Amplified stereo output on a tg-16

[Zeon]

Well I finally figured out why my audio for my rgb mod on my tg-16 was so quiet, i was tapping the audio before it went through the amp! 

My problem now is this, on the tg-16 both audio channels are merged before going through the amp, so if i tap the output from the amp it will be amplified, but mono. I want stereo. So I need some help, anyone with a turbo duo, or preferably turbo booster or tg-cd unit (as the unamplified stereo output goes into them via the expansion bus) I need you to open it up and do the following:

Find the op ap labeled c358c or similiar (should at least have 358 on it, it's 8 pins) and grab a multimeter and trace where pins 1,2,3,5,6, and 7 go.

Tell me if there is anything like a cap, resistor or anything else between the pins and where they go. Audio left and right comes from pins 17 and 18 on the huc6280 processor, with another audio line on pin 20 that i am not sure what it does. pins 1 and 7 are the two outputs, 2, and 6 are the inverting inputs, and 3 and 5 are the non-inverting inputs.

On a tg-16 pin 20 of the huc6280 goes into non-inverting input A on pin 3, the audio left and right from pins 17 and 18 of the huc6280 are going through a resistor each and tied together on the other end of the resistors, this then goes into inverting input A on pin 2 of the 358. Pin 1 goes to the rf modulator for output. Pin 5 is connected to a cap and resistor in series, with the other end of the cap and resistor going to ground and power respectively. Lastly pins 6 and 7 of the 358 are tied together.

Let me know if anyone can help, I really want amplified stereo output!

[Michael Helgeson]

Im confused as to why you don't just tap it off the back expansion port area. Both left and right audio are there. Its line level out, exactly what you need to put out to a stereo receiver or tv via RCA jack or whatever method.
http://www.gamesx.com/misctech/pcebp.php
Look on there, find the audio pins,tap their solder points.

[Zeon]

Ok so i figured a few things out. Originally i had tapped audio from the expansion bus, however it sounded quiet to me. It turns out that i had been playing hu-cards via rf before and cd's on my duo. The audio sounds louder on rf because they are joining the two stereo lines into one making it sound louder. Also red-book audio is louder than the psg audio in general. I just compared the audio from the expansion bus to my duo and they have about the same loudness.

But what really threw me off was that the duo and tg-16 both are quieter than my other systems, at a volume setting of 10 on my tv, my snes, genesis, etc. are louder than the tg-16 or duo which at that point is just barely audible. Also the audio is NOT amped on the tg-16 when going through the expansion bus, I am not even sure if they used an amp on the duo which would explain why it is quieter than my other systems, if they did indeed use no amp in the duo.

IMO the duo and tg-16 should have louder stereo audio than they do, i have to turn the volume up a bit when switching to them.

[Duo_R]

I don't recall the audio tapped from the exp port being unusually low. However that was like 4 years ago since I tested that model (it was a mod for a friend). This is the unit, also tapped into composite video (audio and picture was improved).




Hopefully you made it look pretty.