Saturday, May 30, 2009

CMS (Dual Philips SAA 1099) Recordings

Here's a rarity, carefully sampled for you.

Before the soundblaster, there was the Creative Music System (CMS) (AKA GameBlaster), which contained two Philips SAA 1099 chips.
It pretty much bombed since the OPL2/Adlib was all the rage at that point.

Nevertheless, the thing has some charm. Here are two recordings made on a SB 2.0 CT1350A (with the SAA chips factory installed as legacy option)

Doodle
Loom

More can be found here

Friday, May 29, 2009

8 hours of (why would I buy a flash cart?) later

Cart:



ROM Test:



Note1: this is a bare cart with no battery backup or mapper. Will only run 256 kBit /32KB roms ... which is more than I need for my tests.

Note2: the quote should read please dont _PUT_ your wires in my brain.

Sunday, May 24, 2009

Total Stereo separation ATARI 2600 Jr Mod

There are various NTSC 2600 RCA A/V mods out there. Four years ago (note WAAAAAY before I thought of making chipsounds) there were a only a few that I didn't really like since either the mod was mono, or stereo but with huge L+R bleed that didn't really cut it for me.

Four years ago, I also had about zero electronics knowledge, so I hacked the most horrible thing which you can see here:



Instead of feeding the same voltage source to both channels, like in that schematic, I modded it by added TWO 7805's onto an external duck-taped protoboard onto the console itself.
Each of them "feeding" DC component into one of the two TIA audio outputs.
As always I try to bypass AC coupled electrolytic caps - however dangerous this is - to tap in closer to the original signal as possible (in hindsight I should have buffered the signals as well with an opamp).
However ugly it is, it works perfectly for my own taste.

Whats cool about stereo mods? Well to completely isolate effects used by programmers, remember that two channels is not much.

Pacman's horrible intro "tune"
ET's Landing

Notice the TOTAL absence of Background noise. (mp3 encoding did the worst)

Note#2: The Atari Cartridge PCB is from Pixels Past. Build to use 27128 EPROMS (see previous). So fun code can be easily ran and recorded. Dont worry I do have original game carts for Pacman and ET . Like who doesnt.

Friday, May 15, 2009

We had Joy we had fun, We had EPROMs in the sun.



Yes, am all aware that there are proper tools to do this "professionally". But this is way cooler. One and a half day suffice to erase them to 0xFF's.

Way faster than it used to be in the 70's? (debatable), but I otherwise DO miss the ozone layer.

NOTE from this site
"UV-C radiation, which is lethal, is emitted at wavelengths of 200-280 nm. Fortunately, UV-C is completely absorbed by atmospheric ozone and oxygen. Even with severe ozone reduction, UV-C radiation would still be absorbed by the remaining ozone."

EPROMs require UV-C's (according to wikipedia) ... hum .. anyway, 1.5 day to wipe my 27128's is an actual observation.
I have got 20 or so 271282's (salvaged from an arcade board), so this erasing delay is a non issue for my Console/Cartridge development.

Saturday, May 9, 2009

The weight in gold of obsolescence

Gold price is currently 900 USD an ounce. It is one of the only safe investing bets for the current economy... However that's bad news for you and me.

Last Friday I took off early and indulged in some long overdue electronic junk treasure hunt. Visited two of my best spots in Montreal pcrecycle and 1800parts.

Whats funny in fact is that I was looking for a device I had myself thrown away 10 years ago. The original Sound Blaster 1.0. Who would have thought that I would now need an obscure chip from this board .. not talking about the YM3812 (OPL2) – but a SAA 1099 which would have been, I think very easy to add to chipsounds, especially when i could just compile a little C program in borland DOS compiler and make it scream from its ISA slot in my 486 for my now routine steps of noise pattern and bit mixing analysis.

Only two years ago I remember that place had a HUGE box of ISA audiocards, filled with valuable chiptune goodies on them (got about 15 boards with OPL3 chips on them, inducing the pretty rare Adlib Gold, and (even rarer) a Microsoft Windows SOUNDSYSTEM ... wait did you see that properly? Microsoft branded SOUND CARD!!!


But now all that is.... now nowhere to be found, “Went to Africa a long time ago!”.

...

The later shop owner gave me a odd look, and said -off the bat-, all that went to Germany a while ago (according to him the current biggest player in large-scale computer recycling) Why do we keep hearing about China all the time?... media fascination I guess.

I also Keep Wondering whether or not my obsession with “old junk” is (even remotely) an eco-statement, or if its just retarded geeky nostalgia. Whatever I buy will end up in recycling anyway.

So I have a look around, try to listen to all his stuff about bad customers and the provincial difference in police behavior in a merchant/client dispute.... I just kept obsessing about the damn cards.

Q"Are you SURE you don't have a dump with old ISA cards in them"
A"well each of them is worth 3$ in gold so you would need to give me more, like 5$ each"
Q"O...K... that's not really a problem"

Two stories higher (guy has LOADS of server/printer stuff)
found a container headed for recycling, which I spent 30 minutes digging through.
A bunch of them, mostly crappy Vibra 16 Sound Blasters, but nothing as old as an 8bit SB 1.0 card. However, here's what I scored:



Just couldn't resist its beauty. Also a Gravis GF1 chip is hard to come by, and may become handy in say chipsounds 5.0 ;)

But now with all the children suffering in this sad world, why do I imagine all those SID chips melting in Aqua Regia????

(anyone with a SB1.0 card that wants a free chipsounds license just send me a shout)
EDIT: I just won a rare CT1350A Stuffed with two SAA chips!