VOGONS


Sound Blaster Pro 2 CT1600 Revisions

Topic actions

Reply 100 of 104, by Ozzuneoj

User metadata
Rank l33t
Rank
l33t
James-F wrote:

Moreover the SBPro2 CT1600 (07 and 08), and the two CT2600 revisions (01 and 02), all from 1993-1994 have the same revised PCB layout and are very quiet cards.

Is there any noticeable difference between the 03, 06 and CT1690 rev 02? I have one rev 3, two rev 6 and one CT1690 rev 2 and I'm trying to decide which one to keep.

As mentioned earlier in the thread, the 03 has no crystal, but the others all have them. Have we determined if there is any actual compatibility difference with the crystal?

The 03 has CT1336, but there is apparently no difference between that and the CT1336A (EDIT: On the SB Pro2) ?

Its crazy how much variation there is with these things. One of my rev 6 cards has an older through hole ceramic cap more commonly found on the very old devices (the tall, flat, two legged ceramic caps) and the CT1336A has the old angled creative logo. Compare this to the other rev 6 I have with the more "modern" cylinder type ceramic cap and the more plain, more modern printing on the CT1336A (almost looks more like a Vibra at first glance). The 03 has no through hole ceramics at all but has the older style logo on the CT1336 and older font on the label on the back. To add further confusion, the CT1690 (dated 1993... compared to 91 and 92 on the others) also has the older style ceramic cap and the angled logo on the CT1336A.

I used sbcheck to look at the dsp version too. Both rev 6 cards and the ct1690 rev 2 have DSP version 3.02, the rev 3 has DSP version 3.01.

Is there any difference between these DSP versions? Why would they update it if there was no difference?

Last edited by Ozzuneoj on 2018-11-29, 05:17. Edited 2 times in total.

Now for some blitting from the back buffer.

Reply 101 of 104, by cyclone3d

User metadata
Rank l33t++
Rank
l33t++

On the Sound Blaster Pro 2.0 cards, CT1336 vs 1336A should make no difference. However, on the Sound Blaster 2.0 cards, you need the CT1336 variation to be able to be able to upgrade the cards with the CMS chips.

Yamaha modified setupds and drivers
Yamaha XG repository
YMF7x4 Guide
Aopen AW744L II SB-LINK

Reply 102 of 104, by Ozzuneoj

User metadata
Rank l33t
Rank
l33t
cyclone3d wrote:

On the Sound Blaster Pro 2.0 cards, CT1336 vs 1336A should make no difference. However, on the Sound Blaster 2.0 cards, you need the CT1336 variation to be able to be able to upgrade the cards with the CMS chips.

Yeah, I actually did the CMS upgrade on my CT1350B, thanks to a very generous user here with a GAL programmer. It works great. 😀 I editing my question for clarification.

I'm wondering if the CT1336A was just a cost reducing revision and part of that included removing CMS compatibility since the upgrades were rarely used. Since they produced so many different cards in an extremely short span of time they ended up using leftover CT1336 chips first on the Pro models (despite the lack of CMS compatibility on the card itself), then eventually used the 1336A chips, and neither made any difference for anything but the early Soundblaster (non-Pro) models.

With all the analysis that has gone on with these cards, it seems like any other quality or compatibility differences would have been found by now.

Now for some blitting from the back buffer.

Reply 103 of 104, by Ozzuneoj

User metadata
Rank l33t
Rank
l33t

Just wanted to mention in this thread that I finally found a specific reason why later revisions of this card may have included their own crystal. I have a rev 3 that has no 14.318Mhz oscillator connected to the OPL3 and relies on the OSC pin to get that clock from the motherboard. I have an unusual 386sx board that has a 14.318Mhz crystal and the accompanying IC to make it useful... but it isn't connected to anything! On my board the OSC pins on the ISA slots are all connected together but not connected to anything else on the board. All of my sound cards that rely on the OSC to function did not work properly in this board, including the Rev.3 CT1600... the later CT1600 cards with crystals work fine.I ran a wire from the IC connected to the oscillator to the OSC pin on one of the ISA slots, and now the Rev. 3 works fine.

I just thought of this thread after fixing this issue. Maybe Creative kept running into problems with boards not having a usable OSC, so they fixed it later by having a built in crystal instead.

Now for some blitting from the back buffer.

Reply 104 of 104, by suntac

User metadata
Rank Member
Rank
Member
Ozzuneoj wrote:

I just thought of this thread after fixing this issue. Maybe Creative kept running into problems with boards not having a usable OSC, so they fixed it later by having a built in crystal instead.

Yes, exactly. One shouldn't rely on the ISA OSC signal at all.
I have one VGA card which utilizes this signal and its picture quality is very low with one of my CPU boards due to the unusually high OSC signal phase noise.