VOGONS


First post, by LABS

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EDIT:
Done so far:
+ Firmware rewritten to literally match the original SB2.0's firmware behavior (based on disassembled sources) .
+ The card passes all tests (auto detection, PCM, ADPCM and FM-music) by the original Creative Labs TEST-SBC.EXE utility on a Pentium - even SB2.0 can't do that!!
+ Much better FM handling on machines faster than 486 due to OPL3 usage - for example Prince of Persia plays FM music on a Pentium.

Todo:
- FIFO queue for handling OPL3 commands - should theoretically allow all OPL-enabled games to normally play music on machines faster than a 286/386 (like SOMI, Ultima series, Indiana Jones, etc etc).

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This card is my next humble attempt to design an even more compatible and simple sound card for DOS 😀

It is still a Sound Blaster 2.0 compatible, but I redesigned it from scratch, considering things I've learned from disassembled firmware of the Sound Blaster and what was impossible to implement in an already released Blasterboard without causing incompatibility hell. And it also now uses OPL3 instead of OPL2 for FM.

I decided to make it a separate project with a different name - Sonic Buster 8 (8 for 8-bit PCM)

Current state: Testing and debugging the prototype.

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Some general features:
- Based on Atmega microcontroller
- Dead quiet analog path (-95dB RMS)
- 8-bit PCM / ADPCM mono playback
- Stereo FM music playback (OPL3)
- CD/Line stereo audio input (internal jumper)
- PC-Speaker audio input (internal jumper)
- Dedicated volume controls for all of the above

What else is added so far:
- Firmware updates using DOS utility
- Co-processor mode - uploading and executing custom code on Atmega (experimental)
- New commands for setting precise playback rate
- Up to 65535Hz PCM playback
- Far more tolerant to 486 and faster machines than the original Sound Blasters

Thanks everyone for the suggestions and reports since the release of Blasterboard! A lot of things are now implemented in SB8.

Last edited by LABS on 2024-04-18, 13:49. Edited 14 times in total.

Blasterboard: DIY SB2-compatible sound card on ATmega MCU
Sonic Buster 8: New 8-bit ISA sound card

Reply 2 of 41, by LABS

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appiah4 wrote on 2023-06-14, 09:28:

This is my wet dream 🤣

Wait, you didn't even see the real hardware pictures yet 😁

Blasterboard: DIY SB2-compatible sound card on ATmega MCU
Sonic Buster 8: New 8-bit ISA sound card

Reply 3 of 41, by LABS

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Finally the prototypes.. and ridiculously huge stencil

Blasterboard: DIY SB2-compatible sound card on ATmega MCU
Sonic Buster 8: New 8-bit ISA sound card

Reply 4 of 41, by Tiido

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Large stencil is good, I pretty much always order full size for the important things... the ones cut to small size are often bent out of shape so much that they're hard to get good pasting with 😒
Welcome to the world of meat based pick & placing 🤣 (beats cutting and bending pins and hand soldering bazillion through hole parts)

T-04YBSC, a new YMF71x based sound card & Official VOGONS thread about it
Newly made 4MB 60ns 30pin SIMMs ~
mida sa loed ? nagunii aru ei saa 😜

Reply 5 of 41, by LABS

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Tiido wrote on 2023-06-30, 10:58:

Large stencil is good, I pretty much always order full size for the important things... the ones cut to small size are often bent out of shape so much that they're hard to get good pasting with 😒
Welcome to the world of meat based pick & placing 🤣 (beats cutting and bending pins and hand soldering bazillion through hole parts)

Needs some practice though to grip it well for a good contact in the center 😀

Blasterboard: DIY SB2-compatible sound card on ATmega MCU
Sonic Buster 8: New 8-bit ISA sound card

Reply 6 of 41, by LABS

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Not perfect, but at least there are lots of unused pcbs left from another projects to make it work

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Blasterboard: DIY SB2-compatible sound card on ATmega MCU
Sonic Buster 8: New 8-bit ISA sound card

Reply 8 of 41, by LABS

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keropi wrote on 2023-06-30, 13:47:

very nice!
looking forward to the finished card!

Hey, mate!

Blasterboard: DIY SB2-compatible sound card on ATmega MCU
Sonic Buster 8: New 8-bit ISA sound card

Reply 9 of 41, by appiah4

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LABS wrote on 2023-06-30, 10:31:

SB8-ppcb.jpg

Finally the prototypes.. and ridiculously huge stencil

That is one big ass stencil 🤣

Retronautics: A digital gallery of my retro computers, hardware and projects.

