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The LlamaBlaster

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First post, by Eivind

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I find myself with a bunch of CS4237B and YMF262 chips, and the knowledge of wiring up and configuring these and the RP2040 from previous projects - and I thought, maybe I should put together a nice little all-in-one 8-bit ISA sound card?

I know this has been done in various other projects, but it'll be open sourced and free to put together for anyone interested, so I thought it might be useful for someone else than me.

Planned features:
- CS4237B - SoundBlaster Pro 2 / WSS compatible
- OPL3 (real YMF262)
- PicoGUS
- HardMPU - might be be necessary, not sure about the state of intelligent mode MPU-401 of the PicoGUS. But having the ATmega1284P on board would allow me flexible power-on configuration of the CS4237B, bypassing pesky EEPROM programming and DOS init utilities
- Wavetable header
- mt32-pi header (plug in a Raspberry Pi Zero 2 with the mt32-pi firmware for emulated MT-32 and General MIDI)
- 3.5mm audio jacks (line out, line in, mic in)
- Optical digital output ("toslink")
- 15-pin gameport for joystick and/or MIDI in/out
- Internal analog CD audio input header

Let me know if I've missed anything! 😀

The LlamaBlaster sound card
ITX-Llama motherboard
TinyLlama SBC

Reply 1 of 62, by orcish75

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Awesome!! The CS423x chips are my favourite ISA soundcard chips. I do like Crystal FM, but a genuine OPL3 is better. If it has a really good analogue stage, I'd definitely build one.

EDIT:

If it's gonna be an 8-bit card, perhaps putting an XT-IDE interface on it will also be cool, give XT owners the chance to use large IDE drives.

Reply 3 of 62, by Eivind

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orcish75 wrote on 2024-01-06, 07:56:

Awesome!! The CS423x chips are my favourite ISA soundcard chips. I do like Crystal FM, but a genuine OPL3 is better. If it has a really good analogue stage, I'd definitely build one.

I'll be following Crystal's component selection and layout guide, using a 4-layer stackup and good quality caps - hopefully it'll be good. Only way to tell is to try! 😀

orcish75 wrote on 2024-01-06, 07:56:

If it's gonna be an 8-bit card, perhaps putting an XT-IDE interface on it will also be cool, give XT owners the chance to use large IDE drives.

Do you mean an address decoder + ROM socket, for using the XTIDE BIOS in combination with another IDE controller - or a full-fledged IDE controller with cable connector?
In any case, this is quite a bit outside of what I was thinking of, but it would be easy to at least include the ROM option, if there's enough room on the board. I'll keep this in mind for later!

The LlamaBlaster sound card
ITX-Llama motherboard
TinyLlama SBC

Reply 4 of 62, by Eivind

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Veda wrote on 2024-01-06, 17:01:

SPDIF input would be nice to have (to be used in combination with an AWE64 Digital out, or some CD / DVD drives with Digital output).

There isn't support for S/PDIF input on the CS4237B - so that would require a discrete decoder chip. I was thinking this would be somewhat overkill for an 8-bit sound card, as its main purpose would most likely be (early) DOS-era computers where any CDROM drives would have analog output. I'll note down this suggestion though! 👍

The LlamaBlaster sound card
ITX-Llama motherboard
TinyLlama SBC

Reply 6 of 62, by orcish75

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Eivind wrote on 2024-01-06, 20:09:

I'll be following Crystal's component selection and layout guide, using a 4-layer stackup and good quality caps - hopefully it'll be good. Only way to tell is to try! 😀

Cool! It's doesn't have to be outrageously good, just better than the cards made back in the 90's, they made them as cheap as possible, so the analogue stage was often compromised, hiss, hum, computer "thinking" noises etc.

Eivind wrote on 2024-01-06, 20:09:

Do you mean an address decoder + ROM socket, for using the XTIDE BIOS in combination with another IDE controller - or a full-fledged IDE controller with cable connector?
In any case, this is quite a bit outside of what I was thinking of, but it would be easy to at least include the ROM option, if there's enough room on the board. I'll keep this in mind for later!

Yup, fully fledged controller with cable connector. XTs were generally limited to big, noisy MFM drives (part of the charm for many owners), but having an XT-IDE controller will allow CF cards or IDE to SD card adapters etc. to be connected to it.

Reply 7 of 62, by Eivind

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orcish75 wrote on 2024-01-07, 07:07:

Cool! It's doesn't have to be outrageously good, just better than the cards made back in the 90's, they made them as cheap as possible, so the analogue stage was often compromised, hiss, hum, computer "thinking" noises etc.

Yeah I don't think this'll be an issue, I'm already pretty satisfied with what I ended up with on the ITX-Llama motherboard. Making an ISA card will allow me to get even closer to Crystal's recommended layout, and I'll be using better caps for this one.

orcish75 wrote on 2024-01-07, 07:07:

Yup, fully fledged controller with cable connector. XTs were generally limited to big, noisy MFM drives (part of the charm for many owners), but having an XT-IDE controller will allow CF cards or IDE to SD card adapters etc. to be connected to it.

