VOGONS


First post, by CodeFuApprentice

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Hi everyone,
I remember seeing in one of PhilsComputerLab's youtube videos that you can connect an SPDIF optical output bracket to an AWE-64 or Live card if i remember correctly.
Since then, I've wanted to take advantage of the SPDIF output of my AWE-32 card, so I've just recently bought an SPDIF bracket for it, which has both co-axial and TOSLINK Output. The 3 connector pins are for GND, SPDIF and +5V.

I've been doing a little bit of research about the SPDIF header pins on my CT2760 and can see that Pin 0 is Output and pin 1 is GND. What about for +5v? Do i need this? and if yes, where on the sound card could i connect this to?
Does anyone else have one of these boards with a similar bracket?

AMD K6-3 400 | Gigabyte GA-5AX R4.1 | 256MB PC-100 | 20GB Quantum Fireball LMPlus | Windows 98 SE
*Alternating between: Geforce 2 MX AGP or 3DFX Voodoo 5 5500 AGP. *Sound Blaster AWE-32 CT2760 or Turtle Beach Santa Cruz w/ Yamaha DB50XG.

Reply 1 of 19, by stanwebber

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the awe can be connected straight to the coaxial output which is separate on the brackets i've seen. +5v is to power the toslink output. you'll have to get that from the motherboard or psu.

Reply 2 of 19, by BloodyCactus

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just understand the spdif is only output at 44.1/48khz anything else wont get output. the fm may or may not, its card depending if it goes out the spdif. if your doing soundblaster stuff at say 16khz or stuff (old demos, old games), it wont go out the spdif. also the midi/waveblaster stuff does not go out the spdif too!

the spdif is REALLY limited! imo, not worth it.

also coax + toslink are two different voltage levels, if you connect something to the coax you could damage it from the awe32 signal level.

--/\-[ Stu : Bloody Cactus :: [ https://bloodycactus.com :: http://kråketær.com ]-/\--

Reply 3 of 19, by CodeFuApprentice

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Hmmmm,
After seeing your post about the Coaxial cable voltage, has made me think i don't want to damage either of my CT2760 cards.

AMD K6-3 400 | Gigabyte GA-5AX R4.1 | 256MB PC-100 | 20GB Quantum Fireball LMPlus | Windows 98 SE
*Alternating between: Geforce 2 MX AGP or 3DFX Voodoo 5 5500 AGP. *Sound Blaster AWE-32 CT2760 or Turtle Beach Santa Cruz w/ Yamaha DB50XG.

Reply 4 of 19, by BloodyCactus

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you wont damage the AWE32, you'll damage whatever you plug the other end into! they wont be expecting 5v, they expect -0.5 to +0.5! 1VPP, not 5vPP!

--/\-[ Stu : Bloody Cactus :: [ https://bloodycactus.com :: http://kråketær.com ]-/\--

Reply 5 of 19, by CodeFuApprentice

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'You'd better not plug into the amplifier, There's a slight possibility of Overload'
Yikes!! - *Gets flung across the room* Whoa!!

AMD K6-3 400 | Gigabyte GA-5AX R4.1 | 256MB PC-100 | 20GB Quantum Fireball LMPlus | Windows 98 SE
*Alternating between: Geforce 2 MX AGP or 3DFX Voodoo 5 5500 AGP. *Sound Blaster AWE-32 CT2760 or Turtle Beach Santa Cruz w/ Yamaha DB50XG.

Reply 6 of 19, by stanwebber

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since when does the awe output +5v on the spdif connector pins? that's news to me (i think it's more like +0.5v). unless i missed something the only +5v involved here is to power the optical laser on the aftermarket bracket toslink jack.

Reply 7 of 19, by Tiido

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The 2 pin header on AWE cards is 5V level and not for connection to an RCA plug. Voltage divider is needed the very least and ideally a 1:1 pulse transformer too.

T-04YBSC, a new YMF71x based sound card & Official VOGONS thread about it
Newly made 4MB 60ns 30pin SIMMs ~
mida sa loed ? nagunii aru ei saa 😜

Reply 8 of 19, by stanwebber

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my awe64 gold came with a factory spdif bracket housing a single rca jack. i haven't blown up anything yet, but if i've just been lucky so far i'm surprised creative would welcome this kind of customer relations nightmare not to mention the litigation by supplying the bracket themselves (no 3rd party out).

