Lots of static from speaker issue [Solved]

[processedmeat]

Hi all, I've been racking my brain over this issue I've been having as I'm building a bartop Pac Man machine around the Namco Plug and Play for a fundraising for my non-profit.

As you all know, the plug and play has a single RCA jack for the audio.  When I plug it into a TV, both CRT and LCD, the sound comes out great.  However, in my build, I'm using powered speakers and whenever I plug in the audio, with some adapters, I get a lot of static and the game sounds are very low.

I thought it was the powered speakers that I was using so I switched it out for another, I thought it was the low quality RCA connectors that I got from the dollar store but I still get the same issues with other cables and adapters, and I even bought a Lepai T class mini-amp last night to try with a different set of 4 ohm speakers that has RCA inputs and I keep getting the same issues.

So I'm kinda stuck on my build as I can't figure out this issue and I'm feeling the pressure to finish as the fundraiser is coming up really soon.  So if anyone has any ideas, I would be greatly appreciated.

[JDFan]

How high are you setting the volume from the plug and play ?? -- try adjusting the plug and play volume down a bit and upping the volume on the speakers - could be the volume going into the amplifier is too high and it is then amplifying the static sounds that are coming through the input 

[processedmeat]

Thanks for the reply, but there is no volume pot from the plug and play.   Whether I turn up the volume on the amp or turn it down, I still get the buzzing sound.  When it is plugged into either one of my TVs, there is no buzzing sound and it works perfectly.

The other weird thing is that when even the plug and play is not turned on and powered, the amp still gives a buzzing sound.

I thought it might be the power supply so I swapped it for another one, 6V and I still get the same buzzing sound.

[PL1]

Have you checked the routing of the audio cable and speaker wires?

You may be picking up some EMI. (electromagnetic interference)


Scott

[Slippyblade]

Are you using separate power supplies for the speakers and the PnP?  If that's the case you are fighting floating grounds.  I've run into that on my tablet with powered speakers a lot.  No matter what I did - still had the buzzing.

Try powering both the speakers and the PnP from a single supply.  You may need to install a voltage regulator to get things proper - but I'd bet dollars to doughnuts that that is your problem.

[processedmeat]

Thanks everybody for the replies.

The problem ended up being that the plug and play had a slightly loose power wire that wasn't soldered well at the factory.  Once I reflowed it, it was as good as new.  The only weird thing is why did it work fine with my tv speakers before I reflowed it?  Strange...

Thanks again all.

[JDFan]

Thanks everybody for the replies.

The problem ended up being that the plug and play had a slightly loose power wire that wasn't soldered well at the factory.  Once I reflowed it, it was as good as new.  The only weird thing is why did it work fine with my tv speakers before I reflowed it?  Strange...

Thanks again all.

The TV was probably a bit further away from the wire causing the static than the amp so was not picking up the distortion and amplifying it. Good to hear that you got it sorted