Do ISA cards always require a -V5 rail? \ VOGONS

Do ISA cards always require a -V5 rail?

Topic actions

Post a reply

First post, by d3vilsadvocate

Posted on 2023-02-06, 05:26

d3vilsadvocate Offline

Rank Newbie

Rank: Newbie
Posts: 93
Joined: 2023-01-14, 15:01
Location: Switzerland

Hey all

I'm still in the process of researching the ideal parts for my retro PC. Currently equipped with a P3B 440BX and looking for soundcards for DOS and a PSU.

If I buy a newer PSU (i.e. Seasonic) with 1000W in total and 125W/25A on rails 3V and 5V but no -5V rail, will I still be able to run ISA cards?

I.e. will all ISA cards require such a -5V rail? Couldn't find any pertinent information on Google unfortunately.

Any help much appreciated, as usual 😀

EDIT: I'm currently most interested in either YAMAHA cards or the AWE64, still exploring some others

Last edited by d3vilsadvocate on 2023-02-06, 06:00. Edited 1 time in total.

Reply 1 of 2, by mwdmeyer

Posted on 2023-02-06, 05:28

mwdmeyer Offline

Rank Oldbie

Rank: Oldbie
Posts: 620
Joined: 2012-03-06, 11:35
Location: Sydney, Australia

I think only some old ISA cards really require it. E.g old Sound Blaster.

E.g required: https://www.vogonswiki.com/index.php/Creative … und_Blaster_2.0
Not required: https://www.vogonswiki.com/index.php/Creative … d_Blaster_Pro_2

Vogons Wiki - http://vogonswiki.com

Reply 2 of 2, by Jo22

Posted on 2023-02-06, 05:45

Jo22 Offline

Rank l33t++

Rank: l33t++
Posts: 9660
Joined: 2009-12-13, 07:06
Location: Europe

The MediaVision ProAudioSpectrum16 uses -5v, too.

MediaVision - PAS16? - Help ID the card - Help with drivers

However, the actual power the PAS16 uses isn't much.
It merely needs the negative voltage for the opamp.
The principle itself needs the negative voltage.

In theory, the solution to the problem is very simple.
If you have a cheap sound card (not the precious PAS16) that needs a the negative voltage,
just mount a -5v voltage regulator (with its basic support parts) to the card and use the -12v line as a power source.
Also consider a little cooler, just for the sake of it. Better safe than sorry.

Alternatively, have a look at this thing:
https://www.philscomputerlab.com/voltage-blaster--5v.html

It's essentially the same basic amateurish idea.
Just in commercial form, lacking a fuse, diode and a power LED.

If it was me, I would take the opportunity to make this a DC cleaner card, too.
Adding some filter caps for the other voltage rails.
Or at least add the usual 100nF/1µF/10µF caps, to filter out RF/harmonics.

"Time, it seems, doesn't flow. For some it's fast, for some it's slow.
In what to one race is no time at all, another race can rise and fall..." - The Minstrel

//My video channel//

Go to top of page Go to top of page

Back to General Old Hardware

Main menu

Common searches