Turbografx express Audio output

Hi again,

As I am finally back to my electronics table , I'm finally finalizing my turbografx Express to box it up.

so I wanted to know please : does it produce stereo sound or mono? the point is shall I join the cables going to scart plug left and right and give them one audio to just have louder sound on tv , or is there really a R & L out of it ? because for example mega drive one had stereo out ..

thanks in advance

 

You shouldn't just wire 2 stereo outputs to give mono anyway.

Need to use 2 resistors.

Not saying pce is stereo or mono, just general basics.

 

thanks alot for your reply, can you just explain more please? 2 resistors that would be a connection? join both ends together then give them the same feed ? any values of resistors suggested?

and is there a way to find out about stereo/mono question? I searched a little in Google but couldn't find out.

 

It depends on where you take the signal from. The signal going to the headphone jack is stereo, but it's also internally mixed to mono to drive the (single) internal speaker.

 

excellent information thanks, so what I did was soldering 2 wires to these 2 points, one of them gave me sound the other one didn't so I thought I would just use it for both, but since its a stereo signal going here , may I know the second point please? (photo from internet as I'm at work now )

 

OK, there is some trickery involved here - there is a switch inside the headphone jack that detects if something is plugged into it, and when you just solder wires to the back of the board it's not being operated - so the circuitry is still in "internal speaker" mode, which uses the mono mixdown signal. When you plug headphones in, it both disables the internal speaker and turns the mixing off so that you get both L and R signals routed to the headphone jack.

If you want stereo even when there is nothing plugged into the jack, then you need to connect it earlier in the circuit - the most obvious point being where it comes out of the HUC6280 on pins 17 (left) and 18 (right) - this will always be stereo even if the internal speaker is active.

 

Excellent information, I guess from the IC would be better however I just wanna check if they won't interfere with external controller wires already soldered, then I will do it.

thnx alot

 

1k resistor in series with each channel should be fine. Then connect the 2 resistors together, this is your mono.

But if you are keeping mono just use the already mono source?
Unless now you know its stereo you are going to keep stereo? (this would make more sense imo)

 

many thanks really for the resistors idea, I would have never known it without your assistance.

but as you said yes, now I will use stereo, so do I still use them right after the IC ? or not required? like what do they do to the sound? improve it or something?

thnx

 

the sound from these 2 points is extremely low .. any ideas please?

 

Yeah, the audio output on the PC-Engine is pretty low. Try using a buffer amp - something like this:

https://oshpark.com/shared_projects/uFE90Naz

 

thanks again