VOGONS


Reply 80 of 106, by xeoblade

User metadata
Rank Newbie
Rank
Newbie

I actually just changed it after taking the pictures and posting my reply. 😀

I don't know why it was set to IRQ2 in the first place by the previous owner. The other strange thing was they had "disabled" the joystick port using the special jumper. not sure why you would want to do that unless it somehow free's resources.

Reply 81 of 106, by Scali

User metadata
Rank l33t
Rank
l33t
xeoblade wrote:

The other strange thing was they had "disabled" the joystick port using the special jumper. not sure why you would want to do that unless it somehow free's resources.

Perhaps they already had another joystick port in the system? I used to have both my SB Pro and my GUS in the same system, so I would have disabled the joystick port on one of them as well.

http://scalibq.wordpress.com/just-keeping-it- … ro-programming/

Reply 82 of 106, by Great Hierophant

User metadata
Rank l33t
Rank
l33t

The joystick port of the SB Pro has no speed adjustment capability, unlike that of the GUS or even the SB16. So it is best to use something else in a high speed 386 or a 486.

http://nerdlypleasures.blogspot.com/ - Nerdly Pleasures - My Retro Gaming, Computing & Tech Blog

Reply 83 of 106, by Scali

User metadata
Rank l33t
Rank
l33t
Scali wrote:

Yes, I've only owned one Sound Blaster Pro (CT1600) in all my life, and it's been in 3 or 4 PCs over the years, but I don't recall it ever reversing stereo.

Small update on this: I knew my SB Pro 2.0 was an early model, because when I bought it, I didn't even know there were two versions, but apparently mine came with an OPL3.
I've been working on some DMA/SB DSP code, and as part of that, I made a routine to read the version number. It returns 3.01. So it is the first revision DSP. And as we know, no reverse stereo issue.

http://scalibq.wordpress.com/just-keeping-it- … ro-programming/

Reply 84 of 106, by carlostex

User metadata
Rank l33t
Rank
l33t

Hey guys, i have a CT1330A rev 4. James contacted me when he was requesting people with SB Pro 1's to submit them to scientific testing.

Turns out that my card ONLY outputs in mono. I tried different cables i made sure the mixer was set to stereo and i still have that issue. Both FM and PCM come out of one channel only. To dissipate doubts, i ran a game with support for dual OPL2 and FM comes still out of one channel only. I'm using a behringher mixer so its pretty easy to notice only the left channel works. I tried removing the jack just slightly and soon enough it reverses, L becomes silent and R outputs.

I don't know if this is any configuration problem in the card, like jumpers or so.

I hope i don't have a bad card. I can desolder the jack socket and solder a brand new one but i don't think this is the problem.

Reply 85 of 106, by jesolo

User metadata
Rank Oldbie
Rank
Oldbie

I had a similar problem with a Sound Blaster 2.0 (CT1350B) - only output on the one channel (despite being a mono card).
I de-soldered the jack socket and soldered on one from another sound card but, this only partly solved my problem.

Eventually, I bought one of those 3.5 mm to 3.5 mm adapters and this more or less solved my problem.
I'm still a bit baffled on why it's doing this.

Reply 86 of 106, by carlostex

User metadata
Rank l33t
Rank
l33t

Well i can always solder a new jack. I still have some new ones i got from Mouser. I doubt this will solve the issue but you never know. I might as well recap the board too, although i don't know if i have capacitors for all the board.

I never used this card a lot, just now i decided to change my 386 to a different sound setup.

Reply 87 of 106, by Jepael

User metadata
Rank Oldbie
Rank
Oldbie
jesolo wrote:
I had a similar problem with a Sound Blaster 2.0 (CT1350B) - only output on the one channel (despite being a mono card). I de-so […]
Show full quote

I had a similar problem with a Sound Blaster 2.0 (CT1350B) - only output on the one channel (despite being a mono card).
I de-soldered the jack socket and soldered on one from another sound card but, this only partly solved my problem.

