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8-BIT OPL2 Sound board

Thanks! One rather humble but important topic for ISA sound boards is the bracket. The ISA board template I used for the prototype board fits the Keystone 9202 bracket. That's great for XT-IDE since it has nothing sticking out the back of the board. However, I suspect this board will have at least a stereo headphones jack and a couple of pots poking out the back.

http://www.keyelco.com/pdfs/p62.pdf

Thoughts? Ideas? I recommend keeping the Keystone format since we know those work. Maybe drill out the holes needed or substitute a compatible but better model?

Andrew Lynch
 
I am thinking a little about the software side. Of course, the OPL2 is well supported by about anything from the late 80s, but the other synths supported are not supported by a single program.

Synths supported are the following:
2-op FM: OPL, OPL2
4-op FM: OPM, OPP, OPZ, OPZII

Sumary of functions:
OPL: 9-voices of 2-op FM or 6-voice of 2-op FM plus 5 rythm voices. ADSR envelope on every operator and feedback available on the first op. Fixed-frequency limited tremolo/vibrato option. Sine-waves only. 2 possible arramgements of the operators of each voice.
OPL2: Same as OPL, but with 3 additional selectable waveforms for the operators.
OPM: 8-voices of 4-op FM. ADSR envelope on every operator, one LFO with selectable waveform and frequency, optional noise-mode on operator 4 of voice 8, crude stereo panning. Sine-waves only. 8 possible arrangements of the operators of each voice.
OPP: Same as OPM, without the noise generator. Has multitimbral support added, and finer stereo-panning capabilities.
OPZ: Same as OPP, but with 7 additional selectable waveforms for the operators and one extra LFO.
OPZII: Same as OPZ, but with 8 additional voices and support for frequencies down to 1Hz.

DOS don't provide any standarized interface when it comes to sound, and the only way to add support for some of the synths is to write program-spesific drivers, or individual programs that take use of them somehow (for example a regular tracker).

Another problem is that even though the OPP, OPZ and OPZII all keep backwards compability with the OPM, only the OPM is documented well enough to use. This is quite sad since the OPZII is the most advanced 4-op FM-synth Yamaha ever produced, and provides two independent LFOs, Selectable waveforms, 16 chanels, and support for frequencies all the way down to 1Hz.

The last problem is that it's about impossible to obtain any of the later 4-op synth ICs without actually buying a full-scale synth containing it. For example, the OPZII can only be found in the Yamaha V50 high-end synth, which usually goes for prices beyond $100 USD. The other versions were more common and are easier to get hold of, but one should expect prices between $10 and $50 USD.

Bottom line is that it is problably best to make users write their own software if nessecary. Of course we can always try to write a tracker compatible with the basic OPM, but I am unable to volunteer for this since I don't have the time to start any medium/large-scale programming projects before the end of May.
 
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Hi Per! Thanks! I am looking around for a good 10K trimmer with side access. No luck so far but plenty of these kind:

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=D1AA14-ND

This would work with a little rearrangement of the PCB but it would require a small screwdriver to adjust the volume without opening the case and removing the board. What we need are ones with little twist knobs on it. We could use a pair of miniature 10K pots and just mount them in the bracket and run wires to the PCB but that makes assembly a PITA.

Thoughts, ideas?

Thanks and have a nice day!

Andrew Lynch

PS, other than the 10K side access pots the PCB is basically ready to go. We still need builders to buy enough of the boards to get prototypes. The bare minimum is $150 for 5 prototype PCBs. If you or anyone else is interested please contact me by email at mailto://LYNCHAJ@YAHOO.COM?subject=OPL2 and I will keep a folder of responses. When enough sign up for the prototype boards ($30 each plus shipping) we can get some prototype boards.
 
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Hi! If you are interested in the initial build and test of the 8-bit Generic OPL2 board please contact me by email. We still need builders to buy enough of the boards to get prototypes.

The bare minimum is $150 for 5 prototype PCBs. If you or anyone else is interested please contact me by email at

mailto://LYNCHAJ@YAHOO.COM?subject=OPL2

I will keep a folder of responses. When enough sign up for the prototype boards ($30 each plus shipping) we can get some prototype boards.

Actually you don't have to build the board if you would like to buy one and send or have it sent to a builder who can't afford it otherwise.

Thanks and have a nice day!

Andrew Lynch
 
per said:
I think I found some potentiometers which can be used, of you only bend the pins 90 degrees:

http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_10001_2118791_-1
Click to expand...

Hi Per! If we could find something like that in a right angle PCB mount we'd be good to go. I am not comfortable with the bent pins mounting though. That pot will break off in a short time when builders adjust the volume with the knob. We need something that securely mounts to the PCB with some mechanical strength. Unfortuately most of the pots shown at Jameco and Futurlec are just too massive to work on an ISA PCB.

So far I haven't seen anything that would work better than the vertical trim pots but will keep looking. Thanks and have a nice day!

Andrew Lynch
 
MV75 said:
Not hard to find side pots:

Take your pick, literally. :)

They even have slide ones if you want something different and more accurate, as in you know where the level is by where the slide is.

Granted they're not the cheapest though. :) I'd probably get one from here: http://www.futurlec.com.au/PotRot.jsp
Click to expand...

Hi! Those are just more of the same items I've seen so far. We need a small (fits on an ISA board height clearance) mechanically sound PCB mount potentiometer. Preferably something like a trim pot but right angle and with a small adjustment knob. I'll do another search at Digikey and hopefully something will turn up.

Thanks and have a nice day!

