Oh thanks for letting me know. I guess I'll have to see how much I notice it/it bothers me.

Tiido wrote on 2022-10-09, 12:32:

This card has few issues :
* no way to bypass the speaker amp so it will be too loud and also quite noisy because of it
* no proper voltage regulator for analog side, only a zener based shunt so expect digital noises etc. in the output. There is a spot for a 7805 and this can fix at least this problem.

The amp chip could be bypassed with circuit bending.

I did mean without modifications, with soldering iron, a lot of things become possible 🤣

So the card has arrived now and I'm really happy with it. I am running it through my main PC via audio-out to line-in, but I'm not hearing any noise whatsoever interestingly enough. I don't know, maybe at higher volumes or something it might cause problems, or maybe I've just got tinnitus I'm ignoring that's covering it up, but for now it sounds great.

gdjacobs wrote on 2022-10-10, 02:39:

Tiido wrote on 2022-10-09, 12:32:

This card has few issues :
* no way to bypass the speaker amp so it will be too loud and also quite noisy because of it
* no proper voltage regulator for analog side, only a zener based shunt so expect digital noises etc. in the output. There is a spot for a 7805 and this can fix at least this problem.

The amp chip could be bypassed with circuit bending.

wouldn't it be possible to just desolder the amp and bridge the traces.

Of course, definitely an option and something I have done on a few random low-end cards I have.

Bridge the traces as in bridge Left In to Left Out? etc.?

ya isn't that basically what those jumpers on cards that have them do. a socket in place of the amp might be more elegant.

Warlord wrote on 2022-12-07, 19:26:

ya isn't that basically what those jumpers on cards that have them do. a socket in place of the amp might be more elegant.

Yeah but removin the amp ic from the socket would result in no output then..

When you have those jumpers then that is what you will use, but lowest end stuff doesn't give you that option and other methods will have to be devised 🤣. If the amp chip is socketed and you take it out, yes, you will no longer have any output at all.

Idea is to get Line level output from the card and to bypass the amp. But since on lowend cards you cannot use a jumper to bypass the amp, you re options are remove the amp and route the line level output from the pads that the amp used to be sitting on. I'm not sure what other components you would have to remove or modify but it's entirely feasible.

I'm pretty sure on those cards when you jumper them to bypass the amp you're still getting output no? All you need is 1v. For line level.

For example here is a card that has pads for a TEA2025 but is not using it, but it still works.

https://retronn.de/hwpics/Yamaha_Xwave.jpg

That particular card has two little resistors at the jumper block that does the connection of "line out". All cards without populated amp from factory have a similar thing done on them. To know what to bridge one has to look at the datasheet of the amp chip and see where its inputs and outputs are and go from there, there usually are few more parts to omit or bridge that way too i.e input capacitors are not necessary anymore as there already are the ones that were on output that do this job and there may be few misc resistors etc. to remove too.

Warlord wrote on 2022-12-07, 14:36:

gdjacobs wrote on 2022-10-10, 02:39:

Tiido wrote on 2022-10-09, 12:32:

This card has few issues :
* no way to bypass the speaker amp so it will be too loud and also quite noisy because of it
* no proper voltage regulator for analog side, only a zener based shunt so expect digital noises etc. in the output. There is a spot for a 7805 and this can fix at least this problem.

The amp chip could be bypassed with circuit bending.

wouldn't it be possible to just desolder the amp and bridge the traces.

Yes. That's what I was getting at which Tiido definitely noted. It might even be easier to unpower the chip and bridge the pins, although I'm not certain if that route would be as clean in terms of audio output. The amp chip still might have some parasitic effects even while powered down.

Tiido wrote on 2022-10-10, 05:11:

I did mean without modifications, with soldering iron, a lot of things become possible 🤣

So, the option was raised, but Tiido's choice was to keep the card unmolested. Fair play to him.

Warlord wrote on 2022-12-07, 19:26:

ya isn't that basically what those jumpers on cards that have them do. a socket in place of the amp might be more elegant.

The jumpers usually change the feed point of the output jack from a low Z output after the amp chip to a somewhat impedance matched output after the mixer chip. The amp chip remains connected and powered with perhaps some shunt resistance and capacitance to keep it happy, but limited or no bleed through onto the output jack.

Unpowering a chip never works, it will then start powering itself up through all the other connected pins and this will lead to excess distortion etc. You really do need to remove a chip or utilize some actual disable feature when present.

Tiido wrote on 2022-12-10, 08:29:

Unpowering a chip never works, it will then start powering itself up through all the other connected pins and this will lead to excess distortion etc. You really do need to remove a chip or utilize some actual disable feature when present.

