yes, neither needs -5V, the wavetable header doesn't even include -5V

idk if the MPU401 itself needs it, but I doubt it.
edit: ok found a picture of the back of the card, no contact point for -5V on the ISA, so it doesn't ^^

thanks!

Lately I was thinking too that I might never need the -5V until I've seen the only 386 mainboard I got seriously acting strangely with an ATX psu without the -5V rail. Like crashes, vga output fading to almost invisible signal to the monitor and similar things.. things that disappeared with a -5V capable psu. So I suppose the -5V rail might be needed not only for some cards but in some who knows specific mainboard layout, components combination, more than just a useless obsolete thing. I might be wrong and maybe that PSU had problem, but I was using it before on a powerful P4 3,2Ghz machine and all values were ok in the bios reading, no components inside seems like failing. So I convinced myself of this requirement for such old machine.
Also another thing to consider which psu to use because it's not an easy choice. Some modern psu may not have the voltage stability of the main important rails that older had but older psu might have their problems cause becoming old (capacitors, mosfet etc..).
So it's not an easy choice imho.