Strange polarity issue with new amplifier (Topping PA5 II Plus)

[High Power Dude]

Delivering great stuff isn't the measure of a brand its how you deal with the duds that count. A brand gets one chance to make good, after that they're toast, and rightly so. The dacs and preamp are great, the power amps not so hot.

Really? So you know of a brand that makes every single product flawless?

 

[Palladium]

are you 12?

Nah, just racist.

 

[GoDawgs]

...and to be serious here,that's what a randomly thrown fan on some piece of audio can do:




without fan



with fan

I was just wondering about the H3 spike with the fan, is that from an external fan or something added to the inside of a component? Did they share the same power supply? Is the spike from nearby motor noise or something completely different? I just want to avoid similar problems if it's something as simple as never have nearby external fans/motor equipment interference/noise.

 

[Sokel]

I was just wondering about the H3 spike with the fan, is that from an external fan or something added to the inside of a component? Did they share the same power supply? Is the spike from nearby motor noise or something completely different? I just want to avoid similar problems if it's something as simple as never have nearby external fans/motor equipment interference/noise.

Yes,the spike of H3 and the canceling of H2 is indeed weird.

It's maybe related to the speed of the fan as it's just a plain 120 mm,2000 RPM fan,the ones we use for PC cooling and for the shake of the test I powered it with a 12VDC adapter plugged to a different wall socket and just put it on top of the interface under test (an E-MU 0204) .

I have also seen the effects of other motors,LED lights,HVAC,etc if I measure using another electrical line than the dedicated one I have for my stuff (I have 3-phase electrical system in my house) .

In the specific test,proximity of the fan also matters.moving a few cm further i had less interference.
To take it the the very extreme I also tested it with a very strong hair blower,not blowing directly at it of course as it could melt stuff but just beside it and it was really all over the place,the waveform was like severe clipping.

Fans and audio is no good mix for me after that,that's for sure.

 

[GoDawgs]

Yes,the spike of H3 and the canceling of H2 is indeed weird.

It's maybe related to the speed of the fan as it's just a plain 120 mm,2000 RPM fan,the ones we use for PC cooling and for the shake of the test I powered it with a 12VDC adapter plugged to a different wall socket and just put it on top of the interface under test (an E-MU 0204) .

I have also seen the effects of other motors,LED lights,HVAC,etc if I measure using another electrical line than the dedicated one I have for my stuff (I have 3-phase electrical system in my house) .

In the specific test,proximity of the fan also matters.moving a few cm further i had less interference.
To take it the the very extreme I also tested it with a very strong hair blower,not blowing directly at it of course as it could melt stuff but just beside it and it was really all over the place,the waveform was like severe clipping.

Fans and audio is no good mix for me after that,that's for sure.

I may end up using theses rascals as non-powered airflow stands to allow my air conditioning to do it's thing

 

[Chrispy]

Didn't get thru all the comments but curious did you just fix the amp? Or just leave the polarity on the speakers as you did originally?

 

[nck045]

Didn't get thru all the comments but curious did you just fix the amp? Or just leave the polarity on the speakers as you did originally?

I returned my unit, and they sent me a new one which has been working great