Even worse, I bet the behaviour is quite difficult to predict.

To me sound of early DOS is sound of ESS ESFM and sound of later DOS is sound of SB 128 PCI MIDI.
Anything else sounds off to me including genuine OPL2/3 which has this Yamaha characteristic thing to it I especially hate in YM2612 (Megadrive/Genesis sound chip). ESS cards have almost the same sound as OPL2 but this aspect of sound that irritates hell out of me is greatly reduced.

As for MIDI I like SB 128 PCI with its original 2MB preset. Ensonic unfortunately didn't use the same samples in 4/8MB presets as 2MB preset and these 4MB and 8MB presets are terrible.

For ISA I have lots of various ESS cards including ES1688f which has jumpers. For PCI ESS Solo-1 is the model with the same ESFM implementation and other models are pretty bad for FM synthesis.

e8root wrote on 2023-04-13, 15:21:

To me sound of early DOS is sound of ESS ESFM and sound of later DOS is sound of SB 128 PCI MIDI. Anything else sounds off to me […]
Show full quote

To me sound of early DOS is sound of ESS ESFM and sound of later DOS is sound of SB 128 PCI MIDI.
Anything else sounds off to me including genuine OPL2/3 which has this Yamaha characteristic thing to it I especially hate in YM2612 (Megadrive/Genesis sound chip). ESS cards have almost the same sound as OPL2 but this aspect of sound that irritates hell out of me is greatly reduced.

As for MIDI I like SB 128 PCI with its original 2MB preset. Ensonic unfortunately didn't use the same samples in 4/8MB presets as 2MB preset and these 4MB and 8MB presets are terrible.

For ISA I have lots of various ESS cards including ES1688f which has jumpers. For PCI ESS Solo-1 is the model with the same ESFM implementation and other models are pretty bad for FM synthesis.

That's all fine and good but none of those cards are SB 16 clones, they are SB Pro clones.

Daniël Oosterhuis wrote on 2020-05-26, 22:53:

I've been curious, does anyone know of an ALS-100 based card with Yamaha OPL4 onboard? The design documents for the ALS-100 refer to a reference model with OPL4 support, but I can't find any examples of commercial ALS-100 cards with that.

I did however find old Gerber files for some of those reference cards, including this ALS-100M based design with SCSI CD-ROM and OPL3 as well as 4 support. Really interesting to see, but the old Gerber files are a bit difficult to work with.

ALS100OPL4.png

It's been almost three years, but this popped back in my mind and I really couldn't shake the idea of having PCBs available to upgrade the many crappy, noisy ALS100 cards to something better.
So, I have spent about four to five hours tinkering with probably five pieces of CAD software to get myself to this point:

Long story short, I used CADCAM within PADS Layout to open the original PADS-2000 JOB file for the ALS-100 Reference PCB, which I generated initial Gerbers with.
Then, I imported those into KiCad through its Gerber Viewer, with duplicate top and bottom layers, one set functioning as part of the top and bottom copper layers, the other as the top and bottom solder mask layers (the solder mask layers in the JOB files are almost completely empty).

Then, I generated another set of Gerbers with that, and used gEDA's gerbv to realign the original drill file to them, which also updated said drill file to a format KiCad liked.
I re-did the KiCad Gerber Viewer import, now with the corrected drill file, and finally I got to this point.

All seems well, I can see that all vias and through holes do appear plated, both in the 3D view in KiCad, as well as the one at JLCPCB's website.
This was exhausting, but the dream of an OPL3 + OPL4 ALS-100 card might yet come true!

I want to verify a few things first, but I'll definitely release the files once I've done so.
I'll probably open a separate thread for it.

Too bad ALS100 is not something that can be easily sourced in volume 🙁

appiah4 wrote on 2023-05-10, 11:15:

Too bad ALS100 is not something that can be easily sourced in volume 🙁

Sadly that does seem to be the case, but hopefully this can still serve as a similar solution to the cheapo ALS100 cards, as the AWE64 Legacy is to the AWE64 Value, an upgrade to a lower tier card.
That, and the whole thing that this is an ISA sound card that never was released as a commercial product as far as I can tell, so it's neat to potentially get hands on with one of these.

Should note that this technically uses the ALS100M, but I think that's pin compatible with the normal ALS100, other than its support for more CD-ROM data bus standards.
That said, I wonder if the ALS100M ever even entered production, as I can't find a single card online that uses it?

If it did, seemingly no OEM bothered to use it.
Though the SCSI controller chip support of the ALS100 also never seemed to be used by OEMs, so I guess no one really wanted to bother creating a fully featured ALS100 card, which is honestly a bit sad.