophonics and replace it myself instead of shipping it in for repairs.
Thanks!
You should bypass and play more than 20min since that seems to be the time it starts missbehaving if i read correctly. Let it run for a couple hours bypassed.
If all works well, you can
If all works well, you can
I ran the amp on bypass mode for around 10 hours today. 0 issues. Then I engaged the opamp, ran for another 2-3 hours, once again no issues. Super strange.