Here is the deal: when using SNES/MD/Neo Geo etc. on my RGB capable TV, the screen is perfect. Except when using my psx/ps2 the screen is always flickering/vibrating a bit.
With psx, the start screen with the psxlogo is really vibrating...what causes this? Does this have something to do with another frequency, perhaps 31khz?
SNES/MD/NG have 15khz non-interlaced video (240p), whereas the PSX bootscreen comes up in 15khz interlaced video (480i).
There are exceptions though. Try Ranma 1/2 (the first one) on the SNES. It was interlaced as well. And there are quite some 240p titles on the PS1 and PS2 as well. There are even titles in which you swich between the video modes (e.g. the newer Sega Ages titles on the PS2).
thanks a lot for the info!
Would it help if I used a monitor (hantarex 15-24-31khz?) Or will this "problem" stay? What about plasma or lcd?
It will stay and it will get worse on progressive displays (LCD or plasma). If you deinterlace a 480i signal intp 480p it gets blurry and kinds of bad things can happen depending on the device you use for conversion.
This is the reason why vintage systems look so bad on LCDs or Plasmas without using a decent upscaler (like one from the XRGB series).