2xPSG MegaMod v0.3 — AY-3-8910 / YM2149 SNDH Music Module

Demo Video

• YouTube Demo

What is it?

The 2xPSG MegaMod v0.3 is a dual PSG/SSG module for MegaGRRL, compatible with both AY-3-8910 and YM2149 chips. It is the world's first independent high-speed YM2149 VGM hardware player with full support for Atari ST SNDH music.

Designed collaboratively by Denjhang (PCB) and Natalie (firmware), this module can play all PSG VGM music — including the vast Atari ST SNDH transcription library — with perfect reproduction of advanced SNDH sound effects including Sync Buzzer, SID voice, and digital drum sounds.

v0.3 Improvements Over Previous Version

1. Simplified single-board design — the early 2xPSG MegaMod used an overly complex mixing scheme requiring a separate stacked mixing board. v0.3 condenses all essential functions onto a single PCB
2. Stereo PSG channel switch — a double three-position switch lets you freely assign the stereo position of channels A, B, and C
3. Volume adjustment knob — direct analog volume control on the module
4. Internal mixing / independent headphone jack output switch — route audio through MegaGRRL's internal mixer or directly to the dedicated headphone jack

Key Features

• Dual AY-3-8910 / YM2149 PSG chips — 6 voices total (3 per chip)
• World's first standalone high-speed YM2149 VGM hardware player
• Full Atari ST SNDH support — Sync Buzzer, SID, digital drums, all SNDH effects
• Plays all PSG VGM music — MSX, Atari ST, ZX Spectrum, CPC, and more
• Stereo channel routing — 3-position switch per chip for A/B/C channel stereo placement
• Volume knob — analog level control
• Headphone jack — independent output with internal/external mix switch
• MegaGRRL module format — plug directly into MegaGRRL Desktop

Compatible Music Formats

• PSG VGM (all platforms)
• Atari ST SNDH (via VGM transcription)
• MSX PSG music
• ZX Spectrum AY music
• Amstrad CPC music