It all has begun long time ago, when Chuck Steinman of DataQue created this set of plans for building stereo sound by installing a second Pokey chip inside the best 8-bit computer ever. Once installed, the second channel has all its addresses 16 bytes set higher in the memory ($D210 - $D21F). Since then, dozens of sounds and demos that support this upgrade have been published. Most of these programs were made in Poland, but a few sound-demos were also made in other countries. The most popular programs (in my opinion, of course) playing msx in stereo are Yooomp! and Numen.

Main features :

• GTIA sound mixing on both channnels
• Stereo Indicator Led
• high quality PCB
• ONE wire control to disable/enable stereo  (built in U-switch)
• Equal audio output on both channels
• Stereo mode/ dual mono mode
• ROHS, PB Free

 INSIDE BOX :

• A fully tested and assembled STEREO BOARD V2
• 2 golden plated RCA outputs

Disclaimer

• POKEY CHIP NOT Included 

INSTALLATION STEP BY STEP:

Disclaimer: If you are not familiar with soldering or you do not have proper tools, please LET a pro technician do it for you or send me your ATARI BOARD for installation. Upgrade installation cost is ~15€ only. Contact me to arrange installation. Otherwise, please remeber - wrong tools usage or low skills may damage atari and Your stereo board; any damage/harm to your hardware is NOT subject of any kind of warranty.

• Desolder POKEY from ATARI board or remove it from socket
• Insert stereo pcb into the socket or solder into atari motherboard
• Make connections to STEREO BOARD:
  • A4 – this signal can be found in many places on ATARI BOARD; for example solder wire between CPU  (https://en.wikipedia.org/wiki/MOS_Technology_6502) pin 13 and STEREO BOARD A4 pad
  • BELL – this signal can be found on GTIA CHIP pin 15. Please solder wire between pin 15 of GTIA ( code name CO -14889) and Stereo BELL PAD
  • CTRL - stereo control; if You have ultimate upgraded computer, make connection to M0 pin; otherwise  connect GND to this pin to disable STEREO MODE (deafult ON - LED ON). Use simple "ON-OFF" switch  .

Audio out conenction diagram

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