Noise on AMP when running backup power

[CntrlAltDel]

Hi there,

I'm not sure if this thread should go in backup power or tech support hopefully I wasn't wrong.

Issue I'm having is that when my AMP goes on backup power (grid power down) whether it's a standard Mecer UPS, or EcoFlow Delta Max or EcoFlow River Pro I hear a buzzing sound on my headphones and speakers. The amp I'm using is the Technics SU-VZ220. This issue doesn't occur when the grid power is on and the UPS is in bypass mode or any of the lithium battery backup power are in bypass mode. Strictly only happening when grid power is down.

Does anyone know why this could be? Is there any "de-noise" plug or anything of that sort?

 

[Kilo1-1]

Hi there sounds like it could be a grounding issue with many inverters whenever the power fails your Eskom neutral falls away sort of. That's why large hybrid inverters have a neutral-to-earth bond that's on a relay, so when Eskom fails it connects your neutral to your home earth which in turn drains away the feedback on the neutral. I'm not sure but this might be the problem.

 

[Rickster]

Hi there,

I'm not sure if this thread should go in backup power or tech support hopefully I wasn't wrong.

Issue I'm having is that when my AMP goes on backup power (grid power down) whether it's a standard Mecer UPS, or EcoFlow Delta Max or EcoFlow River Pro I hear a buzzing sound on my headphones and speakers. The amp I'm using is the Technics SU-VZ220. This issue doesn't occur when the grid power is on and the UPS is in bypass mode or any of the lithium battery backup power are in bypass mode. Strictly only happening when grid power is down.

Does anyone know why this could be? Is there any "de-noise" plug or anything of that sort?

Your UPS is probably a modified sine wave, its quite "dirty" power for the Amp.

 

[Adagio_Leopard]

Your UPS is probably a modified sine wave, its quite "dirty" power for the Amp.

Yep. Hes right. Modified sine inverters basically output a square wave.
You're hearing the harmonics from that.

 

[CntrlAltDel]

Yep. Hes right. Modified sine inverters basically output a square wave.
You're hearing the harmonics from that.

Your UPS is probably a modified sine wave, its quite "dirty" power for the Amp.

Thanks for your responses. It looks like this is the case with UPS but not he lithium battery bank which uses pure sinewave. This issue with the amp occurs on both the lithium battery and the UPS.

 

[CntrlAltDel]

On an unrelated note (or related I dunno yet). Today I found out that my DP 1.4 cable even though shielded rested about 10cm of its length on the top of the amp. So when powering off the amp the monitor goes off. But I have another exact monitor right next to it, also with the same DP 1.4 cable, doesnt have this issue because it cable is not resting on the amp.

So by guess, I just lifted the cable from the amp and turned it off, and voila no issue with noise on the headphones when turning it back on and the monitor is now unaffected. ABSOLUTELY INSANE!.