Reply 10 of 41, by Tiido

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LABS wrote on 2023-06-30, 12:49:

Needs some practice though to grip it well for a good contact in the center 😀

Making a perimeter using same thickness PCBs is exactly what I am doing, I tape them down to the desk so they cannot move and then I tape the stencil on them once it is perfectly aligned and then I do the swipe, with another PCB that is just as wide as one side of the PCB being pasted. It helps when the entire swipe is done in one go with good pressure, then the pads end up getting pasted nicely and there's no spillover which normally happens when I have to do anothes wipe in some other part as the stencil often lifhs slighly. It isn't gonna be a problem until you get ot 0.5mm pitch parts though, in which case even small spills can make unwanted bridges but with 1.27mm this is not gonna be an issue ~

T-04YBSC, a new YMF71x based sound card & Official VOGONS thread about it
Newly made 4MB 60ns 30pin SIMMs ~
mida sa loed ? nagunii aru ei saa 😜

Reply 11 of 41, by LABS

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Quite marvelous I must admit 😁

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Now to the hard part - testing and debugging 🤓

Blasterboard: DIY SB2-compatible sound card on ATmega MCU
Sonic Buster 8: New 8-bit ISA sound card

Reply 12 of 41, by LABS

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Tiido wrote on 2023-06-30, 17:02:
LABS wrote on 2023-06-30, 12:49:

Needs some practice though to grip it well for a good contact in the center 😀

Making a perimeter using same thickness PCBs is exactly what I am doing, I tape them down to the desk so they cannot move and then I tape the stencil on them once it is perfectly aligned and then I do the swipe, with another PCB that is just as wide as one side of the PCB being pasted. It helps when the entire swipe is done in one go with good pressure, then the pads end up getting pasted nicely and there's no spillover which normally happens when I have to do anothes wipe in some other part as the stencil often lifhs slighly. It isn't gonna be a problem until you get ot 0.5mm pitch parts though, in which case even small spills can make unwanted bridges but with 1.27mm this is not gonna be an issue ~

I used a plastic card instead and applied the paste with rapid short swipes and the stencil was moving up and down a bit and as a result there were some unpleasant bridges and poorly filled pads which I had to correct by a needle 😕
Your tips are very useful, will try next time, thanks!

Blasterboard: DIY SB2-compatible sound card on ATmega MCU
Sonic Buster 8: New 8-bit ISA sound card

Reply 13 of 41, by SaxxonPike

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Wow! This is really impressive looking. Very tidy, very simplified. Having a discrete mixer is just perfect- we can then make adjustments on the fly without needing to route the individual signals to a mixer or bouncing between app and setup program.

Sound device guides:
Sound Blaster
Aztech
OPL3-SA

Reply 14 of 41, by appiah4

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LABS wrote on 2023-06-30, 18:17:

Quite marvelous I must admit 😁

IMG_2917.jpg

Now to the hard part - testing and debugging 🤓

Such splendour..

Retronautics: A digital gallery of my retro computers, hardware and projects.

Reply 15 of 41, by shevalier

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LABS wrote on 2023-06-13, 21:30:

Hello,
let me introduce my humble attempt to design an even more compatible and simple sound card for DOS 😀

Wow, for the first time I see a correctly cut plane between analog and digital.
Can I whine like an old man?
- Why no via stitching?
https://resources.altium.com/ru/p/everything- … -stitching-vias
- I would recommend using combo pads.
You can solder anything on them, starting from MLСС
- I would ground the mounting bracket a little differently.
- L1 and 2 are best replaced with 1-2 ohm resistors.
Filtering is the same, but there are no uncontrolled resonances.
- V1 and 2 are better to use LM317 / 338 with a capacitor on the adj pin of 10+ uF.
With a voltage drop of 5+ volts across them, they are much better than lowdrop regulators at noise and ripple rejection.

PS. Very nice design.

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Aopen MX3S, PIII-S Tualatin 1133, Radeon 9800Pro@XT BIOS, Diamond monster sound MX300
JetWay K8T8AS, Athlon DH-E6 3000+, Radeon HD2600Pro AGP, Audigy 2 Value

Reply 16 of 41, by LABS

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Thanks for your input, shevalier! I'm actually quite happy with current design with -95dB RMS noise floor which is more than enough for sound sources of such fidelity to consider the audio output as "dead quiet". However at the early stage of designing Blasterboard I already tried almost everything you mentioned. The first prototype even had 2 stages of voltage regulation to extremely reduce the PSU noise 😎

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But the real tests showed that there is no improvement compared with a single pair of 79/78L0x regs when used in such noisy environment. So I dropped that idea in favor of simpler design. What really introduced a horrible noise - was grounding the bracket because of the ground loop. Anyway the construction does not allow to ground the bracket now, as it is mounted using nylon mounts.
L1 and L2 should go away and I'll put wires here, again, in favor of simplicity - the filtering frequency is far far away from the audio spectrum and even from the TL074's bandwidth anyway, so it does not affect the noise and there are 22p caps on opamps for stability.
Interesting article on via stitches by the way 😀
Cheers, mate! 🤙

Last edited by LABS on 2023-07-01, 16:55. Edited 1 time in total.

Blasterboard: DIY SB2-compatible sound card on ATmega MCU
Sonic Buster 8: New 8-bit ISA sound card

Reply 17 of 41, by Tiido

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Yeah, vias in the right place can make a dramatic difference

T-04YBSC, a new YMF71x based sound card & Official VOGONS thread about it
Newly made 4MB 60ns 30pin SIMMs ~
mida sa loed ? nagunii aru ei saa 😜

Reply 18 of 41, by LABS

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Tiido wrote on 2023-07-01, 16:54:

Yeah, vias in the right place can make a dramatic difference

That's exactly why they are not all over the place 😀

Blasterboard: DIY SB2-compatible sound card on ATmega MCU
Sonic Buster 8: New 8-bit ISA sound card

Reply 19 of 41, by LABS

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Engineering 😌

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Blasterboard: DIY SB2-compatible sound card on ATmega MCU
Sonic Buster 8: New 8-bit ISA sound card