Boosting image and sound in A/V mods...

Ok, yes, I know RGB would be better, but I'm not aiming for that just yet.

I've done an A/V mod so I could use common RCA cables with my consoles. So far, only my SMS and TG16 have this mod installed. On the TG16, the video is fine, but audio is kinda low. I tapped the extension connector for the A/V signals using 30 AWG wire.

For the SMS, I tapped the signals through the A/V connector. The sound is ok, but the video starts washed out (SEGA logo at startup bleeds then slowly sharpens).

So, anyone have feedback on how to boost the audio and clean up the video? I've read somewhere to add a capacitor to the video could help. Thanks all!

 

Even s-video would be better than composhite, and if you're in the US, chances are you TV has s-video.

Why don't you just use the proper leads? OK, composite isn't that great, but you shouldn't have THAT bad a problem with the leads. You can even make your own leads, at least for the original Master System and for a Core Grafx.

If you really want to boost audio, obviously use an amplifier... but if there's an issue, you might find yourself boosting noise. Sounds to me like you've done something wrong somewhere along the lines.

 

What are you using to display the composite signal you are getting? On older CRT based TVs composite looks great with American SMS units. On my Dell 2405FPW (which admittedly doesn't have the best composite decoding hardware) it looks like all sorts of trash. With a quick and dirty S-Video mod I found that the picture was oodles sharper and the colors looked far more like they once did on a CRT. This is likely your trouble to start with and the only fix is swapping displays or modding it for s-video (which I can assure you is ridiculously easy. Especially if you remove the RF modulator and put your s-video connector where it once resided).

To make sounds louder I would suggest trying a capacitor. I'm not 100% certain of a value for you to try as I'm not that knowledgeable to pull things out of my hat (the rabbit is busy chewing a hole through it) but I would suggest starting with a 10uF at 16v or higher. You can't go wrong getting a capacitor with a voltage value as high as they can go as that just means it can handle that voltage. The farad rating indicates its capacitance.

As I'm rather tired I can't recall exactly how 10uF would affect an audio signal but it likely will raise the volume noticably. I've never had issue with stock hardware but it is very possible the capacitors in your SMS are dying and need to be replaced - at least the ones that involve themselves with sound output. Given most of them are easily 20+ years old I wouldn't be the least bit surprised if you found this to fix your problem WITHOUT needing to resort to adding capacitors to the output line.

30AWG wire should be fine, small but the signal you're putting over it isn't exactly high in the current department. I'd be more interested in keeping the wires away from sources of RF interference such as the CPU and voltage regulators. They won't kill the audio or picture quality but they will get in the way of having a crystal clear picture if they're affecting it at all.

 

I'm using my LCD HDTV. I didn't stretch out the image to fill the screen.

Anyway, APE, you wouldn't happen to have a link to the quick and dirty S-Video mod, do you?

I'm gonna bust out some of my electronics know-sometimes-how and see how I can get this to work for me.

 

Yeah, LCD's are pretty poor for old consoles.

Have you tried Googling for Master System s-video? If you had, you'd probably have found Bacteria's thread on his mod on this very forum ;-)

That said, it's s-video. Look at the pinout of the CXA1145 and it should be self-evident (s-video = Y/C).

 

LCD + old games console + composite = awful image quality. This is just a universal truth. S-Video *may* be an improvement but it depends on how badly the image quality is being affected by the set's scaling hardware. I've seen people upgrade from composite to RGB and the difference on their HD set wasn't anything to write home about.

For SMS, TG16 etc use a CRT if at all possible. You'll appreciate the difference.

 

http://www.digitpress.com/forum/showthread.php?t=141873

 

Yeah, I kinda figured. I used to play on a 20" CRT TV back in the day. I reverted to my old ways of sitting close to the TV...part of my problem.

Anyway, thanks for the links and the input.