XRGB 2 audible hum at higher volumes

[nickgoracke]

A little background: I recently purchased an XRGB2 in hopes of getting the best possible video out of my older consoles.  I bought Euro RGB cables for each of my systems, and have an RGB extension cable modded such that the female end has a Euro pinout, and the male end has a Japanese pinout (this may be important?).  I have no complaints with the video - it's gorgeous.  I currently have the audio hooked up to my 2 channel system, and I like to play CDs and games with the volume UP.

Problem is, there's an audible hum which seems to be coming out of the XRGB.  When a console is hooked up but not turned on, there is no hum no matter how high I turn the volume.  When I do have a console turned on, however, I can hear a hum whenever I'm at a game menu screen with no sound (I'm guessing the hum is present at all times, but it's just masked by the game volume).  I've tried multiple systems and multiple games with the same results.  I've also tried using a step-down converter for the XRGB 2.  I have not been able to eliminate the hum.

Could this be a problem with my wiring?  Maybe a pin that I missed or some fundamental problem with simply converting an extension cable to go from Euro to JP?  Or is this just a flaw with the XRGB 2 (interference from within the unit)? 

Any ideas would be appreciated. 

[NFG]

What you're describing sounds like a ground loop, where there's a level difference between the grounds of the different components.  The Saturn especially is very bad for this.

The solution I think is to ensure all your ground wires are awesome, no bad solder, no missed ground pins (especially on the 21-pin connectors, but also on your other connections).

[nickgoracke]

What you're describing sounds like a ground loop, where there's a level difference between the grounds of the different components.  The Saturn especially is very bad for this.

The solution I think is to ensure all your ground wires are awesome, no bad solder, no missed ground pins (especially on the 21-pin connectors, but also on your other connections).

The Saturn was the first system I noticed it on, and by far the most obvious.  I'll play around with the ground pins... but assuming all looks good there, I'm wondering if there's anything that can be done about it.  I've seen similar 'ground loop' threads on audio forums suggesting moving components to different outlets (currently the TV, XRGB, and game system are on the same outlet), so I suppose that's one simple thing to try.

Thanks for the input!

[nickgoracke]

Sorry, bit of a typo there.  Audio forums suggest moving everything to ONE outlet - TV, XRGB, and game are on one outlet, while the amp is on another.  I'll try moving them all to one output tonight and post results. 

[nickgoracke]

Well, unfortunately my lunch break experiments weren't very encouraging.

Plugging the PlayStation directly into my amp with stock AV cables produces no audible hum, no matter how high I turn the volume.
Plugging the PlayStation into the XRGB with stock AV cables produces an audible hum at high volumes.
Plugging the PlayStation into the XRGB with my RGBB cables produces an audible hum at high volumes (takes less volume than the stock cables to hear the hum).
(Both tests using the XRGB were tried with 2 different headphone-jack to stereo-RCA cables)

Additionally, everything was running off of the same outlet and all other devices were unplugged/disconnected when doing the test.

I'm reasonably convinced that either something inside the XRGB itself isn't grounding properly, or the audio circuitry/passthrough is just poorly designed.  I might see if I can break the audio out of the RGB cable and just bypass the XRGB alltogether and see if that solves the problem.

[nickgoracke]

I feel really stupid for not checking this before, but...

Looking at my PSX and SNES cable, I've noticed that there isn't a pin for both grounds.  Each connector has one ground pin in the game connector hooked up to audio ground in the SCART connector, but the 2nd ground pin in the game connector is not hooked up/there is no wire for it (I assume this would go to pin 21 on the SCART connector - the big metal shield on the outside).

I'm now thinking this might be the cause of the hum... sound reasonable? 

Also, random question, is there a good way to crack open a cheapo 3rd-party SNES connector?  Seems lthere aren't any visible clips holding it together...

[nickgoracke]

This is absolutely driving me crazy, but here's where I am.

Neo Geo does not seem to have any buzzing/humming when using RGB through the XRGB.  Yay.
Everything else buzzes (to different degrees).

I've been mainly working with the SNES, and after about a million different experiments, I found something weird...

If I hook up up only 3 wires at the SNES connector (Audio left, Audio right, Ground) and feed these to the XRGB via the SCART connector, there is no hum.
If I hook up the rest of the wires at the SNES connector (R, G, B, C-sync, Ground 2) but don't even connect them at the SCART connector end, it hums.

So no new connections, but all wires are live... and it causes a hum.  I've tried this on two separate cables (both purchased from eBay, not official).  Is this making sense to anybody else?