Eventually, I bought one of those 3.5 mm to 3.5 mm adapters and this more or less solved my problem.
I'm still a bit baffled on why it's doing this.

It's not a mono card, it's fully stereo when playing CMS/GameBlaster music with the SAA1099 chips like previous cards.
So there is a stereo amplifier chip driving the left and right channels on the output connector, even if PCM and FM are sent to both channels.

Reply 88 of 106, by firage

User metadata
Rank Oldbie
Rank
Oldbie
carlostex wrote:

Turns out that my card ONLY outputs in mono. I tried different cables i made sure the mixer was set to stereo and i still have that issue. Both FM and PCM come out of one channel only. To dissipate doubts, i ran a game with support for dual OPL2 and FM comes still out of one channel only. I'm using a behringher mixer so its pretty easy to notice only the left channel works. I tried removing the jack just slightly and soon enough it reverses, L becomes silent and R outputs.

Technically, mono means the entire mix is on one channel (that goes out on both sides of a stereo plug), while I assume you're getting one channel of stereo and thus only half of the mix. What you're saying sounds like there's definitely some alignment issue with the jack; the left channel is at the tip of the plug and the right channel in the ring connection, and you're only hitting one or the other depending on position.

jesolo wrote:
I had a similar problem with a Sound Blaster 2.0 (CT1350B) - only output on the one channel (despite being a mono card). I de-so […]
Show full quote

I had a similar problem with a Sound Blaster 2.0 (CT1350B) - only output on the one channel (despite being a mono card).
I de-soldered the jack socket and soldered on one from another sound card but, this only partly solved my problem.

Eventually, I bought one of those 3.5 mm to 3.5 mm adapters and this more or less solved my problem.
I'm still a bit baffled on why it's doing this.

What kind of adapter solved it? That's weird. You guys must know what mono plugs (and TRRS as opposed to TRS) look like and aren't using those anywhere.

My big-red-switch 486

Reply 89 of 106, by CkRtech

User metadata
Rank Oldbie
Rank
Oldbie

I wouldn't be surprised if those of you with stereo output issues have failing capacitors on the output of the TEA2025B amp.

Displaced Gamers (YouTube) - DOS Gaming Aspect Ratio - 320x200 || The History of 240p || Dithering on the Sega Genesis with Composite Video

Reply 90 of 106, by carlostex

User metadata
Rank l33t
Rank
l33t
firage wrote:
carlostex wrote:

Turns out that my card ONLY outputs in mono. I tried different cables i made sure the mixer was set to stereo and i still have that issue. Both FM and PCM come out of one channel only. To dissipate doubts, i ran a game with support for dual OPL2 and FM comes still out of one channel only. I'm using a behringher mixer so its pretty easy to notice only the left channel works. I tried removing the jack just slightly and soon enough it reverses, L becomes silent and R outputs.

Technically, mono means the entire mix is on one channel (that goes out on both sides of a stereo plug), while I assume you're getting one channel of stereo and thus only half of the mix. What you're saying sounds like there's definitely some alignment issue with the jack; the left channel is at the tip of the plug and the right channel in the ring connection, and you're only hitting one or the other depending on position.

Yes you are absolutely right and your description really hits the nail on the head. I may try different cables and replace the jack. But i'm more inclined to a capacitor problem.

Reply 91 of 106, by carlostex

User metadata
Rank l33t
Rank
l33t

Turns out that there's is indeed sound on the right channel but it is extremely low, to the point i had to Turn gain on the mixer right channel to the max and still there's little volume. What could this be? Dead capacitors for the board amp? The amplifier is apparently doing nothing for the right channel

Reply 92 of 106, by CkRtech

User metadata
Rank Oldbie
Rank
Oldbie
CkRtech wrote:

I wouldn't be surprised if those of you with stereo output issues have failing capacitors on the output of the TEA2025B amp.

