Two years ago, Ian Scott created the picoGUS card that uses ISA sound card emulation using the RaspPi’s Pico’s microcontroller. My July 2023 post was the first post to mention the card and I’ve had it on my radar ever since. Last summer I received my own copy and tried assembling it into the trusty 80486—except that that didn’t work out well because the card was… too small? After fixing the motherboard standoffs, the motherboard broke down. Four months later I finally replaced it, only to experience another sound card related issue: CPU/BUS sound interference.
So here we are, in 2025, more than six months after the bright red card with the totally awesome polpo! squid logo on did nothing but gather dust: all lights are set to green, it can finally be plugged in, next to its much older and bigger brother the Sound Blaster 16. Just look at the photo below and then at the photo from the Sound Blaster post and you’ll know what I mean by “bigger brother”:
The biggest difference between this card and most other retro-inspired “new old” ISA sound cards like the Resound OPL3 is that the PicoGUS is only pretending to be a specific sound card, which is quite ingenious. The name obviously gives away its primary purpose was to come as close as possible to perfectly emulating the much-revered (and much too expensive right now) 1992 Gravis Ultra Sound (GUS) card. Back then the GUS was remarkable because it could use sample-based synthesis (MIDI playback) with lots of hardware audio channels. It was also one of the first that featured 16-bit 44.1 kHz stereo.
That means no wavetable daughter board was needed: its modifiable instrument patches could be flashed into the RAM on the card itself. This made it a popular but expensive card for musicians and demo scene hackers, yet most DOS games did not take full advantage of it: they still primarily targeted OPL-based FM synthesis which the GUS did not emulate very well. For the hardcore DOS fanboy, that meant having to buy not one but two sound cards. Don’t look at me, I have three. Or four? In the nineties, we only had one of Creative’s hugely popular Sound Blaster variants, so I never got to experience the true GUS experience, making it a bit difficult to objectively evaluate whether the PicoGUS lives up to its name.
In theory, if you own a PicoGUS, you don’t need to own any other card: on boot, you can simply tell the card to behave either like a genuine GUS, or like a Sound Blaster. In your AUTOEXEC.BAT, a few lines need to be added:
SET SOUND=C:\SB16
REM -- SB16 settings
REM SET BLASTER=A220 I7 D0 H7 P330 T6
REM C:\SB16\DIAGNOSE /S
REM C:\SB16\MIXERSET /P /Q
REM -- PGUS settings
SET BLASTER=A220 I5 D1 T3
SET MIDI=SYNTH:1 MAP:E
SET ULTRASND=240,1,1,5,5
SET ULTRADIR=C:\ULTRASDN
C:\PICOGUS\PGUSINIT /mode sb
In sb mode, it reads settings from Creative’s BLASTER variable software is also looking for. In gus mode, it reverts to ULTRASND config instead (the ULTRADIR is still required to load MIDI and mixer info—for Creative, you usuaully call MIXERSET yourself here). Of course I can’t have two different sound cards both behaving like a Sound Blaster on the same A220 port. I could configure the PicoGUS to listen on port 240 instead, like in the ULTRASND setting, but many games have that port hardcoded as part of an implicit convention.
Let’s try and record something in both modes to hear the difference. I usually grab Rise of the Triad (ROTT), DOOM, and Duke3D for stuff like that, but for the GUS, games like Descent or Jazz Jackrabbit used to have better support for that specific card. This is a poor attempt at capturing the differences, if you want a side-by-side comparison check out the video by AnyBit Fever Dreams.
Sound Blaster Mode
As references, here are my previous recordings from ROTT, recorded in OPL mode:
Creative SB16 CT2290;
Creative PCI128 OEM;
Creative Audigy;
PicoGUS in SB Mode;
Sound Blaster mode is effectively SB 2.0 mode that emulates OPL2, not OPL3, meaning slight noticeable differences pop up in games if you’re used to playing with a genuine OPL3 card. Duke Nukem II for instance uses a certain compression mode (ADPCM) to interweave music and sound effects which is currently not supported. Also, when testing certain games, the sound effects seemed to glitch out and sometimes not playback at all. I’ve had this happen in Goblins Quest 3 (sometimes it played, sometimes it didn’t), and in ROTT (effects were cut off halfway through resulting in strange effects).
I couldn’t get Duke3D to accept the emulated Sound Blaster, whatever setting I tried. Most differences in OPL-based music playback aren’t immediate apparent but I do prefer the more gritty sound of the real deal that also guarantees better compatibility and comes with OPL3 mode. Of course, you don’t buy a PicoGUS just for Sound Blaster mode. Still, for the above ROTT recording, it gets pretty close to the real deal!
Gravis UltraSound Mode
Here’s Duke Nukem 3D:
Creative Audigy in SB16 Mode;
Creative Audigy in MPU Mode;
PicoGUS in GUS Mode;
Whoops—the 486 crashes after the main screen; the PC is underpowered to properly run The Duke. I should have recorded a WaveTable version but thanks to the bus interference problem I can’t do that with the new motherboard… Oh well. Here’s DOOM instead:
At least that sounds how it should be! … But I achieved a similar effect with my cheap Serdaco S2 WaveTable header that I plan to upgrade to a DreamBlasster X2. That is, if I find a way to get rid of that crappy motherboard that seems to be boycotting my SB16. I recorded zero noise coming from the PicoGUS line in.
Other Modes
If you inspect the configuration options you’ll notice that besides the perhaps obvious AdLib mode (which can be interesting for older games not supporting a Sound Blaster that plays in AdLib mode), another notable mode the PicoGUS supports is MPU-401. The card even comes with a MIDI output port I haven’t tampered with yet, but others on YouTube have so check that out if you’re interested. A real MT-32 is still on my wish list.
In the end, is it worth it to get a PicoGUS? I don’t know. If you grew up with a genuine UltraSound and can’t get your hands on a vintage one as they’re crazy expensive now, I suppose. If not, perhaps get a WaveTable extension for your Blaster instead. I have the feeling I am unjustly discrediting the awesome card as I’ve barely scratched its surface and I mostly run OPL-based software instead fully GUS-supported ones.
That said, if you do want OPL3 or proper SB support, you’ll still need to rock at least two sound cards, as not all games seem to recognise the PicoGUS in SB mode, and the combination of sound + music playback gets funky once in a while. Of course, if supported, you can totally configure a game to use card 1 for sound FX and card 2 for music playback.
I guess the fully integrated sound chips most of us use nowadays does make things a bit less complicated. No more EDIT AUTOEXEC.BAT, reboot, curse, power off, unscrew your card, fiddle with physical jumper settings, put back in & retry, curse some more, …