Mains Audio Hum throughout whole system, please help ASAP!

[peach]

Greetings all,

I am a musician and have a great off the grid house and all the power is running off Solar panels to 12v batteries and then converted via an inverter. The major issue I have is that there is 50hz mains hum noise over everything in the house, I have tried to running a cable from the inverter to the earth spike in the ground by the panels but it made no difference.

Any advice would be welcomed, hopefully I just need to buy a power filter or similar? I am happy to try ANYTHING as I need to resolve this issue as soon as possible.


I live in New Zealand and we run 240v here.
Many thanks in advance.

[FunGas]

Have a Google for mains conditioners, I bought one over 20 years ago as a kit and it's only been switched off a few times since I put it together.

Avoid the plugstrip types, they may be cheaper, but they don't do much, I seem to remember about two dozen components in my kit - check the hifi forums for threads galore...

[inetdog]

Greetings all,

I am a musician and have a great off the grid house and all the power is running off Solar panels to 12v batteries and then converted via an inverter. The major issue I have is that there is 50hz mains hum noise over everything in the house, I have tried to running a cable from the inverter to the earth spike in the ground by the panels but it made no difference.

Any advice would be welcomed, hopefully I just need to buy a power filter or similar? I am happy to try ANYTHING as I need to resolve this issue as soon as possible.


I live in New Zealand and we run 240v here.
Many thanks in advance.

If your inverter is a Modified Square Wave (MSW) type, it will produce enormous amounts of 50 Hz and higher harmonic noise which may be picked up by the wiring of your audio system. Grounding the inverter chassis will have no effect on this at all.

Replacing it with a Pure Sine Wave (PSW) inverter would make the hum reduction easier, but a power conditioner on the input of your audio system might help.

Be very careful not to run any of your interconnects (or even speaker cables) anywhere close to the mains wiring. If they must cross, do it a right angles and do not run them parallel for any distance.

You may find it helps to actually disconnect the ground wires from your audio equipment power connection cords.

[peach]

Thanks guys for the replies, I am now a bit clearer on what I have to do, I have a 3 stage Pulse Width Modulator Inverter so I will look into a pure sine wave one as the whole house (lights etc) all hum and it is driving us crazy!

Many thanks!

[inetdog]

Thanks guys for the replies, I am now a bit clearer on what I have to do, I have a 3 stage Pulse Width Modulator Inverter so I will look into a pure sine wave one as the whole house (lights etc) all hum and it is driving us crazy!

Many thanks!

Very good.

Yes, the square edges of the output waveform can cause mechanical hum in light bulb filaments, etc. A similar problem with humming light bulbs can happen with solid-state dimmer switches which also produce (near) vertical edges in the voltage waveform. For theatrical lighting, special filtering has to be installed to overcome this.

If I recall correctly, the higher wattage filaments are more subject to humming.

Your appliance motors will also thank you for getting a PSW inverter.

PS: I have never heard of a three stage PSW Inverter. That may be referring to the charger function of a combined inverter/charger, which is commonly used in RVs and other applications where mains voltage is sometimes available. It says nothing about what the AC output waveform looks like.

[moguitar]

SW inverters

I had to put thick aluminum foil on the cabinet with my sine wave inverter to block the RFI it produces, and put line clamp-on conditioners on the extension cords to my amps. Plus the power cord and amp cords advice is good. Cross at 90* or not at all if possible, even the effects power. Some cheaper SW inverters put out a lot more noise than others, and some amps are more sensitive than others, too.
My regular house power is modified square wave and only the ceiling fan makes noise. The amps are on a dedicated Prosine 1000 in the garage addition, and I shut off the XPower3000(MSW Inverter) that goes to the addition sub panel, when I use the SW for playing. Otherwise the noise in the electric lines is heard.
Use only the best shielded instrument and speaker cables, too. Of course you know about single coils and CFLs, so go with LED lights and/or humbucker guitars.