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Odd problem with the SMSL DA-9 Amplifier

decoRyder

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I got this amp not too long ago, and I think it's a great amp for the money. However, when I connect it throughput on my powerline ethernet will drop by about 75%, and the powerline ethernet adapters will frequently lose connectivity to other adapters and re-initiate the handshake process. The DA-9 seems to 'inject' a lot of noise, or interference, which causes this behavior. Has anyone else experienced this behavior, with this or another amp using a switching power supply?
 

milan616

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There's no output filters on these SMSL(/Loxjie/Sabaj) designs so if your speaker wire or DA-9 is running near your POE hardware it could be inducing high frequency noise. Try physically separating them as best you can. The DA-9 power supply might also be spitting out high frequency noise back into the AC line as well, which could possibly be cleaned up with a ferrite choke on the power cable, but that will require input from a forum member much smarter than me.
 
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decoRyder

decoRyder

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There's no output filters on these SMSL(/Loxjie/Sabaj) designs so if your speaker wire or DA-9 is running near your POE hardware it could be inducing high frequency noise. Try physically separating them as best you can. The DA-9 power supply might also be spitting out high frequency noise back into the AC line as well, which could possibly be cleaned up with a ferrite choke on the power cable, but that will require input from a forum member much smarter than me.

The DA-9 is actually hooked up to a power conditioner, and the power cord has a ferrite choke... I tried any which way, as long as the DA-9 sits on the same phase as my powerline ethernet adapters it will kill the signal and performance.
 

Toku

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The MA12070 chip used in the DA-9 uses a very simple method for the output noise filter, allowing high frequency noise to leak from the speaker line to some extent. It will be affected if your Powerline Ethernet device is close to the speaker line. Therefore, consider arranging it as far away from the speaker line as possible.

On the other hand, Powerline Ethernet is also regarded as a problem as a device that disperses noise around. It gives intense noise to radio reception and often makes it difficult to receive broadcasts. In Japan, where I live, he doesn't use Powerline Ethernet much because it adversely affects the radio wave environment.
 
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decoRyder

decoRyder

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The MA12070 chip used in the DA-9 uses a very simple method for the output noise filter, allowing high frequency noise to leak from the speaker line to some extent. It will be affected if your Powerline Ethernet device is close to the speaker line. Therefore, consider arranging it as far away from the speaker line as possible.

On the other hand, Powerline Ethernet is also regarded as a problem as a device that disperses noise around. It gives intense noise to radio reception and often makes it difficult to receive broadcasts. In Japan, where I live, he doesn't use Powerline Ethernet much because it adversely affects the radio wave environment.

The powerline ethernet adapter is indeed very close to the DA-9, and I have no way to remedy that - thanks for the insight, much appreciated.
 

epiceric6

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I got this amp not too long ago, and I think it's a great amp for the money. However, when I connect it throughput on my powerline ethernet will drop by about 75%, and the powerline ethernet adapters will frequently lose connectivity to other adapters and re-initiate the handshake process. The DA-9 seems to 'inject' a lot of noise, or interference, which causes this behavior. Has anyone else experienced this behavior, with this or another amp using a switching power supply?

Powerline modems are very unreliable. They produce heaps of interference, and they are also prone to any interference on the power line. Wireless Mesh could be your way to go, depending on your situation though. What's your normal throughput via the powerline? I once believed that powerline is better than wireless, but you just need to remember that powerline modem is very inefficient in transferring data and may or may not be better than WiFi in the perspective of throughput, latency and stability. Give the modern WiFi Mesh a try and you might be surprised.
 
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decoRyder

decoRyder

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Powerline modems are very unreliable. They produce heaps of interference, and they are also prone to any interference on the power line. Wireless Mesh could be your way to go, depending on your situation though. What's your normal throughput via the powerline? I once believed that powerline is better than wireless, but you just need to remember that powerline modem is very inefficient in transferring data and may or may not be better than WiFi in the perspective of throughput, latency and stability. Give the modern WiFi Mesh a try and you might be surprised.

I have a very difficult environment - bridged/meshed setups are unfortunately out of the question, since I have too much interference from neighboring devices, and the powergrid relay station across the street. I get about 120-140 Mb/s using powerline, which is absolutely sufficient - it's just too bad the SMSL DA-9 reduces that throughput by about 75%:)
 
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decoRyder

decoRyder

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You may try add a ferrite in the power cord of the DA-9 and see if it helps. Loop the power cord through the ferrite a few turns for stronger filtering.
For example: https://www.digikey.com/en/products/detail/fair-rite-products-corp/0431173551/8593994

I did try the ferrite core - didn't work. I came up with a solution though, very hackish but I'll post it here anyway, in case someone else has the same problem:

I had a better quality step-up transformer flying about, hooked that up to my filtered main power supply, and attached the DA-9 to the 220v output - perfect - no more interference; at least none that reduces throughput on my powerline ethernet!

Thanks for all the help and suggestions I very much appreciate it.
 
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