😁

Displaced Gamers (YouTube) - DOS Gaming Aspect Ratio - 320x200 || The History of 240p || Dithering on the Sega Genesis with Composite Video

Reply 93 of 106, by kithylin

User metadata
Rank l33t
Rank
l33t
carlostex wrote:

Turns out that there's is indeed sound on the right channel but it is extremely low, to the point i had to Turn gain on the mixer right channel to the max and still there's little volume. What could this be? Dead capacitors for the board amp? The amplifier is apparently doing nothing for the right channel

I always thought it was just a design of the cards. They didn't bother designing the cards to be proper output for both channels, they didn't care at the time because stereo sound wasn't a big deal yet. That's just my thoughts though. I was pretty sure the CT1330A was supposed to be mono from the factory originally. I might be wrong though.

Reply 94 of 106, by firage

User metadata
Rank Oldbie
Rank
Oldbie

Mono cards don't have mono connectors or dead output channels. When they're working right, you can use the same stereo headphones and speakers as stereo sources, it's simply one shared channel on both sides.

If you're fixing a dead channel using a cable adapter, I would suspect it's just Y-splitting the working side rather than addressing the issue.

When it's a capacitor problem, I don't see how adjusting the plug in the socket switches the output from one side to the other.

My big-red-switch 486

Reply 95 of 106, by CkRtech

User metadata
Rank Oldbie
Rank
Oldbie
kithylin wrote:

They didn't bother designing the cards to be proper output for both channels, they didn't care at the time because stereo sound wasn't a big deal yet.

Stereo was part of the whole appeal of the Sound Blaster Pro and the Pro AudioSpectrum when they hit.

Displaced Gamers (YouTube) - DOS Gaming Aspect Ratio - 320x200 || The History of 240p || Dithering on the Sega Genesis with Composite Video

Reply 96 of 106, by kithylin

User metadata
Rank l33t
Rank
l33t
CkRtech wrote:
kithylin wrote:

They didn't bother designing the cards to be proper output for both channels, they didn't care at the time because stereo sound wasn't a big deal yet.

Stereo was part of the whole appeal of the Sound Blaster Pro and the Pro AudioSpectrum when they hit.

Then I have no idea. I didn't get my CT1330A until about 2007'ish and mine was mono from the day I got it.

Reply 97 of 106, by carlostex

User metadata
Rank l33t
Rank
l33t

I checked the TEA2025B datasheet and they recommend One 16V 470uf capacitor for each channel to decouple the output DC.

I measured the voltage on each of the capacitors right after i turned off the machine and one of the capacitors loses voltage much faster than the other. Quite a difference. I'll get both capacitors replaced tomorrow, i think i have some 16V 680uf Panasonic FC's.

BTW the datasheet does not object to using higher capacitance capacitors as replacements but it does warn about potencial problems using lower capacitance values.

Reply 98 of 106, by CkRtech

User metadata
Rank Oldbie
Rank
Oldbie

Hey there, carlostex. So just checking - You're aware that deviating from the numbers of the stock caps used on the card will alter the sound (i.e. low frequency cutoff) from the original Creative Labs intended design?

Displaced Gamers (YouTube) - DOS Gaming Aspect Ratio - 320x200 || The History of 240p || Dithering on the Sega Genesis with Composite Video

Reply 99 of 106, by carlostex

User metadata
Rank l33t
Rank
l33t
CkRtech wrote:

Hey there, carlostex. So just checking - You're aware that deviating from the numbers of the stock caps used on the card will alter the sound (i.e. low frequency cutoff) from the original Creative Labs intended design?

It might change the sound, but the design wasn't Creative Labs decision, those values are recommended by ST Electronics who makes the TEA2025B stereo amp chips. Creative just used the values they recommended, at least for the output decoupling caps. I already ordered a few Panasonic FC 16V 470uf, so for now i just want to find if those caps are the real issue.