re: Turbo Duo audio channel from HU6280

[duo_r]

anyone? I found this link showing that pin 17 and 18 on the 6280 chip is for audio (it is in french):

http://wiki.pcengine.info/pmwiki.php?n=Hardware.HuC6280

and translated to English:

http://babelfish.yahoo.com/translate_url?doit=done&tt=url&intl=1&fr=bf-home&trurl=http%3A%2F%2Fwiki.pcengine.info%2Fpmwiki.php%3Fn%3DHardware.HuC6280&lp=fr_en&btnTrUrl=Translate

It says "see left audio note" but I don't see any details. So does the 6280 have the audio channel pre amped? And can in theory I pull from here and create my own sound amp if the Duo's sound is having issues? I am in the process of replacing all the Caps, but I am creating a contingency plan...

[kendrick]

The 6280 pinout is available on the GamesX wiki:

http://gamesx.com/wiki/doku.php?id=schematics:hu6280_netlist

Unfortunately, the 'see audio note' notes are based on Lawrence's original observations and may have been lost to the mists of time. Big-L, anything you can add here?

[NFG]

Unfortunately, the 'see audio note' notes are based on Lawrence's original observations and may have been lost to the mists of time. Big-L, anything you can add here?

There was nothing in my notes of interest, except that the PCE's audio amp had a mono channel from the EXP-BUS mixed with the stereo audio from the PCE itself...  And maybe some useless notes about how I was getting tured of the whole circuit tracing thing by this point in the project.   =)

If I remember correctly these lines just feed into the PCE's audio amp (a small 8-legged thing I think, can't remember the part number offhand).

[duo_r]

Was that part the 7 pin M51131L? Mitsubishi chip? I am in the process of replacing ALL the audio caps so it might be a mute point (but just a backup).

Also - related to sound, many of the caps went bad prematurely because they were not good quality, but because of their location to the heat sinks. What is normal temp for those heat sinks? The reason I ask is the heat sinks are putting out a good amount of heat (maybe 120 degrees) and I am not sure if that is normal.

[duo_r]

change to original question - will the Turbo Duo ever be capable of digital audio like the other consoles? My initial research says no.

[NFG]

change to original question - will the Turbo Duo ever be capable of digital audio like the other consoles? My initial research says no.

I believe you are correct.

[l_oliveira]

change to original question - will the Turbo Duo ever be capable of digital audio like the other consoles? My initial research says no.

I say you should be able to make both the ADPCM and CD-DA outputs encoded on a SPIDIF output as both come out from the chips in I2S format (Serial PCM for CD-Player D/A chips) but it would require mixing both into a single stream and maybe digitizing the PCE CPU audio pins output for mixing, also. I think it would be too complex.

Machines from that age (PCE-CD/Mega-CD and Neo Geo CD) would often employ multiple digital to analogic converter chips and a analog mixer at the output (there were no accessible digital mixing technology back then) while newer system mix their outputs digitally to save money by using only a single DA/chip and less analog parts.