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Doing some testing...


Albert
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Getting ready for next week's Portland Retro Gaming Expo and I'm killing two birds with one stone.. Testing POKEY copies of Super Circus AtariAge, while at the same time testing six different Atari 7800 systems (these systems have been modified with s-video and composite video outputs and stereo audio). Only five of the systems are visible here. The sixth is upstairs, but it's hard at work as well!!

 

Hope to see some of you in Portland next weekend!

 

..Al

 

SCAA_Testing.jpg

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(these systems have been modified with s-video and composite video outputs and stereo audio).

 

Prey tell how these 7800s were modded for stereo? I've asked about this before and gotten crickets in response. How is the Pokey mixed in if the TIA channels are separate out? Details man...details!

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I wasted a little bit of Al's time, my PLD code for SCAA was buggy, so I re-wrote it. Plus side is, he can now use 27C256 or 27C512 for EPROM's. I still maintain that the 7800 was made by the devil though.

 

Yes, there are plenty of "evil" 7800s, and they are not very consistent between different units.

 

..Al

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Yes, there are plenty of "evil" 7800s, and they are not very consistent between different units.

 

..Al

 

What is odd though, is, there are nice ones as well. I had a challenge going with myself, to see how much of the unused address space can be mapped into a real RAM chip. One out of 5 systems let me map an area of memory, that would just crash the others. I think it was $2800-$3000, which most people describe as a mirror. A lot of the memory maps out there are out of date, I think I gave one to RevEng, PMP etc., that I have proven works and could be used with a single plug-in board, pretty simple decoding logic within 64K. But there is always one bitch 7800, good or bad. LOL

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yeah this!!! I just did the UAV mod and video is fantastic, but I'd love to add real stereo sound instead of dual mono.

Seems to be a trade secret!! LOL I imagine the gist of it is to have a separate circuit where you run the two TIA channels and have them mix the pokey channels blending those in between the two as a center channel. So basically the pokey is always in mono with the TIA channels separated out. The mixing is the trick in this case.

 

Wonder if Bryan's new audio mixing board he just released does this? But I've not see specifics for it in the case of the 2600 or 7800 setups.

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Getting ready for next week's Portland Retro Gaming Expo and I'm killing two birds with one stone.. Testing POKEY copies of Super Circus AtariAge, while at the same time testing six different Atari 7800 systems (these systems have been modified with s-video and composite video outputs and stereo audio). Only five of the systems are visible here. The sixth is upstairs, but it's hard at work as well!!

 

Hope to see some of you in Portland next weekend!

 

..Al

 

SCAA_Testing.jpg

 

My new desktop wallpaper. :D

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In all seriousness, that's an amazing setup you have there. If I was electronically inclined, that's the kind of thing I'd love to do.

Having Tempest and Black Widow machines wouldn't hurt!

(I think I found what's happening to all the POKEY chips!)

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In all seriousness, that's an amazing setup you have there. If I was electronically inclined, that's the kind of thing I'd love to do.

 

Having Tempest and Black Widow machines wouldn't hurt!

 

(I think I found what's happening to all the POKEY chips!)

 

Haha!

 

There are more machines not visible in that photo. :)

 

..Al

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