ECN Forum Forums General Topics of the Trade Non-US Electrical Systems & Trades RCA 45EY 2 record player

Here's a comparison. The blue line represents a true sinewave -- the type of power you get by plugging into a mains outlet.

The red is the type of waveform you get from a modified sinewave inverter. Those steep vertical sides to the waveform contain many harmonics, extending well up into the high audio and even radio frequency range.

Thank you so much for your responses gentlemen.
I now have, thanks to you, a better understanding of inverter power, however I still dont know how I would attempt to get rid of this noise, its like aussie said it has a hot chassis etc etc so how on earth can I earth the player to get rid of it.
Im at my wits end!!!!
Regards

First thing is to try earthing the 12v supply. Connect the negative terminal of the 12v input of the inverter to a metal water pipe, the earth pin of a GPO or some other object known to be earthed.
If the turntable is constructed on a steel chassis then try earthing that.
I know that some US made record players did not isolate the shield of the pickup cable so I'm not going to say go and earth that directly, though you could try doing so via a .01uF capacitor. Taking this a bit further, you can also try earthing the amplifier chassis via .01uF capacitor. Earthing via a capacitor like that will still allow the chassis to be live, but yet earth it at higher frequencies.

hello aussie.......
I have as you suggested connected an earth to the metal motor board and the 12v inverter input,while these connections did make a difference they only seemed to change the tune of the noise......and perhaps reduce it slightly.
I have purchased a .01 mf 275v poly cap..
should I connect this across the mains leads into the amplifier or on one side only ?be it active or neutral?
I have replaced the pick up cable and I can assure you it is new and properly shielded
kind regards

Cowabbi,
Be prepared for a bit of experimentation here...you might need to try different places to connect the capacitor and you also might need to increase it's value. Interference suppression is often more of an art than a science and what works for some things won't work for other things.
Try first across the 120VAC input where the mains lead is terminated in the record player.
Try from both sides of the 120V supply to the chassis of 1) the amplifier 2) the turntable.
Try from the shield of the pickup to the turntable chassis and then the amplifier chassis.
Try all these things with and without the earth connection to the turntable chassis.
Reverse the 120V plug in the inverter.
Try connecting the earth to each side of the 120VAC supply via the .01uF. Try connecting the pickup shield to earth via the capacitor.
If any of these start to look promising try increasing the value of capacitor; try .1uF.
Try also right across the 120V right at the inverter output socket.
If you're not getting anywhere there, get a mains suppression filter (not just a surge arrestor - that may not have any filtering) like used for computer gear( a 240V one is quite suitable), put 120V plugs on it, and connect between inverter and record player. You will probably have to earth the filter as the earth pin of the inverter socket will probably go to nothing.
Let us know how this lot goes