http://queststudios.com/smf/index.php/topic,2175.0.html
Although its about the AWE 32, you'll also find a lot information that applies to the SB16 (the Vibra chips combine the functionality of multiple chips of the SB16 into one chip). It seems that the Vibra 16 chips (CT2501) and Vibra 16S (CT2504) were bundled with the OPL-3 (or its OPL-3M variant), other Vibras were using the CT1978 chip (Vibra 16 Pro) or had the functionality built-in (Vibra 16C, 16VX). (I compiled this information based on photos of Sound Blasters, so it might not be accurate)

Thanks a lot!

This is really in detail.... Very interesting. So it seems as if I was right when the SNR appeared to be better than with the other SB cards (16 and AWE32) that I have. CT2800 - sounds as if I've got a "lucky card"...

Do vibra chips have the infamous "hanging note" bug?

Out of curiosity I bought one of these off of ebay for 8 dollars. I have been using a awe64 gold which of course doesn't have the real opl3 chip.

Plugged it in last night and I was blown away. OPL3 music sounds so much better on this board be because of the real Yamaha chip. Granted I am a choir teacher so my ears are pretty sensitive, but wow the sound was better.

I also noticed that there did not seem to be as much static in the digital audio. I looked on the board and it uses a different mixer chip than my AWE64 gold. Could this be the reason?

Those Vibra cards are the first round of Ensoniq technology absorbed into Creative - that's why they have a much lower noise floor among other things.

I was considering getting an ISA SB16 and/or an ISA card with real OPL3. Now I never could decide which one to get, but now I also got me this CT2800. It is an example with real OPL3 ofcourse, with amplifier but without IDE controllers.

Now I used it next to two PCI soundcards in the same system for half a day and did some experimenting (Vortex-2+Daughterboard and an YMF-724).
All that is really required to get the SB16 going is DIAGNOSE /s. Without this command even windows 98 does not detect it. DSP is 4.13. Dos drivers nag about my DOS version being 7.10, and you need "setver" to fool these. Although there really isn't to much of interest in these install packages.

Now I tried a midi daughterboard on the SB16, and it works OK with some games. But in Hexen map E1M2 i could indeed 'enjoy' the hanging note bug. I get similar behaviour with Tie-fighter coll. CD, accompanied by delays between tracks. All midi problems vanish when I disable sound FX in the game and only select music. (nothing new... now If I had two of these SB16 cards?)

Sound Blaster Pro compatibility; I hear the sample, but not in stereo. So it does not offer anything over plain soundblaster compatibility. I mainly tested this with Tie Fighter's sound setup.

OPL3 sounds fine, similar to my YMF-724.

Noise level is OK. Nothing annoying.

Funny thing is you can use vortex-2 dos emulation (au30dos.com) next to
the soundblaster 16. And I set the SB16 up to be used for OPL3 and the vortex-2 for everything else. (but I actually had the YMF-724 for OPL3, so where is the improvement?)

I just bought another card: SB Vibra 16S CT2890. It also has an OPL3. Apart of some jumpers (I think some of those IDE port jumpers are missing) the only difference seems to be a chip (bigger than the vibra chip) labled CT1705-DCQ - does anyone know what it is good for?

By the way: both cards have a CD/IDE connector.

I purchased a CT2800 about a month ago on Ebay. It's a CT2800 SB 16 Vibra with an OPL3 chip. It's great. Its supposed to be P&P but it isn't. You have to tell win98 to search for hardware then direct it to the driver. In DOS you pretty much have to manually config everything. But it's a great card.