I see the appeal of putting an IDE interface on here, but I'm still not 100% sold on the idea as there are numerous open source cards out there doing this exact thing.
Well, there aren't that many more components needed for what you're asking (and I've made these before, so I know it's not hard). More a question of do I want to spend board space on this, and whether it kinda takes focus away from the sound card part. Like I said, I'll keep this in mind when the time comes for doing the layout. 😀

The LlamaBlaster sound card
ITX-Llama motherboard
TinyLlama SBC

Reply 8 of 62, by florian3

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Are you going to add PicoGUS' USB joystick port? If there is no space on the bracket you could maybe add an internal USB header.
If there is enough space then adding a TRS MIDI out jack would be convenient.

Reply 9 of 62, by Eivind

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stacker139 wrote on 2024-01-07, 00:00:

Are EMU/AWE or CT1920 parts a good idea (only footprint or components totally assembled from donor boards)?

I don't need donor boards for this, the only components that aren't made anymore are the CS4237B, YMF262 and YAC512 - and those are all readily available new-old-stock.

The LlamaBlaster sound card
ITX-Llama motherboard
TinyLlama SBC

Reply 10 of 62, by Eivind

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florian3 wrote on 2024-01-07, 14:00:

Are you going to add PicoGUS' USB joystick port? If there is no space on the bracket you could maybe add an internal USB header.
If there is enough space then adding a TRS MIDI out jack would be convenient.

Hm, I hadn't even considered the PicoGUS used for a USB joystick/gamepad input. I don't think there's room on the bracket for a USB-A connector though... Unless I ditch the microphone input. I don't think I've ever used that, and I imagine the same goes for most people. As for MIDI, that's already present on the DB-15, can be broken out into full-sized MIDI in/out connectors with the ubiquitous adapter/cable, like this one:

db15-midi-cable.png
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The LlamaBlaster sound card
ITX-Llama motherboard
TinyLlama SBC

Reply 11 of 62, by florian3

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Eivind wrote on 2024-01-07, 15:02:

As for MIDI, that's already present on the DB-15, can be broken out into full-sized MIDI in/out connectors with the ubiquitous adapter/cable, like this one:
db15-midi-cable.png

Personally I just find those breakout cables inconvenient and if I was in the market for another one I wouldn't even know where to buy one that is built correctly. But I still prefer those over mini DIN 😉.

Reply 12 of 62, by DerBaum

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florian3 wrote on 2024-01-07, 16:34:
Eivind wrote on 2024-01-07, 15:02:

As for MIDI, that's already present on the DB-15, can be broken out into full-sized MIDI in/out connectors with the ubiquitous adapter/cable, like this one:
db15-midi-cable.png

Personally I just find those breakout cables inconvenient and if I was in the market for another one I wouldn't even know where to buy one that is built correctly. But I still prefer those over mini DIN 😉.

whats the difference between a gameport breakout cable and a midi cable dangeling from the back of your pc?

I would suggest internal headers on the card to attach your own types of connectors, like the seperated midi signals from the gameport into a midi connector. Then you can have a nice second slot cover if you really want.

BUT think about the size of midi connectors... you will probably have to break them out into smaller connectors and then build a adapter to full size midi... Like creative did on the early live cards with external midi but without the frontpanel.
200252a.jpg

FCKGW-RHQQ2

Reply 13 of 62, by Eivind

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DerBaum wrote on 2024-01-07, 16:43:
whats the difference between a gameport breakout cable and a midi cable dangeling from the back of your pc? […]
Show full quote
florian3 wrote on 2024-01-07, 16:34:
Eivind wrote on 2024-01-07, 15:02:

As for MIDI, that's already present on the DB-15, can be broken out into full-sized MIDI in/out connectors with the ubiquitous adapter/cable, like this one:
db15-midi-cable.png

Personally I just find those breakout cables inconvenient and if I was in the market for another one I wouldn't even know where to buy one that is built correctly. But I still prefer those over mini DIN 😉.

whats the difference between a gameport breakout cable and a midi cable dangeling from the back of your pc?

I would suggest internal headers on the card to attach your own types of connectors, like the seperated midi signals from the gameport into a midi connector. Then you can have a nice second slot cover if you really want.

BUT think about the size of midi connectors... you will probably have to break them out into smaller connectors and then build a adapter to full size midi... Like creative did on the early live cards with external midi but without the frontpanel.
200252a.jpg

I do like the concept of using TRS connectors for MIDI, as it's actually a recognized standard, and you can get cables in most music stores.
However, we still have very limited space on the ISA bracket - at least if we want to keep the DB-15.
Since this card will have very good internal options for MIDI (Wavetable boards, mt32-pi), I'd guess having the DB-15 is more useful than dedicated MIDI ports...? I'm open to being convinced otherwise though, if any of you have good arguments? 😀

The LlamaBlaster sound card
ITX-Llama motherboard
TinyLlama SBC

Reply 14 of 62, by florian3

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DerBaum wrote on 2024-01-07, 16:43:
whats the difference between a gameport breakout cable and a midi cable dangeling from the back of your pc? […]
Show full quote
florian3 wrote on 2024-01-07, 16:34:
Eivind wrote on 2024-01-07, 15:02:

As for MIDI, that's already present on the DB-15, can be broken out into full-sized MIDI in/out connectors with the ubiquitous adapter/cable, like this one:
db15-midi-cable.png

Personally I just find those breakout cables inconvenient and if I was in the market for another one I wouldn't even know where to buy one that is built correctly. But I still prefer those over mini DIN 😉.

whats the difference between a gameport breakout cable and a midi cable dangeling from the back of your pc?

