I find that info interesting. You let you connect a headphone jack on the computer if you wished.

Anonymous Coward wrote:

For anybody curious to know, I found the pinout for that damn test point connector on the early creative labs cards. It's the bi […]
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For anybody curious to know, I found the pinout for that damn test point connector on the early creative labs cards. It's the big one located just in front of the IO ports (usually as AUDIO PWD)

From top to bottom:

1 MIC GND
2 MIC GND
3 MIC IN
4 SPK GND
5 SPKR Speaker Output - Right Chan
6 SPKL Speaker Output - Left Chan
7 SPKRL Left Speaker return
8 SPKRR Right Speaker return

The jumper next to it (usually labelled RSPK_EN) is connected to to pins 5 and 8 on the AUDIO PWD connector (so that you can jumper those two pins together).

http://support.dell.com/support/edocs/dta/SBPRO/00000009.htm

I was hoping this jumper block might hold the key to disabling the internal amp, but sadly no.

Oh man I was looking for this information!

I have a Soundblaster Pro 2.0 OEM (CT1680) and couldn't find information on jumpers. Most are obvious (IRQ, address, DMA) but I always wondered about these pins just behind the jacks...

Question for you!

If you remove these two jumpers that seem to feed the signal back into the card, does this get you the signal before the volume dial? So if you dial the volume dial, it has no effect? That would be a good solution in case your volume dial is on the way out...

I have a SB 1.5 and the dial need some wiggeling to get it going 😁

Or are these pins simply an easy way to hook up test equipment for creative tech guys...

If you are still looking for a solution how to get a non amplified signal I had a look at the SB 1.5, 2.0 and Pro cards and they all use a TEA2025B Stereo amplifier chip.

You can get the datasheet from here: http://www.datasheetcatalog.org/datasheet/stm … ronics/1523.pdf

It looks like you just need to grab the signals going in from pin 7 and 10. And tehre are plenty of areas to get ground, even on the chip itself on various pins.

You really just need to solder 3 wires on the back of the card and you are done. It looks like a peace of cake to be honest, and I will for sure give it a go. I have big plans for doing recordings and if I can get a good signal from every card, pre amplified it would make my life a lot easier , especially on the really old cards with busted volume dials!

I will likely just use a IC test clip rather than soldering. Don't really like soldering on vintage stuff 😁

Anonymous Coward wrote:

I was hoping this jumper block might hold the key to disabling the internal amp, but sadly no.

Reading this tells me that there is some kind of disadvantage to the CT1600's design, but I'm not exactly sure what it is. Why would disabling the internal amp be an advantage? Is it to help reduce "noise" when you use desktop amplified speakers? (I think I've asked this before, some time ago, but I'm not sure if my guess was right or not.)

Good question! I am certainly not a audiophile, but I can think of a few things (more guessing I suppose):

- The onboard amp is cheap / average quality
- This might add noise?
- Could make it harder to record (input to loud)?
- A line out signal with a external amp is more desirable? Sounds better?

For me personally, I would like to avoid having issues with busted volume dials, especially when playing with Gameblaster which is Stereo and the I don't want one channel to be louder than the other...

AFAIK I can tell all of these Creative cards use the same amplifier chip. I looked at 1.5, 2.0 and Soundblaster Pro 2.0...

From SB16 onwards they put a jumper on the card which allowed you to change the output from amplified to line-out. So all good with those cards! They also seem to have a better volume dial. E.g. the volume dial on my SB Pro 2.0 is smooth and works well.

AWE cards I believe had a line-out and speaker out. At least that's what my AWE64 got.

Still I found that my 1.5 was way louder than the Pro, but I guess this might be a mixer setting. Cards up to 2.0 didn't have an audio mixer, wheras all later cards had a mixer which you could control through software...

I guess because I didn't install any Creative software, the mixer was set to a moderate level...

Interesting, thanks for the info.
BTW, it's amazing how robust the CT1600s appear to be. They're about 20 years old now, and I've never come across a defective one.

True!

My CT 1680s look like brand new. These are OEM version of SB Pro 2.0 and I guess they where doing nothing in Office PCs for many years before someone pulled them out and put them on ebay...

The sound is very clean. During my research I read that from SB Pro onwards they had a low and high pass filter. Still unsure what that means / impact on the audio. But that explains why the sound I got from the 1.5s sound a lot more RAW and not as polished / filtered...

But boy do I love Gameblaster sound. I played "Last Crusade" on DosBox in Gameblaster mode, but the music often "got stuck" and it just wasn't smooth. So I guess the emulation still has a lot of catching up to do...

Regarding the Creative Gameblaster, I found some online recordings -

http://queststudios.com/smf/index.php?topic=2974.0

Good recordings though they sound very very clean. Almost too clean for that real authentic Retro sound...

It's been a while and my memory is a little rusty, but as I recall the results from playing around with the test point was not very encouraging. I was hoping that perhaps it would allow me to bypass the volume wheel, but sadly it seems to sit in between the volume wheel and the output jack, which isn't terribly useful. I also believe I already tried stealing the signal from the amplifier chip as you suggested. In theory that should work, but you'll need to add a capacitor of certain size to each channel, or the signal will be too quiet to hear anything. Definitely go back and try everything again though, perhaps I overlooked something. I also tried cutting the power to the amp chip, but it wasn't effective either. In the end I just went for a Crystal based ISA card.

Anonymous Coward wrote:

It's been a while and my memory is a little rusty, but as I recall the results from playing around with the test point was not very encouraging. I was hoping that perhaps it would allow me to bypass the volume wheel, ....

Reading your O.P, and also your recent message above, I am still unsure as to what your ultimate goal is. Why exactly do you want to bypass the volume wheel?

I want a line out, because the amplified output on the old creative cards didn't have much in the way of filtering. They're noisy.

Anonymous Coward wrote:

I want a line out, because the amplified output on the old creative cards didn't have much in the way of filtering. They're noisy.

Thanks for the explanation.

Would it be possible to use Creative Test Point connector to connect Sound Blaster to any CD-audio input on GUS? That would leave GUS Line In free for Roland sound cards.

I don't want to connect anything to Sound Blaster Line In. Try to connect GUS to Sound Blaster Line In and the GUS will sound like a Sound Blaster. I definitely don't want same thing happen to Roland so at the moment I cannot chain all three cards together.

That should be possible, but have you thought about simply getting a external audio mixer? It will surely be superior to any mixers found on any of these Sound cards...

Mau1wurf1977 wrote:

That should be possible, but have you thought about simply getting a external audio mixer? It will surely be superior to any mixers found on any of these Sound cards...

i was just going to suggest the same thing... plus this way you can turn off output from the card(s) you're not using, to minimize noise.