Reply 10 of 19, by stanwebber

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egads, i guess i don't really have a factory bracket. what i got is just wires and an rca jack. i feel ripped off, but then i only paid $3 for the card with free shipping.

Reply 11 of 19, by BloodyCactus

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The AWE64 puts out -0.5 to 0.5 VPP. The AWE32 puts out 0-5V! they are different.

AWE64 outputs coaxial spdif by design.
AWE32 outputs TTL spdif by design.

some devices can accept TTL voltage levels but its not a gauruntee, so 5v optical on coaxline can destroy things but other things can shrug it off.

why did it change? I think industry as whole moved from ttl design for spdif.
also when awe64 dropped, draft versions of AC97 spec was around and it specified the non-ttl voltage for spdif format for its connectors.

--/\-[ Stu : Bloody Cactus :: [ https://bloodycactus.com :: http://kråketær.com ]-/\--

Reply 12 of 19, by Cloudschatze

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In reality, many S/PDIF inputs will tolerate the signal from an AWE32 without issue, and direct RCA connectivity seems to have been a fairly common practice with these cards; the recommendation for which came from both Creative and various books/publications. I've yet to encounter a reference to damage occuring as a result of this recommendation, but the possibility certainly exists.

For my part, I've been running the "straight" S/PDIF output from an AWE32 (CT3900) into an external pre-amplifier/processor for over fifteen years now, in addition to occasional connectivity to an Edirol UA-1D.

Reply 13 of 19, by Tiido

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I wasn't aware AWE64 does a proper coax level on its header, good to know.

As far as damage goes, I actually fried the SPDIF input on my ESI Juli@ from using TTL SPDIF on it directly. It worked for a while but then one day it stopped and the receiver chip got a hole in it... It was a 3.3V only part and eventually that 5V level made it fail.

T-04YBSC, a new YMF71x based sound card & Official VOGONS thread about it
Newly made 4MB 60ns 30pin SIMMs ~
mida sa loed ? nagunii aru ei saa 😜

Reply 14 of 19, by Cloudschatze

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Tiido wrote on 2022-12-21, 02:02:

It was a 3.3V only part and eventually that 5V level made it fail.

Sorry about your loss. 😀

That's an interesting distinction though. If the Juli@ part had been 5V, presumably that would have either prevented or lessened the likelihood of failure?

Reply 15 of 19, by Tiido

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ESD diodes won't be activated on that pin if it was a 5V device and most likely this wouldn't have happened. I have done some modifications to the card to make it more rugged for this type of damage but I need to find a new receiver chip to really put it into the test 🤣

T-04YBSC, a new YMF71x based sound card & Official VOGONS thread about it
Newly made 4MB 60ns 30pin SIMMs ~
mida sa loed ? nagunii aru ei saa 😜

Reply 16 of 19, by Stretch

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I use the +5V pin from the PC Speaker connector on my Soundblaster 32 to power the toslink port on the ASUS S/PDIF bracket.

Win 11 - Intel i7-1360p - 32 GB - Intel Iris Xe - Sound Blaster G8

Reply 17 of 19, by CodeFuApprentice

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Stretch wrote on 2022-12-21, 14:48:

I use the +5V pin from the PC Speaker connector on my Soundblaster 32 to power the toslink port on the ASUS S/PDIF bracket.

Hmmm, That's actually quite a clever suggestion for powering the optical port. Before your post, I had wondered if any of the pins nearby to the SPDIF pins could supply +5V.

I thought i'd clarify that my original intention is to use the TOSLINK port, and not the co-axial port. TOSLINK always seemed the safer of the 2 to me.
Am i wrong for thinking non conductive, and not shorting out components?

AMD K6-3 400 | Gigabyte GA-5AX R4.1 | 256MB PC-100 | 20GB Quantum Fireball LMPlus | Windows 98 SE
*Alternating between: Geforce 2 MX AGP or 3DFX Voodoo 5 5500 AGP. *Sound Blaster AWE-32 CT2760 or Turtle Beach Santa Cruz w/ Yamaha DB50XG.

Reply 18 of 19, by mkarcher

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CodeFuApprentice wrote on 2022-12-21, 16:44:

Am i wrong for thinking non conductive, and not shorting out components?

Not at all, and also add "not able to create ground loops" to the advantages of optical over coax.