Andrew Lynch

PS, I think this part will work at least well enough to evaluate the prototype board

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=3310C-001-103L-ND
 
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lynchaj said:
Hi! Those are just more of the same items I've seen so far. We need a small (fits on an ISA board height clearance) mechanically sound PCB mount potentiometer. Preferably something like a trim pot but right angle and with a small adjustment knob. I'll do another search at Digikey and hopefully something will turn up.

Thanks and have a nice day!

Andrew Lynch

PS, I think this part will work at least well enough to evaluate the prototype board

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=3310C-001-103L-ND
Click to expand...
Should do the trick alright. That ones similar to the A10K trim pot on my Amstrad Adlib compatable card but without the threaded portion.
 
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Ok ok, the ones I linked at futurlec, I think you could mount them to a backplate instead, as per the nut/washer in the picture, same as a slider, just mount it to backplate and have an optional header on the board that you could then plug a cable into, or, would the spacing of the pins of a pot be fine to just put in a 3pin header instead anyway on the board?
 
Hi! We've got a couple of builders signed up for a prototype board but still need a few more to get this project going to the hardware stage. What might help is that if you are aware of other hobbyist communities that might be interested in this or future developments along these lines is to pass the word of the project along. See if we can get more hobbyists to participate and achieve some sort of OPL2 project "tipping point".

Another possibility is CCTALK as there may be people interested in OPL2 synthesizer chips there and/or vintage gaming communities. Where ever they come from, we need more active builders to get to hardware prototype stage or we stall out. Active builders don't necessarily have to *build* the board. They can buy board(s) and send them to other hobbyist who will build and test but can't afford the hardware.

Spread the load and we can get there! Thanks and have a nice day!

Andrew Lynch
 
I have feature request. Maybe not for the prototype but for later boards:
Input connector for connecting PC-speaker sound from motherboard to the sound card.
Output connector for internal speaker (so PC-speaker and OPL2 sounds could be heard without external speakers).
PC-speaker volume should be adjustable.
 
Hi! I added the thumbwheel pots to the OPL2 board and updated the board drawings on the N8VEM wiki. Hopefully more builders sign up so we can get some prototype boards.

Thanks and have a nice day!

Andrew Lynch
 
Can you consider to add some YM3012's with the prototype-boards, or should users have to get their own ICs? The reason I ask is because http://mysite.verizon.net/res8aiig/ICparts/ICparts.htm seems to be the only websites which has bulk quantities of them, and it's radically more cheaper per-IC to buy 10 compared to the priuce of only one.

Of course, the price of the IC ($7.45) would then be added to the PCB cost.
 
Hi! My plan is to only supply prototype PCBs -- if we make it that far. Builders will have to source and supply their own parts and assemble the boards. The prototype PCB is basically ready to go and waiting for enough builders to join in and share the cost burden. The project will stay at this stage unless we get enough to make the prototype PCB order viable. I'll make the schematics, PCB layout, BOM, etc but won't order PCBs purely on spec so hopefully more will join up.

Making kits and/or assembling boards is not practical for me. Pre-ordering bulk parts tremendously increases the upfront investment and pushes risk well beyond my tolerable level. This project has great potential but I consider it outside of the N8VEM homebrew computer theme -- somewhat like the XT-IDE, AT2XTKBD, and SCSI2IDE projects. I am certainly willing to help and have already invested many hours into the project. Even for N8VEM projects though only in certain rare cases will I cache hard to get parts and then provide those on a rare exception only basis. Making PCBs is one thing but making kits and/or pre-assembled units is entirely different. Like all community projects there are no assurances this one is viable so we'll just have to wait and see what happens.

If someone else is willing to do group buys of parts and supply to builders that would be great. It is a community project and what will happen will happen. One thing is for sure though, we need more participation for it to proceed to the next level of hardware prototyping. Otherwise it joins its many neighbors in the "cold storage" locker of non-viable projects. It may get converted into an ECB board though since it is a relatively simple design.

Thanks and have a nice day!

Andrew Lynch
 
Hi! Is anyone else interested in this project? So far there are a couple of builders interested in build and test of the initial prototype boards. We are well short of any sort of critical mass on this project though. If you'd like to see this Synth board project come to be its time to get involved. There seemed to be enough interest early on but it has faded away.

Thanks and have nice day!

Andrew Lynch
 
I think that the idea is cool, however I've no real use for an Adlib clone. A full-on SB clone that includes intelligent-mode mini, adlib compatibility, and maybe even a header to use a wave board would be ideal for me... i.e. the "ultimate sound card" idea that was presented in another thread. Please note that this isn't a complaint - I certainly don't have the talent to design hardware or program the firmware! Just a statement on what I, personally, would find most useful.

With that said, if this project does come to fruitition, I'll probably purchase and build one just to have it. I think that these community projects are too cool, and you guys just have me in awe with your ability to create them, and in the sense of this project, to do so in such short amounts of time!
 
Maverick1978 said:
I think that the idea is cool, however I've no real use for an Adlib clone. A full-on SB clone that includes intelligent-mode mini, adlib compatibility, and maybe even a header to use a wave board would be ideal for me... i.e. the "ultimate sound card" idea that was presented in another thread. Please note that this isn't a complaint - I certainly don't have the talent to design hardware or program the firmware! Just a statement on what I, personally, would find most useful.

With that said, if this project does come to fruitition, I'll probably purchase and build one just to have it. I think that these community projects are too cool, and you guys just have me in awe with your ability to create them, and in the sense of this project, to do so in such short amounts of time!
Click to expand...

Sb gold64's are still easy to come by, and I ordered a simmconn for mine the other week, still waiting for it, but they still sell them. :) Let's you make a device better than a mt32 with the right sound bank.

I see a real need for an ad-lib clone when you see the real deal going for $300.
 
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