Re: PiGUS: Gravis Ultrasound emulator on an ISA card with Raspberry Pi

Posted on 2022-06-12, 14:47

by

by polpo

in Marvin \ Sound

in Marvin \ Sound

so raw pi IO in bare metal mode is fast enough to handle ISA bus transactions? :o I assumed you would need pico RP2040 with PIO to respond fast enough. Add ~$2 8MB SPI PSRAM APS6404L and you could do any sound card emulation on pico Yes, it's fast enough, amazingly. It took some discussion on …

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PicoGUS: ISA sound card emulator with Raspberry Pi Pico (Gravis Ultrasound, AdLib, MPU-401, Tandy, CMS)

Posted on 2022-06-11, 21:52

by

by polpo

in Marvin \ Sound

in Marvin \ Sound

This project originally started out based on a "full" Raspberry Pi but I moved to using a Pi Pico. I recommend looking at the later pages in this thread - things get going with the Pico on Page 5 . Current status: * Hardware v1.1 hardware design and gerber files are available - currently "build-your …

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Re: Newly made Gravis Ultrasound compatible cards ... what's the degree of interest?

Posted on 2022-01-31, 15:51

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by polpo

in Marvin \ Sound

in Marvin \ Sound

A bit off topic, but at the 24 Hours of Daytona race last weekend, there was a car with what looks like the GUSar logo, just with the S in a different position. I’m wondering if the GUSar Lite sound card logo is referencing some company I’ve never heard of. The car is run by a Russian team, so I …

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Re: PCB destroying adhesive found in my Roland Sound Canvas SC-55mkII (inspect your synthesizer!)

Posted on 2022-01-22, 04:48

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by polpo

in Marvin \ Sound

in Marvin \ Sound

I opened my SC-55mkII up and the glue is still kind of pliable and doesn’t seem to have caused any corrosion on the board. Still doesn’t look good and I’ll be scraping it away just in case. I opened it up just after unplugging it and the nearby heatsink is still pretty warm. With my current setup I …

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Re: Mixer for computer collection

Posted on 2022-01-17, 21:10

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by polpo

in Marvin \ Sound

in Marvin \ Sound

I use a 6-channel mini mixer and it works and sounds great: https://www.amazon.com/Moukey-MK0149-RD-FR-Ultra-Low-Noise-6-Channel/dp/B08BBXK8CY/. This brand also makes 4 and 8 channel versions of this mixer. I'd love something with quick mute buttons but for only $26 the value is pretty incredible. …

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Re: Why doesn't Secret of Monkey Island (awmonkey.mid) sound correct with Roland MT32 + UM-ONE + MidiPlayer (Windows 10)

Posted on 2022-01-12, 19:16

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by polpo

in Marvin \ Sound

in Marvin \ Sound

I just tried playing MI_1.MID from the SCUMM Bar's MIDI pack on my MT-32 and it sounds exact to the game. The message inside the midi file says it for the MT-32. I played it back in DOS with DOSMID on the MPU-401 interface on an ESS sound card, but that shouldn't really be any different than playing …

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Re: CRT nostalgia vs the 15KHz monitor whine

Posted on 2022-01-08, 05:35

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by polpo

in Milliways

in Milliways

I love that I can’t hear CRT whine any more, it does make using CRTs far more enjoyable! Drives my kids nuts, though. They ask me if I had to deal with the noise all the time, and I had to reply, well yeah, what else could we do?

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Re: ISA Network - Speed / CPU overhead - Best options?

Posted on 2022-01-08, 05:23

by

by polpo

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Of the three that you have, the 3com is definitely the best. The D-Link is NE2000 based so it will perform the same as the other NE2000 card. With the speed of machine that you have, you may not see much perceived performance difference at 10Mbps, but you’ll probably see less CPU usage with the …

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Re: Tube Time: Announcing The Snark Barker, a 100% Compatible SB 1.0 Replica!

