Hi, it's a 486 PC ? How fast? Could be that the OPL2 can't keep up with it.

Probably not a speed problem because that card was released around the same time 486s came out...

What other games/softwares have you tried to test FM/MIDI?

Ensure you are using a PSU with -5V, or get a VoltageBlaster to achieve the same effect. The original SB needs no drivers.

Jo22 wrote on 2024-09-23, 20:52:

Hi, it's a 486 PC ? How fast? Could be that the OPL2 can't keep up with it.

It’s a 486 dx2 66. I can’t right now but I can check the bus speed in the bios … maybe it’s not set correctly.

Thx

Linoleum wrote on 2024-09-23, 21:14:

Probably not a speed problem because that card was released around the same time 486s came out...

What other games/softwares have you tried to test FM/MIDI?

Just the test program… I am noticing any issues with these early PCs is a huge time sink between floppies, things not working, and no instructions

I need to find some more time to try some other things.

Thx

wbahnassi wrote on 2024-09-23, 21:41:

Ensure you are using a PSU with -5V, or get a VoltageBlaster to achieve the same effect. The original SB needs no drivers.

The PS is an old AT by Crown. When I get a chance to look I’ll doublecheck for -5 V.

Thx

Heatvent wrote on 2024-09-24, 02:09:

Jo22 wrote on 2024-09-23, 20:52:

Hi, it's a 486 PC ? How fast? Could be that the OPL2 can't keep up with it.

It’s a 486 dx2 66. I can’t right now but I can check the bus speed in the bios … maybe it’s not set correctly.

Thx

Hi, thanks for the info. The 486DX2-66 was a very popular CPU, some consider it the sweet spot of the DOS era. 😀
However, the SB Pro 2 and Pro Audio Spectrum 16 had been around in the 486DX2-66 days, as well. And both had OPL3.

There were still plain Sound Blaster compatibles being made, though.
But they sometimes had an modern OPL2 (SMD form factor) or an OPL3 already.

Hm. Hard to tell if it's a speed problem or not. If the PC has a Turbo button, it might be worth trying it out.
I'm afraid that's all that I recommend for now. It's tricky to troubleshoot from very far away. 🙁

Jo22 wrote on 2024-09-24, 04:06:

Hi, thanks for the info. The 486DX2-66 was a very popular CPU, some consider it the sweet spot of the DOS era. :) However, the S […]
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Heatvent wrote on 2024-09-24, 02:09:

Jo22 wrote on 2024-09-23, 20:52:

Hi, it's a 486 PC ? How fast? Could be that the OPL2 can't keep up with it.

It’s a 486 dx2 66. I can’t right now but I can check the bus speed in the bios … maybe it’s not set correctly.

Thx

Hi, thanks for the info. The 486DX2-66 was a very popular CPU, some consider it the sweet spot of the DOS era. 😀
However, the SB Pro 2 and Pro Audio Spectrum 16 had been around in the 486DX2-66 days, as well. And both had OPL3.

There were still plain Sound Blaster compatibles being made, though.
But they sometimes had an modern OPL2 (SMD form factor) or an OPL3 already.

Hm. Hard to tell if it's a speed problem or not. If the PC has a Turbo button, it might be worth trying it out.
I'm afraid that's all that I recommend for now. It's tricky to troubleshoot from very far away. 🙁

It does have turbo so will give that a try. I have a 386sx16 board so maybe I can see if it works on that pc. Again, just need to find sytimr to tear it all down, install drivers, etc.

Thanks for the ideas though. I probably wouldn’t have known speed could be an issue.

Thx

Heatvent wrote on 2024-09-24, 11:56:

It does have turbo so will give that a try. I have a 386sx16 board so maybe I can see if it works on that pc. Again, just need to find sytimr to tear it all down, install drivers, etc.

Thanks for the ideas though. I probably wouldn’t have known speed could be an issue.

