Buzzing noise on audio when picture is bright with SCART to component converter

Hey guys,
As I've posted previously in the thread about buzzing noise on a Super Nintendo, I'm having an issue with a buzzing sound coming from my surround sound speakers when the game displays a bright image. Getting an official, well-shielded Nintendo brand cable didn't solve the issue like it did for the OP. I think I've narrowed the issue down to my SCART to component converter, here's what I've noticed.

• Unplugging the component cables from the box does NOT stop the buzzing
• Unplugging the SCART cable from the box DOES stop the buzzing
• When plugging in the SCART cable, the buzzing begins BEFORE the cable is inserted far enough into the socket to actually get a picture. It starts right about when the metal surrounding the pins touches the metal of the socket. As I recall, with SCART, the metal surrounding the pins is the ground, so I'm suspicious there might be a grounding issue.
• Unplugging the audio plugs from the box DOES stop the buzzing
• The buzzing does NOT go away when you use a console that has the ability to output audio via it's own audio cables (i.e the RCA jacks on the Mega CD)

I've soldered in a pair of RCA female plugs in order to give my converter box audio output capability, and I'm suspecting I've done something wrong with the mod. Basically, I soldered the left cable to the "left" pin of the SCART plug, the right cable to the "right" pin and soldered the copper shielding to the "ground" pin. I tried smothering the soldering in hot glue just in case the partially exposed wires were getting interference (though I would have thought the metal shell of the box would have been blocking it), but I'm thinking I'll remove all this and instead solder in a 3.5 headphone jack, I'm hoping this will be a cleaner mod and might also solve the issue.

Thoughts?

 

x

 

Well, as I've already said, I'm using an official Nintendo cable, which is very thick and solved the noise issue for the guy from the previous thread, but didn't for me. Which is why I suspect something else.

 

add some shielding - aluminium foil will work
perhaps some shrink tube as well
also make sure the ground pins are securely connected

 

try using a different ground point for the audio connectors you added to the scart to component box, im using cheap ass 99p scart cables for rgb with no issues even with volume ramped up.

i'd also check the scart pins and make sure none are bent / touching. but im sure you've check that, are you getting stereo audio other then the buzzing?

 

You mean to the cable itself? Like I said, I'm pretty sure the cable is sufficiently shielded, not to mention I tried the foil thing in the past with a poorly-shielded N64 S-video cable, which did nothing, I actually needed to replace the wiring.

I'm currently using pin 4 (audio ground) for grounding, there's a lot of other choices for grounding, including pin 21 which is for the shell. What would you suggest? Yeah, I'm getting stereo sound as usual, though a buzzing sound is introduced to the audio when there's a bright image.

 

Fireaza, I'm not sure if you checked my replies on the older thread about noise on brighter image.

I've build the entire cable using a single different cable, every single one of them individually shielded and it doesn't matter.
The problem lies on the revision of the console you're using.

I have 2 different RGB to component converters. The gaming one that is $50 on ebay. The one that doesn't carry audio. And a 115 GBP one from JS Technology.
The same applies to both. The noise is present. No matter the cable and no matter the converter.

Now the only thing that's left are: console dc adapter and the console itself.

BTW: reading your post more carefully I would suggest you getting an audio system, like an stereo amp, and hooking the audio direct to it. It seems to me that this might be something with your TV.

 

It could be the console itself, as I don't notice the issue with my Saturn or N64. I've got hooked up to my 5.1 AV receiver, not my TV, so I'm already doing that

 

The SNES is known to have a humming noise in audio. I did the same thing you did to my scart to YUV converter and at first i thought i had done a bad job on the solder but its not, its the SNES. Its just something you're going to have to live with.

 

It would be great to add this discussion to the "best snes revision" thread.

My famicom does the buzz noise. I'll test with my brazilian snes.

 

Do you think soldering a set of RCA jacks directly to the SNES' audio chip would solve the issue?

 

To be honest, I don't know. I was considering that.

Yesterday I've build a female scart socket to use with an arcade monitor I have here.
The interference I usually see were all gone.
The image was incredible clear.

Maybe it has something to do with the TV, I don't know.

 

What about lining the inside of the SNES with foil or something? :\

 

theres also a digital audio mod, not sure what it involves extra work wise but that should eliminate any noise and give much clearner and cleaner audio