[nickgoracke]

Well, based on my last post, the only thing I could think of was that the RGB signal was somehow interfering with the audio.  I had already tried:

-Connecting/checking all grounds (no change)
-Not sending the audio through the XRGB (no change)
-Using/not using an extension cable (no change)

Finally tonight, I tried simply breaking the audio out at the SNES connector.  All Video signals are sent to the XRGB via one wire, and all Audio signals are sent to the stereo system using another (hooked them up to a headphone jack).  Big improvement.  If I put my ears up directly to the speakers, I can still hear a very very slight buzz, but it's totally acceptable now.

Whew, what a mess... and it'll only get messier as I'll need to do some stereo mods on my Saturn, PSX, Master System, SNES (current solution is too ugly), and... I think that's it, actually.  Still way more work than I bargained for, though.  The picture sure is gorgeous though...

[Holering]

Ok what you are describing sounds exactly like my problem. I'm using a regular rgb to ypbpr converter however (has no audio outputs. why would they do that...lol)

Yeah nomatter what I connect it always produces an audible hum-buzzing (gets louder depending on how bright the picture is). The sad part is that I've used an audio breakout on the scart lead going from the SNES system itself and only hooked it up to my mini hifi stereo using headphones. Everything else was unplugged (power and everything) except for the stereo and snes which were using the same outlet-powerstrip. There is still a dreaded buzz-hum that gets noticeably louder-noisier depending on the scene-brightness being displayed (the t.v. is actually off and unplugged just like everything else!! It's still there!). SNES and stereo are at least 8 ft. away from any other metal object-electronic-batteries-remotes. The noise is still there....

This does not happen using the svideo cable I have which I ordered from nintendo

Have you fixed this problem? What was it?

I'm gonna improve all my grounds and see what happens

[phreak97]

can anyone verify that the US snes composite AV cable has no components in it?

[NFG]

can anyone verify that the US snes composite AV cable has no components in it?

The US SNES composite AV cable has no components in it, confirmed.

[rolins]

I have a Saturn and XRGB-2 but I don't seem to experience this audible hum. I can turn up the volume on the speakers as loud as I want and I still don't get buzz. If it helps any my XRGB-2 is modified for euro-scart and I'm using a 120v - 100v step down converter with it.

[RGBcrazy]

The "hum" you are experiencing is present with all consoles. Most of the time it is really low and you can only notice it when you have your ears to the speakers of the tv, in my case. Almost all my consoles have it, though I don't hear it.

[Holering]

I really wish this guy Nickgoracke was still around...

Yeah well I spent over an hour getting everything ground inside the darn snes scart lead (just on the male scart end) and no improvement what so ever...

I really wanna ask Nickgoracke or anybody else how they get the darn cable open on the male end that goes into the actual system (would also like to know for the dreamcast as well). Mine is some third party cable that I got off ebay and there doesn't seem to be any visible tabs at all whatsover. There's only this tiny little hole on each side that a pin might fit into but otherwise I'm gonna try and see what I can do without destroying it...

Yeah this is ridiculous I don't see how it does this noise since it doesn't do it with any standard composite/svideo cable. Why does it do it only when I'm using rgb through scart?? On every system too wth. It really sucks as the noise is very noticeable as well. It's like the picture signal is going into the sound cause it's so strong or something...

I've tried getting help from here http://www.avforums.com/forums/showthread.php?t=814977
They even said scart sucks which I do kinda agree with cause with time these connectors would seem to get pretty worn out and some pins might start slipping inside. These people are really great smart people though they got like the best forums for electronics.

[Anthony1]

This "hum" issue is a real problem. I've now owned two different XRGB2 units, and both of them had this issue. I think it's highly unlikely that I just happened to get two XRGB2 units that just happened to have this humming issue. I think if I got 5 more XRGB2 units, all five would have some kind of humming issue with various systems. I have a relatively high end audio system, and I run all my audio to that. I like to play my games at a pretty high volume, and no matter what I do, I hear a "humming" or "buzzing" noise in the background. It depends on the system. Some are more pronounced than others, but I think all of them have it to some degree. I think what I'm going to do, is build a Scart RGB cable for the XRGB2, but keep the audio lines seperate.  Basically, keep the audio away from the XRGB2 unit, and just run the audio directly to my stereo setup. This way, I should bypass any humming issue. Right?

[undamned]

I noticed hum on my XRGB2+, but I just cracked it up to be crappy audio amplification in the unit.  It's a video upscaler, not a high-end audio processor.  I'd recommend running separate audio, like others have suggested.  If you're not too scared, you could install RCA jacks in your console's body and then just use the A/V port for video signals only.
-ud