Side effects to adapting ATX to AT? \ VOGONS

Side effects to adapting ATX to AT?

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First post, by King_Corduroy

Posted on 2015-01-08, 14:54

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Hi guys I just installed an ATX power supply in a 1995 Packard Bell 812CD using an ATX to AT adapter and I'm noticing the midi is very quiet. I used the same card on a different system and I don't remember the midi sounding quite like this.

The soundcard is a Sound Blaster Vibra 16S with real onboard OPL. It should sound acceptable but it really sounds weak, weaker than usual. Are there any side effects known for using ATX PSUs in these older AT computers?

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Reply 1 of 9, by kokornov

Posted on 2015-01-08, 15:43

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Does your ATX power supply have -5v rail?

Reply 2 of 9, by bristlehog

Posted on 2015-01-08, 16:41

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SB Vibra cards don't require -5V rail. Only SB 2.0 does.

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Reply 3 of 9, by King_Corduroy

Posted on 2015-01-08, 17:06

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So any other idea's why it's so quiet? I mean it's REALLY quiet, I have to turn down the digitized sound effects on games to about a third of the volume and I have midi turned up all the way in windows and in the games.

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Reply 4 of 9, by bristlehog

Posted on 2015-01-08, 17:32

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Why do you think it's the PSU that you should put to blame? Can you try some other OPL3-compatible card to eliminate the possibility that this particular SB model is for some unknown reason incompatible with this particular system?

Note that if you really don't have -5V rail, you should also avoid Media Vision Pro AudioSpectrum 16 cards, they are OPL3 compatible but won't work without -5V.

Last edited by bristlehog on 2015-01-08, 17:37. Edited 1 time in total.

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Reply 5 of 9, by King_Corduroy

Posted on 2015-01-08, 17:37

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No I was just wondering because I had read or heard what Kokornov said somewhere else also. I don't remember where though, and at the moment I don't have another OPL card laying around.

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Reply 6 of 9, by bristlehog

Posted on 2015-01-08, 17:39

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What is your card's CTxxxx number anyway? If it's CT2940, I have one here and can test it against an ATX PSU that has no -5V rail.

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Reply 7 of 9, by mockingbird

Posted on 2015-01-08, 21:20

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It's not just the card that requires -5V. The motherboard might require -5V for something as well.

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Reply 8 of 9, by Artex

Posted on 2015-01-08, 22:56

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Are you using one of these? I've had no problems using them in my builds.

http://www.ebay.com/itm/251025150787

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Reply 9 of 9, by King_Corduroy

Posted on 2015-01-08, 23:17

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This is the cable I'm using, I imagine it's basically the same thing. I'm just using an old Bestech power supply off an HP computer. Other than midi being rediculously quiet the whole computer works beautifully.

Cable:
http://www.ebay.com/itm/351259254906?_trksid= … K%3AMEBIDX%3AIT

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