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GameSX.com => Audio Mods => Topic started by: acem77 on March 22, 2011, 06:41:55 AM

Title: Digital audio mod Atari Jaguar
Post by: acem77 on March 22, 2011, 06:41:55 AM
I've been toying around with some digital audio mods.
I have found a way to mod the jaguar.
It works for the most part but I need to find the best clock speed. Getting a little jitter.
So far the using the clock from a psx works the best ill have to do some tests and solve the problem.
I will post more details later.

big picture
http://www.greatlakesvista.com/download/mods/JAG_MB.JPG (http://www.greatlakesvista.com/download/mods/JAG_MB.JPG)

update some tones are tinny sounding/echoing, not really jittering.
Title: Re: Digital audio mod Atari Jaguar
Post by: acem77 on March 24, 2011, 03:03:36 AM
Found the MCLK signal on the mother board using the Tom and jerry docs and an oscilloscope.
good news its seems to work good on my sony
bad news then my denon will not  undrestand  the signal....
if i use an other MCLK the denon works again and i get the tinny echo...
seems like the BCK spacing is longer...

I orderd a Cirrus Logic CS8420 and a soic to dip adapter to test i hope this can auto correct the issue....
dont know what else to try. maybe a new crystal thats a better m atch for the master clock.
Title: Re: Digital audio mod Atari Jaguar
Post by: Stefan_L on March 27, 2011, 03:33:03 AM
Interesting :)
I have plans on getting a Jaguar and will of course try and S/PIF modify it also, can you please add more detail on wich pins that are bclk, mclk, data, lrclk?
What is the samplerate of the Jaguar?

And also could you post a recording on how it sounds? :)
Title: Re: Digital audio mod Atari Jaguar
Post by: acem77 on March 30, 2011, 02:52:14 AM
I have some rough numbers from an old 20mhz scope , i just bought a new digital scope ill post more later.

developers' documentation includes a section showing how the digital audio subsystem.
"U5" is the chip i pulled the signals from
http://mdgames.de/jagschem.zip (http://mdgames.de/jagschem.zip)
Title: Re: Digital audio mod Atari Jaguar
Post by: acem77 on April 01, 2011, 02:52:50 AM
I have had some more luck.
I got the new cs8420ic in the mail and hooked it up.
Large image
http://www.greatlakesvista.com/download/mods/jag_cs8420ic.JPG (http://www.greatlakesvista.com/download/mods/jag_cs8420ic.JPG)


Here is a sample video with audio. this is not to demo how clear it is since the speaker and recording is of poor quality. but to demo a clean constant digital output.
http://www.greatlakesvista.com/download/mods/jag_digiaudio.wmv (http://www.greatlakesvista.com/download/mods/jag_digiaudio.wmv)