I would suggest internal headers on the card to attach your own types of connectors, like the seperated midi signals from the gameport into a midi connector. Then you can have a nice second slot cover if you really want.

BUT think about the size of midi connectors... you will probably have to break them out into smaller connectors and then build a adapter to full size midi... Like creative did on the early live cards with external midi but without the frontpanel.
200252a.jpg

Imho the gameport MIDi is fine for people that actually need MIDI input. But most probably don’t and then you have an extra unused 2m MIDI-In cable dangling behind the computer.
For the Mini DIN MIDI ports that Creative, Roland etc used you can’t easily get adapter cables for.
The 3.5mm TRS to MIDI adapters on the other hand are readily available, the connectors and ports are more robust than Mini DIN, and easy to plug in without crawling behind your computer with a flash light.

Reply 15 of 62, by florian3

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Eivind wrote on 2024-01-07, 17:16:
I do like the concept of using TRS connectors for MIDI, as it's actually a recognized standard, and you can get cables in most m […]
Show full quote
DerBaum wrote on 2024-01-07, 16:43:
whats the difference between a gameport breakout cable and a midi cable dangeling from the back of your pc? […]
Show full quote
florian3 wrote on 2024-01-07, 16:34:

Personally I just find those breakout cables inconvenient and if I was in the market for another one I wouldn't even know where to buy one that is built correctly. But I still prefer those over mini DIN 😉.

whats the difference between a gameport breakout cable and a midi cable dangeling from the back of your pc?

I would suggest internal headers on the card to attach your own types of connectors, like the seperated midi signals from the gameport into a midi connector. Then you can have a nice second slot cover if you really want.

BUT think about the size of midi connectors... you will probably have to break them out into smaller connectors and then build a adapter to full size midi... Like creative did on the early live cards with external midi but without the frontpanel.
200252a.jpg

I do like the concept of using TRS connectors for MIDI, as it's actually a recognized standard, and you can get cables in most music stores.
However, we still have very limited space on the ISA bracket - at least if we want to keep the DB-15.
Since this card will have very good internal options for MIDI (Wavetable boards, mt32-pi), I'd guess having the DB-15 is more useful than dedicated MIDI ports...? I'm open to being convinced otherwise though, if any of you have good arguments? 😀

Yeah I wouldn’t trade the DB-15 for a TRS midi out if there is no space.

You could also look into those 3.5mm/Toslink combo ports.

Reply 16 of 62, by Eivind

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florian3 wrote on 2024-01-07, 17:25:

Yeah I wouldn’t trade the DB-15 for a TRS midi out if there is no space.

You could also look into those 3.5mm/Toslink combo ports.

Yes, I remember those from my minidisc days! 😁 Don't think I've ever come across those connectors, but maybe I haven't searched enough. Let me know if you can find them in stock somewhere!

The LlamaBlaster sound card
ITX-Llama motherboard
TinyLlama SBC

Reply 17 of 62, by DerBaum

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what i wanted to say was: if you have some kind of internal header (like it does with a wavetable header) it doesnt matter wich kind of connection you want for your midi because you can always make the specific adapterbracket you want by yourself. If i want mini din because i have a ton of those cables i can make one for my purpose. If i dont want midi i dont make one.

FCKGW-RHQQ2

Reply 18 of 62, by florian3

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Eivind wrote on 2024-01-07, 17:32:
florian3 wrote on 2024-01-07, 17:25:

Yeah I wouldn’t trade the DB-15 for a TRS midi out if there is no space.

You could also look into those 3.5mm/Toslink combo ports.

Yes, I remember those from my minidisc days! 😁 Don't think I've ever come across those connectors, but maybe I haven't searched enough. Let me know if you can find them in stock somewhere!

Digikey has a Cliff FCR684204T

Reply 19 of 62, by Eivind

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florian3 wrote on 2024-01-07, 17:50:

Digikey has a Cliff FCR684204T

Yes, look at that! 😀 Thanks!
Here's what I think might fit on a single bracket:
TRS-style (3.5mm) MIDI out
3.5mm line in
3.5mm line/headphone out + optical out
Female USB-A
DB-15

MIDI-in would have to be through the DB-15, and no microphone in.
This I think would do nicely for me personally.

The LlamaBlaster sound card
ITX-Llama motherboard
TinyLlama SBC