Thx

Hi! It's just an idea. I hope it helps, good luck! 😀 👍

So I had some progress on this. I loaded the "Power-On Defaults" and it would work although a bit distorted. I did a lot of trial and error with the BIOS settings and the following seemed to do the trick...

• Disabled the "Internal Cache Memory". Bit of a bummer but this is what was preventing the card from working for some reason.

• Set the "Bus Clock Frequency Select" to 1/4. Since I have a DX2 66 Mhz, the board is running at 33MHZ so this sets the bus frequency to 8.25 Mhz (if I understand correctly). This is what cleared up the distortion. The "Power-On Defaults" value was 7.15 Mhz which is slightly below the 8 Mhz ISA bus clock speed.

Thanks for the advice on the speed because I am not sure I would have thought through some of the other issues like the bus speed. I will probably move this card to my 386SX PC as it is probably a little more compatible and period accurate and put a slightly later SB in this machine.

Thanks again for the help!

Heatvent wrote on 2024-09-27, 04:40:

So I had some progress on this. I loaded the "Power-On Defaults" and it would work although a bit distorted. I did a lot of tria […]
Show full quote

So I had some progress on this. I loaded the "Power-On Defaults" and it would work although a bit distorted. I did a lot of trial and error with the BIOS settings and the following seemed to do the trick...

• Disabled the "Internal Cache Memory". Bit of a bummer but this is what was preventing the card from working for some reason.

• Set the "Bus Clock Frequency Select" to 1/4. Since I have a DX2 66 Mhz, the board is running at 33MHZ so this sets the bus frequency to 8.25 Mhz (if I understand correctly). This is what cleared up the distortion. The "Power-On Defaults" value was 7.15 Mhz which is slightly below the 8 Mhz ISA bus clock speed.

Thanks for the advice on the speed because I am not sure I would have thought through some of the other issues like the bus speed. I will probably move this card to my 386SX PC as it is probably a little more compatible and period accurate and put a slightly later SB in this machine.

Thanks again for the help!

Hmm, I wonder if putting the Soundblaster 1.5 DSP firmware on would improve the speed sensitivity, I don't recall having such issues with the Snark Barker reproduction card which is a clone of the card you have there. It's definitely working in a DX2-66 (maybe DX2-80) system without any issues with the cache.
386sx is the best fit for the card imo 😀

The bus speed stuff makes sense, 1/4 is what I'd use with a 33mhz bus system. That power on default setting may have been a dire choice to improve compatibility, I think the other default settings in the BIOS would set a more sensible value.

The "Power-On Defaults" in AMIBIOS are equivalent to safe mode and disable pretty much everything for the sake of compatibility. There are also "BIOS Setup Defaults" which turn most things on / standard operating mode.

It would be a good idea to try with various games.
OPL2 is known to be slow - on fast CPUs it needs software to include proper delays.
I guess TEST-SBC.EXE doesn't do the delays, but there should be no such problems with Pentium-era games.

Thanks, that's helpful to know. I will still probably move the SB 1.5 to my slower 386 since it's a mono card and use something around circa 92-93 in this machine. I have a card in the 386 but I don't recall which SB model but I do seem to recall that it's settings are done via the driver rather than jumpers so should be newer (may by a SB 16 or a Pro?).

Thx!

I moved the CT1740 to the 386SX. I had a SB Pro 2 in the 386 so I am going to move that to the 486. The 386 is pretty much useless except for it is what I had back in the day (Leading Technology 6800SX 386SX 16Mhz). I know I had a sound blaster and I actually think it could have been the 1.5 ... I just don't recall. It may also have been the pro version. Anyway, the 386 is just for this nostalgic reason and isn't really capable of running much so the 486DX2-66 will be my go to for DOS. Probably better to have the SB Pro in this machine anyway.

FWIW, the CT1740 seemed to be pretty happy in a 386 and worked perfectly!

The CT1600 is now installed in my 486 DX2 and it seems to be happy there. I was able to enable the internal cache with no issues so PC is running a little faster and sound is fully working too!

Thanks for all the help!