VOGONS


First post, by Adriaan

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Hi, I’m trying to wire up an YMF704C but the documentation is very hard if not impossible to come by, others than the very limited datasheet.
Is there someone out here who can send me a circuit diagram how to hook up this chip?
I have some expertise in using the YMF262 (hard and software) but now I’m in the dark with this YMF704C…

HELP!! PLEASE….

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Reply 1 of 8, by Thermalwrong

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Which document are you referencing? The YMF721 datasheet is the better one to check, the YMF721 and 704 are pretty much the same, maybe slight improvements or better quality samples, but the pinouts should be the same for each. Personally I've only used the YMF721 by adding it to a board that didn't already have it. I can give front & back pictures if you want to trace where each wire goes tho.
Adding OPL4 wavetable to Yamaha YMF719 card

Reply 3 of 8, by Adriaan

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Thanks!
I just got in touch with Tiido, and he proved to be of great help.
The chip is making sounds, albeid at a very low volume and I can only hear a piano sound (not using the FM part at the moment).
So I’m trying to figure out how to increase the volume and change instruments.

Reply 4 of 8, by Adriaan

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I discovered why the volume was so low and distorted...
It was all because I made a mistake.
Looking at the datasheet of the YAC513 I thought to notice that this chip can be used by an YMF721, but it said YMF271.... My mistake, the YMF721 needs an YAC516.
So I orderen some and the coming weeks I cant work on this project.
Laterrrs

Reply 5 of 8, by Shreddoc

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Adriaan wrote on 2021-11-11, 20:48:
I discovered why the volume was so low and distorted... It was all because I made a mistake. Looking at the datasheet of the YAC […]
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I discovered why the volume was so low and distorted...
It was all because I made a mistake.
Looking at the datasheet of the YAC513 I thought to notice that this chip can be used by an YMF721, but it said YMF271.... My mistake, the YMF721 needs an YAC516.
So I orderen some and the coming weeks I cant work on this project.
Laterrrs

Can you disclose what your project is? It sounds very interesting.

Reply 6 of 8, by Adriaan

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Sure, my hobby is working on a modular synthesizer, design and build most modules by myself (and sometimes I get help from a forum member…)
I have made several modules around the YMF262, and I think they sound great.

https://youtu.be/-cAcPInczns

But I bought an YMF704 and I’d like to build a module around this chip as well. Just curieus how the wavetable sounds and if I can get it to work with both the FM and Wavetable section.
As you can see, there is also a BluePill on this board, because I would like to experiment with automated music.

Reply 7 of 8, by Shreddoc

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Sounds really cool, will be great to see what capabilities you can draw out of the 704.

I don't have any software which does it, but imagine a custom tracker where you can combine FM and wavetable playback within the same song and have it play back natively through the one chip.