Posted on 2022-01-08, 05:11

by

by polpo

in Marvin \ Sound

in Marvin \ Sound

I was thinking it was a pretty square-y sounding sine. Looking at the wave in my (admittedly bottom of the barrel) scope from my snark barker, it’s definitely squareish but not perfectly so. I wonder if that’s down to any filtering or flaws in the design in the analog section of the original Sound …

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Re: What retro hardware you killed today or in the past :(. Killing spree stories+serial killers are welcome.Rest in pie

Posted on 2022-01-07, 17:10

by

by polpo

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I was doing some reflowing on the GUS Max 2.1 card since it would lock up at the detection using the DOS setup program or when I enable it in Windows 95C's device manager. I reflowed the following to see if the issue would get fixed: [...] Apparently, the ICS1614 GF1 chip is done for and the card …

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Re: Tube Time: Announcing The Snark Barker, a 100% Compatible SB 1.0 Replica!

Posted on 2022-01-07, 01:41

by

by polpo

in Marvin \ Sound

in Marvin \ Sound

I sent in a fix for SBDIAG just yesterday. The SAA chips can produce noise (for "drums") and sine waves. SBDIAG turned on the sine generator, but forgot to turn off the noise generator. Try to download the current SBDIAG.EXE from github, and try again. That did it! The sine waves sound perfectly …

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Re: Tube Time: Announcing The Snark Barker, a 100% Compatible SB 1.0 Replica!

Posted on 2022-01-06, 22:29

by

by polpo

in Marvin \ Sound

in Marvin \ Sound

Following up on my own post: Folks who socketed your TEA2025Bs: how are they holding up? I’m thinking about socketing mine because the 2 I’ve used so far in my Snark Barker are both bad: one had distortion in the right channel and the other had no output at all. I went ahead and socketed the new TEA …

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Re: Tube Time: Announcing The Snark Barker, a 100% Compatible SB 1.0 Replica!

Posted on 2021-10-09, 15:13

by

by polpo

in Marvin \ Sound

in Marvin \ Sound

Folks who socketed your TEA2025Bs: how are they holding up? I’m thinking about socketing mine because the 2 I’ve used so far in my Snark Barker are both bad: one had distortion in the right channel and the other had no output at all. Also both SAA1099s I got from China were extremely bad - basically …

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Re: Strategies for troubleshooting low DMA not working on 386 motherboard?

Posted on 2021-10-01, 03:12

by

by polpo

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Good idea to try the original 82C206 in the socket. I just did it and it showed the same original symptoms. So yeah, it was indeed bad.

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Re: Strategies for troubleshooting low DMA not working on 386 motherboard?

Posted on 2021-09-30, 23:36

by

by polpo

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

So, egg on my face: I traced the DREQ1 and DACK1 lines based on my photo above with the chip off. I checked for continuity and found that there was no continuity on DACK1 to where I was expecting it to go on the board. After I popped the 82C206 chip back out and gave things a good look, I finally …

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Re: Strategies for troubleshooting low DMA not working on 386 motherboard?

Posted on 2021-09-30, 20:39

by

by polpo

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Good spot! I relocated R22 and C77 to the bottom of the board because they interfered with the socket.

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Re: Strategies for troubleshooting low DMA not working on 386 motherboard?

Posted on 2021-09-30, 15:10

by

by polpo

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I desoldered the 82C206, put in a PLCC socket, and inserted the 82C206 I got on eBay. Good news: the system boots and high DMA still works. Bad news: low DMA still doesn’t work. Next I’m going to start tracing signals that are DMA related around the board and test every logic chip they go through. I …

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Re: Strategies for troubleshooting low DMA not working on 386 motherboard?

Posted on 2021-09-28, 21:30

by

by polpo

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

So I've purchased a 82C206 and hot air rework station, as the chip is not socketed on this motherboard. Wish me luck, I've never done SMT soldering of this scale before! I'm going to watch plenty of tutorials on YouTube first.

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Strategies for troubleshooting low DMA not working on 386 motherboard?

Posted on 2021-09-18, 15:06

by

by polpo

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I have a 386sx system that I'm building with this motherboard and I seem to be having problems with anything that uses low DMA channels 1-3. This first manifested with the system not being able to boot or access floppy drives. It would hang on booting from floppy, or if booted from a CF card would …

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Re: What retro activity did you get up to today?

Posted on 2021-08-25, 14:47

by

by polpo

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Testing the AT clone case I pulled out of my parents' attic. It held our family's first PC, a 286 with EGA graphics, 40MB hard drive, and 287 FPU (to run AutoCAD). I have a pic of the actual system when it was new! E17p0qVWYAIVius.jpg E9RlO-zVgAMgDuO.jpg Very cool although a little sad that it was …

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