VOGONS


First post, by Paal

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Hi!

First time posting here.

I have taken my old 80486DX out of the closet and installed the Sound Blaster CT-3670, which I thought would be a great replacement because the original CT-2230 had developed a problem related to the music, which was waaay to low and the sound effects were okay. I suspect there could be an capacitor issue with the music problem, but I haven't got a clue on which and how to test and check for the capacitance value. Help here is greatly appreciated!

The CT-3670 has been installed and works according to the input settings, but when I connect the cable to the "SPK out", there is a continious high buzzing outputting through the speakers that won't go away, unless I go into diagnose.exe and let the computer autodetect the settings for it. Then the buzzing goes away and everything works fine, until the next time I turn on the computer. I have tried different ISA slots, but with no success. I have tried cleaning the contact pins, but that didn't help either.
I have visually checked the PCB and the capacitors looks all good, not bulging or dried out.
There is no DRAM installed on the board.

I have used the drivers from the Vogon vintage library to install it.
When the card worked, I had great sound quality, but didn't get the sound effects to work properly. When I got the sound effects to work, it was lower and "drowned" into the music.

Reply 1 of 11, by jheronimus

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but when I connect the cable to the "SPK out",

You should generally avoid using speaker out — its output is amplified which can probably cause some of the noises you're hearing. Just plug your speakers into Line out, and you should get better quality.

Also make sure that other components aren't causing interference with your speaker. I once had a Genius mouse that weirdly caused constant buzzing in my Creative speakers.

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Reply 2 of 11, by cyclone3d

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What does your autoexec.bat look like?

You should have these lines in addition to the SET BLASTER statement.

C:\sb16\diagnose /s (if this isn't there, it makes total sense why it isn't working until you run diagnose)
C:\sb16\aweutil /s
c:\sb16\mixerset /p /q

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Reply 3 of 11, by Paal

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jheronimus wrote:

but when I connect the cable to the "SPK out",

You should generally avoid using speaker out — its output is amplified which can probably cause some of the noises you're hearing. Just plug your speakers into Line out, and you should get better quality.

Also make sure that other components aren't causing interference with your speaker. I once had a Genius mouse that weirdly caused constant buzzing in my Creative speakers.

I have switched to using Line out and sound quality is pretty much the same. Didn't notice any improvement over the Speaker out.
At least I have sound on the Line out channel, so that brought me one step further! 😀

Reply 4 of 11, by bjwil1991

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Paal wrote:
jheronimus wrote:

but when I connect the cable to the "SPK out",

You should generally avoid using speaker out — its output is amplified which can probably cause some of the noises you're hearing. Just plug your speakers into Line out, and you should get better quality.

Also make sure that other components aren't causing interference with your speaker. I once had a Genius mouse that weirdly caused constant buzzing in my Creative speakers.

I have switched to using Line out and sound quality is pretty much the same. Didn't notice any improvement over the Speaker out.
At least I have sound on the Line out channel, so that brought me one step further! 😀

Check to see if the commands that @cyclone3d posted above as those are required to prevent the buzzing noises.

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Reply 5 of 11, by Obiwan

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Cyclone3D should be right: diagnose.exe is required to set up properly your card on every boot. Mixerset allows to set up the volume.

Older SoundBlasters use jumpers and newer ones (less old) use diagnose.exe. It is not a driver and does not take conventional memory.

Reply 6 of 11, by Paal

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cyclone3d wrote:
What does your autoexec.bat look like? […]
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What does your autoexec.bat look like?

You should have these lines in addition to the SET BLASTER statement.

C:\sb16\diagnose /s (if this isn't there, it makes total sense why it isn't working until you run diagnose)
C:\sb16\aweutil /s
c:\sb16\mixerset /p /q

My autoexec.bat does look like this and I have also the SET BLASTER values.

Reply 7 of 11, by Paal

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Thanks all for contributing!

I decided to do a format and a clean MS-DOS install just to be sure that I've had erased all the settings and values of the old sound card (CT2230). I downloaded the CTCMBBS.EXE from Creative Labs wesite and the SBDIAGNOSE.EXE, instead of using the Sound Blaster AWE32 DOS/WIN drivers.
Now everytime I start up, the AWE32 PNP and all of the BLASTER settings configures sucessfully without problems and when the Mixerset lines are loaded, then the buzzing goes away.
It's like the buzzing is enabled by something and can be disabled in or by the Mixerset. Before I did this, the buzzing was constantly, unless I unticked the AGC (Automatic Gain Control) in SB16SET and then it disappered.

Still, I don't know what to make out of it. It's like it corrects itself after the computer has gone through the BIOS configurations and starting MS-DOS.
The sound effects are still way to low. 😢

Reply 8 of 11, by Paal

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Update:

Luckily for me, Philscomputerlab uploaded a video about the CT3670 at the end of last year. I've adjusted my settings in the Mixerset to correspond to the settings in his review, but I've also adjusted the output gain on both channels to +2. Now I get strong decent sound and fx on most of the games I have tried and some other works okay with a little tweaking in their own setups.
So I have more likely withdrawn from the thought of the sound card in itself being the problem, but the sound card acts like an audible promoter for the buzzing, but the Mixerset corrects the buzzing by the settings when loaded in autoexec.bat. So the problem lies between the cold start-up and the loaded settings by the Mixerset. I haven't got a clue about what to do next? 😢

Reply 11 of 11, by derSammler

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It's like the buzzing is enabled by something and can be disabled in or by the Mixerset. Before I did this, the buzzing was constantly, unless I unticked the AGC (Automatic Gain Control) in SB16SET and then it disappered.

Sounds like the microphone input is enabled, which would pretty much explain the buzzing sound since you have no microphone connected - also explains why it goes away when you disable AGC, because that cransk up the volume when no microphone is actually connected.